e80f9d68   
   From: pds@ktb.net   
      
   Patrick Turner  wrote:   
   > But I still prefrer the CT choke because you can get a driver LTP to   
   > have a higher RL than you'd get with the McIntosh syle of   
   > bootstrapping and there is NO PFB. The choke involved need not be a   
   > huge heavy or expensive thing. In my 8585 I used a 10mm stack of 32mm   
   > tongue GOSS with 8,000 turns of 0.15mm dia wire and that gave very   
   > high L and high Z across the audio band.   
      
   I needed huge driver voltage swing for PP CF project and chose a CT   
   choke for the driver.  Bootstrapping seems like an inelegant solution.   
   If NFB broadens bandwidth and decreases distortion then PFB...   
      
   I used a Lundahl 1667/5ma as the load for a 6BL7 dual triode with a CCS   
   tail.  B+ is 450v and the CCS is set for 15ma per triode.  At 1Khz I   
   measure ~440Vrms before clipping.   
      
   At the time, the Lundahl CT chokes were $85 USD from K&K Audio.  Now I   
   think they are near $200 USD which makes this a more difficult choice.   
      
   I've wondered about using a much less expensive standard PP Hi-Z primary   
   transformer with a resistor terminated secondary.  Has anyone ever tried   
   this?  Should it work?   
      
   - Paul   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)