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. 
broadstone

Showing 4 responses by invalid

Can you use 5ar4 rectifier tubes in the cary amp, they have less voltage drop than the 5U4G
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.
oldhvymec: the 866 is a mercury half-wave rectifier tube. It must be warmed up first before any B+ voltage is applied! Otherwise it can explode! Anyway two are needed for full-wsve rectification.


I run two 866a's in my super rectifier, it has a standby switch for preheating. They do not explode, they can arc over if not preheated for about 1 minute if they have been in circuit,  and if they haven't been in circuit they need about 30 minutes warm up.
I'm running a super rectifier with Taylor 866a tubes to power my preamp, I know a preamp doesn't need this much juice, but it really made a big difference in the sound. My preamp sounded really good before the super rectifier, but now it's so much better. I want to get his bigger super rectifier that uses 872a tubes and has a diode/ tube switch.