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Epiphone Valve Junior

Loud little bastarsds can come in small packages.

 

Epiphone Valve Junior

 

The evj if you didn't know has become something of a sensation because of it low price making it an great platform for modding. There turned out to be a lot of people like me who were always interested and in amp building or modding but were put off by some concern like the spending all the money for the components and not having it work, not having confidence when it came to both theory and practical knowledge, not having the skill or just the fear of deadly voltages. One or combination of these reason stopped me and others. Then the evj came along. $99 dollars for a head(even cheaper on ebay) it was the the perfect platform platform for modding. It saves the cost of buying cabinet, chassis, power transformers, etc that would easily cost more than the whole amp. Also because of it popularity & the fact that it is still in production a lot of people own them or can purchase them which so it comes with a large knowledge base and somewhat of a community. I personally had great success modding it and am planning on doing more with amps.

The are a lot of great source for EVJ modding:

sewatt

Is an invaluable resource not just of EVJ but other single ended amps. It includes the 300+ page thread from the 18watt site. If you need information or have questions it probably can be found there. The also have part list spread sheets, schematic, and other docs to aid your modding.

Steve's DIY Guitar Amp Pages

Some very good info and pictures.

turret boards

They sell nice kits and boards page but also show parts lists and layouts.

valvejunior.com

A improved original version.

euthymia

More good info on mods.

 


WARNING THERE IS DEADly AMOUT OF ELECTRICITY INSIDE OF A TUBE AMP. IT CAN INJURE AND KILL YOU. IF YOU DON'T KNOW WHAT YOU ARE DOING NOT NOT WORK ON THE INSIDE OF YOUR AMP. IF YOU ARE NOT COMFORTABLE WITH IT DO NOT DO IT. IF YOU ARE ON THE INFLUENCE OF DRUGS(LEGAL OR ILLEGAL), ALCOHOL OR SIMPLy ARE NOT IT THE RIGHT FRAME OF MINE TO DO SOMETHING POTETNAILY DEADLY DO NOT DO IT. AND NEVER ASSUME THAT CAPS ARE DISCHARGED. If YOU WANT TO ASSUME THAT DO NOT WORK AN AMP.

 

I modded my evj combo to give it more of a marshall sound but change the values & you can make it sound more like a Fender, Vox or your own Frankenstein. Be aware that some oprobelms with noise, over voltage, and mismatched output transformer have been fixed in the new version of the amp. You need to really check to prevent unnecessary mods.


The two simplest mods Tubes & an OT yielded the best results for me.

Tubes


The sovateks the EVJ comes with are pretty bad. One I had rattled horribly. The consensus opinion is the replacing both the EL84(6BQ5) and 12AX7(ECC83) with JJ's sound great. Both are available at the Tube Store and my favorite Tube Depot. Also tried the a Tung-Sol 12ax7 which was different but still good. Maybe a little more aggressive sounding. My favorite though was the JJ 12au7(ecc81). Which sounded great especially the clean sounds. If you didn't know you can use the replace the 12AX7 with lower gain 12AT7(ecc82) and 12AU7 tubes. These are easy mods any on can do because you don't even have to open the amp up.


Output Transformer


I have read a lot of very knowledgeable amp builders state this was the most important component of a amps sound. Now i am a believer. The new version of the EJV have a well matched OT. I had a older version with a mismatched OT. If you have the new version you may not need to replace it but old version you defiantly should.

I replaced the the puny little stock OT with a Hammond ESE. I got mind from Angela Instruments which I have done business with a few times with out a hitch. The ESE is almost as large as the stock power transformer. A DSE can be used, the Heyboer, Weber or even the outrageously expensive kit form Mercury Magnetic's the doesn't even work well. The ESE really opened up the sound & a tight low end emerged. It was a totally different & better amp after that. Pretty darn close to what i thought a single ended amp should sound like. For $35 it was a great value. And easy also. You can reuse one hole and drill another for the bigger OT that you choose. Hook up the wires according wires up according the the info on your new OT and your done. You may need to get some of those crimp on plug the attach to the board though. Most knowledge people think the ESE & DSE is the best bet for this amp because it impedance is prefect for it. I can't stress enough how much difference this made.


Speaker

I haven't changed the speaker myself. This is mainly because i read so many reports of people ending up not liking the new speaker and returning to the stock one. Though some people that dislike ceramic switch to the weber alnico with good reportedly good results.

Board mods:


I did the Marshalized Mods which you guessed it give it more of a Marshall sound. Info on that mods and the Fender and Vox mods can be found at the links above. I change out the crappy jacks and volume pot also. You can add all sorts of other mods like a master volume pot, tone controls, nfb, etc. Plus a host of component value changes the provide a host of different results. I kept it fairly simple. I think the single pot is pretty damn cool so i want to stick with that. If you have a older version it is a good idea to voltage into the sweet zone no matter what mods you choose to do. You could start with a whole new board also.

Have fun with the little guy!

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