Epiphone Valve Jr. Mods

The Epiphone Valve Jr.

The Valve Jr is a nice inexpensive entry level practice amp. But within this little amp is the potential for a nice bluesy mic'ed stage amp.

Stock the VJ is pretty gritty and edgy and incapable of anything resembling a clean tone. But with a few selective mods it can be cleaned up and the tone opened up to quite a substantial improvement in tone. The basic single-ended output design will never be as clean as a push-pull design at it's full power level, but it can be made much better.

With a different approach the amp can be turned into a metal-monster with some modifications of the gain stages, either keeping with the EL84s or switching to 6V6s.

For the price, and a few mods, the Valve Jr is hard to beat for a low power amp.

 

Examples:

— A Super-Mod'ed Valve Jr, with repainted and relabeled faceplate, in a New Mergili Cabinet

 

If you had a mod in mind that you don't find here, just email me and we can get it done.

 

Valve Jr. Gain & Character Mods

Overdrive - I $30 w/ miniature panel-mounted switch

This mod provides a gentle gain boost of about 2X. It can be tailored for a Bright boost or a FAT/Full boost. For a bit more edge and bite, this is a nice Boost mod, whether tailored for Bright or Full tone.

Overdrive - II $40 w/ miniature panel-mounted switch

With this innovative mod design the features of Overdrive-I are combined with a rebiased preamp to allow a deeper compression level than normal for this amp. The result is an amazing level of distortion and grid-overdrive character not present in the stock amp. The gain boost can be customized, as with the Overdrive-I, for a Bright or Full tone.

Clean Switch $35 w/ miniture panel-mounted switch

This is the mod for the Valve Jr. if you want a higher-headroom clean tone from this amp. Stock the VJ is a very edgy toned amp — the Clean Switch offers a switchable alternative with pure single-ended Class-A clean tones. The mod is implemented with an all-pass negative feedback around the power amp stage to soften up the edgy asymmetry of the stock single-ended output. Applicable to the stock EL84 and the converted 6V6 variations. It really makes a difference, though retains the crunch character of a Single-Ended design when cranked.

Valve Jr. Tone Mods

Single-Knob Tone-Control $35 w/ front-panel chicken-head knob

A basic but very functional treble-boost/cut style tone-control. In the boost end of the range it is similar to a Bright boosted Overdrive-I, with more gain than the stock Amp.

Heyboer Output Transformer $70  
EdCor Output Transformer $60  

This is a natural mod for the Valve Jr, whether in the EL84 or 6V6 configuration. The stock output transformer is a bit light in the low end, lacking warmth and openness, and a bit soft in the high-end lacking sparkle. Replacing this with a Heyboer transformer really adds a warmth and a bit of high-end sparkle rounding out of the tone to the amp. The Heyboer transformer has an outstanding tone, comparable to the much more expensive Mercury Magnetics transformer. The EdCor transformer is also very similar in tone, and comparable to the Hammond transformers, both a little lighter than the Heyboer, and the EdCor is a little less expensive. I like these transformers better than the Hammond for price/performance, but if you prefer Hammond, email me, I'll get you one and put it in there {$75 w/Hammond}

Valve Jr. Features Mods

Additional Speaker Jack $30

This is a fairly common request from owners of the Valve Jrs without the 4/8/16 ohm jacks — add another jack so I can connect up an additional cab. — The mod consists of an additional jack next to the existing one. A cable must be plugged into the internal jack to activate both jacks. The Valve Jr can drive down to 4 ohms stock, so an external 8 ohm cab will work fine.

Standby Switch $30 w/ miniature panel-mounted switch

A miniature toggle-switch is wired into the power-supply for classic standby mode. Labeling included (optional).

 

 

 

 

Valve Jr. Architectural Mods

6V6 Conversion $40 + 6V6 Tubes $57 w/TAD 6V6s

Converting the Valve Jr. to use 6V6s rather than EL84s really makes this a different Amp. It turns this reasonably priced little amplifier into something quite similar to the Fender Champ, with a much warmer tone and a much sweeter overdrive character. I retain the cathode bias for a classic tone. The low end is opened up and the highs are crisper and sweeter. With the 6V6 mod, I have found that the existing output transformer is just fine. The 6V6s more than make up for the shortcomings of the OPT, though with an upgraded transformer the bias can be shifted around a bit for a hotter Class-A tone and a little more low-end.