Hi Myles...any update? Yes, i know...its only been 24 hours...yeesh...sorry, just very curious.
OK they're installed First rxn: they are 2x as heavy as the 6550s and about 1/4 to 1/3 larger. Big puppies!
Hi Myles...any update? Yes, i know...its only been 24 hours...yeesh...sorry, just very curious.
OK they're installed First rxn: they are 2x as heavy as the 6550s and about 1/4 to 1/3 larger. Big puppies!
Ok, it's been 14 minutes, how do they sound?
It's always a good idea to turn your bias pots down when you first install new tubes so that you don't draw too much plate current and your tubes glow cherry red before they blow. I don't wait an hour before I set initial bias though. I set the initial bias right away, check it in 15 minutes, then recheck again after an hour.
Here's more on the subject from CJD...
Ed passed this along to me. We have been very much taken with the sound of the new KT120 tubes. Sound quality is even better than our earlier favorite, the "winged C" tubes from Russia. The KT120s are a plug-in replacement for the 6550s on all of our amplifiers. They have higher voltage and dissipation ratings, so should prove extremely reliable (though it is a bit early to be sure of that). The power output of a given amplifier will not change when the KT120s are substituted for 6550s. They are capable of being run for more power, but only if the amplifier is designed for that (higher plate voltages and a different turns ratio on the output transformer). But this means that they are being run very conservatively when simply replacing 6550s.
Aside from catastrophic failures (arcing or short-circuits), I find that output tubes often are good for about twice as many hours as the more critical input and driver tubes (as long as not operating with disastrously low impedance loads - no worries with your Wilson speakers), so should be good for around 3000 hours. When the time comes to replace the outputs, I would definitely switch to the KT120s.
Myles...
This comment was not my opinion but a response form CJD to my question to them about replacing the eight 6550s in my LP140 monos with KT120s. As a matter of fact though, I just recently replaced the 6922s in my GAT with NOS Mullards from Holland ECC88s or E88CCs. Always get that mixed up. Also a nice little upgrade. Hmm... you could sell the great ART and get the GAT... just two tubes, one chassis and great, maybe better sound.
Bob
Hi Bob,
yes...that is a lot! As you know, GAT only has 2. Zanden has 4. And i am Class A SS, so no tubes there. far fewer! In any event, i am sure you have your own excellent sources of NOS tubes. If it helps, try Brent Jessee (Audiotubes.com i think) and tell him i say hi...absolutely great to work with. I have been buying tubes from him for years, and you will likely read many good things about him on the 'net. Enjoy your music as well!
Sorry for any confusion. Actually have the GAT I had the ART preamp for about 12 years, deciding not to upgrade to the ACT2. It was only when heard the GAT that finally, heartbreakingly, sold my beloved ART III. I was lucky enough to have the opportunity to compare the ART III with the GAT and it was no contest. One item though, that I find essential to get the most out of the GAT is the SRA Isobase. Besides the drop in the noise floor, there's a huge (not hyperbole) increase in the unit's dynamic range.
The ART I was referring to was the amplifier The problem I have with tube rolling is that I find it next to impossible to find quiet small signal tubes, esp. for phono stages. I actually have a NOS pair of Tele E188cc/7308s that will eventually try in the GAT. And as a really true NOS tube is getting harder and harder to find, I find myself drawn to finding the best of the new lines of tubes since they will hopefully be available for some time
As far the output tubes go, I have recently switched over to the KT120s (yes 16 of them!) and am burning them in.
Myles,
Not to long ago I set up some Symposium roller blocks under the GAT not thinking it would make much difference an sat down to read while listening to a little music. To my surprise... a difference! As you know the GAT isolates the tube boards internally so I thought if was a waste of time but not so. Do you think the SRA platform would make a further improvement?
Whatever tubes they sent me in the TEA 1bc seem to be holding up okay... knock on wood... so I'm leaving well enough alone. My best sound is the new RR LP Stravinsky. Amazing.
Also, how are the KT120s doing. Mine are still great.
Bob
Yes Myles
You told me the GAT was quite a bit better than the ART3. Not that I didn't believe you, but like you I was reluctant to let go of the ART.
I have had my GAT for a couple of months now. one set of 6922's went noisy after a couple of hundred hours thou. I think I am over the burn in hump of 400 hours - right Lloyd
- it does sound awesome.
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