In Reply to: Re: Is there a good set of plans for a good tube OTL amp posted by Thorsten on January 22, 2005 at 11:33:19:
I yield to your superior knowledge in this field, Thorsten, but you should know that the Atma-sphere amps operate well (in my system, optimally) with no NFB whatsoever. One can apply a few db of NFB if one likes, to reduce the output impedance when and where necessary. Moreover, there are fundamental differences between designs based on the circlotron (Atma-sphere et al) and those based on the original Futterman circuit, in terms of stability, use of triodes in a balanced output stage, etc. Also, I hesitantly would say that the use of an autoformer at the speaker-end of cables, to boost the impedance seen by OTL amps on the order of 2X does not present the problems inherent to the design of a transformer-coupled output stage. In other words, the autoformer/OTL strategy is potentially less "harmful" to the signal than the OTC strategy.
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Follow Ups
- A comment - Lew 07:06:36 01/24/05 (1)
- Re: A comment - Thorsten 11:44:43 01/24/05 (0)