From: Stefano D'Angelo <[email protected]> Date: 2011/2/27 Subject: Re: [LAD] RDF libraries, was Re: [ANN] IR: LV2 Convolution Reverb To: Giuseppe Zompatori <[email protected]> Cc: [email protected]
2011/2/27 Stefano D'Angelo <[email protected]>: > > > Ciao Giuseppe, > Ciao Stefano, Taking this email to a new thread. >Well... they seem to have a lot of stuff there. :-) > >However, I wonder how they do it... I think they are probably using >some black box modeling, since multiple nonlinearities+feedback in a >single system is very hard to model. > They are very silent on this sadly, don't know what they are doing. > >The kind of stuff I'm trying to do is accurately model a class A amp >with a single triode using white box techniques... to give you an idea >of what it sounds like see this: >http://www.youtube.com/watch?v=cdNtmaIdLdo - it is part of my MSc >thesis presentation (100.000 lire guitar, dated and slow laptop, cheap >speaker and cheap camera... only the sound card is good). > >I guess you speak Italian (at least your name suggests that), so enjoy >my weird southern accent. :-P > Very interesting, I tried compiling your thesis with permafrost to try this out (obtaining the source from the pdf has been hell BTW) but it bails with an "m_pi" undeclared input/output function... Anyway, are you limited to the simulation of a half triode with white box techniques? I think you should model at least both halves of a triode if you're after accuracy, a single triode amplifier won't even work in real life (I build tube amps, I know) ;) Also class A amplifiers aren't very popular amongst guitar players (mainly because of their clipping behavior). You also want a multi-stage preamp with different filtering/biasing points between stages. You might think I am crazy but that's what you'll discover yourself by observing schematics to popular guitar amps. Here's a simple (early Fender-like) amp topology: Tube n. 1 ------------------------------------------------------- Tube n. 2 Tube n. 3 and 4 | | | | 1st triode -> Tone stack -> post tone stack recovery triode -> P.I. (Phase inverter) triodes -> (at least 2) Pentodes -> O.T. (Output Transformer) -> Speakers ^ ^ | | Presence pot<--------------------------------negative-feedback--------------------------------------------- This is the easiest PP (Push Pull) class A/B amp I could come up with (sounds pretty darn good in real life). It has got a tone stack, 4 tubes (2 triodes and two pentodes) and an OT/speakers, do you think this is feasible computational-wise with permafrost? >Well, they say guitarix has improved, yet the last time I was all but >satisfied with it. You may want to take a look at invada plugins, if >you haven't already. Invada has a simple generic tube drive function AFAIK, I still prefer the CAPS* amp over it as it's at least based on a real amp. >Stammi bene, > >Stefano Anche tu! -Giuseppe _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
