Epiphone Valve Junior Project

owwdatune · Posted: Fri Apr 27, 2007 6:15 am Post subject:

.....way to go stan.....now all you need to put the finishing touches on that baby is either a low bias JJ Eurotubes EL84 & a Tung-sol 12AX7 ----OR--- a JJ Eurotubes mid bias EL84 & a JJ 12AX7 ...(get the set from www.thetubestore.com ...read the tube reviews while you're there) ...the 1st set will offer up a bit more of a nifty creamy type overdrive texture than the 2nd set...you'll also want to upgrade the output transformer to a Hammond 125cse ( i got mine at www.STF-electronics.com for $35..00 plus shipping).....the stock OT is of the improper specs for a SE class A EL84/12ax7 type amp-----i promise you these changes -along with your new mods- will give you an amp that will be a keeper that you'll love to play, especially if you're running into a quality speaker Exclamation

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owwdatune · Posted: Fri Apr 27, 2007 6:22 am Post subject:

NICE REVIEW BTW....i just love reading about this stuff #Scramble

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SAguitar · Posted: Fri Apr 27, 2007 6:42 am Post subject:

Thanks, ~T~!!! The next step was going to be the OT, but I didn't have the foggiest which one to get or where to find it, so I was going to ask you that very question! Thanks for the tips, and I will be procuring the transformer and the tubes pronto-like.

Hmmm... here's another newb question, what about that smaller transformer on there, is that a choke? Hint: I don't even know what a choke is. Anyway, is it OK, or should it be swapped out also?

And yes, this amp-modding is fun, I'm liking it! My biggest problem so far was in dropping an errant tiny piece of solder on the board which crossed two paths there that shouldn't cross! I did that in removing a capacitor that the BitMo kit said to just snip off. Naaahh... I had to do it the "right" way, y'know, heat up the leads and pull it out of the circuit board. But in doing that I left a very, very small bit of the shiny stuff on the board in a bad place...

It sure sounded like hell when I tried it out, whatever I did, the amp was producing sounds so high that I could barely hear them, and my dogs left the garage post haste! It took me a good three hours to find that little piece of solder, too. One by one, I removed each of the mods, until I had Junior back to stock. On the last step of that process, I was looking at that one point with a magnifying glass and found that tiny drop of solder, and figured that was the problem, but I finished taking it back to stock just to prove to myself that I hadn't fried some resistor or something else. Well, I turned it back on, and it sounded like it originally did, so I started all over. But that time I made it through with everything working as it should! Whew! Rolling Eyes

Thanks for the encouragement, I'm off to do some online shopping!

Stay tuned,
Stan
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"I love the smell of hot solder in the morning. It smells like victory."

owwdatune · Posted: Sun Apr 29, 2007 5:53 am Post subject:

Not sure what happened to your original post that started this thread SA....here is the jist of it tho---i copied/pasted it so peeps would know what we're talking about >>>

SA wrote>>>
i'm such a beginner with amps... I finally got my Epiphone Valve Junior on the bench this weekend, and did a few BitMo mods to it. Of course, I messed up somewhere in the middle of the project, and probably put 12 hours into what could have been a 3-4 hour project. I finally figured it out, though! And the little booger sounds great now!

Step One: I put in a tone control with a big gain boost option on it. The tone control works like an early Fender amp, and yields a nice, wide range, very satisfactory. It works well with both my Tele and my Les Paul, which is usually a good test.

Step Two: I wired in a three-stage gain change switch. This was interesting (at least for me, the rookie), and tapped into two different places in the board. Eventually, I got it right, and these option take it the 5 watts from a nice, clean tone (with a little overdrive), to a moderate overdrive, and then to a full roar! This can be used in combination with the boost on the push-pull tone control to effectively produce 6 different gain stages from two simple controls.

Step Three: I put in a Standby Switch. No tube amp should be without one.

That's all I've done to Junior so far, but I can say that I am very happy with the improvements. I was impressed, but not really knocked out by its tone in stock form, but these upgrades make it a flexible, formidable little amp. It is able to achieve a wide range of tones, is very responsive, and a lot of fun to play.
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owwdatune · Posted: Sun Apr 29, 2007 6:05 am Post subject:

owwdatune · Posted: Sun Apr 29, 2007 6:27 am Post subject:

owwdatune · Posted: Sun Apr 29, 2007 7:13 am Post subject:

hey there stan.....i remembered seeing somewhere that you mentioned the new BitMo attenuator..... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=140103783405&fromMakeTrack=true&ssPageName=VIP:watchlink:middle:us ....it looks really cool & should fill the bill.....however for myself, i went with a tubeJuice attenuator http://www.tubejuiceattenuators.com/ so i could use it with all my cab/speaker combinations--i've got a couple that are 16 ohm that i love....if memory serves me, i think that Epi Vjr. cab houses a 16 ohm speaker. #Flash

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SAguitar · Posted: Sun Apr 29, 2007 4:45 pm Post subject:

Hey ~T~! Thanks for bringing my post back! I don't know where it went either!

Anyway, I did order Bitmo's 10-uator, and already received it. Unfortunately, all his stuff is in kit form, and Bruce forgot to include assembly instructions with it! I'm like lost without those, so I emailed him, and asked him to send me a PDF of the stuff so I can put it together.

Those TubeJuice units look great, too, maybe I'll have to get one of those for some of my other little units!

I have seen those Epi Valve Junior cabs in a catalog, and they do have a 16 ohm Lady Eminence speaker in them. What the heck is that? I've never heard of a Lady Eminence before. They're only about $128 for a loaded cab, so if the speaker's any good, that's not a bad price at all. And they look as cute as the little Junior Head!

Right now, I'm playing Jr. through an old Kustom cab that I put two 10" Carvin speakers in, and it sounds pretty good running at 8 ohms. What might be the diff playing it through one 12" at 16 ohms?

And yes, I'm startin' to get the urge to build me an amp from a kit... when it gets to be unavoidable, I'll have a lot more questions for you! Cool

Thanks, bro,
Stan
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"I love the smell of hot solder in the morning. It smells like victory."

tw001_tw · Posted: Sun Apr 29, 2007 5:12 pm Post subject:

SAguitar · Posted: Sun Apr 29, 2007 5:15 pm Post subject:

Yup! Just what I needed, one more addiction! Laughing

_________________
"I love the smell of hot solder in the morning. It smells like victory."

SAguitar · Posted: Thu May 03, 2007 4:44 pm Post subject:

Hey Terry!

I just got the cutest little transformer today! Whooo-eeee!

OK, now, it's got like 7 wires coming out of it! How do you hook all those up? do they just have the same colors as the one they're replacing, or do I need to go to night school to figure this thing out?

Help! Please!
_________________
"I love the smell of hot solder in the morning. It smells like victory."

SAguitar · Posted: Wed May 16, 2007 11:30 am Post subject:

Update on the Valve Junior Project!

Step Four: A Hammond 125cse output transformer was installed into Junior, and he went up a level. The clarity and power seemed to take a noticeable jump into the stratosphere. After the other three steps, this one seemed to bring it all together and really focus the tone into a solid beast. Junior just keeps getting better!

Step Five: I put in two new tubes (that's all of them!). Junior got a Tung-Sol 12AX7 and a JJ Eurotubes EL84 stuffed into his main board, and he's very grateful. The tone has become even more focused, with a new brightness on the high end that makes Teles sing, and Jr.'s loose bottom end got tightened up and more defined. Nice improvement!

Step Six: I got BiMo's 10-uator, assembled it, and attached it to the back panel of the Epi. This little attenuator works great, and now I can let Junior roar with all his 5 watt might, and still roll back the volume to a very nice level for practicing at home without bothering my wife in the next room. Very impressive! In addition to being an attenuator, this unit has a variable level, speaker-voiced line output so I can plug directly into a mixer for recording or live performance. Or I can use Junior now as a preamp, and run him into a bigger guitar amp. When going straight into a mixer, or recorder, and without a speaker plugged into Junior, the power resistor will engage act as a dummy load, protecting my little friend.

I think I'm about done with this project, at least for now! I am totally stoked about this little amp, and I've learned a bit about amps by going through this. The Epiphone Valve Junior is a great place to start, and after some mods, can become an incredible little amp. Cool

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"I love the smell of hot solder in the morning. It smells like victory."

tw001_tw · Posted: Wed May 16, 2007 3:29 pm Post subject:

GOOD JOB!!!!!

you planning on posting some gut shots of your handy work?

SAguitar · Posted: Wed May 16, 2007 7:00 pm Post subject:

I just came in from the garage after 3 hours with Junior, and... I'm a Happy Camper! Very Happy

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"I love the smell of hot solder in the morning. It smells like victory."

owwdatune · Posted: Sat Nov 10, 2007 11:00 am Post subject:

thats what its all about my friend Cool

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