Using solid state rectifiers on Cary SLI80 Amplifier

Atmosphere, over the years I’ve learned much from your posts and I appreciate this response which I think I mostly understand. Anyway, because I’ve already bought them I’m going to try the ss rectifiers simply out of curiosity. I have one question, though; for those ss diodes that are designed to mimic tubes, if part of that feature is to more slowly ramp up the application of power, will that not also affect these diodes’ reaction speed overall and negate the reason for their substitution in the first place? Im probably overthinking this and a bit over my head technically but this all started when I went back to using the relatively low sensitivity Martin Logan CLS2 speakers and was looking for a bit more dynamics still keeping the Cary in the system. 

Atmasphere not atmosphere. Damned spelling correction feature. 

As usual Atmasphere is spot on. I like the bass with SS rectification much more than tube in general. Check the voltage spec of your power supply caps and be sure they can handle the higher voltage per Ralph’s comments. New transformers spec’d to deliver the needed B+ voltage is certainly reasonable. Yes,  very costly. 

if part of that feature is to more slowly ramp up the application of power, will that not also affect these diodes’ reaction speed overall and negate the reason for their substitution in the first place?

Yes, to a certain degree. You don't have to worry about the tube rectifier going bad... For my part, I'd put the amp on the bench and see how bad things are when a set of HEXFREDs are installed. Measure the power supply voltages at idle, compare to the ratings of the caps (usually if you exceed 85% you're risking over-voltage under certain conditions).


One thing that can be problematic is the power supply is charged up long before the tubes are so there is no load. The no-load voltage is much higher! Some manufacturers (and I've no idea about Cary in this regard, I'm not calling them out), because a tube rectifier is used, will have lower voltage caps in the power supply as a result. But with a solid state rectifier, the caps will be in a no-load situation and so will be much higher than when the power tubes are warmed up.

If that no-load voltage is too high you can destroy the filter caps- and it won't just be the input caps to the power supply that are that high- **all** of the filter caps will be at this voltage until the tubes warm up. So you really want to be careful! It can be really upsetting when a filter cap blows its guts out.


If any of this sounds intimidating, good- if that's the case, you really might want to resist that urge to see what can be done. OTOH, if you feel like *perhaps* also replacing the filter caps maybe it won't be any problem. But at some point you might want to consider building the amp up from scratch.

Ok, before considering any circuitry mods to accommodate rectification considerations, I wanted to know whether exchanging the tubes for ss would be worth pursuing in the first place. I plugged in the YJR Yellow Jackets, reset the bias to Cary’s 75mA recommendation and started listening.
The sound across all frequencies seemed tighter and with increased dynamics but the biggest improvement seems to be in timbre, especially listening to solo guitar music. Overall, the sound across the board just sounded more crisp (less tubelike?) similar to my favorite ss amp, the Ayre V3 which is very musical like the Cary but with a seemingly tighter overall presentation. So now I have some idea about the sound but I still have important decisions to make primarily regarding which setup I prefer listening to and whether I want to invest what’d be necessary to assure amplifier reliability.