Rectifier Valve's kind of overall compression...

[alex frias]

When I use some vintage amps with rectifier tubes in their power supplies I experience a mild compression when pushing the amp up to the maximun. I'm not talking about the general tube distortion and compression all we know and love, but it happens in a different way in tube amps with solid state diode rectifiers on them.

Any thoughts about how to simulate this kind of thing using solid state components in a FET or CMOSFET distortion/amp simulator?

[drewl]

What you're hearing is called "sag" in which as the amp is driven to full power the power supply can't keep up and starts to drop or 'sag" giving you that nice soft compression you're hearing.
Now companies like Weber that make a solid state rectifier replacement (copper cap) achieve the same effect with a couple diodes and resistors, you can even request any amount of sag you desire.

You could make it more complicated, but you don't need to.

[alex frias]

Thanks for the reply, I implement a kind of "sag" in some fuzz pedals but it affects them in a very static way as I just use a simple resistence to decrease the current supplied.
Maybe it can go further on without a very complicated project. Who knows the nice trick?

[petemoore]

  Guessepi...
  He tells me of algorythms [and wiring] involved with his mind experiments, however a working prototype is cost prohibitive, he hopes maybe someday there will be a mass production effort based on the promising M-E results which will bring the expense to a reasonable level.
  He also said he likes to stay away from digital processing but today that's where some of the more popular 'mass produced prototypes' for 'sag sound' exist.
  He said: look at 'the Punisher', courtesy of the Tone God.

[Jered]

  I was lucky enough to watch a demonstration of the Weber product drewl just mentioned, and they work, surprisingly well. Didn't have to push the amp into deafening levels either. Great tool to have when recording, if your trying to get that "sag" effect.