Epiphone Valve Junior Modifications

[duhvoodooman***]

A couple of additional comments on the BOM items:

1. You'll notice that the resistors needed for the R1/R2 changes aren't listed. That's because I got them right here at work for nothing. One 1 M and one 22K. Same with the 1/4 female spade connectors I used, and the wire.
2. I listed three different tone caps in the BOM--50, 68 and 100pf ratings. You'll only need one. I'd skip the 50 completely, and go with the 68 by default, or the 100 if you really like a bright, jangly tone. On the other hand, they're only about 70 cents each, so it wouldn't hurt to get a couple.

[duhvoodooman***]

Here's a couple of audio clips I recorded with my Valve Jr's new brightness switch off and on. Clip descriptions:

#1 - My Epi LP with tone controls at midpoint. The same basic riff is played twice, first with the brightness off, then with it on. The first pair is recorded with the p'up selector in the middle position, i.e. with both p'ups. The second pair is the bridge p'up only.

#2 - My Strat, with the treble controls dimed, to accentuate the highs. The first pair is recorded from the neck p'up and the second pair, from the bridge. Again, the first of each pair of riffs is with the brightness off, and the second with it on.

Clip #1

Clip #2

With the 68pf tone cap, the effect is fairly subtle, but clearly audible. If you were looking for more brightness than this, the 100pf tone cap would be the way to go. I may change it at some point, just to hear the difference for myself. But it sounds just about right to me now, so maybe not!

[Nelskie]

DVM - You're right, the difference with the brightness switch "on" is clearly audible - and yeah, it does sound good. Out of all the clips you've posted, the tone that really stands out to me is your Strat with the neck p'up, with the brightness switch "on". Very tasty! Those new Texas Specials sound like they're doin' the trick for you.

After all those mods, pictures, posts, and now . . . clips, I'd say it's time for you to go get a cold one, grab the Strat, plug in to the Jr., and enjoy the fruits of your labor. Nice job, my friend!

I'm waaaaaayyyyy stoked to dig into my Jr.!!!

[duhvoodooman***]

Thanks, Nelsk. It being Saturday and all, I'll probably do exactly that at some point!

Also, notice what you didn't hear in the "dead air" spots between the clips--hum. At the volume setting I was using, there's no audible hum or buzz at all.

[Nelskie]

DVM - Went to Mouser.com this morning, and ordered the parts for my Valve Jr.'s "Voodoo Mod". If they're here at Ice Station Zebra (aka NoDak) by the latter part of next week, I should be knee-deep in creamy, hum-free Class A mojo come next weekend!! Provided that I don't electrocute myself!

[Nelskie]

For those of you who’ve read the duhvoodooman’s fantastic Valve Jr. Mod mod page, and heard the sound clips, you already have a pretty good idea as to the potential of the Epiphone Valve Jr. amp. There’ve been numerous comparisons of the Junior to other low-watt wunderkind – but apples to apples, it would be safe to say that the Epi is undoubtedly playing the role of Rocky Balboa vs. either of any of its higher-priced competition.

I’ve been using my Valve Jr. amp in semi-stock form (new tubes & speaker) for about (10) months, and in that time, have come to appreciate the genuine nuances of its tone. Still, every time I plugged in, I couldn’t help but wonder whether or not there were gains to be made with the implementation a little electronic wizardry.

Using the DVM’s mod page as my base, I purchased the required parts for my project from Mouser.com, and they arrived shortly thereafter. Mouser is a good place to get quality electrical components at a reasonable price. Shipping was quick, and the parts were well-packed. A trip to Home Depot for a battery-powered soldering pen, and I was ready to turn my Junior to a bona-fide tone machine.

After a few test-soldering runs, I felt I was ready to make it happen. My first undertaking was to solder a small jumper wire on the bottom of the board. And so, I patiently applied my limited soldering skills to this task. After nearly an hour and a half, and still no success, I came to the frustrating conclusion that the task of modding an amp was probably best left to people who are more adept to this kind of thing - - not to mention to someone with at least modest soldering skills – which I obviously did not have. Even though I was a bit let-down about not being able to execute the mods myself, I did give it a shot - - which in my book counts for something. My point here is this: even basic mods do require some skill and knowledge. If you don’t feel that you can take the job from start to finish – let a professional do it. It’ll save you a lot of headaches – and of course, a lot of frustration.

Now that that the mods are finally done, I can definitely say that the amp sounds even better - and I really liked the way it sounded before. Here is my take on some of the key aspects of the Voodoo Project:

1.) Hum – Virtually non-existent with a humbucker-equipped guitar. Much, much better with a single-coil equipped guitar – most particularly at higher volume levels. Now, we must understand that “hum” is inherent to the Class A amp design, irregardless of what Obi Wan Kenobi says at Amptone.com. So, unless you want to fork over another $700 - $1,000 for a real boutique number, any advances you can make in this territory with the Valve Jr. should be measured with that in mind. These mods do a very good job at reducing ambient hum, which in turn, allows more of that great Class A tone to come through.
2.) Brightness switch – In my opinion, this is the mod that really pushed this project over the top. Having the option to brighten up the tone on this amp is like giving your Strat (5) more p’up positions. Or, for you Lesmeisters – (3) more p’up positions. Currently, I am running a Weber Alnico 8S speaker in my Jr., and the bright switch really takes full advantage of the “chimey” vintage-type tones that are the trademark of this type of speaker. I used the 68 pf cap, and would agree with DVM’s observations that this is the perfect medium. However, your own preferences may require more, or less, in this dept.
3.) Response – As I’ve mentioned on my previous posts, the Valve Jr. is an extremely responsive amp. The smallest variances in pick attack and guitar vol / tone adjustments are transposed by the amp into magical tonal mojo. The new mods have most definitely enhanced the responsiveness of the Junior – particularly in the depth and definition of the tone. As I played my Korean Strat through the amp, I marveled at how the notes “jumped” out of the speaker. Major chords had a resounding “fullness”, and increased sustain – both with and without the brightness switch engaged.
4.) Volume – I wasn’t expecting any increases in this area – and yet, the amp now seems to be louder. Part of this could be attributable to the J & J tubes I am currently running, which break up just a bit earlier than the stock Sovteks did, and have a “grittier” attitude. It may also coincide with the characteristics of response, as are noted above.
5.) Overall Tone – Reducing the ambient noise has had a significant effect on the overall tonality of the Valve Jr. It is almost like I am hearing this amp again for the first time. And now being face-to-face with that fact, it is somewhat perplexing that the design engineers at Epiphone weren’t able to come to this same conclusion. But, as we’ve touched on many times here at Fret.Net, even simple improvements can have a dramatic effect on overall tone. This project is a perfect illustration of that fact.

These recent mods cost me $73 - $23 for the parts, and $50 for the labor. Added to the $165 I had into the unit prior to this ($119 for the amp; $26 for the tubes, $30 for the speaker), this brings the total of outlay for my Valve Jr., in its current form – to $228.00. In my book, its been money well-spent. And despite its diminutive size, the little amp produces some very BIG tone.

So what else is there to compare the Valve Jr. to tone-wise? Well, for starters, you may be able to procure a 1968 or later Fender Champ for around $300 - $350, or slightly more depending on condition. A Fender Blues Jr. will push you into the $400 range. The Crate Palomino and V-5 Series are two other low-watt Class A amps that will fit the bill nicely, and are both in that $350 - $400 range as well. I’ve played all of these amps, and would now put my Valve Jr. in the same league as these amps. Bottom line – there’s probably a Benjamin and some change to get you to that next level in the low-watt Class A feeder chain.

As for comparisons to real boutique numbers – there are none. This is a mass-produced Chinese amplifier, constructed with cheaply-made components, and stricken a bevy of design deficiencies. But with the right approach, and a little good ol’ American know-how, there are some fantastic tones to be had.

In closing, I would give the Epiphone Jr. “Voodoo” Mod Project two solid thumbs up. These are all cost-effective mods make a huge difference to an amp that already rocks right out of the box. If you have a jones for a low-watt Class A amp, I’d say that you should at least consider the Valve Jr. as a starting point, and then seriously consider employing these mods to your amp. You can always move up into a vintage, or higher end Class A model. The Jr., in stock or modified form, will allow you to explore the gamut of fabulous tones that this amp design is famous for - at a cost that won’t leave you gasping for air.

My next plan for my Valve Jr. is to mate it’s vastly improved tone with an Electro Harmonix Holy Grail reverb pedal. The results of that endeavor may just require me to change my nickname to “Indiana”.

[mrmudcat]

Great stuff as always voodoo.Im really digging and enjoying reading your posts and threads!!!: Ive been a lil quiet just observing watching and learning:

[Duff]

I am debating building a solid pine, stained or oiled, expanded metal grill covered with cloth from walmart, trimed in front with small strips of pine screwed on holding the cloth in place. Big, closed back, lots of room for resonation, no port. Could put in a port or design to remove a 4 inch board from the back for open back sound.

Might sound good. Only can estimate the sound and am not a sound engineer.

Also, the cost of a nice speaker, 12 inch, and materials might be as much or close to a new vj 12 inch cabinet, 16 ohms.

If I made one it would be an 8 ohm so I could use it with my HRD.

Any ideas? Would the solid wood cabinet sound better than the epi 16 ohm one?

Thanks in advance,

Duffy

[oldguy]

I am debating building a solid pine, stained or oiled, expanded metal grill covered with cloth from walmart, trimed in front with small strips of pine screwed on holding the cloth in place. Big, closed back, lots of room for resonation, no port. Could put in a port or design to remove a 4 inch board from the back for open back sound.

Might sound good. Only can estimate the sound and am not a sound engineer.

Also, the cost of a nice speaker, 12 inch, and materials might be as much or close to a new vj 12 inch cabinet, 16 ohms.

If I made one it would be an 8 ohm so I could use it with my HRD.

Any ideas? Would the solid wood cabinet sound better than the epi 16 ohm one?

Thanks in advance,

Duffy

Duffy,
Lopoline is having a sale.....

http://www.lopoline.com/home.html

[F_BSurfer]

Yes I check out DVM's page pile of good info in one place

I haven't made it as far as the bridge rectifier yet
I did something to create what i have going on now just wish I would have done one mod at time and test live and learn!!!!

[tunghaichuan***]

Yes I check out DVM's page pile of good info in one place

I haven't made it as far as the bridge rectifier yet
I did something to create what i have going on now just wish I would have done one mod at time and test live and learn!!!!

When you get ready to do the unregulated DC heater mod, PM me and I'll dig out the Mouser part numbers. When I did the Voodoo Baby VJ rebuild, I used an eyelet board from turretboards.com and had problems with heater hum. I ended up building a small board to house the DC rectifier components.

tung

[Duff]

I went out and purchased a VJ Cab at GC for 129. It sounds good. I'll have to break it in.

The Jensen P12N in my Tweed HRD at 8 ohms seems to sound louder and better, especially when pushed to distortion. It gives a nice smooth distortion with lots of growl.

The VJ cab pushed to distortion gives a more rough growling sound. Maybe it was just the guitar I was using. I'll experiment more. Plus the overall volume is not as high as with the 8 ohm I don't think. But this could be a good thing because you can get that distortion at a lower level. Maybe my guitar processor pedal will smooth out the distortion or breaking it in might help.

Any ideas?

The VJ cab doesn't sound bad by any means, don't get me wrong. Maybe I just spoiled myself playing the head through that two hundred dollar Jensen speaker in the HRD Tweed.

Duffy