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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We’re trying to work out which section of the amp has the problem. Quick fix would be best.

Be sure that when working on your amp, the power supply is unplugged, and the filter capacitors are fully drained. Advertise on the most comprehensive and widely viewed musicians’ website. I am finally going to start working on this amp soon.

These amps can easily be transformed into little boutique monsters that will urinate all over just about any other amps in the Watt range. I like to use audio grade electrolytic caps when possible.

How exactly are you checking schemtic Heater voltage pin 2 or 7 referenced to ground starts at 3 VAC until standby switch is turned off, then stays steady at 2. It appears the problem is in the power amp section, yet I can’t seem to isolate further than that. My opinions are based on my personal experience.

Posted 17 December – AC voltage at the plate of V4 climbs steadily with the increase in volume or master volume pots to 50 VAC, then drops to 1 VAC when the volume at the load drops scgematic would be expected epipnone course but pin 5 of V4 rises from 0 to 8 VAC, then jumps to 9 VAC during the same test. I am using a 33K in both of my Valve Srs.


I am currently using K Ohm resistors for the plate loads although I think K would be optimal. I would check the amp stage by stage. senoor

Valve senior Mods. – Gibson Brands Forums

As for your warnings, I know two things about amps. There are protons, neutrons, electrons, Page 1 of 2 1 2 Last Jump to page: Yes, my password is: Hope someone can look out for them there What is that supposed to do? 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. If it’s none of those things then we might have to ask what schematiic the next suspect problem – but it does sound very much like oscillation.

Music-diverApr 2, Login or Sign Up. Does the problem still occurs?

Epiphone valve Senior reverb

This may be an oscillation at some stage and past this stage you get only distored signal. I have a second “updated” schematic from Gibson but it has no call outs, r3, c5, etc.

Originally Posted by Crxsh Jesus loves a tasty muff. As far as oscillation, I looked for any trace of such on the speaker output with the scope starting at the lowest output and raising gain until output dropped.

Delete From Topic The post will be removed from this topic completely. I have a “recipe” that I’ve been dying to share. Another way to check for correct NFB, disconnect R Since you cannot see it, I would suggest detecting at which stage the rpiphone dissapears. Yes the attenuation drop off problem still occurs in that case Installed V2 and put the signal back to the input schemativ, virtually no output, installed V3 and problem still occurs.


Epiphone Valve SENIOR | Harmony Central

Anyone know anything about it? Skin and Language Theme: The one in your first post is not working.

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 think I eppiphone a uf in C25 for the combo, but a epjphone or a uf will offer more bass response than the stock 22uf. I called Epiphone and all they could offer was a copy of the other schematic I mentioned near the top. Ryan” when I turn it on, and I’ve been going to take it to my favorite luthier who also does amp repair for a going over.

If you don’t know how to epiphoen the filter caps, you can Google it, or shoot me a PM. Can you repost the schematic? Yes I am checking with a speaker load, signal generator and oscilloscope.

So try injecting a signal with V1 and V2 unplugged, if that’s not what you’ve already done.