From: sbench@aol.com   
      
   Hi Patrick and all,   
      
   Depending on how much time you wish to invest in the simulators, you can get   
   pretty impressive results, including some of those items, like picking values   
   for you.   
      
   I use LTSpice quite regularly for a lot of purposes. To check various circuit   
   values, you can use a STEP PARAM "directive" which allows you to see   
   simultaneously the effect of different circuit values. You can alter several   
   parameters at once in a table    
   to check which Rs and Cs go together best. I have found great agreement   
   between the simulation and measured performance.   
      
   One of the nice features is that you can play into the simulation a .WAV file,   
   alter the frequency response accordingly, and write back out a .WAV file.   
   Thus, you can hear for yourself how the result is going to sound. By adding   
   various tubes into that    
   same simulation, you can get a reasonable feel for how different tubes are   
   going to affect (if at all) the sound. Spice simulation of different tubes is   
   NOT sufficiently good to allow you to hear the difference between two brands   
   of the same tube, but it    
   gives you a reasonable idea of the sound, though.   
      
   Whether simulation is for you is a matter of your own needs, of course, but   
   sometimes it helps to understand just what those programs can do for you.   
      
   LTSpice is a free download from Linear Tech (www.linear.com) and they do   
   support a Forum for Spice users. Yeah, the forum is free too.    
      
   Hope that helps,   
      
   Stephie   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)