Epiphone Valve Junior mods - advice wanted

Dave · Post by **Dave** » Tue Oct 09, 2012 3:26 pm

I am pretty sure my next step in the world of the eternal tinker is to start mucking about with a nice simple amp. I hear the Valve Jr's are simple things to muck about with. Would this be a good first step? Any other suggestions? Any particular mods?

Need to be something I can pick up for cheepz!

Sloan · Post by **Sloan** » Wed Oct 10, 2012 12:11 am

Buy an old tube pa head. Find a schematic or whatever those old service sheets were with the parts layout etc (can't think of the name). Lots of the old stuff had info actually stuck to the covers, which was always very helpful. Study the schematic next to some early fender amp schematics and make changes based on that. You'll learn some stuff pretty quick and have a good sounding little amp.

I played an amazing sounding Bogen Challenger once, but be careful as there are some solid state challengers.
http://www.ebay.com/sch/i.html?_trksid= ... &_from=R40

Stromberg Carlson is another brand that was common when I was dealing with this stuff.

Dave · Post by **Dave** » Wed Oct 10, 2012 7:46 am

CHeers for the headsup SLoan. I am pretty unsure about electrics and schematics etc, so if this is the sort of thing that can be learned on the job then that's cool. I'll keep my eye out for cheaps PA. I nearly got a Selmer silver PA amp with the idea of making it guitar ready. It's basically like the Silver Selmer treable n' bass but with moar knobs. Looked fucking rad.

Saw your Epi video on youtube a few days back - did you try any mods on it?

toez10 · Post by **toez10** » Wed Oct 10, 2012 11:38 am

The nice thing about the Valve Jr, when compared to a random tube amp, is that there is a lot of step-by-step modding information available for the Valve Jr. While an old tube amp from organ might be capable of being a better sounding amp, it might be much more difficult for someone who doesn't have some experience in following an amp schematic, and circuit flow.

Post by **Doog** » Wed Oct 10, 2012 12:42 pm

Dave wrote:CHeers for the headsup SLoan. I am pretty unsure about electrics and schematics etc, so if this is the sort of thing that can be learned on the job then that's cool. I'll keep my eye out for cheaps PA. I nearly got a Selmer silver PA amp with the idea of making it guitar ready. It's basically like the Silver Selmer treable n' bass but with moar knobs. Looked fucking rad.

Saw your Epi video on youtube a few days back - did you try any mods on it?

Sloan's idea sounds rad, I wanted to do the same with an old Sound City 50w tube PA head I had, but I have NO idea what happened to it.

Sloan · Post by **Sloan** » Wed Oct 10, 2012 4:50 pm

Dave wrote:Saw your Epi video on youtube a few days back - did you try any mods on it?

I didn't do any mods, but I did work on a fellow's VJ that he had modded with a Plexi SE circuit board. The stock transformer had blown so I had to install a new one and other stuff (he wanted more gain).

[youtube][/youtube]
"This is an Epiphone Valve Jr. head modified with the Plexi SE v1.1 pcb. It is set to 'Cascade' mode (similar to Marshall JCM800). It also has a Hammond 125ESE output transformer. A few of the resistors and capacitors have been changed as in popular jcm800 modifications (bright cap etc..). "

toez10 wrote:The nice thing about the Valve Jr, when compared to a random tube amp, is that there is a lot of step-by-step modding information available for the Valve Jr. While an old tube amp from organ might be capable of being a better sounding amp, it might be much more difficult for someone who doesn't have some experience in following an amp schematic, and circuit flow.

This is a very good point and something to consider. Once you get into an amp, you can pretty much mess around with the preamp section and experiment to your heart's content without worrying about messing anything up, but get some drastic changes.

onedaycloser · Post by **onedaycloser** » Wed Oct 10, 2012 6:29 pm

I had a modded VJ for the past few years. It had just about everything done to it besides ripping out the circuit board and being rebuilt. I bought it from a dude online (MyLesPaul forum, SeWatt.com forum and AgileGuitarForum.com) named TWANG, dude knows just about everything regarding the VJ's. It's a solid platform to mess with but you can run into problems with ruining the traces on the PCB.

Check out the VHT Special 6 and Special 6 Ultra tho, they sound great stock but come with circuit boards meant for modding (turrets and eyelets vs. pcb traces). I've got a S6 Ultra that all I've done is swap tubes and smokes.

VHT Special 6 Ultra

SGJarrod · Post by **SGJarrod** » Wed Oct 10, 2012 6:45 pm

If you are admittedly not good with electronics and schemes I would recommend starting with pedals. They are easier and cannot kill you.

endsjustifymeans · Post by **endsjustifymeans** » Wed Oct 10, 2012 6:47 pm

SGJarrod wrote: I would recommend starting with pedals. They are easier and cannot kill you.

speak for yourself...

Bill Oakley · Post by **Bill Oakley** » Sat Oct 13, 2012 1:01 am

Sloan wrote:Buy an old tube pa head. Find a schematic or whatever those old service sheets were with the parts layout etc (can't think of the name). Lots of the old stuff had info actually stuck to the covers, which was always very helpful. Study the schematic next to some early fender amp schematics and make changes based on that. You'll learn some stuff pretty quick and have a good sounding little amp.

I played an amazing sounding Bogen Challenger once, but be careful as there are some solid state challengers.
http://www.ebay.com/sch/i.html?_trksid= ... &_from=R40

Stromberg Carlson is another brand that was common when I was dealing with this stuff.

I have a Bogen Challenger CHB-100 (? I think) and a Valve Jr Head I got in a trade. The Challenger is a really good sounding amp when used for guitar. Has some funky connections on the back though but are easily replaced with standard 1/4" jacks. I plan on doing something with the Valve Jr but I just don't know yet. I haven't played it much. That thing needs a master volume bad though. That may be first.

I agree that the Valve Jr may be a good place for you to start out since there is so much documentation on the modification of it. Just read up on doing it safely.

Sloan · Post by **Sloan** » Sat Oct 13, 2012 5:27 pm

Sloan wrote: those old service sheets were with the parts layout etc (can't think of the name).

These are called PHOTOFACTS (typically Sam's Photofacts)