In Reply to: RE: SET Class A posted by danlaudionut on January 4, 2015 at 21:55:48:
I realised after I posted that the word subjective is totally wrong in this instance, possibly relative was the word I'm looking for.
I mean Class A is Class A and sticking with A1 for the moment, it's just good practice and very normal to bias a tube somewhere near the "mid-point" ... but mid-point of what? Sure the A2 limit is well defined on the pos side but the so called non-linear region isn't. One man's non-linear region might be quite acceptable to someone else and it therefore follows that "Deep Class A" is a relative term.
"Deep Class A" also infers (to me at least) that it is the most linear region. However, if you bias at the mid-point as you described this is not the most linear bias point if lower distortion rather than maximum power is your goal. In fact, taking things to the extreme, a typical triode generally becomes more linear with higher current, as the bias is moved closer to 0V - well away from the mid-point. Sure you reduce positive swing room but lower distortion results from the tubes's lower internal resistance.
I personally think that the term Deep Class A is as useless as describing a SET working in Class A and that's my point ... not that it's a big deal.
Naz
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Follow Ups
- RE: SET Class A - Naz 01:02:59 01/05/15 (0)