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previous: Mike B Dave,The measured p... -- 8/12/1999 1:09 PM View Thread

Re: Another spitfire question: OT

8/12/1999 11:02 PM
SpeedRacerRe: Another spitfire question: OT
To elaborate more on Mike's excellent post, the distortion and power do vary with load imp, and more to the point (of tone) the MIX of harmonics changes.. typically you have a greater % of 2nd at lower loads, which drops as you increase the load and while that occurs, the odd order HD tends to increase. Your max power point is (generally) a point where the 2nd HD is trailing and the 3rd (and higher) hasn't really climbed yet. There's a great chart in one of the RCA books with the 6L6's reponse at given loads. Your harmonic mix can have a profound effect on the tone of the transformer and how it reacts to the rest of your amp circuit. I say "can" rather than "does" BC I've found in my own research that load changes of as little as 10% can be very audible when incorporated into the wind of a tranny, but I've also mis-loaded the 2ndary (say on a Fender) by a factor of 100% and not noticed as big a change.. It's very peculiar.  
Reliability-wise, low loads will tend to increase plate current and can lead to reliability issues (as noted).