hybrid power amp and more questions

[hpupo]

Hello

I have a few questions for the experienced engineers out there:

- has any one ever heard of such a hybrid power amp with solid state phase splitter and tube class AB power amp for guitar (i cant stress this enough)?

- on a classic guitar power amp, how much usually the PI distorts? I mean by design...

- does anyone know of any literature about guitar amp distortion, but from a point of view of the listeners? I understand all the math involved in analyzing the distortion characteristically of this and that amp, but how does that affect the sound for someone listening to it?

Thanks a lot

 

[leadbelly]

First off, this is a guitar amp question, so it belongs in the MI forum.

I'm not 100% sure what you're driving at, but I think I know the gist of your question: how you design a guitar amp from scratch to have a desired distortion characteristic, and how does the PI fit in, classic amps etc. I'll throw out some suggestions.

There was an excellent article on guitar amp design evolution over the 50's and 60's sixties in Guitar Player a couple of years ago. Quite a good read on the subject, best I've come across yet. It will answer your PI distorion in classic amps question. Maybe find it at your library?

As for your solid state PI question, no I don't know of a specific model that has an SS PI and tube outputs, but I'll bet there is one. As for being able to achieve a tube PI overdrive sound with SS, there are a number of FET based circuits that claim to do that. They claim that using overdriving a FET cascode gives a similar sound to overdriving a tube LTP (more even order distortion IIRC).

 

[hpupo]

Thanks....please someone move this to the appropriate forum...
You almost got the question. I know my question may sound strange, but i will try to refine it. Lets say i want to use, for example, a digital simulator for the preamp distortion but still have all the dynamics and sound of a tube power amp. Also, lets assume, for a though experiment, that i can get any type of preamp tone i want from the digital simulator. Basically i want to know what kind of role the PI distortion plays in the overall DYNAMICS of power amp distortions. Can i consider PI distortion as just one more part of preamp distortion?

Thanks

 

[leadbelly]

Well, your question is still phrased in an odd way, but I'll again answer what I think you are driving at.

In classic tube amp overdrive tones, you can be hearing any single or combination of overdriven input tubes, PI, or output tubes.

If by simulating preamp overdrive you mean you are simulating the distortion of an overdriven common-cathode 12AX7, and then want to know if that plus a tube output stage will essentially perfectly mimic a classic tube amp, the answer is no. You need to address the sound of an overdriven PI, either in the simulator or with a real tube PI.