[59] Epiphone Valve Junior mods

Date: December 7th, 2007 | Comments : [6] | Categories: amps, tubes.

Epiphone Valve Jr. head

My new Epiphone Valve Jr. amp head

If you saw my previous post on the Epiphone Valve Junior 5w amp head, you know that I bought it to experiment with some mods and circuit changes. I’ve been looking over the schematic and drawing up some of the mods that I want to try. Here is the initial list of mods I want to make to this little beast.

  • Add a tone control
  • Reduce preamp gain
  • Add a switch for a feedback loop
  • Add a triode/pentode switch
  • Add a conjunctive filter on the OT
  • Add a standby switch

I’m not planning on changing output transformer in the first round of mods, though I have one on hand that would be suitable.

I want to reduce preamp gain because if I need overdrive from the amp, I will use a booster pedal to drive it hard enough to go into saturation

I might also end up changing the values of a few components.

There will be a page on my web site dedicated to the mods and the link will be added to this post when I get it online.

The Epi Jr. is a nice little amp for the dollars and I look forward to turning it into a custom unit drenched in good tone!


6 Responses to “Epiphone Valve Junior mods”

[282] JHS Says: 1:34 am, February 2nd, 2008

I recommend tp change the 1N4007 diodes for BY… or other ultra low noise fast revovery Schottky diodes. 1N400.. diodes will be to slow and imply a lot of hiss to the circuit.


[367] 搅拌机 Says: 2:39 am, March 12th, 2008

Your blog is very beautiful!

[448] Murray Mcleod Says: 7:55 pm, June 16th, 2008

I just got a valve jr and have been looking online for the last few days trying to find the coolest ideas for moding this thing. I finally found it here.

Also, your website rules.


[620] ted stephens Says: 11:08 pm, February 27th, 2009

what a bout a tung-sol 12ax7 in the preamp section and a bigger transformer and and cut down on the input resistor it shouldn t be this big and for a tube try several and keep them all brands including mesa boogie to rca it doesnt matter if it sounds just leave it alone………

[727] Murray Mcleod Says: 11:01 pm, June 9th, 2009

I completely removed the input resistor.

[2697] Buzzard Says: 8:19 am, March 25th, 2012

Hi, great blog !!
I wonder if a standby switch is useful for my Epiphone Valve Junior.
I don’t really use it that often, but when it’s in use, it turned on and off often, or not at all through the day.
Any ideas ??
Thanks, and best Regards


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