Upgrade from a Cary SLI-80 integrated amp

They're also very good in my Atma-Sphere gear.

My main system for some time now has been all Atma-Sphere(MP-1, MA-1's) and I'm extremely happy with the sound.

The heart of my second system is the SLI-80 F1, all-triode, direct coupled version. It came with EL34's which to my ears sounded thick, slow, and rolled off at the extremes. I immediately replaced them with Black Treasure KT88's which made a tremendous improvement; think night and day!

I also replaced the Sovtek 6922's(which suck), the 6SN7's, and 5U4 rectifiers with NOS and again huge improvements across the board. Long story short, while the SLI-80 F1 is still somewhat outclassed by the 8 times more expensive Atma-Sphere gear, I can listen to it for hours enjoying every minute. I think it's a fabulous sounding integrated and can't think of anything I'd want to replace it with!

Dminches, do you have a way to test your NOS TS6550's? I don't want to alarm you but those old Tungsol's, in good condition, are quite rare. I ran across 8 of them quite some time ago and was looking forward to hearing them in a pair of CJ's I used to own.

Initial listening was rather disappointing, with sluggish dynamics, rolled off highs and wimpy bass. Testing on my Hickock revealed they were on their last leg but fortunately I was able to return them.

I've been told those tubes are among the best of the 6550/KT88 types ever made so would think you'd get reasonably good bass.

Dminches, glad to hear your T-S's are in good shape. I didn't want to cause you concern but there are a lot of so-called NOS tubes floating around, especially on Ebay, that are on their last leg.

I too use Mullard rectifiers and like them a lot. Not as familiar with the Amperex 6922's but am sure they're a big improvement over the Sovteks.

I own dozens of NOS 6SN7's including the RCA VT-231 gray glass. They're very nice in some applications but tend to sound a bit soft at the extremes. You might want to try a couple Sylvania GTB chrome tops. To my ears, they sound cleaner and a bit more robust than most of the RCA's and they're fairly cheap and readily available.

Two other sleepers I'd highly recommend are the GE 6SN7 GTB "wafer bottom" and the GE 6SN7 GTA. I've used both of them in my Atma-Sphere gear and Modwright/Sony 5400 and they both sound wonderful; especially the "wafer bottom"!