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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Valve senior Mods. – Gibson Brands Forums

This will smooth the AC hum, and keep your amp whisper quiet, even when “dimed”. Can you tell me anything about the 4 resistor array at that location?

It is oscillating at frequencies above audio.

calve If it’s anything like the VJ tone wise it should kickass. I called Epiphone and all they could offer was a copy of the other schematic I mentioned near the top.

DC voltage remains steady on both plate and screen grids at and respectively with light bulb current limiter in line of the supply AC Heater voltage pin 2 or 7 referenced to ground starts at 3 VAC until standby switch is turned off, then stays steady at 2.

To do xenior I would perform some basic tests: As for your warnings, I know two things about amps. Does the problem still occurs?


I thought that they already had a big brother to the Valve Jr. That’s not the ultimate cure, or not a good one, it just tells you where the problem feedback is. V1 has been removed for some time, 2 weeks? That was the only place where I could get a changed response.

Cshematic V2 and V3 are valev in you’ve only eliminated the reverb. If anyone has a different opinion, please do not be a “hater” as the kids like to say on the World Wide Webbut offer an alternative suggestion. I like the M series caps, which are currently produced by Cornell Dubilier. It is serving no purpose.

The factory value is 68K Ohms. Epiphone Valve Standard- Please Help? Changed the tubes 1 at a time more than once.

Gibson Brands Forums: Valve senior Mods. – Gibson Brands Forums

Since you cannot see it, I would suggest detecting at which stage the signal dissapears. My only suggestion is that the OP removes the ‘lamp limiter’.

So, that being said, you should upgrade the following capacitors with the same values: Even with zenior I’ve not really been able to get a decent tone. How would I eliminate the PI section? 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 you’d get those same tubes from the donor Valve Jr. This is not nearly as difficult or epiphne as you might think.


Board Classic Stanton Language: With V1 and V2 removed, signal injected to C13, I have rerouted the output leads and tried holding them as far away from the power tubes as I could with no change.

Epiphone Valve Senior problem

Then we’ll know if it’s the preamp or power amp. You should keep a copy of this. A quick fix would be just to replace the tank in the Valve Senior, just find the epiphonw that fits dimensionally and seniof https: Then put it back on standby for a few seconds, take it off standby and it comes back to life until the gain reaches a certain level.

Attacking possible causes is often a waste of time unless you have found out where in the amp the problem occurs. You can experiment with different values for that resistor, scyematic i think 22K or 33K is where it’s at. We haven’t yet taken it. Posted 17 December – This can be very “boomy” sounding, but the factory Valve Sr.

Epiphone valve Senior reverb

A handwired Senior with a handwired reverb on top is a nice dream rig. Apr 2, 2. T here is not really one single mod that will bring the amp to life, but a combination of upgrades and “tweaks”.