KT-120s in a c-j Premier 11A

When I called c-j months ago,

Try calling them again. From what I've read a few AR amps will not work with them without significant power supply modifications. But most do and are NOW approved. As far as CJ they may have tested more models than when you first inquired. Personally I would not not drop in tubes the manufacturer did NOT approve for that model. Could make for a very costly repair. BTW I believe today CJ approves of the KT120 in the 140.

cj is as far as I know, now using the KT120s in place of the 6550s. I just recently retubed my ART with 16 of those suckers. I think part of the issue might have been that cj wanted to burn through their existing stock--since if you look at the KT120s, their date code is 2006.

Xti16,

Took your advice and called c-j and got Ed's voicemail in customer service. Left him a message about wanting to use the KT-120s in my 11A but haven't heard back from him yet.

If I do, I'll post his response.

Myles,

I've used the KT-120s in my Premier 140 and didn't have any problems but the 140 is currently out of commission which is why the 11A is back on active duty. Since it's an older unit with aging parts, I was hesitant to just plug in the 120s without getting c-j's blessing. I hope Ed gets back to me before I do something irresponsible like just try them out.

I took a look at your system. Wow! I'm sure it sounds just wonderful.

Thank you both for taking the time to respond to my query.

Regards,

I went ahead and tried them in the 11A. They've been running about 7 hours now without any issues so far. The transformer casing may be running slightly hotter than normal or it could be just my imagination. They sound pretty darn good: kind of a cross between the richness of a KT-88 and the detail of a 6550 but not to the full extent of either.

For a current production tube, they're quite good. Not a vintage Tung-Sol but then what is, except the original?

Glad they are working out. I'm tempted to try them someday. I was lucky to score a couple of quads of the original TS solid black and grey plates. Extremely musical (lost a little detail compared to current production 6550's) and I'll admit the black plates are my favorites out of the 2. I'm using some current production Eat kt88's right now and they are super excellent but they come with a heavy price. Also the Eat's don't seem to be too reliable - lost 2 already :-( but I did buy them used.