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previous: Peter Snow Re: Modeling Amps -- Which do you like? -- 10/28/2003 2:22 AM View Thread

12AX7 -> modelling preamp -> all tube power amp?

10/28/2003 2:50 AM
Steve A.
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12AX7 -> modelling preamp -> all tube power amp?
Peter:  
 
I can't see how how a 12AX7 on its own can duplicate the sound of output tubes.  
 
    I think that the 12AX7 is used as "spice" in the preamp section, to introduce some non-linearity and compression to the sound.  
 
    The live applications for modelling amps that seem to work okay usually involve running the amp through the PA system, rather than using the power amp section of the amp to fill the room.  
 
    I guess cost must be the reason that none of the companies have tried coupling a modelling preamp with an all-tube power amp section. I'd include an all-tube preamp with such an amp so that you could switch out of the modelling mode when you wanted to. And maybe include patches with a 12AX7 tube at the front of the preamp and the modelling options after the tube.  
 
    They could program in different operating parameters for the power amp section, like varying the bias voltage for different patches, or switching it from fixed to cathode bias. Maybe select between different B+ voltages and patch in different chokes (or choke resistors) to add some sag to the power supply. Add all of this up and you are looking at a $3,000 amp, at least until the fixed costs of R&D are paid off...  
 
    If you are playing an all-tube amp with non-tube FX plugged into the FX loop that isn't going to be completely different from what I am suggesting...  
 
--Thanks!  
 
Steve Ahola

 
Replies:
Dutch [QUOTE]I c... -- 10/28/2003 7:50 PM