Tube sound: Tung Sol KT 120 vs KT 88

@moose89 you might look over some older Agon threads on this, a few bits of info here and there about 8-10 years back. fwiw, I owned a new/upgraded SLI-80 Signature myself. Kind of had to go overboard with mine to get it to sound how I wanted it. The stock EH KT88s were okay, not great. Some on Audiocircle will call them "bad" sounding. New Genelex Gold Lyon KT88s were better when paired with proper 6SN7, and proper 6922s. A local tech friend made some internal upgrades on my new SLI-80. I put the stock EH tubes in the box and saved them for amp resale time. Truly enjoyed my fully upgraded SLI-80, and would have kept it with the right efficiency speakers. Just needed a little more drive for my room, setup.

As I recall, you won’t necessarily get more power with KT120s in the SLI-80, however maybe a tad more drive on the bottom end, and a different type of midrange you may/not like as well as with really good KT88s in your amp. A possible tradeoff. While Cary may tell you it’s okay to run KT120s in the SLI-80, I don’t believe it’s optimized for them, really good KT88s can be the sweet spot in THAT particular amplifier. Circuit design, transformers, plate voltage, different in these amp. Can be design/tube specific.

The other CAD-120S amp was optimized to run with KT120s. While I run KT120s or KT150s in a different brand mono tube amps today, bigger transformers, higher plate voltage (just different),  imo the SLI-80 can sound very nice (more musical) with upgraded KT88s, 6SN7s, 6922s and higher end coupling caps. Also, can share the SLI-80 sings its best when paired with the right speakers, a little higher efficiency speaker helps with that amp to get better drive out of it.

• Did you go for the standard SLI-80 Signature version or opt for the coupling capacitor upgrades or anything above std stock build?
• What speakers are you running with your SLI-80 now?

Thank you a lot for your response SL I 80 integrated amp with headphone jack. My output tubes are Svelvania 6550 quad. And I am running Cornwall fours.

the other tubes are Genelex Gold Lion 6922’s, EH 6SN7’s, with some Tung Sol USA rectifiers ordered on EBay. Crazy but I bought it on eBay as it looked new, and when I received it all the wrong fuses were installed and the AC fuse was blown. There were slow blows where there needed to be quick blows, and I don’t even know if it works yet because I bought it when it was obtained through consignment. I thought to myself wow, if it just doesn’t power up, it must be bad fuses, which has proven true. But I need the rectifier tubes to test what I have installed and replaced which was an assortment of KT 80/8  of which two of them were gold lion, but they had black and circles on the sides of the tubes which I guess means they got burned somehow and the others were EH. Not a matching quad. It will be a fantastic deal if everything internal was protected by blown fuses, which I won’t find out until I get the rectifier tubes in the mail. I have replaced proper fuses to my knowledge, and I am no electronic genius. I have returned after purchase to SLI Dash 80s on eBay that I have been over $3000 worth on each to my door refunded now. This amp is only costing me $1000 so I have some money to play with. Thanks for your help. 

Thank you a lot for your response SL I 80 integrated amp with headphone jack. My output tubes are Svelvania 6550 quad. And I am running Cornwall fours.

the other tubes are Genelex Gold Lion 6922’s, EH 6SN7’s, with some Tung Sol USA rectifiers ordered on EBay. Crazy but I bought it on eBay as it looked new, and when I received it all the wrong fuses were installed and the AC fuse was blown. There were slow blows where there needed to be quick blows, and I don’t even know if it works yet because I bought it when it was obtained through consignment. I thought to myself wow, if it just doesn’t power up, it must be bad fuses, which has proven true. But I need the rectifier tubes to test what I have installed and replaced which was an assortment of KT 80/8  of which two of them were gold lion, but they had black and circles on the sides of the tubes which I guess means they got burned somehow and the others were EH. Not a matching quad. It will be a fantastic deal if everything internal was protected by blown fuses, which I won’t find out until I get the rectifier tubes in the mail. I have replaced proper fuses to my knowledge, and I am no electronic genius. I have returned after purchase to SLI Dash 80s on eBay that I have been over $3000 worth on each to my door refunded now. This amp is only costing me $1000 so I have some money to play with. Thanks for your help.