Cary SLI-80 tweaks and improvements?

Some of this can depend how old and what generation/model your SLI-80 is. If you don’t know, check the serial and call Cary and ask. There were a few nice changes/upgrades over the years and outside vendors who created their own series with upgrades, i.e. F1, and even those can be upgraded again. For example, is it a Base model or Signature model, are any of the factory upgrades applied over the years, i.e volume control installed, signature wiring yes/no, how old are those Ruby 6550s, etc. This depends on how you want to attack it, piecemeal -or- possibly go for the whole batch of common upgrades all at once (I recommend this approach, so worth it).

Many of us here could likely go on for pages here about all of the things to look for and try, dare I say send it to Cary to test and apply upgrades, or better yet find a really good local tech to test it. For example,, look over at the caps/age installed, test the tubes/transformers, and more - inside. A really good tech can quickly assess it and speed you forward fwiw. Good techs do this quite regularly. 

I owned a fully factor upgraded Signature, then had a local tech buddy help me discover more upgrades replacing caps again, a few diodes, better Silver wiring inside, then tried a few different quads of KT88s, various vintage input/driver tubes, and 6SN7s. I think upgrading to the really good coupling capacitors and [new] main output tube changes made the most notable differences to me in one shot. Get this - Cary actually bought my SLI-80 back from me for more than retail price to study the upgrades we did. The new owner was absolutely thrilled with it. Ended up going with a SLP-98 preamp istead and separate amps. That souped up SLI-80 was sweet, should have hung on to it actually. Again, mine was already a Signature model to begin with. Seriously, I’d just seek a great tech if you want to cut to the chase and start enjoying it more, sooner. It’s worth testing/upgrading if you can. Best of luck.

In the hands of a very skilled tech, you can get a bit more out of the amp and make it more enjoyable with your current speakers. The stock model has the lower grade volume control getting in the way, limited coupling capacitors (may even be dried out), standard wiring to the binding posts, and clearly using limited tubes. I ran Gold Lyon KT88s in mine, and they were decent, not too bad. You could try PSVANE, and we did these in a buddy’s upgraded Jolida amp, they were very nice new.

btw, helped a buddy upgrade his VA speakers, the end result required woofer cone replacements and entire crossover replacements with help of Danny at GR research. In hindsight my friend should just have replaced the factory x-over parts with better parts a few levels up, and left the crossover design alone imo. We tried a simple parts upgrade because he was cheap, but it made a difference. Then the GR upgrade, which I felt was overboard. And, I’ve heard that amp with Klipsch RP600Ms, and would not waste your money IF you can simply get the same tech to replace crossover parts in your existing VAs instead. Just trying to save you money, and cut to the chase, a lot of hype out here imo.

Even if it takes a solid year to find and you have to drive/haul the gear 5hrs away to find the right tech, it can be worth it. Best of Luck.

Cary still only lists these including the Grayhill switch. A local colleague did additional upgrades on mine beyond the std stuff Cary offers. The newer upgrades were better imo than the older F1 upgrades. The newer Mundorf caps really made a difference over the older Jensens too on my buddies 98 pre. He had both versions in his preamp too. I sold mine, will see I if I can find the name of the upgrades volume potentiometer etc. Cary does not offer it iirc. 

1) yes, you are replacing them as I understand it.  Best to ask Cary what they do.  Personally I like the tube rectifiers but I'm sorta old school in my thinking perhaps.  

2) Grayhil is the updated input selector switch, as pehare noted above.  

I'm not sure where my local tech sourced the volume control and he's long retired and out of all that now. Just doing the caps, input selector, silver wiring at the back to one set of inputs and possibly speaker terminal too can help.  

As noted, there is nothing wrong with the stock form amp, has it's own warmed signature the stock way too. The new/upgrades add a bit more transparency and detail IF that's what you are looking for. Some are NOT.  A personal taste imo.    I originally had the Jensen oilers in mine and later went to the Mundorf caps. The older-older gen1 version Jensen oilers should be replaced, they had some batches fail years back. This leaned many to try the newer Mundorfs that had different results most seem to like.  Best to go for it and listen, see if you like it or not.