GAT Tubes

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jasper
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GAT Tubes

Post by jasper »

Hello everybody! I've got a specific question and would appreciate some insight. I have a GAT preamp and heard about a tube upgrade that supposedly provided a quantum improvement. So unable to just leave well enough alone I sent off for a pair of Golden Lion E88CC/6922 tubes to replace the factory set. Well right away I heard the difference and felt really good about the decision. Unfortunately in short order, the noise floor slowly got louder until there was a distinct hiss from both channels that was pretty disturbing between albums/cd's and definitely affected the musical experience when playing music. I went out of town for a couple of weeks and when I returned, immediately turned on the system to listen to some music. At that point the Golden Lion's didn't even have 40 hours on them. Well, the hiss had turned into a nasty crackling that had every indication it was blown tubes in the GAT. I'm about to put back the original tubes and expect it to return to normal but I'll miss that improvement the first time I heard the GL tubes! After doing a little research, I found some comments from reputable sources that it was not recommended to role tubes in a GAT. But then there were others who fully endorse the idea. Any thoughts?
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Joe Appierto
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Re: GAT Tubes

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As I understand it, the latest generation c-j preamps are not easy on tubes. Whatever the reason might be I keep reading the same comments regarding tubes going microphonic, becoming noisy, and just generally dying an early death. The EH tubes that come with these units are tough but not necessarily the last word in sophistication, sound staging, and just plain musicality.

Please bear in mind that my experience with c-j preamps has been with the older, kinder and more gentle models. That having been said, you might want to directly contact reputable tube vendors such as Upscale Audio, Vintage Tube Services, Jim McShane, and Brent Jessee, for example, and see what they have to say. Luckily, I guess, the GAT only uses 2 tubes so it's not like you have to load 6 into a Premier 16 or 10 into an ART. Just guessing here, but I'd imagine that something like earlier production Telefunken or Siemens might be good matches. They aren't cheap by any stretch of the imagination but then they aren't going to sound anything like EH and they will last. Sometimes you truly get what you pay for.

Speak to the experts, though.
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jasper
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Re: GAT Tubes

Post by jasper »

Thanks Joe and appreciate the feedback! I put the factory tubes back in the GAT this morning and its fixed. Even the factory tubes are a tiny bit noisy but not too bad. I got the GL tubes from Kevin at Upscale and when I talked to him, he sort of tried to steer me away from doing it but I had to try them anyway. I'll call around as you suggest and find out more when I've got some time. Its not like the preamp doesn't sound good with the factory tubes........its FANTASTIC !!! (after it broke in which took several hundred hours.) But in my obsessive lust for more I had to spend a couple hundred bucks to try to squeeze more out of it! I think I'll go play around with VTA/SRA for a while instead. Take care.
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Re: GAT Tubes

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You're welcome. The GAT's reputation precedes it and I'm sure it sounded wonderful straight out of the box but as you say, the Teflon capacitors take a while to form and break-in before it sounds its best. I'm a little surprised that Kevin didn't have specific recommendations for the preamp. Please don't be discouraged in your experimentation. As good as the stock tubes sound (after all these were the type that the GAT was voiced around), I'm sure they can be improved upon. C-J's tube choices are based upon ready availability as much as on their inherent sound. A little experimentation on your part will most likely lead to even greater satisfaction if you have the patience. Good luck.
Oppo BDP-105D and PSA DS DAC
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Re: GAT Tubes

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Thanks again Joe. I just listened for a couple of hours with the system warmed up and with the original tubes. I sort of miss the Golden Lions; just more of a good thing to enjoy. Perfect world would be that sound and reliability without noise. I'll stay on it. Btw, I see you have an Oppo 105D. I sent mine in to Modwright for their rehab/mod with new power supply and its everything the reviews are saying! Probably world class at no where near the price. Might want to give Dan Wright a call at some point to get the skinny. Take care.
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Re: GAT Tubes

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I know we're getting off topic and I apologize for that. Having the 105D modified/upgraded by Dan is something I've thought about on and off for the last year I've had it. For almost 10 years I owned a ModWright/Music Hall RAM CD25 that I'd purchased from Response Audio. Dan had done a series of changes to the basic 96/24 CD player including adding a pair of 5687 tubes for the output stage. Even after purchasing an Oppo 95, I kept the RAM CD25 because it was just so darn musical.

Now you've got me thinking again. :)
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Re: GAT Tubes

Post by jasper »

Nice! I bought a 9.0SWL preamp from Dan a few years ago (his 1st from scratch piece) and it sort of sat around in a small system in my living room for 10 years. Over the years I'd kept up with any upgrades then recently sent it back for a power supply upgrade, then put it in my Quad/ CJ system that was hosting an ET3 SE at the time. Love that preamp by the way, and its true, the ET3 delivers a healthy dose of that GAT-ness I crave at a fraction of the cost. Well, bottom line is the 9.0SWL is not coming out. I guess in the back of my mind it was sort of a tongue in cheek shoot out that I undertook one day, laughing under my breath, just knowing the MW had no chance. Well after several days, with my jaw stuck hanging open, I happily accepted the truth. So I added a Sutherland 20/20 phono preamp, (the 9.0SWL is line stage only; ET3 has an excellent phono section), and the system is dead quiet, tons of texture, detail, and space, much tighter bass,
and more transparent. Anyhow that's a wordy way of saying, Dan's mods have come a long way and the Oppo mod is some of the best money I've ever spent in Audio. I also had him do the Bybee rail upgrade for the Oppo and ordered upgraded tubes from Galen Carol and Kevin at Upscale per Dan's advise. Only thing, imo, is it takes at least 100 hours for the Oppo to break in, but when it ripens to perfection, all grain or any tinge of brightness will dissolve and it's tough to tell the difference from my best vinyl. Take care.
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