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In the Forum: Audio Discussions
In the Thread: “A” sound from “B” system?
Post Subject: Re: “A” sound from “B” system?Posted by deemon on: 8/4/2005
Hi all !

 morricab wrote:

Hi Romy,

Could you explain a little more about the amp?  If I understand you correctly it is a 1 tube stage with solid state (Mosfet or Bipolar??) output.  If it is Mosfet then it is likely to be running without negative feedack, is that right?  I am quite interested in this kind of amplifier because I have heard a couple that can compete very well with the better tube amps I have heard.  My own amp is a Sphinx Project 14 that is using 2 tube stages and MOSFET output with no negative feedback.  I have also an amp on loan that is using only 1 tube stage and MoSFET output with no feedback.  Both can drive just about anything and both sound quite correct tonally and dynamically.  The sphinx is also biased about 30 watts Class A and the smaller amp is about 15 watts Class A, so under normal conditions they never leave Class A.  I don't know how many other hybrid amps you are familiar with, Romy, but another one to check out that I heard good sound from was the Pathos InPower. 

Yes , it's one tube stage ( SRPP ) input with bipolar follower output . I used a very special output circuit , it works without feedback in AB class . And what is interesting - the bias is relatively small , not more than 1 W in Class A , so we have "pure" AB .....  

Best regards

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