In Reply to: Theory behind OTL posted by F. Madi on August 2, 2006 at 05:35:03:
While this is a broad generalization, there are two basic subclasses of practical OTL tube amplifier: AC coupled and DC coupled. The DC types generally fall into one of two topologies: Circlotron and Futterman (however, there are AC coupled Futterman types, and several variations of the basic Futterman circuit). There are other topologies, such as the H-bridge, but these have not been overly popular with manufacturers.The AC types tend to be basic cathode-follower or totem-pole outputs. There is also an occasional bias among certain OTL 'purists' against the AC coupled types. While the AC types do manage to do away with the output transformer, they rely on a (typically large, electrolytic) coupling capacitor at their outputs, to block DC. OTL headphone amplifiers are usually the AC type.
In addition, there is one other class of OTL that is really in a category all its own - take a look at the Berning ZH-270 to see what this type is about. It's a clever, novel design which relies on parts of the circuit operating in the low RF domain.
A simple google search on "otl tube amplifier" turns up many relevant hits. Convert it to an image search, and you'll turn up various schematics. Mix in some of the terms and proper nouns from this post, and you should have plenty of reading.
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Follow Ups
- Re: Theory behind OTL - Legendre 07:45:12 08/02/06 (1)
- Re: Theory behind OTL - F. Madi 10:50:26 08/02/06 (0)