Yellow Jacket Solid State Tube Rectifier

If you have a vintage-style amp with a tube rectifier, you probably already know how it influences your tone, so I apologize if the first part of this review is informational. "Tube sag" is basically the result of voltage getting converted from AC to DC (before it hits the power tubes). Tube rectifiers could be thought of then as the fuel injector in your car. When you step on the gas pedal, the injector can only inject so much. The same thing applies for tube rectifiers -- they can only "inject" (covert) so much voltage -- so when voltage demands are high, such as when you are playing massive chords or bass notes, the "sag sound" is amp "accelerating" (continuing the car analogy). In other words, your low-end will sound loose and flubby, which adds a lot of warmth to your tone. Solid State Rectifiers are not restricted to the limitations of vacuum tubes, and so as "fuel injectors", the voltage conversion is (relatively) instantaneous. The Effects.... in my AC30, there was dramatic difference in how tight the amp sounds now. The amp now has the thump of a Marshall and my pick attack is more transparent. Other than being a pain to install (AC30's are NOT service friendly), the Yellow Jacket SS rectifier fit easily and snuggly into the tube slot and that was that. However, the second reason why I got a SS rectifier in the first place is because AC30's run hot, and the CC2 series in particular slams the GZ34/5AR4 with a little too much voltage when flipping the standby switch. So, in addition the tonal improvements, my amp is now set up for better electrical efficiency (which means less internal wear and tear).

Worked great in my friedman dirty Shirley

NOTE: Don't just drop this in an go... You'll definitely need to re-bias your amp. Without re-bias, this will almost certainly push your tubes way hotter than spec. Tone is subjective, so I hesitate to rate this based on my perception of the tone. Plus, this is simply a device to regulate electrical flow to the tubes in an amp. Assuming if does it's job perfectly, the tone may (in some amps) get worse because the amp circuit was not designed for diode rectification. My experience, however, was this: There is a noticeable difference in the tone of the amp. I am trying it in a clone of a 1966 Marshall JTM45. It is definitely brighter and harder sounding, which is usually the intent when one switches to diode rectification. For my taste, I am not sure if I like it or not. There are a lot of things sounding better... Better string articulation. Perhaps also better touch sensitivity. Classic rock chords seem crisper and have a bit more growl. However, on the down side, there is a lot more ice-pick in the ear brightness that I haven't figured out how to dial out yet. It is possible that with some tweaks to the treble, and maybe beam-blockers on the speakers, that this will be a great improvement. I think it will be a few weeks before I know.

I needed a rectifier for my SF Champ. I tried this SS item and now my practice amp is back in business. I might buy a tube rectifier in the future but meanwhile I'm up and running.

I bought to make my hand built black face Fender Princeton sound a little more punchy. It made it sound like a solid state amp. I'll stick with the tube rectifier.

Does a great job. Does increase the overall DC supply voltage a bit, but that is generally a positive! It will eliminate rectifier tube 'sag' and will make your tone a bit crisper overall.

Tighten up your sound with this rectifier replacement

This solid state rectifier is my preferred replacement for any vacuum tube rectifier. None of the other reviews I have read mentions a CRITICAL piece of advice that is printed on the back of the very small owner's advice packed in with the Yellow Jacket - If simply plugged in in place of a vacuum tube rectifier, the high voltage DC in your amp will come on instantly. however your power tubes are not ready for that. Full DC voltage on power tubes with cold cathodes will damage them. Solution? Install a "standby" switch to allow a warmup time, maybe 30 to 60 seconds, so that the other tubes' cathodes will be already hot when the DC voltage from the Yellow Jacket comes on. The details of that will be easy for any good old-time electronics geek: if you are not one, find a friend who is. On my amp, I installed a two-pole switch on both sides of the 670 volt AC transformer winding that feeds the two anodes of the rectifier tube.