I’m working on a Epiphone Valve Senior guitar amp that works fine I will try to attach a schematic with some voltages I measured added, but. Looking at the schematic I think you could borrow two 12AX7s from the Valve Sr to use as a preamp tube in the Valve Junior Reverb unit but. Download GIBSON EPIPHONE VALVE JR service manual & repair info for electronics experts.
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Originally Posted by Crxsh Jesus loves a tasty muff.
Epiphone Valve SENIOR
What do you suggest to try next? I will try to attach a schematic with some voltages I measured added, but had trouble doing that last time. Another way to check for correct NFB, disconnect R These amps can easily be transformed into little boutique monsters that will urinate all over just schmatic any other amps in the Watt range.
First, you should bump up all of the filter caps. So, that being said, you should upgrade the following capacitors with the same values: Well, do it anyway and tell us what happens, in full detail your posts are a bit shorthand tbh. Posted 12 October – So I haven’t seen any responses on this post for a couple days now, am I doing something, or not doing something correctly?
I think my next suspect would be a bad OT but that’s a long way second to oscillation. Ryan” when I zchematic it on, and I’ve been going to take it to my favorite luthier who also does amp repair for a going over. This will transform the reverb from “Out of epiphoone, Useless, Over the top” to just about the best tube driven reverb circuit you’ve ever heard. Carefully unplugged each wire 1 at a time, labeled and routed as far from the board and each other as possible Except the pairs which I twisted together, then tightened each spade lug.
Epiphone Valve Senior problem
And yes, a new 12AT7 will do just fine. This will smooth the AC hum, and keep your amp whisper quiet, even when “dimed”. I called Epiphone and all they could offer was a copy of the other schematic I mentioned near the top. That was the only place where I could get a changed response.
I love the 6V6’s so I’ll probably try the Valve Senior when it hits the streets. Then it drops off again.
I put a few notes on the schematic one of which says when I touched the VOM probe to junction between the cathode pins on V3 it caused the same effect as turning up the gains. My first guess is that at elevated gain settings, the amp is going into oscillation.
As always any suggestions are much appreciated! I was reluctant to probe with the scope around the plate voltages so used a meter set to AC volts. V1 has been removed for some time, 2 weeks? Yes I am checking with a speaker load, signal generator and oscilloscope.
Next swapped tubes both power and PI to no avail. Originally Posted by bigdrums You need to help us to help you.
Epiphone valve Senior reverb | Telecaster Guitar Forum
Do you already have an account? You see eppihone Enzo says something the rest of us just nod in sage silence, but really it’s what we’re all thinking Alas we still have some confusion about tube numbering. I’d been thinking about adding another 12ax7 to my valve jr.
Originally Posted by Seniior Forever And wiklund is smart, i’m in agreement with him. I don’t see anything I can detect as oscillation on the scope. I found this photo from summer namm last year: This is not nearly as difficult or expensive as you might think. These are just initail tests, which I would perform in order to learn about the root cause of the problem.
Is that where you meant? Any help will be greatly appreciated. Most people use a 10K in that application, but I’ve found that to be just a little too hot and my intention was to build a really dirty amp.