Valve Junior Rebuild

[hippiebob01]

Hey guys,

I got a Valve Junior head yesterday and its already got the gears turning in my head. I want to rebuild it into possibly a 5w Champ-like (possible with an EL84?) or similar amp.

Any suggestions would be appreciated. Im a total newbie when it comes to all this rebuild stuff, although I have rewired my Strat and Tele (so I do have some wiring experience). So I may need some basic instructions when we get this off the ground.

[ziess]

My suggestion is do it!
The PT probably won't have a 5VAC rectifier heater tap so I'd recommend going the copper cap route (TJ can help you with the centre tap for the HV winding using some diodes).
I've always thought that these things (the wee Champ 600s, the Gretsches, the VJ etc.) are great rebuild platforms.
You'll end up with a much more rugged amp and you can customize it to suit. How about, say, a switchable tonestack?

Is this your first foray into amp building? You're going to love it.

Tommy.

[hippiebob01]

yeah, ive never ventured into building before. about the furthest ive gone into amps are remelting solder joints and running a jumper wire. so what parts will be reusable from the VJ? will i need new transformers?

[ziess]

You should be able to reuse the chassis, transformers etc. I'd replace the pots, the board, the jacks, the switches and the pilot light.

Hey, I've a schem of a Champ 600 to 5F1 conversion with a switchable tonestack I could email you if you like. Might give you an idea of where to start.

Tommy.

[hippiebob01]

thanks tommy.

[ziess]

Email sent.

Tommy.

[Mesotech]

I would suggest that if you just got the head yesterday, you might first want to play it stock for a while before ripping it apart. In the meantime, there seems to be a ton of simple mods already for these amps without going the entire rebuild route.

Mine is still stock, but I've considered adding a tone stack. It's a great little amp "as is", and I use it live quite frequently as my "baby marshall" when the venue is too small to run my big Marshall.

I do imagine that in time, I will gut it and rebuild it, but probably just do a rebuild of the existing circuit in a hand wired version. From that point, it would become easier to mod it further.

[Don]

I don't know if they're down permanently or temporarily, but there's a site, sewatt, dedicated to small single ended amps, mostly the Valve Jr. They have (had?) a bunch of mods and schematics.

There's really no need to gut the amp and completely re-build it if you're trying to make it Champ-like. It's already mostly there, just swap components to taste!

I did this to a new Gibson GA-5 with great results (though it was already a turret board amp)!

Keep in mind that these little amps store enough voltage to kill you, evan after being unplugged, just like their big brothers!

[ampdan]

I recently did one of these for somebody.

Before


After

[LGS]

Ampdan,

Is that one of those turretboard.com boards? I have been resisting the urge to cut into my Junior.

[ampdan]

Ampdan,

Is that one of those turretboard.com boards? I have been resisting the urge to cut into my Junior.

Yep. Ken has several versions. Excellent quality boards.

[rockntommy]

I would suggest that if you just got the head yesterday, you might first want to play it stock for a while before ripping it apart..

I agree.
I found just changing the tubes made a huge difference.
Currently using a Polam EL84.
Made this thing a whole new amp in my opinion.