From: jh@org.de   
      
   Am 23.02.2014 03:18, schrieb Stephie Bench:   
   > So, I thought as a curiosity,  I'd spend a couple hours in Spice land and   
   see if those interesting specs Patrick came up with could be achieved. Lets   
   review them... bass, mid, treble controls. At midpoint on all controls, +6dB   
   at 100Hz, 0 at 400Hz, and    
   +6dB at 5kHz. Max bass, 10dB at 100Hz, min not too important. Mid, + and - 9dB   
   at 400Hz, with little effect at 200Hz znd 3..2kHz. Max treble, +15dB at 5kHz,   
   min not too important. I put a couple added constraints: power=250v, 12AX7s   
   only, overall more or    
   less unity gain, insensitive to input impedance or output loading, supports 1v   
   input level, and no inductors.   
   >   
   > What I achieved uses 2 12AX7s and has the following characteristics.   
   > Input Z, > 1meg, and insensitive to input Z.   
   > Output: cathode follower and no effect on response by reasonable load.   
   > Bass: mid, +6dB at 100Hz. Max, +10.5dB at 100Hz. Min, -1dB at 100Hz.   
   > Mid: mid, 0dB at 400Hz, max, +10dB at 400Hz, min, -11dB at 400Hz. Effect of   
   the mid pot is less than a dB at 200Hz and 3200Hz.   
   > Treb: mid, +6dB at 5kHz. Max, +15dB at 5kHz. Min, +3dB at 5kHz.   
   >   
   > The bass and mid are implemented as tuned circuits, using a section of a   
   12AX7 each as gyrators. I was actually intrrested in seeing whether that would   
   work reasonably well; and it does.   
   >   
   > Incidentally, setting things up for flat rather than boosted response   
   provides symetrical boost/cut for all 3 controls.   
   >   
   > The pots for control are all 50k pots, and I alloeed for 1k residual   
   resistance at the pot extremes.   
   >   
   > Anyone wanting the Spice file can email me.   
   >   
   > -Stephie   
   >   
      
   Hi Stephie,   
      
   ...as Patrick is searching for something "guitar related" - is there any   
   possiblitiy that a real guitar player can taste the reaction and the   
   sound of an amp incorporationg the gadget?   
      
   regards   
      
   Jochen   
      
   --- SoupGate-Win32 v1.05   
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