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Motorboating; what is it, 'why?', and how to fix it?

  • Thread starter Wharfcreek
  • Start date Mar 25, 2018


Jack of all trades, master of none!!

  • Mar 25, 2018

I just completed a build of a little Single Ended EL84 guitar amp. I tried to follow a schematic from a Fender Tweed Princeton amp as best I could, but this was a 'left-over' parts project and I really had to rather 'make due' in some cases. The Princeton schematic uses a 6V6 and is at a much higher voltage than my PT could produce. I have a schematic for a similar amp that Antique Electronic Supply sells as a 'kit'...there MOD102 kit. I also incorporated parts of it into this build as well; particularly the output section and PS supply. I did use a choke......a Hammond unit, a 156 I believe......1.5H, 200ma, 50 ohms. Anyway....... the amp is about 98% there! It's up and working, has 'acceptable' numbers in most places. I've got about 230V on my EL84 plate, about 190V on the screen, and about 125V on the two 12AX7 plates. I'm running a 150 ohm cathode resistor, bypassed with a 100uf/100V cap, and showing about 5V across that resistor which I believe calculates to about a 32ma current draw on the tube...which is a 'new' JJ 6BQ5. I say I'm at about 98% because I have one remaining issue, which is that the amp will 'motorboat' from about 3/4 volume level on up. If kept below this level, it sounds and plays fine. But, hit about 2/3 to 3/4 on the VC and it breaks into this even with the guitar vc turned all the way down. So, just looking for some suggestions as to what to do about this? Any help would be appreciated. Many thanks!! Tom D.  

Tom Bavis

Motorboating is a low frequency oscillation, often due to feedback though the power supply. Coupling caps shouldn't be too big, power supply filters may have to be larger if your supply has more droop than Fender's original. The original 5E2 circuit used 22K and 8 uF for the filter to the two 12AX7 stages - you may have reduced that resistor - if so (or even if not!), increase that filter cap and see if it helps. Also try a bigger filter cap after the choke.  


Ultrasonic oscillation due to poor circuit layout can sometimes present as motorboating, if it pulses because of grid blocking. It's especially important to keep output stage anode wiring well away from the signal path in low-level stages. A scope would tell the story.  

My PS filters are: 1 & 2, 47uf @ 350V, 3, 22uf @ 350. That should be more than ample to support the 'upgrades' from Fender's 8uf. Coupling caps: Actually this amp was built using the tone circuit from a 5E2 Princeton. That amp uses a 250K pot for it's tone control, with a .0005 on one side of it.....going to the plate of the 12AX7, and the other end to the input side of the tone pot. The other side of the tone pot goes to a .005 which goes to ground. There's still a .02 from the first plate connected 100K ohm resistor...then to the input side of a 1 meg VC pot, where the other side of the VC pot simply goes to ground. I should mention that the wiper of the tone control goes to the junction of the 100K resistor at the input side of the VC pot. MIke, I'm going to go back and look at layout issues...... but I'm thinking I should be OK. Hard to tell.......and I wish I had the 'scope' skills to figure it out that way. I'm wondering if the fact that this problem doesn't resent itself unit you get to 2/3 to 3/4 of the drive level on the VC doesn't mean something? If I were to cut the voltage by increasing the you think that might change anything? TSD  


Fish fingers and custard!

Does it motorboat with no input connected if you turn up the volume? If so check all ground connections and look for ground loops caused by multiple connections  

Dr. a, yea, it does do it with nothing plugged in. I also have a 'grounding' input, the input grid on the first section of the 12AX7 is 'grounded' . I guess that means that the problem lies somewhere within the tone control part of the circuit, the Volume control, and the second stage 12AX7, yes? I didn't see any obvious 'grounding' issues, but I don't have any kind of 'star' ground with's more of a 'chassis' ground much like the way the AES kit is designed and built.  

The 6BQ5 screen shouldn't be connected to the same power supply node as the 12AX7s - it draws more current than they do, so variation in screen current makes the supply voltage change, which makes the plate voltage on the first stage change, which gets amplified by the following two stages.. and the screen current changes some more. So, move the 6BQ5 screen to the FIRST B+ point like Fender did, and increase your cathode resistor to get back to the previous bias point.  

If you can post a high resolution schematic, such that we can zoom in on it and it doesn't look too small to read, that would be helpful.  

Doc, posting a picture of the AES MOD schematic. That was what I used as the basis for both the power supply and output section. The tone section came from the 5f2 Princeton schematic. I used a 10K on the input (along with the 1 meg), and the both 1.5K 12AX cathodes are bypassed with 25uf/25v caps. Tom, my PS is a CT type PT with the CT to a chassis ground, and both HV outputs to a 1N4007 diode. The output of the diodes goes to a 47uf cap and the Hammond choke. The output of the choke is the B+.....along with another 47uf cap. The OT is connected here as well. From there I go to a 18K / 1W resistor, which feeds the screen, a 22uf cap, and a 1K resistor. This 1K feeds the 12AX7. What I'm now thinking is that I should have yet another filter cap in this at this point, I don't. I'll try putting something there and see what happens. Would be great if that's all it took!!  



  • mod102_schematic.pdf 193.7 KB · Views: 34



I'm vertical and breathing...most of the time..

  • Mar 26, 2018



Active member.

Are you saying you did not have a power supply cap for the 12ax7 preamp section? And do you have that 100k resistor there as well on the 5f2 schematic?  

Yes, I came off the 22uf to the screen......and also a 1K that fed the two 100Ks that went to each 12AX plate. Tomorrow I'm going to see if I've got another 22 or a 20uf @ 350 or 300V and put that at the 1K and see what happens! Hopefully that'll fix it!! If not....back to the drawing board.....and the forum!! TSD Larry.... you know I've got one of each around here, plus a little Yamaha on the little John boat! TSD  


junk junkie

Inclined to agree about splitting the screen and the driver stage power supply up. Honestly I'd run the output transformer from HV, the screens from B1 and the driver from B2 but thats me. Adjust the 200 ohm cathode resistor if needed to get the bias right, and/or increase the size of the 100 ohm resistor if you really need less screen voltage. As it is, the screen supply will sag horribly through a 22K resistor. I guess that might be on purpose, I can't get my head around guitar amps though. Stuff that is sometimes done on purpose there would be something you'd just cringe at in a hifi amp.  

Thain, that's rather the idea behind me doing this. In having built about 20 of Mr. Gillespie's Magnavox 8600 amp, I think I understand that unit fairly well now. Not completely, but I think I've got the basic idea. I also built that MOD102+ kit from AES. Pretty simple, and it worked perfectly well. I ended up finding 3 power transformers, 2 of which were the 269EX and one that was about as close to the 269EX as I think you could get. I also had some SE 5K output transformers, so I decided to attempt to build another of the amps similar to the 102+ kit. If I haven't mentioned it already, the '+' version of the 102 Kit is rated at a slightly higher output wattage (8 vs 5), and comes with a few extra bells and whistles like having a 'pull' switch on each of the 3 controls; 1 for 'bright' on the treble control, pull for 'mid boost' on the bass control, and the VC pull switch adds some further gain to the amp.....or so it's supposed to do. The '+' also comes with a 3-way off/standby-on/run power switch vs just off/on. Anyway, I wanted to build just a simple SE EL84 version of something like the tween Princeton of using those diagrams as well as both the MOD102 and the '+' diagram, I set out to build the thing based on using the 3rd of my PTs as well as one of my existing OTs. The idea was to keep it as simple as possible, but have a 'tone' control vs no tone or Bass/Treble. So, I had to figure out how to run all these different aspects together into one amp....using my parts, and actually making it work. And, aside from the motor-boating problem, I'm 'almost' there! So, to address this motor-boating, the suggestion is to move my screen supply to the same place as the B+. Just another question before I do this, and I think Tom Bavis addressed it with his post above. But, in doing as suggested, the Plate and the Screen on the OT are going to be at 'about' the same voltage.....and in so doing, I'm going to experience a pretty significant increase in current draw from the tube. In looking at that MOD schematic (in my post #9), they're running both the 6BQ5 screen AND the 12AX7 from the same B+2 position and that amp doesn't have that problem. I also wonder if the difference in voltage between 6BQ5 Plate and Screen....if that's not part of what is producing some of the characteristic sound of the amp? I know that in many Hi-Fi amps the screen and plate are at about the same voltage level. I've seen some schematics where the plate is actually running at a lower voltage.....but I believe most of these diagrams are where a UL OT is used. But, in this MOD design, the difference is pretty 75+volts! In moving the plate and screen voltages to being nearly equal, will I loose some of the performance aspects of the amp that are actually rather appealing as a guitarist? Also, I think this is going to play hell with the Bias......and I'll be looking at using something like that 470 ohm resistor that Fender used on that Princeton as pictured above in post 9???  

OK, after reading Tom Bavis's post above, I got to thinking about how I'd addressed my builds on Dave Gillespie's Maggie revisions.......and in that build, like the MOD102, both have only 3 stages to the PS. However, when I construct Dave's amp, I add a 4th stage because I add a dropping resistor after my 5AR4 rectifier. In this revised MOD build, I added a choke. So..... in effect I also had 4 stages, but had only put a PS cap in 3 of them. My 1 - 3 stages had 'capacity', but my 4th stage, after my 1K resistor and in feeding the plates on the 12AX...I had no cap. So.....I added one! I dug through my supply of filter caps, found a 20uf @ 350, and installed it at that 1K resistor. Problem fixed!!! Motor-boating is gone, and the amp plays great from just barely opening the VC all the way to full throttle! The ONLY symptom that it exhibits that I find a bit odd is that at about 3/4 volume there is a dip in the noise level. As you go from all the way 'down' to gradually turning 'up' the VC, you begin to hear some amplification coming from the speaker. Even with nothing plugged into the amp...which 'grounds' the input jack...there is still some audible noise as you turn it up. But, at about 3/4 to 7/8 of the way up...there's like a 'spot' where the noise level drops off. Yet, when I 'play' the amp......the sound increases throughout the sweep of the VC. So, no 'dead spot' in amplification......just in that background noise. I'm going to live with it for now! The amp sounds great and performs well, and should be easy to 'repeat'. My next step will be to attempt to draw up a diagram of the final product, post it, as well as do a little photo shoot of the thing and post that as well. To all above, MANY THANKS for the guidance and suggestions. I'm sure the other changes suggested might have worked equally well......but this 'final fix' seemed easiest to try, and having it solve the problem, I'm just glad I don't have to go through and mess around with trying to get the bias right again. Happy Soldering!! Tom D.  

I don't know that I'd move the screens to the same place as the B+, I'd move both the screen and the plate "over one". Output transformer straight off the rectifier, screens after the 100 ohm, driver after the 22K. If the screen sag is integral to the sound of the amp, leave the screens where they are and add another branch off the supply with a 22K resistor to a cap. Feed the driver off that. I wouldn't tie the driver downstream of the screen just because they will still have some level of interaction that might cause you trouble. basically the idea is to not have the screens and the driver connected together so they can't interact with each other.  

Thain, I get what you're saying, and I understand the idea. I may give a shot at trying your suggestion....just to see if it makes the amp sound any different/better. BUT...that it's working now, it's really pretty impressive for a little 'flea' guitar amp. I've heard a lot of these over the years, including OE Fender units......and a good number of them didn't sound nearly as good. This one is still a bit 'gainy' that it's into 'break-up' after about 1/4 to 1/3 on the VC. But......from a 'player' perspective, that's not necessary a bad thing. It becomes a matter of 'how' it breaks up.....if it's 'controllable'.....and not so compressed or 'faltering' that it just sounds bad. So, I'm really not all that disappointed with that aspect of it. The little 'noise' glitch rather confounds me.....but not to any level that I believe it's in need of further attention. Rather, I'm just going to consider it as a personality trait. But, if changing the PS leads around as you suggest can correct that....then perhaps it's worth a try. I just know that this change will 'initially' play hell with the bias......and that's another balancing act that takes time too. Anyway.......all good comments and, many thanks! Tom  

Wharfcreek said: Thain, I get what you're saying, and I understand the idea. I may give a shot at trying your suggestion....just to see if it makes the amp sound any different/better. BUT...that it's working now, it's really pretty impressive for a little 'flea' guitar amp. I've heard a lot of these over the years, including OE Fender units......and a good number of them didn't sound nearly as good. This one is still a bit 'gainy' that it's into 'break-up' after about 1/4 to 1/3 on the VC. But......from a 'player' perspective, that's not necessary a bad thing. It becomes a matter of 'how' it breaks up.....if it's 'controllable'.....and not so compressed or 'faltering' that it just sounds bad. So, I'm really not all that disappointed with that aspect of it. The little 'noise' glitch rather confounds me.....but not to any level that I believe it's in need of further attention. Rather, I'm just going to consider it as a personality trait. But, if changing the PS leads around as you suggest can correct that....then perhaps it's worth a try. I just know that this change will 'initially' play hell with the bias......and that's another balancing act that takes time too. Anyway.......all good comments and, many thanks! Tom Click to expand...

I'd say the noise is VERY 'typical' of guitar amps! As my amp is built, I have a 10K resistor off the input jack and going directly to the input grid on the first stage of the 12AX7. The MOD amp uses just a straight wire, and the original Fender uses a 68K. I chose the 10K only to temper the input just a bit, without really bedding it down. I tried to build it such that all the passive parts made connections without needing any further leads or wires. But, where the VC connects to the input grid of the second stage of the 12AX, I DO have a shielded wire there! With the exception of the plate lead to the second stage, I don't think I have any 'wires' cut to make any connections. Even my input grid connection to the 6BQ5 is made directly with the resistor vs any leads. I just built one of the MojoTone Tweed 'Deluxe' kits......and this amp that I just build is, I believe, much quieter. 'Noise' isn't really a problem. You mention taking a this one of Gerry Weber's 'Amp Camp' deals? I know he does those pretty regularly! I have had many good conversations with him over the years. About 20 years ago (or so) I was DEEP into guitar amps! I not only owned a good number of them, but I had people in the area bringing them to me for 'repair'. I think over the course of about 6 to 8 years or so, I must have gone through well over 200 guitars amps for one reason or another. In 'collecting' them myself, I couldn't afford to have them professionally 'tuned up'.....or have hums fixed, or anything else for that matter! I was buying these things at junk stores, pawn shops, music stores, etc, all over the east coast as I traveled from town to town, state to state. Any 'deal' I could find on a guitar or amp.....I bought it! Single life and 'divorce recovery' will do that to you. I also got myself into a I justified all this by 'playing' as well. Of course, I'm absolutely NO GOOD!! But....I had fun. Anyway, the need to fix all these things necessitated me learning how to do that I couldn't afford the professional costs of service. Luckily for me, I had a good Mentor in the form of Jeff Bober, formerly of Budda Amplification and now of 'East' amplifiers! Budda got sold to Hartley Peavey....but it was quite successful for a good long run. I think Hartley killed it! Anyway, to finish the story...... the band broke up....and I wanted to I sold about 90% of all that I had, closed up the basement shop, and move from Annapolis to Baltimore. Along the way I discovered an old Dynaco ST-70. That was 20 years ago now.....and it's been 'home audio' ever since. But, this sticking my toe back into Guitar amps is kind of fun. I believe I was still very much in the early learning stages back then. While I could 'set a bias' or change coupling caps, or even make a broken amp work again.....I had no real understanding of what I was doing. That has come to some level over the past 20 years with the home audio stuff. But, even now, I struggle, as indicated here in this thread. Not putting a 4th cap into the PS filter section is rather a 'rookie' mistake IMHO! I hope you have fun with building the amp you're going to build. I think the Princeton schematic above is a pretty good choice if you want at least one tone control. I think some of the Champ amps had just a VC....which in retrospect is perhaps how I'd do it next time! The guitar already has a tone why add one to the amp? (rhetorical question....not a conversation starter!! OK.....gotta run! TSD  

Very cool! I would enjoy one of webers classes, I will be using one of his alnico speakers in my amp but no to it being his class. My circuit analysis teacher is really into building guitars so he has a guitar building class at the college that I don't need but just want to take for fun. I'm always showing him the stereos I'm working on and he is always working on his guitars, really cool electronics teacher. Thanks to getting into audio circuits about 5 years ago and audiokarma and youtube the electronic courses are a breeze.  

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Author Topic: 5e3 New Build Troubleshooting Hum/Oscillation  (Read 4681 times)

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Re: 5e3 New Build Troubleshooting Hum/Oscillation

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5e3 motorboating

Is this cap polarity is right ?
Robinettes stuff is used by a lot of people and I consider it to be known-good, but maybe I should undo the mods, go back to the stock Fender circuit, and get that working. Then add the MV and feedback switch back in.  

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Could a faulty Bright cap be causing both problems?
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unsolder one leg n test
"Kicks In"?? Like 9.1 is low-hiss and 9.2 is big hiss? That's oscillation, supersonic. Layout.
From the pictures the soldering on the back of the pots looks beaded meaning it doesn't look like its soldered properly. All the other solder joints look good.  

5e3 motorboating

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Quote from: Champ_49 on July 24, 2020, 01:26:43 pm From the pictures the soldering on the back of the pots looks beaded meaning it doesn't look like its soldered properly. All the other solder joints look good.  
Quote from: shooter on July 24, 2020, 12:02:26 pm unsolder one leg n test
Solders and wire dress
Is V1 a 12AY7?
Quote from: Latole on July 25, 2020, 01:34:53 pm Solders and wire dress
Quote from: Champ_49 on July 25, 2020, 03:07:44 pm Quote from: Latole on July 25, 2020, 01:34:53 pm Solders and wire dress

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. The February 1957 Fender price list shows the at $129.50 which is equal to $1,145 in 2017 inflation adjusted dollars.

There were several other models of the ' ' but the 5E3 is by far the most popular. The 5E3 amp kit phenomenon is still going strong so there's lots of new tube amp guitarists that would like a not-too-technical explanation of how the amp works, what each component does, and how changing those components will affect the amp's voice.

I recommend you take a look at my and webpages for a detailed explanation how vacuum tubes work in the very simple Fender 5F1 guitar amp. I won't be going over tube theory and other introductory material here so check it out if you have trouble understanding this webpage. For information on the and circuit see this. If you like to mod your amps check out my webpage. I also have a page dedicated to the magical amp.

Jump down to the to see what a real 1957 5E3 looks like.

such a unique voice are its funky interactive volume and tone controls and it's raw, deep voice. Both volumes and the tone controls all interact to create some unique tones. Its rawness comes from both preamp gain stages having bypassed cathodes for maximum gain and with no negative feedback loop breakup comes on early. This leads to little headroom, early dirt and a lazy transition from clean to distortion.

The 5E3's very large coupling and bypass capacitors give the amp more bass response than most but this can lead to boominess and 'farting out'. Amplifying all those low frequencies uses a lot of power and can overwhelm the power supply circuit which leads to voltage sag, output volume compression and 'note bloom.' The relatively small output transformer also contributes to output volume compression. Its cathode biased power tubes sound rounder, tubey and warm compared to more modern fixed bias amps.  Its old school, almost no gain cathodyne phase inverter doesn't drive the power tubes as hard as amps with a long tail pair phase inverter. From a modern perspective the 5E3 has many design 'defects' but they come together to create a unique and beloved tone that's still gaining in popularity.

We'll start the analysis of the 5E3 with my annotated versions of the original Fender schematic and layout diagrams for a broad overview of the amp's function then we'll dive deeper and examine individual components and their value tweaking.

to view the full size (readable) annotated schematic. A .

The amp's signal flow in the schematic above is shown by the thick grey line from the input jack at upper left to the speaker at upper right (to see the larger, readable version of a diagram on this page just click on the diagram). The very low level AC signal voltage from the guitar's coils enters the amplifier at upper left through one of the . Typical signal level from the guitar pickup coils is about 0.1 volt AC rms but can vary greatly due to the number of pickups, their design and of course how and what is played on the guitar. Quiet jazz played on a guitar with a vintage single coil can produce signals below the single digit millivolt range (0.001v).

The 5E3 has 2 channels, the Normal and Bright Channel. The Bright Channel is brighter because of the addition of a single component, the or Brite Cap, which allows high frequencies to bypass the Bright Volume control at lower volume settings. The lower the volume the more highs are bypassed so the Bright Channel is usually preferred for lower volume playing. The original Fender Bright Cap was 500 pF (pico Farads) but modern standard cap values have made it convenient to use an equivalent 470pF instead. Using a larger value Bright Cap will allow lower frequencies to pass around the Bright Volume control. Using a smaller value Bright Cap will raise the cutoff frequency so less mids would be affected. The Fender 5F6A used a tiny 100pF Bright Cap so only very high freqs were passed around the volume control. Many modern guitar amps use a mid size 250pF Bright Cap.

The 5E3 is famous for it's control interaction. Both volume controls and the tone control all interact with one another even when only one channel is in use. . Both volume controls alter how the tone control functions. When the 5E3's Bright channel volume is turned full down its bright cap is connected directly to ground on one end and connected to the bright end of the tone pot on the other. The bright cap then acts as a high freq tone cap that bleeds high freqs to ground. It's not a huge effect but the brightest setting on the tone control moves to less than max on the tone dial. This only occurs when the Normal channel is in use, the Bright channel does not suffer from this control quirk. It's another reason (besides the bright cap) the Bright channel is brighter than the Normal channel.

--especially at high volume levels. This is where much of the 5E3 magic resides. Here's an informative quote on setting the controls from clintj, " "

Each channel has two , a . The Lo jacks' inputs run through a voltage divider formed by the two 68K Grid Stopper resistors which cuts the guitar signal in half (-6dB). If you find that you prefer the Lo input jacks you should consider using the Hi jacks and just turn down the volume on your guitar which gives you the same signal level but you'll have control at the guitar. . Plug a short cable into two jacks in the normal and bright channels for a thicker tone that's paralleled through both channel's preamps (example: guitar is plugged into Bright Hi jack then jumper from the Bright Lo jack to the Normal Hi jack). For the graduate level explanation of how the jacks work and how jumpering the two channels together works .


Each channel has an on its Hi Input Jack. The Input Resistors set the amp's input impedance and they act as tube V1's grid leak resistors. For best signal voltage transfer from guitar to amp you want a low impedance from the guitar and a high impedance for the amp (at least 10 times more impedance for the amp is a guide called "the rule of 10"). This intentional impedance mismatch trades guitar pickup coil current for voltage--this is called impedance bridging. 1 megaohm is a standard value for most all guitar amps so there's no reason to tweak its value. A higher value would add impedance but also add noise. A lower value would decrease noise but reduce the voltage signal from the guitar. Some high gain amps use lower value grid leak resistors to intentionally attenuate the signal to control gain between amplifier stages.

In the 50's and 60's were used and if you want your amp to look 'period correct' then use them but are over 10 times quieter than carbon comp so use them if you want the best quality audio and lowest noise. Resistors generate the white noise hiss you hear when the amp is turned up to max with no guitar plugged into the amp. The input and grid stopper resistors are a good place to use metal film resistors because their hiss will be amplified by every gain stage.

resistors help stabilize the amplifier by removing much of the audio signal above human hearing. The Hi input uses both 68k grid stoppers in parallel so the grid stopper resistance is actually 34k. Grid stop resistors on the first amplifier stage do remove some high freqs from the guitar signal so some modern amps use smaller grid stoppers and some amps do without them altogether. You can use an alligator clip wire to jumper around the grid stopper resistors to try the amp with lower or no grid stopper resistance but the difference is very subtle and only affects very high frequencies but it may add some "sparkle." The optimal location for a grid stopper resistor is on the tube grid (input) pin itself so there's no bare wire after it to act as a radio antenna to pick up radio frequency interference (RFI).

. Click so you can modify this layout diagram yourself.


    The Input Resistors act as tube V1�s grid leak resistors.

    The volume pots act as the tube V2A grid leak.

    Load Resistors transform the amplification stage from current to voltage amplification.

    Coupling capacitors block the flow of high voltage DC but pass the AC guitar signal voltage to the next amplifier stage.

    Cathode Resistors set the cathode bias voltage.

    Cathode Bypass Capacitors allow signal voltage to bypass the cathode resistor to boost gain.

    The Output Transformer steps down voltage but steps up current to drive the speaker voice coil which is a simple electromagnet.

After going through the grid stopper resistors the audio signal flows down the wire to the 's pin 2 (control grid), which is the entry to the 'A' half of the preamp tube ( ). It's called V1A because tubes were called 'Valves' and this is tube number 1 and we're using half of the tube, the 'A' . A triode has three electrodes, a grid, cathode and plate (anode).

12AY7 is the type of tube and it's really two tubes in one ( ). The grid is the 'control valve' that controls the flow of electrons through the tube. The AC guitar audio signal charges the grid positively and negatively as it alternates. A positive grid will allow electrons to flow from the cathode, through the grid to the plate. A negatively charged grid will block the flow of electrons through the tube.  See for more info.

Notice that tube V1 has only one valued at 820 ohms. It is shared by both triodes (both halves) of V1 so the cathode resistor is approximately half the value of a cathode resistor used for a single triode such as V2A's 1.5k cathode resistor. Two triode circuits sharing one cathode resistor will pull twice the current through it so you have to cut the resistance in half to get the same voltage drop across the resistor. The voltage drop across the cathode resistor puts the cathode at a positive voltage compared to the control grid (normally around +1.7 volts DC). This voltage difference is the triode's bias. Some modern high gain amps bias their preamp triodes cooler using a 2.7k cathode resistor or bias it hotter with an 820 ohm resistor. Both will reduce headroom and boost preamp distortion. Increasing the cathode resistor value also reduces gain and decreasing it will boost gain.

The hottest bias for a preamp gain stage I have ever seen in a commercial amp is an 820 ohm cathode resistor (not shared). The coldest bias I have seen is a 39k cathode resistor in a Soldano high gain amp. The very high value cathode resistor is designed for early clipping to intentionally generate preamp distortion. This type of preamp stage is called a and was first used in the amplifier.

The 5E3 uses a 12AY7 preamp tube for the first gain stage. You can substitute a higher gain 12AX7 to boost amplification, reduce headroom and increase breakup and distortion. The preamp tube amplifies the guitar audio signal then sends it out pin 1 (plate) to a or 'cap.' Coupling caps are sometimes called 'blocking caps' because they block DC (direct current) voltage. DC flows in only one direction where AC (alternating current) alternates its direction of flow--the electrons actually change direction and move back and forth through a circuit.

High voltage DC power used by the tube is brought in through the . Load resistors change the amplification stage from a current amplifier to a voltage amplifier. Many modern amps have load resistor bypass capacitors to remove frequencies above human hearing to stabilize the amplifier and prevent oscillation in high gain amps. You can also remove "ice pick highs" with a load resistor bypass cap.

The wire between tube pin 1 (plate) and the load resistor carries up to 250 volts DC. Coupling capacitors allow the AC audio signal to pass through but block the high voltage DC and keep it from flowing into the following amp stage.

: Caps are actually made with sandwiched conductive plates but I like to visualize them as having a stretchable rubber membrane inside that blocks the flow of electricity. When voltage is applied to a capacitor the 'rubber membrane' stretches and bulges as electrons try to flow through it. The higher the voltage the more the membrane  bulges. If you quickly reverse the capacitor's voltage polarity it will go from bulging one way to bulging the other way. This is what a small AC signal does--it stretches the 'membrane' back and forth as the voltage alternates which allows electrons on both sides of the capacitor to move back and forth (alternate) but a constant DC voltage that is trying to flow in one direction will be blocked by the membrane.

uses very large value .1uF (micro Farads) coupling capacitors which allow low frequencies to flow through the amp. These low frequencies use  a lot of power and cause the 5E3's infamous "loose low end" and can lead to severe blocking distortion known as "farting out." Reducing the value of the coupling caps will filter out some lows and tighten up the amp and make the amp more humbucker pickup friendly. The overdrive tone will also tighten up. Modern, high gain amps use extremely small coupling caps (0.0022uF) to reduce bias drift, blocking distortion and keep the overdrive tone tight. See my page for more info. Some people lower the value of the 5E3 coupling cap in only one channel and leave the other channel alone so you can choose between standard or a tighter, more modern tone (see the ). Smaller coupling caps can also improve the way the 5E3 works with FX pedals, especially gain boost, delay and reverb pedals.

Another way to trim the 5E3's low end 'fat' and tighten up the amp is to reduce tube V1's or V2A's . Both have a 25uF 25v cap that is large enough to boost all guitar frequencies but many modern amps use a bypass cap as low as .68uF (680 nano Farads) to boost only mid and high freqs. If you wanted to alter just one of the 5E3's channels you'd have to separate the V1A and V1B cathodes by adding another cathode resistor and bypass cap (see the ).

After the coupling cap the guitar audio signal flows to the volume and tone potentiometers (pots). The acts as a variable voltage divider which when turned down will attenuate the signal voltage. Volume knob left = less voltage signal and lower volume. Volume knob right = more voltage signal and higher volume. Changing the volume pots from 1 meg to 500k (1 million ohms to 500,000 ohms) will send more signal to ground and attenuate the signal path.

The in combination with the create a variable RC (resistance capacitance) low pass filter which removes high frequencies by shunting them to ground. Using a higher value tone cap will lower the cutoff frequency of the tone control so it will affect more mid frequencies. Reducing it will raise the cutoff frequency and affect less mid freqs.

The guitar signal next flows to tube 's pin 7 (grid). This stage acts as the second gain stage which boosts the guitar signal voltage. The audio signal leaves tube V2A via pin 6 (plate) and flows to another coupling cap that blocks DC. The signal then flows to the cathodyne where the guitar signal is split into two streams for the two power tubes. The signal enters at V2B's grid and flows out its plate to a coupling cap and on to power tube V3's grid. This signal is inverted compared to the phase inverter input. The signal also flows out V2B's cathode to a coupling cap and on to power tube V4's grid. This signal is not inverted so the two signals flowing to the power tubes are 180 degrees out of phase--mirror images of one another--one is inverted and one isn't. Unlike the 5F6A long tail pair phase inverter, the 5E3's cathodyne phase inverter barely amplifies the guitar signal. It's differential gain factor is always slightly lower than 2. If you upgrade the 5E3 to run big 6L6 power tubes the cathodyne phase inverter won't be able to drive them to full distortion the way a long tail pair phase inverter can.

After the phase inverter the guitar signal flows through another coupling cap to block high voltage then to the . Like the preamp grid stopper resistors they help filter out noise above human hearing to prevent oscillation but they also perform another important function, they help control blocking distortion to keep the overdrive tone sweet even when pushed very hard. Like all grid leak resistors you can use the value to control the input signal voltage. A larger value grid leak will cause less signal attenuation and a smaller value will increase attenuation. Typical power tube grid leak values are 100k and 220k.

The , are sometimes referred to as the output tubes. While the preamp tubes have three electrodes: Cathode, control grid and plate (a tube with 3 electrodes is called a triode) the power tubes are pentodes with five electrodes: Cathode, control grid (g1), screen grid (g2), suppressor grid or beam forming plates (g3) and plate. The screen grid is held at a constant, high positive voltage to help pull free electrons from the cathode, through the control grid to the plate. The suppressor grid helps prevent electrons from bouncing off the plate. It is tied directly to the cathode.

Although the 5E3 doesn't have them, are used in most amps to prevent tube damage from excessive screen grid current. These resistors are usually between 470 to 1500 ohms and rated for 3 or 5 watts of heat dissipation. The 6V6GT is a beam pentode and therefore flows little screen current so the 5E3 can get away with running without screen grid resistors. But if you want to run non-beam, true pentodes like the EL34 then you should install 1k  5 watt screen resistors. Screen grid resistors will also increase the screen voltage drop when screen current flows which will increase the amount of power tube distortion caused by screen voltage drop. Adding a 470 ohm 3 watt resistor to the 5E3 can add sweet sounding power tube distortion so it is a modification to consider.

The power tubes are the final stage of amplification. Where the preamp tubes are voltage amplifiers, V3 and V4 are power amplifiers and their output is expressed as watts. The guitar signal enters at pin 5 (control grid) and leaves via pin 3 (plate) and flows through the .

The output transformer's primary and secondary windings are really just two wire coils wrapped around an iron core. The input, or primary coil winding uses electric current flowing through the coil to generate a magnetic field or flux. This magnetic field fluctuates with the AC signal voltage. The magnetic flux flows around the transformer iron core to the  secondary coil which generates a voltage in the secondary coil winding. You can alter the voltage and current from primary to secondary by changing the ratio of coil wraps from primary coil to secondary.


: The primary winding has 200 wraps of wire in its coil and the secondary has 100 wraps. If a 10 volt 1 amp alternating current is applied to the primary winding the secondary will generate 1/2 of the voltage but twice the current so 5 volts and 2 amps would be put out by the secondary winding.  This is what an amplifier's output transformer does, it steps down the signal's voltage but steps up the current because the speaker's voice coil needs current to move the speaker cone.

At high volume the 5E3's output transformer reaches saturation which tends to compress the signal. Once saturated an output transformer can't flow any more flux or get any louder so loud notes are capped but softer notes are still amplified so there's less volume difference between loud and soft guitar notes. Upgrading the 5E3 to a larger, higher watt rated output transformer will boost maximum volume and reduce compression (the output will be more dynamic, accurate and solid state sounding)--but some of the magic lies in its high volume compression.

The output transformer's primary takes in a high voltage, low current signal (high impedance) and puts out a low voltage, high current signal (low impedance). Typically about 320 volts of swing from the power tube plates flow into the output transformer primary and about 12 volts AC flows out the secondary through the blue wire to the speaker jack and on to the speaker

The has a built in switch that grounds the output transformer's secondary when no speaker is plugged in. It does this because if you power up the amp with no speaker connected the output transformer will generate very high voltage in the secondary winding and fry itself if it sees an open circuit. The ground switch on the jack gives the transformer secondary a closed, short circuit which it can handle much better than an open circuit. Always have a speaker connected to a tube amp when you power it up. The is tied directly to the main speaker jack's tip and ground. Because of the main jack's ground switch . You should use an 8 ohm aux speaker along with the cab speaker which will give the amp a 4 ohm load which Fender considers safe for the amp. A 4 ohm aux speaker will give the amp a too low load which will reduce output and stress the power tubes.

From the speaker jack the signal moves on to the . The alternating current audio signal flows through the speaker's which generates a magnetic field. The voice coil is simply a single wire wrapped into a coil as shown below. The magnetic field created by the voice coil is either attracted to or repelled by the speaker's magnet. Positive voltage in the voice coil generates a repulsive magnetic force and the speaker coil and cone moves outward away from the speaker magnet. Negative voltage generates an attractive magnetic force and pulls the speaker cone inward. between moving outward and inward as the guitar signal voltage alternates between positive and negative.

This in and out movement of the voice coil and creates air pressure waves that our ears perceive as sound--the sweet sound of electric guitar. When the speaker cone moves outward a positive air pressure wave is created and when the cone moves inward a negative (low pressure) wave trough is generated. These air pressure waves move our ear drums in and out. The ear drum movement is translated into neuron activity which is sent to the brain where pleasure is created, thus electric guitar + amp = pleasure.

The guitar amp is also used to shape the tone and control distortion giving us the clean, mellow sound of jazz guitar or the animal growl of hard rock. . Audio amps are usually designed for absolute minimum distortion. See for specific information on how overdrive distortion is created.

in red, in magenta, AC load line in yellow and in green. For information on how these lines were charted see .


Now that we've covered the signal flow I'll go back and cover the other amplifier components that I didn't mention. (or 100, 220 or 240 volts AC in other countries) runs through the and on to the . The fuse is a 2 amp slow blow fuse. Slow blow means it won't blow instantaneously when the turn-on power surge runs through it. Sustained current greater than 2 amps is required to blow the fuse.

After the amp's fuse and On/Off switch the 120v AC runs to the (PT), through its primary winding, then back to the wall plug via the white neutral wire*. The power transformer has three secondary windings. The first winding steps the 120v AC up to 650 volts AC. Two other small secondary windings step the 120v AC down to 6.3 volts AC and 5 volts AC (notice all voltages output by transformers are always AC). The 6.3 volts is used to power the pilot light and heat the preamp and power tubes' heater filaments which heat the tubes' cathodes. The 5 volts is used to heat the rectifier tube's cathode.

* When I first learned that the power transformer primary coil was made up of one long wire that directly connects the 120v hot wire to the neutral (ground) wire I wondered why it didn't short out. The reason is the primary and secondary coils are coupled together by the transformer's iron core. Alternating current in the primary coil creates a magnetic field or flux that is captured by the core. That flux flowing around the core creates an AC voltage in the secondary coil. The load (impedance) placed on the secondary winding by the amplifier is transferred through the core to the primary coil. That impedance keeps the primary coil from "shorting out."

The 650 volts AC power from the is fed directly into , the 5Y3 . V5 is a full wave dual plate rectifier tube that converts alternating current (AC) into direct current (DC), which the amplifier's electronics actually need to function. The power transformer and rectifier tube have internal resistance that cause voltage sag when higher current is demanded. Installing a higher rated power transformer can reduce voltage sag and "stiffen" the amp's tone, make it sound "punchier" and help tighten the bottom end.

370 volts of DC flows out of the rectifier tube's pin 8 (cathode) and is referred to as voltage (from old Battery Positive designation). You can raise the DC voltages in the amp by swapping out the 5Y3 rectifier tube for a higher output tube but be careful because your 6V6 power tubes can be damaged by too high a plate voltage. Higher amp voltage tends to increase output power, tighten up the tone and make it "punchier."

The B+1 DC voltage flows to the output transformer's primary winding and to the circuit board's three large . These resistors and capacitors form RC (resistance capacitance) low pass filters that take the lumpy, pulsing DC output of the rectifier tube and smooth it out--the smoother the better. Any waves or ripples left over in the DC power would be added to our audio signal and heard as 120Hz hum in the preamp and power tubes. The filter caps also act as a power reservoir so the larger the value of the capacitors the "stiffer" the amp sounds because the amp can react to power demands with less voltage sag. Low frequencies demand more power so larger capacitors can really help the low end and prevent "farting out."

Notice the resistors between the filter caps. These are that reduce the 370 volts DC B+1 down to 295 volts DC then to 250 volts DC . The B+1 voltage from the rectifier is tapped off to feed directly to the output transformer's primary center tap which feeds the power tubes' plates. The 295 volts DC B+2 is connected to the power tubes' pins 4--the screen grids. The 250 volts DC B+3 is used to power the preamp and phase inverter tubes but it's stepped down even more by their load resistors. The filter capacitors and voltage dropping resistors also decouple the three B+ power nodes to prevent interaction, feedback and oscillations between the preamp and power tube. You can raise or lower the B+2 and B+3 voltages by adjusting the value of the voltage dropping resistors.

Now that you know how the 5E3 works .

maximum power use of the 5E3.

The 5E3 Deluxe's 5Y3 rectifier uses 2 amps of 5V heater current. Other rectifiers: GZ34 uses 1.9 amps and the 5U4 uses 3 amps.

, KT88/6550:  , KT66:  , EL34/6CA7:  , , EL84/6BQ5: 0 , 6L6: 0 , 5881: 0

 355-0-355 volts AC RMS. The 0 means the transformer has a grounded 0 volt center tap and the transformer puts out +355v on one wire while simultaneously putting out -355v on the other for a 710v AC RMS voltage wire-to-wire.


: Solid state full wave diode:

. This would be the B+ voltage with no preamp or power tubes installed.

under load is estimated at 16%

= 8,000 The 5E3 standard output transformer is 8,000 ohm primary : 8 ohm secondary

to automate these calculations.

        V1A 1.1ma = 110v drop across 100k plate load resistor = 110v / 100k

        V1B 1.1ma = 110v drop across 100k plate load resistor = 110v / 100k

        V2A .83ma = 83v drop across 100k plate load resistor = 83v / 100k

        V2B .84ma = 47v drop across 56k plate load resistor = 47v / 56k

        V3    38ma = 19v drop across 250 ohm cathode resistor / 2 = 19v / 250 / 2

        V4    38ma = 19v drop across 250 ohm cathode resistor / 2 = 19v / 250 / 2



. Upload the to the to have an eyelet or turret board built for about $20.

. This is a basic 5E3 circuit, there are no modifications that will affect the tone. I have deleted the totally unnecessary Standby Switch and .

. The cable shield is grounded to an input jack ground tab. The V1 end of the cable is not grounded to prevent a ground loop. A nice, clean option is to use shielded microphone cable which has four conductors and run both input wires through one microphone cable. Shielded cable isn't a necessity in the 5E3 but if you use standard wire I recommend you run it along the chassis floor and below the circuit board to allow the chassis act as a noise shield.

. The B+3 filter cap is moved to supply V1 directly. The V2A coupling cap is reoriented to reduce cable runs. Wire routing is optimized for shorter runs, 90 degree wire crossings and maximum separation between grid and plate wires.

The choice of resistor is up to you but . Metal film resistors generate 1/10th the resistor hiss compared to carbon composition resistors but I did follow R.G. Keen's suggestion to use 1 or .5 watt carbon comp resistors on just the phase inverter load and tail resistors for a little carbon mojo. A 10 watt 250 ohm cement resistor is used for the power tube cathode. The plate load resistors are bumped up to 2 watts and the voltage dropping resistors are upgraded to 3 and 5 watts for component longevity.

that is only grounded at the Normal Low input jack. The power transformer high voltage center tap is connected directly to the B+1 filter capacitor negative terminal to minimize hum. The typical split-bus ground sends all the preamp return current through the chassis. This ground scheme doesn't flow any current through the chassis which any electrical engineer will tell you is a good thing.

. If you want to use an artificial 6.3v center tap then I recommend putting the 100 ohm resistors on the V3 power tube socket like .

I also shortened up the component span to keep from stretching the small component leads so much.

. They are shown "ghosted" on the circuit board between the power tube cathode resistor and the B+2 filter cap. I add them to all my 5E3 builds because they help protect the tubes during heavy overdrive and they sweeten the power tube distortion. If you do want to use them then do not use the red wire that runs from the B+2 cap to the power tube pins 4, use the wires from the top of the screen resistors to pins 4 instead.


Version of the 5E3 Deluxe

The addition of the V1B local negative feedback circuit will slightly reduce Bright Channel gain and distortion and help tame the extra gain from the 12AX7 in V1 (5E3 uses a 12AY7 in V1). Adding 470 ohm power tube screen resistors would sweeten power tube distortion and help protect the tube from screen failure during heavy overdrive. The amp uses a star grounding scheme with isolated Cliff input jacks connected to an AC only ground through capacitor C15. The headphone circuit's 2.2k and 100 ohm resistors form a voltage divider which cuts the amp's output to the headphone by 96%. The headphone output suffers from the lack of speaker tone shaping and breakup. I recommend anyone owning a Standard 12 try a 12AY7 in V1 for a more authentic 5E3 tone.

These pics are from a near virgin 5E3. All photos in this section were generously donated by Keithb7.



. It's a great sounding but simple guitar amp.




Merlin Blencowe, , 2nd Edition. This is my personal favorite tube amp book.


Merlin Blencowe,


Morgan Jones, , 4th Edition.


Richard Kuehnel, , 3rd Edition.


Richard Kuehnel, , 2nd Edition.


Richard Kuehnel,


Robert C. Megantz,


It's fairly technical but it's the only book written specifically about guitar amplifier overdrive. It includes many graphs to help make the material easier to understand.


T.E. Rutt,

[ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ]

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5e3 motorboating

  • Specialty Area

Anyone gig with an original 5E3? And if so…

  • Thread starter bluesroom
  • Start date Jun 19, 2023
  • Jun 19, 2023

Active member

What speaker do you use, how do you set it up with the interactive controls, and what guitar and effects? Thanks  

  • Jun 21, 2023

Well-known member

Plug into the Bright…volume and tone above halfway. I set the ‘off’ Normal channel to somewhere at 7-8. Everything is available…lively cleans to nice distortion. the best speaker I have heard for a 5E3 was a P12P…from the same tweed era.  

  • Jun 22, 2023



I have probably over 1000 gigs on mine. Stock P12R reconed. Like Wally, plug into Bright channel and look for the sweet spot on the other volume. I keep the tone between 8 and 12 depending on the guitar and how much gain I's a gain control. Jumpering channels sounds good at home but makes mud and slush onstage. For more oomph, I love a P12Q.  



charliechitlins said: I have probably over 1000 gigs on mine. Stock P12R reconed. Like Wally, plug into Bright channel and look for the sweet spot on the other volume. I keep the tone between 8 and 12 depending on the guitar and how much gain I's a gain control. Jumpering channels sounds good at home but makes mud and slush onstage. For more oomph, I love a P12Q. Click to expand...
Wally said: Plug into the Bright…volume and tone above halfway. I set the ‘off’ Normal channel to somewhere at 7-8. Everything is available…lively cleans to nice distortion. the best speaker I have heard for a 5E3 was a P12P…from the same tweed era. Click to expand...
brandtkronholm said: How loud is a tweed Deluxe (5e3)? Is it loud enough for a small room blues/jazz open mic? Can the “correct tone” be achieved in an ensemble (drums, keys, maybe horns) without sound reinforcement? Is there a modern Fender amp that is close or comparable? Click to expand...
brandtkronholm said: Is a tweed Deluxe comparable to a Pro Jr.? Click to expand...




Technology is your friend. If your 5E3 isn’t keeping up, then just dial it in to the sound you like, and mic it into the board. I notice that even many “arena” bands guitarists (like the Eagles or Clapton) rarely use anything bigger than a good combo amp onstage these days. When you think about it, it makes sense - they can use similar rigs to what they used in the recording studio.  

  • Jun 23, 2023
Wally said: Fender builds a ‘57 5E3 Reissue amp. How loud? It will not keep up with a heavy-handed drummer or a loud bass Player, imho., unless it is mic’d. If one had somethinglike a Fryette power station that has a 50 watt power amp for reamping a small amp, then one has a great tool….attenuator, rea per, load box for silent recording. A quiet jazz group? Maybe an unassisted 5E3 would keep up, but you would want a high efficiency speaker in the amp. I would suggest playing through one to get a feel for what goes on there. Your loud might be my middle ground. The Pro Jr. has some relationship to the simple tweed preamp. It has a different phase inverter, and the output secti9n is fixed biased as opposed to the cathode biased 5E3. Good little amps for what they are. The Pro Jr. IV has cooler Biasing. The earlier ones run very hot. Click to expand...
charliechitlins said: Mine is freakin loud. Totally giggable un-mic'ed with a 5-piece band with sax in a 100 person room.. Even louder with a P12Q If it starts to get a little too wooly, I step in an E-H LPB-1 that, for whatever reason, tightens it up. Click to expand...

The formula for a little more dirt for leads involves using the guitar volume knob to push the front end of the amp more. Roll the guitar volume back, dial the amp to the mythical "edge of breakup" and when you turn the guitar volume up, you'll bring the dirt.  


All Access/Backstage Pass

charliechitlins said: The formula for a little more dirt for leads involves using the guitar volume knob to push the front end of the amp more. Roll the guitar volume back, dial the amp to the mythical "edge of breakup" and when you turn the guitar volume up, you'll bring the dirt. Click to expand...

One of the only mass produced amps I thought hung with my 56 Deluxe was a Pro Senior. Pro Jr. In a bigger cab with a 12" speaker. Delicious. An un-mic'd 10 always sounds too dinky to me.  

  • Jun 24, 2023
charliechitlins said: An un-mic'd 10 always sounds too dinky to me. Click to expand...
charliechitlins said: One of the only mass produced amps I thought hung with my 56 Deluxe was a Pro Senior. Pro Jr. In a bigger cab with a 12" speaker. Delicious. An un-mic'd 10 always sounds too dinky to me. Click to expand...
brandtkronholm said: Link: Pro Sr. Looks fun! Click to expand...

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5E3 Testing and troubleshooting

Moderators: pompeiisneaks , Colossal

Post by Mojojtm » Mon Apr 04, 2022 12:20 pm

User avatar

Re: 5E3 Testing and troubleshooting

Post by martin manning » Mon Apr 04, 2022 12:41 pm

Post by Mojojtm » Mon Apr 04, 2022 12:52 pm

martin manning wrote: ↑ Mon Apr 04, 2022 12:41 pm That all sounds good. You won't have any high voltage until you put the rectifier tube in, so that is another smoke test. Then you can put the output tubes in (make sure the speaker is connected). If that works, you should be safe from any catastrophic shorts. Many people will use an incandescent bulb in series with the AC input power to limit current for these first steps.

Post by Mojojtm » Mon Apr 04, 2022 1:08 pm

Post by Mojojtm » Mon Apr 04, 2022 1:10 pm

Post by Phil_S » Mon Apr 04, 2022 1:17 pm

Post by Mojojtm » Mon Apr 04, 2022 1:24 pm

Phil_S wrote: ↑ Mon Apr 04, 2022 1:17 pm Voltage will be low with the limiter in circuit. The main purpose of the bulb limiter is to detect a short that would damage the amp. As I understand it, you must use an incandescent bulb. These bulbs are getting harder to find. If you have a 60W or higher rated bulb in the tester and it looks OK, you can remove the limiter. Then you will get a true voltage reading and it will be higher than what you reported to us.

Post by Mojojtm » Mon Apr 04, 2022 1:28 pm

Post by martin manning » Mon Apr 04, 2022 1:29 pm

Post by martin manning » Mon Apr 04, 2022 1:40 pm

Mojojtm wrote: ↑ Mon Apr 04, 2022 1:28 pm Ok done! I read without Light Bulb limiter 491V DC so little higher but not much of difference I'd say this is ok isn't?

Post by Mojojtm » Mon Apr 04, 2022 1:46 pm

martin manning wrote: ↑ Mon Apr 04, 2022 1:29 pm 150W is high for this relatively low power amp. You won't see much reduction in voltage. A 40W would be safer, IMO.

Post by Mojojtm » Mon Apr 04, 2022 1:58 pm

Post by martin manning » Mon Apr 04, 2022 2:06 pm

Post by Mojojtm » Mon Apr 04, 2022 2:25 pm

martin manning wrote: ↑ Mon Apr 04, 2022 2:06 pm Sure, and you can compensate by turning the volume down. The additional gain will reduce the headroom as compared to a 12AY7. I don't know why people like to install the preamp tubes first. IMO installing the power tubes will bring the voltages more into line, and the power stage is where errors or faulty components are likely to cause damage.

Post by martin manning » Mon Apr 04, 2022 2:56 pm

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See the full list of destinations in Perm , browse destinations in Perm Krai , Urals , Russia , Asia or choose from the below listed cities.

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Hotels in popular destinations in Perm

  • Perm' hotels »
  • Kondratovo hotels »
  • Ferma hotels »
  • Yuzhnyy hotels »
  • Bol'shaya Mos' hotels »
  • Nizhnyaya Kur'ya hotels »
  • Kostoryata hotels »
  • Turbina hotels »
  • Gayva hotels »
  • Ogryzkovo hotels »
  • Soboli hotels »
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Learn more about the map styles

Each map type offers different information and each map style is designed for a different purpose. Read about the styles and map projection used in the above map (Detailed Road Map of Perm).

Detailed street map and route planner provided by Google. Find local businesses and nearby restaurants, see local traffic and road conditions. Use this map type to plan a road trip and to get driving directions in Perm.

Switch to a Google Earth view for the detailed virtual globe and 3D buildings in many major cities worldwide.

Mercator map projection

This map of Perm is provided by Google Maps, whose primary purpose is to provide local street maps rather than a planetary view of the Earth. Within the context of local street searches, angles and compass directions are very important, as well as ensuring that distances in all directions are shown at the same scale.

The Mercator projection was developed as a sea travel navigation tool. It preserves angles. If you wish to go from Perm to anywhere on the map, all you have to do is draw a line between the two points and measure the angle. If you head this compass direction, and keep going, you will reach your destination.

Popular searches

A list of the most popular locations in Russia as searched by our visitors.

  • Novosibirsk Oblast
  • Ural Mountains
  • Kabardino-Balkarian Republic
  • Kaliningrad Oblast

Recent searches

List of the locations in Russia that our users recently searched for.

  • Republic of Dagestan
  • Saint Petersburg
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The Maphill difference

It's neither this road detailed map nor any other of the many millions of maps. The value of a map gallery is not determined by the number of pictures, but by the possibility to see the world from many different perspectives.

We unlock the value hidden in the geographic data. Thanks to automating the complex process of turning data into map graphics, we are able to create maps in higher quality, faster and cheaper than was possible before.

Forever free

We created Maphill to make the web a more beautiful place. Without you having to pay for it. Maphill maps are and will always be available for free.

Real Earth data

Do you think the maps are too beautiful not to be painted? No, this is not art. All detailed maps of Perm are created based on real Earth data. This is how the world looks like.

Easy to use

This map is available in a common image format. You can copy, print or embed the map very easily. Just like any other image.

Different perspectives

The value of Maphill lies in the possibility to look at the same area from several perspectives. Maphill presents the map of Perm in a wide variety of map types and styles.

Vector quality

We build each detailed map individually with regard to the characteristics of the map area and the chosen graphic style. Maps are assembled and kept in a high resolution vector format throughout the entire process of their creation.

Experience of discovering

Maphill maps will never be as detailed as Google maps or as precise as designed by professional cartographers. Our goal is different. We want to redefine the experience of discovering the world through the maps.

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Maps are served from a large number of servers spread all over the world. Globally distributed map delivery network ensures low latency and fast loading times, no matter where on Earth you happen to be.

Spread the beauty

Embed the above road detailed map of Perm into your website. Enrich your blog with quality map graphics. Make the web a more beautiful place.

Maphill is the web's largest map gallery.

Get a free map for your website. Explore the world. Discover the beauty hidden in the maps.

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Category : Perm Krai

 ]  ]  ]  ]  ]  ]  ]  ]
requiring frequent . As many pictures and media files as possible should be moved into appropriate subcategories.

Federal subjects of the Russian Federation:

  • The City of Perm is the krai's administrative center.
 image   flag image   coat of arms image   locator map image 
Instance of
Part of
Official language
Head of government (2020–)
Highest point
Maximum temperature record
Minimum temperature record
Authority file
BabelNet ID:
OpenStreetMap relation ID:


This category has the following 22 subcategories, out of 22 total.

  • Unidentified locations in Perm Krai ‎ (395 F)
  • Perm Krai in art ‎ (2 C)
  • Books about Perm Krai ‎ (3 C)
  • Culture of Perm Krai ‎ (15 C, 2 F)
  • Districts of Perm Krai ‎ (45 C)
  • Documents of Perm Krai ‎ (1 C, 1 F)
  • Economy of Perm Krai ‎ (13 C, 2 F)
  • Fountains in Perm Krai ‎ (1 F)
  • Geography of Perm Krai ‎ (17 C, 2 F)
  • History of Perm Krai ‎ (16 C, 2 F)
  • Information graphics of Perm Krai ‎ (2 C, 6 F)
  • Komi-Permyak Okrug ‎ (7 C, 5 F)
  • Medicine in Perm Krai ‎ (2 C, 1 F)
  • Nature of Perm Krai ‎ (17 C, 19 F)
  • People of Perm Krai ‎ (53 C, 25 F)
  • Photographs of flags of Russia in Perm Krai ‎ (4 F)
  • Politics of Perm Krai ‎ (2 C, 3 F)
  • Settlements in Perm Krai ‎ (25 C, 39 F)
  • Symbols of Perm Krai ‎ (5 C, 2 F)
  • Videos from Perm Krai ‎ (1 C)
  • Views of Perm Krai ‎ (9 C, 18 F)
  • Wikivoyage banners of Perm Krai ‎ (2 C, 32 F)

Media in category "Perm Krai"

The following 108 files are in this category, out of 108 total.

5e3 motorboating

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  • Ural economic region
  • Volga Federal District
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Roma communities in Perm Krai: historical and ethnical aspects

Profile image of Dmitrii  Vaiman

Two large groups of Roma are settled in the territory of Perm Krai, the Ruska Roma and Kalderari. Roma live both in cities and countryside. Roma living in the countryside keeps elements of traditional culture. In Perm Krai we can find different families of the Ruska [Russian] Roma: Gorbovichi, Nemzengery, Bashnengery, Polyaki, Sapuny, Gubany. In contrast to the Kalderari the community of Ruska Roma is based not only on family-territorial principle. Sometimes community is based on ethnic-territorial ground when the Ruska Roma living in an urban area despite family ties can be a part of the community. Traditional activity of Ruska Roma living in countryside is a seasonal grazing of livestock. One of the main sectors of activity is trading. Roma sell cars and jewelry. Kelderari live in compact groupings in Perm. They call themselves Moldavska Roma and consider themselves to be part of Ruvoni [wolf in Romani language] family. Traditional activity of Kelderari is metal work (especially tin-smith’s work) which impact also their modern business. The main work activity of men till now is working with metals such as base metal trading and metal items repair. Traditional women activity is fortune-telling. Bilingualism, traditional way of living, ethnic isolation, unique and particular material and spiritual culture are common for all of Roma. The main problems for Roma nowadays are safeguarding of ethnicity and as well as some educational and social issues.


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  1. Motorboating in 5E3

    5e3 motorboating

  2. How the 5E3 Works

    5e3 motorboating

  3. How the 5E3 Works

    5e3 motorboating

  4. How the 5E3 Works

    5e3 motorboating

  5. How the 5E3 Works

    5e3 motorboating

  6. How the 5E3 Works

    5e3 motorboating


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  2. Motorboating around Dordrecht NL May 2024

  3. AVATOR 20e and 35e Outboards

  4. Mercury Avator 7.5e Electric Outboard: Intelligent, All-Electric Propulsion

  5. MotorBoating

  6. Motorboat at Terrasta Cancun, Mexico Spring Break 2010


  1. Motorboating; what is it, 'why?', and how to fix it?

    Motorboating is a low frequency oscillation, often due to feedback though the power supply. Coupling caps shouldn't be too big, power supply filters may have to be larger if your supply has more droop than Fender's original. The original 5E2 circuit used 22K and 8 uF for the filter to the two 12AX7 stages - you may have reduced that resistor ...

  2. Tube Guitar Amp Troubleshooting

    Motorboating (amp sounds like a boat engine) is usually caused by a weak or damaged power supply filter cap. You can temporarily alligator-clip an extra filter cap in parallel with the caps, starting with the first filter cap. ... For the 5E3 Deluxe and other tweed amps the tape would be applied to the inside of the wooden back panel to cover ...

  3. my 5e3 tweed deluxe build

    I built it accordingly to Modulus Amplification 5E3 layout but with added standby switch. The voltages are all within 5% range of typical 5E3. ... It fixed the DC leak but I would motorboat on 12. Just moving the wires a little with a chopstick solved it. In conclusion the input is very sensitive! Maybe try moving some of the wires up top?

  4. Motorboating in my 5e3

    Motorboating in my 5e3 08-20-2012, 09:18 PM. Hiya, My weber 5e3 clone which I have had working (on and off) since 2009 has now started motorboating when the volume controls are high. All the controls effect the speed/volume of the motorboating. There is also wicked hum in the normal channel.

  5. 5E3 first stage interference

    5E3 first stage interference. General discussion area for tube amps. Moderators: pompeiisneaks, Colossal. 11 posts • Page 1 of 1. harleyboy2112 Posts: 33 Joined: Sat Oct 17, 2009 7:30 pm Location: south dakota. 5E3 first stage interference. Post by harleyboy2112 » Sat Feb 24, 2018 2:32 pm.

  6. 5e3 New Build Troubleshooting Hum/Oscillation

    Re: 5e3 New Build Troubleshooting Hum/Oscillation. Measured from the ground terminal of the jacks, all other ground points in the amp, and the chassis itself are all 0-0.5 ohms. Here are some pictures. Some of the solder joints look gooey, but it's reflections from the chassis and overhear light.

  7. New Tweed Deluxe/5E3 build

    Yesterday I ordered a mojotone chassis, 5e3 small parts kit and classictone OT/PT. I'm currently finishing up installing a metro loop in the plexi and should be ready to start the tweed deluxe build early next week. I'll start posting pictures once I have all the parts laid out.

  8. How the Fender 5E3 Deluxe Amp Works

    The 5E3 uses a 12AY7 preamp tube for the first gain stage. You can substitute a higher gain 12AX7 to boost amplification, reduce headroom and increase breakup and distortion. The preamp tube amplifies the guitar audio signal then sends it out pin 1 (plate) to a coupling capacitor or 'cap.'.

  9. My 5e3 Tweed Deluxe is quite poorly, can you help

    My 5e3 circuit amp is made up from a heavily damaged late 1950s tweed Deluxe. Much was lost but the transformers, along with some caps and resistors made it through. All that was missing was replaced and the amp converted to a head along the way. Before I bought it the owner even had it fitted with a full compliment of 1950s

  10. Advice/tips on a good 5E3 build

    Bump up the first B+1 (and maybe B+2) power cap/s to 32uf to improve filtering (and maybe firm up the sound). Add screen resistors to the output tubes for some insurance/compression. Bump up the grid stopper resistor values on the output tubes (1.5k doesn't really do much, 10K would be better).

  11. Tweedle Dee

    The 5E3 combo chassis is a bit tight though and after considering a whole bunch of other mods I settled on the idea that less is probably more. The four inputs allow for a lot of different frequency variation, with the low channel inputs offering a nice smooth bass on the normal channel and a crisper one on the bright channel. Sustain is ...

  12. Who makes the best 5E3 amp right now???

    Seminole224 said: Lazy J is another to consider that's not necessarily "new". The J20 is the standard 5e3, but you could also consider his J5 and J10 models. Mark Kane makes a pretty good 5e3 with some Dumble mods that corrects the bottom end. I've had the Lazy J20. It was completely overpriced in my humble opinion.

  13. Anyone gig with an original 5E3? And if so…

    With the mids of a 5E3 Deluxe you can frequently get a good cut through the mix (generally speaking) without having to crank the volume to the moon. I'll most times use an RC Booster, Greer Lightspeed, Tim, or Boss GE-7 to cut a little bass and boost the mids/low highs a bit. That does seem to help being heard if there's another guitar(s ...

  14. The best type of motorboating

    Things get a little crazy on our last day sailing around the Greek Islands. Nicole lets loose and puts on a show for everyone. She also teaches us how to p...

  15. 5E3 Testing and troubleshooting

    Re: 5E3 Testing and troubleshooting. by Phil_S » Mon Apr 04, 2022 1:17 pm. Voltage will be low with the limiter in circuit. The main purpose of the bulb limiter is to detect a short that would damage the amp. As I understand it, you must use an incandescent bulb. These bulbs are getting harder to find.

  16. Чусовой Map

    Чусовой is a town in Perm Krai, Urals and has about 45,500 residents. Чусовой is situated nearby to Chusovoy and Железнодорожный. Mapcarta, the open map.

  17. Detailed Road Map of Perm

    Detailed street map and route planner provided by Google. Find local businesses and nearby restaurants, see local traffic and road conditions. Use this map type to plan a road trip and to get driving directions in Perm. Switch to a Google Earth view for the detailed virtual globe and 3D buildings in many major cities worldwide.

  18. Category:Perm Krai

    Perm Oblast. Komi-Permyak Autonomous Okrug. Maximum temperature record. 42 degree Celsius. Minimum temperature record. −56 degree Celsius. official website. 59° 14′ 00″ N, 56° 08′ 00″ E.

  19. Roma communities in Perm Krai: historical and ethnical aspects

    A new research stage of the Rozhdestvensk archaeological complex, the largest medieval complex in Perm Krai, began in 2008. During the study, new data on the structure and typology of fortifications of the Rozhdestvensk settlement were obtained: along the eastern boundary of the site at the edge of a ravine an ancient filled up moat and a later constructed palisade were discovered.