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. 
128x128broadstone
Your willing to give stuff a shot, try a super rectifier


Oldhvymec I was going to suggest that but people on here will think I'm just a fanboy, but it would make a substantial difference in the bass if he ran a super rectifier with 3b22 or 866a tubes in it.

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I'm a fan that's the reason I suggested it... What other people think and 5.00 dollars will get you a cup of coffee, right.. :-)

Me, I just like the weird $hit..:-).

Regards
When he was still there, I discussed this topic a length with the former designer who made the initial design changes with the SLI-80 introducing ss rectification. I owned a SLI-80 Sig with many mods and before the rectification change was made official on that amp. I did like the presentation and bloom, and decided not to make the rectifier mod from tube to ss on mine. I instead sold that amp along with another high power Cary and moved to tube monos with ss rectification. While my new amps are a little faster with more bass control, sometimes I do miss the characteristics of tube rectification, often times finding myself looking to pick up another amp with it to swap in/out every once in a while. Grass may seem greener. A different sound, I like both for different reasons, fwiw.
A SS rectifier will have less voltage drop and will cause a rise in the B+ voltage. The bias voltage will also be affected if it is not already regulated. Plus the fllter caps will be hit with a turn on voltage surge if there is not already a slow turn on relay in place. 
A good idea to increase filter cap life if they are not protected by a B+ delay relay is to replace the 5U4 with a vintage original 5AR4/GZ34. These have a slow warm up time and don't slam the filter caps like the 5U4 and other rectifiers. Plus the slow warm up lets the heaters  reach optimum temperature before B+ voltage. This is beneficial for power transformer life.
I'd forget about using SS rectification and just change to an original 5AR4/GZ34 - not new production!