Upgrade from a Cary SLI-80 integrated amp

I am using NOS TS 6550s in my SLI-80 F1. Are KT88s preferable?

My current tubes, all NOS, are 4 TS 6550s, 2 RCA 6SN7/VT231 gray glass, 2 Mullard GZ34s and 2 Amperex 6992s.

I would like to get a bit more bass out of the amp given that I am using it with a pair of Nola Boxers. Any suggestions?

The KT88 will give you more bass when compared to your TS 6550, but you might be giving up other sonic benefits of the TS 6550.

In addition, the ultralinear setting will also give you more bass compared to the triode setting.

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.

Rfogel8, I tested the quad with my B&K 550 tester and they all tested very strong. I don't think the tubes are the issue. I think I need to get used to the Nola Boxers sound signature. I am used to listening to Vandersteen 5As so my ears need to adjust. I just wanted to hear what others have been using in the Cary. Thanks.

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"!