Power amp tube type and saturation during profiling

    I have been doing some research to better understand the role that power tube type and saturation plays in our profiling process and why some profiles work better than others for me in various situations.


    I found this discussion on power tube type and properties and the inherent relationship to the potential sound and feel of the amplifier. Perhaps this is old news to many but thought it interesting to keep in mind as we pick amps and power tube types and at what levels of power stage drive we profile an amp.


    http://mesaboogie.com/amplitud…r-amps-power-section.html

    Kemper has recommended not cranking power-stage drive too much for Profiling; it's in the manual.


    There's a shortcoming that's more-apparent when Profiling some amps than others (sorry - can't remember which, mate, but someone will likely chime in if he or she knows), but as a general guideline IIRC CK himself suggested not going beyond 40% drive.

    That's a problem for a bassman or a plexi then :P


    Wasn't the problem more that the kemper isn't good at two different kinds of distortions combined? i.e. you can do preamp distortion, you can do power amp distortion, but you can't do both preamp and power amp in the red.


    I've heard some people claim the Kemper can't do crossover distortion, so the brown sound effect/cold biasing your tubes. I know that the bias control in the amp section is nothing to do with actual amp tube biasing in that regards. But I'm not sure if that's true or not, effects such as the shaper stomps seem to offer those sorts of sounds, but I don't have a pignose or 5150 to test and see whether the profiling process itself is capable of figuring out those tones in the amp block or not. Anyone else know?

    Quote from Per

    Wasn't the problem more that the kemper isn't good at two different kinds of distortions combined? i.e. you can do preamp distortion, you can do power amp distortion, but you can't do both preamp and power amp in the red.

    This is how I remember it.


    I also seem to recall that one of the amps that several people have had trouble with is the Vox AC30 (top boost?).

    Yes, that's how I remember it too, guys. I should have been more-specific by mentioning the combined pre-and-power thing.


    Michael, the AC30 was the only one that popped into my head when writing that (although I'm sure there is at least one other), so I'd say you're correct.