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!
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.
JHS
Your blog is very beautiful!
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.
peace.
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………
I completely removed the input resistor.