Until this discussion I’d never heard the term “super rectifier” and I’ve been in this hobby off and on since 1959. My previous thinking about rectifiers has been that, because their function is not in the signal stream, their influence on sound personality/quality would be minimal and should be the last priority in pursuit of circuitry modifications to influence sound. Experimenting with biasing levels, though, has changed my mind. Although I’ve never considered myself to have the ability to discern subtle changes, adjustment of the Cary bias amperage from 75 to 90mA was significant even to me and I thought I’d found a nice compromise between the Cary and several of my favorite ss amps. When Cary reps advised against the biasing increase or the substitution with ss rectifiers it was for reasons of shortened tube life, not degradation of sound quality. Anyway, I have a couple of ss rectifiers that I bought to replace the 5U4’s (as an experiment) but I’m a little afraid to try them based on warnings expressed here. I’m willing to accept some degree of shortened tube life associated with heavier biasing but my concerns about ss rectifiers damaging other components resulting in the need for expensive and time consuming repairs are what my worries are about.
Using solid state rectifiers on Cary SLI80 Amplifier
One might wonder why experimenting with such a high performing amplifier as this SLI80 Signature is but I would like to try this to see if doing so will tighten bass and/or percussive sounds from things like drums and piano. I’ve tried raising the bias above the Cary recommended 75mA and the sonic difference was significant but, because the higher resulting voltages to the tubes would be continuous while operating, Cary recommended against it primarily because of predicted shortened tube life. I’ve taken their advice and adjusted the amperage down to 80 from the 90mA that I was trying. Now, based partly on Cary’s having switched to solid state rectification in their newer amps, I thought it made sense to try it on this older amp and need advice concerning exchanging the tube diodes with solid state replacements. What I’ve learned from several sources is that the resulting instantaneous power to the tubes and power transformer could cause damage or, at least, blown fuses. Without adding circuit protection that delays the impact, does anyone have experience with this modification or insight otherwise. I do have a variac to lessen the initial impact of this experiment if I decide to do so. Thank you.
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- 29 posts total
- 29 posts total