From: info@turneraudio.com.au   
      
   Hey Patrick, you can do better than that!    
      
   Ah, well, probably I could, but I am a retired self taught amp-worker person   
   who may have already published enough so that if anyone needed to known what I   
   think, ( or that I think at all, or used to think, ) it could be gleamed by   
   the fact I've not    
   experimented with a whole range of amp topologies and stuck firmly to those   
   that gave me good enough measurements better than most text books indicate is   
   a good enough standard. I sold amps to ppl, and every amp I sold was different   
   to the last, but had    
   within it the same mental approach, and this for eg, did not include ISTs,   
   because of their BW limitations, and THD injections to the signal path. I did   
   allow myself to use of choke feed to driver stages, but always with a series   
   resistance between end    
   of choke and anode to isolate the ugly behavoir wound items can cause in audio   
   amps.   
      
   You actually touched on the    
   reason that circuit does what it does in your response. And I’m    
   surprised that Phil has not chimed in with his ideas.     
      
   Well, perhaps he saw no mutual benefit in responding. The purpose of   
   discussion groups sensibly conducted is that posters exercize their mind as   
   well as readers. My experience here since 2001 has surely exercised my mind at   
   least.   
      
   Here is a hint to give you a lead to the operation of the circuit. You    
   can find enough information in the RCA Tube Manual RC-14 to get you    
   going. Don’t think you will find much to help in RDH4.    
      
   RDH4 and all other books I have don't have your circuit you posted.    
      
   The IST has nothing to do with the circuit other then as a phase    
   invertor. It will run well from any common power amp front end. Even    
   your favourite. So go back & take another look!    
      
   OK, I will, but seems like triodes were like FB resistors, but I have to   
   return to make sure. I've got 101 projects to complete - very happy now   
   without audiophile customers to drive me broke and snd me insane.   
      
   Not much biking these days, altho I got out for a little more than 50 km    
   yesterday. Busy with the log splitter & otherwise getting the place    
   ready for winter. I will soon trade the bike for skis. The weather to    
   turn cold & snow this week.    
      
   Opposite here, warming up, early mornings good on bike, but have a bout of   
   back trouble rite now. Maybe a week or two off bike, its always good to quit   
   for a week or three each year when I have averaged 12,000km. I just have a   
   house to care about, hedges,   
    lawns, wysteria, and plumbing, draining, electrical et all -been 35 years   
   since I needed to hire a tradesman, because I am one.   
      
   Not much electronix this summer either. Lots of yard work on 4 ½ acres.    
   Had to chop up five large trees that came down in storms. And the    
   electrical boxes I put way out in the yard after 35 years the wood was    
   shot. I put 110/220 volts underground the full length of the property    
   when we built here. Very handy, but lots to repair as everything seems    
   to wear out. Me too!!    
      
   I'm having a good run with my work with very few repairs needed, and am   
   reaching the stage when house begins to fall down around me and I don't hafta   
   give a shit about it, I ain't tryna keep up with the Jones's and I like   
   frugality, fine music played    
   live, bicycles, socially cheerful companions, and farnarcling around with   
   primitive electronics, and the rest of the world is forgiven for their stern   
   faced determination to make a lotta mistakes.    
      
   In the meantime, here is something else to get your mind around.    
      
   Yeah, The pear seems at ease with its connections. So few of them, wheras a   
   bunch of grapes is needed to represent the carp in box of modern   
   electro-junkery.    
   Patrick Turner.    
      
   John    
      
      
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