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31

Tube Amp Building - Tweaks - Repairs / Re: Questions about Rehabilitating a 65 Super Reverb

« Last post by Dumbmonkey on September 05, 2025, 05:32:53 am »

Stratomaster
I totally understand, and I don't want to keep piecemealing it like I have been; it makes me feel like a total hack.  I'll definitely give the signal tracing another try.
A couple questions about signal tracing:
wouldn't it be easier with an oscilloscope?
how hard is it to do basic signal tracing with an oscilliscope (ie, for a newbie)?
what affordable oscilloscope would anyone recommend for a complete beginner?
As always, thanks for all your time!

32

Tube Amp Building - Tweaks - Repairs / Re: Deluxe 5E3 tone stack

« Last post by pdf64 on September 05, 2025, 04:34:19 am »

I'm looking at rebuilding my Bell&Howell Deluxe-ish clone.  I built it with a standard 5E3 tone stack, with the interactive Volume and Tone controls.  But then I got to wondering:  What if the volume and tone controls were wired one after another, in series instead of in parallel?

With the original arrangement you get treble cut and boost (if the vol pot is not at maximum). But with your arrangement you only get treble cut, so it's a less versatile configuration.

Wouldn't there also be an inherent bass cut due to the 470pF cap feeding the tone pot?

33

Tube Amp Building - Tweaks - Repairs / Re: Deluxe 5E3 tone stack

« Last post by Merlin on September 05, 2025, 03:00:09 am »

I'm looking at rebuilding my Bell&Howell Deluxe-ish clone.  I built it with a standard 5E3 tone stack, with the interactive Volume and Tone controls.  But then I got to wondering:  What if the volume and tone controls were wired one after another, in series instead of in parallel?

With the original arrangement you get treble cut and boost (if the vol pot is not at maximum). But with your arrangement you only get treble cut, and also volume loss, so it's a less versatile configuration.

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Tube Amp Building - Tweaks - Repairs / Re: Deluxe 5E3 tone stack

« Last post by AlNewman on September 05, 2025, 01:16:32 am »

Probably hard to say without a schematic as built.  I think the 5E3 works because the 2 input stages interact with each other.  If you only have 1 input into the same tone stack, you're probably missing half of the equation. 

If you go to TSC, you can look at different options, I would think now you're closer to a princeton than a deluxe.  With one tone control and a volume out, the Framus looks interesting, as well as the Big Muff.

http://www.guitarscience.net/tsc/info.htm

35

Tube Amp Building - Tweaks - Repairs / Re: Deluxe 5E3 tone stack

« Last post by kagliostro on September 05, 2025, 12:43:24 am »

Only one consideration

A pentode has more gain than a triode but the signal loss Is higher if a pentode Is followed by a Tone Control than what happen to a triode

Franco

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Tube Amp Building - Tweaks - Repairs / Re: Deluxe 5E3 tone stack

« Last post by Platefire on September 04, 2025, 11:49:11 pm »

If I remember correctly sluckey made the attached drawing to show how the normal channel interacts with the bright channel on a 5E3. If he sees thesehe may elaborate on it more.

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Tube Amp Building - Tweaks - Repairs / Re: Deluxe 5E3 tone stack

« Last post by tubeswell on September 04, 2025, 10:15:10 pm »

Anyone know the reason the Fender 5E3 controls are wired together like they are?  What's the reasoning?

My reading of all the Fender amp typologies through the 40s, 50s and 60s was that Leo wasn't trying to make amps more distorted as he went along, he was trying to get them to sound cleaner.


The stock 5E3 effectively has 2 triodes 'in each channel' before the (unity gain) cathodyne stage - that is more than enough to drive a 6V6 grid to full clipping. If you make it three preamp triodes before the cathodyne, you will get even more distortion - which may well be your goal YMMV. (If you put a pentode in there - like you have in your schematic - even more distortion)

38

Tube Amp Building - Tweaks - Repairs / Re: Questions about Rehabilitating a 65 Super Reverb

« Last post by stratomaster on September 04, 2025, 08:52:02 pm »

Hi all!
I'm gonna bet that anyone following this thread is getting pretty sick of my postings.
Tubeswell, thank you for the info, it was really enlightening and will be a good guide for me moving forward.  I had checked that .022 coupling cap before (it's a ceramic disc) and tried replacing it with an Orange Drop, but that didn't change anything.  I checked the 500pf in series with that and got a few milivolts of DC so I replaced that with a SM that I had here.  Still no changes. 
Could the issue possibly be someplace in the pots?  I cleaned them all out with Deoxit, but I didn't pull them and clean the brass plate.  I'm going to try that and see if that does anything.  I have some new shunting jacks, resistors and bright switch on the way, should I try redoing the inputs as well?
I have to keep reminding myself that the amp is 60 years old, and was in a shed, so I shouldn't be surprised with all the issues.

It could be a lot of things. Guessing and replacing parts is like playing Battleship.

If you stuck with the systematic signal tracing I suggested you'd have zeroed in on at least the problematic section of the circuit by now.

I'm imploring you to resume signal tracing.

39

Tube Amp Building - Tweaks - Repairs / Re: Questions about Rehabilitating a 65 Super Reverb

« Last post by Dumbmonkey on September 04, 2025, 08:39:14 pm »

Get the entire book...

     https://trinityamps.com/ForumGallery/trinity/resources/Jack_Darr_Handbook.pdf

Wow! Great!  Thank you!!!

40

Tube Amp Building - Tweaks - Repairs / Re: Questions about Rehabilitating a 65 Super Reverb

« Last post by Dumbmonkey on September 04, 2025, 08:27:17 pm »

Hi all!
I'm gonna bet that anyone following this thread is getting pretty sick of my postings.
Tubeswell, thank you for the info, it was really enlightening and will be a good guide for me moving forward.  I had checked that .022 coupling cap before (it's a ceramic disc) and tried replacing it with an Orange Drop, but that didn't change anything.  I checked the 500pf in series with that and got a few milivolts of DC so I replaced that with a SM that I had here.  Still no changes. 
Could the issue possibly be someplace in the pots?  I cleaned them all out with Deoxit, but I didn't pull them and clean the brass plate.  I'm going to try that and see if that does anything.  I have some new shunting jacks, resistors and bright switch on the way, should I try redoing the inputs as well?
I have to keep reminding myself that the amp is 60 years old, and was in a shed, so I shouldn't be surprised with all the issues.