The Valve Jr transformation is complete....

[Ch0jin]

Yeah, but that's Oz Dollars, works out to $347.50 USD.

HAHAHA, thats so something an Aussie would say about US currency traditionally.

FYI I just bought a bunch of stuff from GGG via paypal with the Exch rate at 97c so AUD/USD is damn close to 1-1 right now. Awesome for kit builders outside the US!!!

I'll start another thread when they arrive, but as a sneak preview for DVM, adding to my two fuzz's, BMP and Tremelo will shortly be....BSIAB, ITS8 and a delay.

Oh and to keep this post somewhat on topic.. I'm 90% convinced I'll pick up a rev3 Valve Jr Combo if they have one in my local store this weekend. Sounds like the go as they have a decent OT in them to start with, better tubes (maybe) and hum issues resolved. I'll post that up too if I pull the trigger.

[duhvoodooman***]

Resurrecting an old thread here, rather than starting a new one. To quote the old Paul Harvey line, here's "the rest of the story":

Quite a while back, I started to run into a problem with intermittent signal distortion and volume loss on my multi-modded v.1 Epi Valve Jr. combo. I'd get the volume suddenly modulating and a nasty static-y distortion happening at the same time. It was definitely vibration related, as it happened mostly on initial pick attack, and got worse as the volume was increased. But it wasn't tube-related, since multiple tubes (both preamp & power) produced exactly the same behavior. With other amps available to me, I pretty much just kicked the VJr to the back of the gear pile and stopped using it. Which was too bad, 'cuz when it was right, it was chock full of cool sounding 5W Class A single-ended goodness.

A few weeks ago, I decided to try and pin down the problem, and took the amp apart looking for a bad solder joint, lifted trace on the PCB or some similar issue. Poked around extensively in the chassis with a wooden probe to see if I could locate the problem, but I had absolutely no luck. Maybe it was a component with an intermittent problem, but I'll be damned if I could find it.

While I was "under the hood", I couldn't help noticing how amateurish a lot of my soldering work looked! This was one of my earliest projects and it showed! I was also struck by just how cheap and flimsy that first stock VJr PCB looked, now that I've had some experience with other amps. Just on the basis of visual appearance, it wasn't surprising that the amp might have problems.

Rather than spend any more time trying to fix that cheap old board, I decided to just replace it. An outfit called Watts Tube Audio sells replacement boards for the various versions of the VJr in both eyelet and turret configurations, so I was checking them out. But when I started looking at their offerings, I found that they also sold "loaded" boards, i.e. with the required components already mounted--just mount it in the chassis and make the required connections to the rest of the amp. Not only that, but they offered several versions with different tonal characteristics: stock, Marshallized, Voxy, Fenderish and Suprolicious, with the latter two available in both EL84 and 6V6 versions. Though not cheap at $110, there was (and still is, as of mid-Sept.) a sale going on, dropping the price to $75. Based upon the amount of time that would save me in sourcing the needed components and soldering it together, that seemed like a pretty sweet deal! Here's a photo of one of these loaded boards off their website:



After exchanging a couple of e-mails with Ken, the "head guy" there, I decided on the Voxy version. They build 'em to order, and I received mine just about 2 weeks after placing the order. It's a high quality little board, neatly fabbed and a very sturdy 1/8" thick. I went with the "red swirl" color, vintage Marshall-style. They provide layout diagrams on their website that serve as the guide for installation. That process was very straightforward....especially after getting some expert advice from resident Fret.net amp guru Tunghaichuan. Mostly a matter of tying in the power and output transformer wires, several ground connections, and wiring the input jack and volume pot.

It fired right up and sounds just great. Starts breaking up around 10 o'clock on the volume knob and is a real crunch machine by 2-o'clock or so. I still have the Tweed-style 1-knob tone control, gain boost toggle switch and standby switch features that I had added to the VJr back in early 2008. I didn't bother to hook up the treble boost toggle I'd installed back then, though, because it's plenty bright sounding as is. I've been running it through my 2x12 cabinet, since the onboard 8" speaker doesn't have much low-end punch.

If I get motivated enough to pull the chassis out of the cabinet again, I'll take a couple of photos and add them here.

[vroomery]

How expensive would it be to source the rest of the parts and make it a head version? I've been looking at the valve junior lately and was going to mod it into a more vox like sound anyway, so this might be a really cool option.

[duhvoodooman***]

Got ambitious and pulled out the chassis for a couple of photos:

[tunghaichuan***]

Looks great, DVM.

Got ambitious and pulled out the chassis for a couple of photos:

[Tig***]

My EVJ board arrived today. Its the Voxy version as well. Hopefully I'll wire it up next week.

[Ch0jin]

Ah the yellow board. Should provide slightly glassier treble and more intricately shaped highs than the red one DVM has....

[Tig***]

Ah the yellow board. Should provide slightly glassier treble and more intricately shaped highs than the red one DVM has....

You know it!
Yellow boards are the secret to increased touch sensitivity as well, but don't tell DVM.

[duhvoodooman***]

Ah the yellow board. Should provide slightly glassier treble and more intricately shaped highs than the red one DVM has....

You know it!
Yellow boards are the secret to increased touch sensitivity as well, but don't tell DVM.

But the red boards have more tonal warmth and superior gain characteristics. This is widely known....

Seriously, that's great, Tig. Looking forward to hear what you think of the finished product.

BTW, Bloozcat just got one of these new VJr boards, too....

[duhvoodooman***]

How expensive would it be to source the rest of the parts and make it a head version? I've been looking at the valve junior lately and was going to mod it into a more vox like sound anyway, so this might be a really cool option.

Not sure what you're asking. Do you already have a Valve Jr. that you want to convert? If so, what version? Or are you talking about building a head from scratch?

[Tig***]

Cool, that got my interest. However, I can't find any EVJ populated boards on their website.
I'd like to get a Vox voiced one to replace my dead EVJ's board.

[duhvoodooman***]

Cool, that got my interest. However, I can't find any EVJ populated boards on their website.
I'd like to get a Vox voiced one to replace my dead EVJ's board.

About halfway down this page:

http://www.turretboards.com/guitar_a...ve_junior.html

I'm talking about building one from scratch. It might be more cost effective to buy a head and replace it with a complete board.

I expect that it would be considerably cheaper to buy a VJr head and modify it than to build from scratch. The cost of transformers, chassis, hardware and cabinet would add up pretty fast. I'd suggest looking for a used head on eBay or CL.

[Tig***]

Thx for the guidance. I had a killer headache yesterday and couldn't find it.

I'm really liking what I see so far.

So, it looks like you had to cut off the stock connectors and solder the wires directly to the board, right? Do they supply adequate instructions on wire placement? It sounds like yo and Tung had to adapt your past mod's to the new board. My only mod is a tone pot.

Also, how does the EVJ sound now after you've had a chance to play with it?

[duhvoodooman***]

So, it looks like you had to cut off the stock connectors and solder the wires directly to the board, right? Do they supply adequate instructions on wire placement?

Yes, had to cut off the stock spade connectors on the transformer wiring and solder directly to the board. The layout diagram makes it pretty clear what you have to do, I thought. There are some grounding wires that have to be added, too, also shown on the layout.

Also, how does the EVJ sound now after you've had a chance to play with it?

Sounds very, very good. Definitely has that juicy, single-ended Class A character. Kind of a rustic & untamed edge to the tone. This version has better clarity and more treble end than my previous mod. Candidly, I think I went a little overboard in hot rodding that one!

[Tig***]

Yes, had to cut off the stock spade connectors on the transformer wiring and solder directly to the board. The layout diagram makes it pretty clear what you have to do, I thought. There are some grounding wires that have to be added, too, also shown on the layout.


Sounds very, very good. Definitely has that juicy, single-ended Class A character. Kind of a rustic & untamed edge to the tone. This version has better clarity and more treble end than my previous mod. Candidly, I think I went a little overboard in hot rodding that one!

Looks like something I can handle then. I'll pull the trigger tonight.

Not sure which components to choose...
Mallory 150 or Orange Drop cap's, as well as 1 watt carbon film or 1/2 watt carbon comp resisters. I'm not sure if they make much of a difference in tone or reliability.