Epi Valve Jr mods

[TheArchitect]

I am in the middle of modifying an Epiphone Valve Jr. I picked up most of the changes from 18watt.com and a thread @ BAM.

I have changed a number of resistor/cap values and I am adding a gain pot, a gain boost toggle and a toggle to change the resistor values on the input. The changes are reported to not only add some gain but also tweak the eq a bit.

Hopefully nothing goes poof when I finally finish and put some juice to it but if I have to take something out while I am learning, I would rather do it on an amp that is less than $100 than one of my Marshalls

 

[JumpMarine]

Re: Epi Valve Jr mods

Good luck, post some clips when you are done.

 

[Lu_B]

Re: Epi Valve Jr mods

I haven't moded my Valve Special on the electronics front but have changed the speaker to a Celestion Tube 10 and its made a good difference to the clarity. Tubes are next but can't decide on what!

 

[fingerace]

Re: Epi Valve Jr mods

I am in the middle of modifying an Epiphone Valve Jr. I picked up most of the changes from 18watt.com and a thread @ BAM.

I have changed a number of resistor/cap values and I am adding a gain pot, a gain boost toggle and a toggle to change the resistor values on the input. The changes are reported to not only add some gain but also tweak the eq a bit.

Hopefully nothing goes poof when I finally finish and put some juice to it but if I have to take something out while I am learning, I would rather do it on an amp that is less than $100 than one of my Marshalls

good luck with it! I think InstituteOfNoise has modded his epi valve jr also...

btw you are the one who had me gassing for that yamaha SA2200. I still remember your thread. "every other guitar seems flat compared to this" :laugh2:

 

[TheArchitect]

Re: Epi Valve Jr mods

good luck with it! I think InstituteOfNoise has modded his epi valve jr also...

btw you are the one who had me gassing for that yamaha SA2200. I still remember your thread. "every other guitar seems flat compared to this" :laugh2:

Entirely possible. Sounds like a comment I would have made.

 

[Oldslowhand]

Re: Epi Valve Jr mods

This subject was the longest thread ever on the Fret.net and is well worth a (long) read, covers just about anything you can do to this amp!

http://www.thefret.net/showthread.php?t=74

starts with a general discussion then moves on.........and on............and on..................

 

[TheArchitect]

Re: Epi Valve Jr mods

Mods done, No smoke and I have sound. Thats good right?

Mods done:
R1 - 1meg
R2 - 10k and toggle to bypass
R6 - 100k and toggle to bypass
R7 - 250k pot
R8 - 1k
R9 - 680 Ohm
C3 - Pulled
C4 - 3.3 ohm
R15 - 10k
1k 1w resistor added to pin 9 trace

Very impressed overall. I was able to get some very nice crunchy rhythm sounds. Lead sounds and max gain rhythm sounds had the wax paper/comb kind of grittiness I really don't like. I think this is probably just the nature of el84's pushed hard. The Marshall 18's I have tried exhibited this as well as the Budda amps I have tried. The speakers I tested with were Vintage greenbacks in a 70's Marshall cab and brand new Emi Texas Heats in a repro bassman 2x12 cab.

I might like to hear just a touch more low end and remove the was paper/comb sound when pushed. possibly a slight reduction in highs as well but that is really dependant on the gain level.

Also, If I were to do another I would want the max head room clean flavor just for the variety.

 

[the guy who invented fire]

Re: Epi Valve Jr mods

for those of you that are modding and rodding the Valve Jr...David Allen is selling a killer transformer that is built by Heybore thats a direct replacment for a valve Jr it's more than likely a a killer transformer! Heybore iron is some of the best out there IMO!

 

[TheArchitect]

Re: Epi Valve Jr mods

This baby is a smokin' little amp now. A lot louder than I would expect a 5w amp to be. I decided to run it through my THD hotplate which really worked because the attenuation tends to roll off a little bit in the high and low end which was perfect. Very comfortable volume and even better tone.

I will probably find another use for the toggle on R2 and may replace the transformer but over all for $99 and $30 bucks in parts from radio shack this thing is the buy of the century

 

[Bezmotivnik]

Re: Epi Valve Jr mods

Um...what was the question again?

I got one of these combos last week. $107 from MF. Now that they've fixed the AC filament noise problem, I'm fine with it the way it is...though I think that the lightbulb attenuator thing might be worthwhile and some of the other cap & resistor changes in the front end could help. If I come across the components in my junk I may swap them out, but it's perfectly adequate for my needs out of the box -- though it came with a hissy preamp tube I replaced.

I stuck it into a nightstand next to my bed. I have amps all over the house and in my studio, but I actually USE this one.

 

[Bezmotivnik]

Re: Epi Valve Jr mods

Tubes are next but can't decide on what!

I went through a bunch of different preamp tubes without any earthshaking changes. I settled on a quiet GT/Shangung shortplate and let it go. I just got bored swapping tubes, to be honest. I was going to use a 12AX7LPS, but those longplates go microphonic in combos most of the time, often very quickly.

You don't have a lot of options with the EL84 and it probably makes less difference in the overall sound in this amp than the preamp tube, especially if you're not driving the thing into power-stage distortion...which I'm not, as these 5W get pretty darn LOUD!!! thereby defeating the amp's purpose for me. I have a houseful of loud amps -- I want a quiet one I can use. The relatively thick low end on this amp works perfectly for the fairly clean, jazzy sound I like.