Is the GAT / ET5 hard on tubes?

[vintage_tube]

Originally Posted by turntable

I will contact cj as I am pissed.

That's ashame -- hope you or the fine folks at cj gets to the bottom of the issue -- they are great components.

Best in your troubleshooting/resolution.

Bob

[turntable]

Originally Posted by joeinid

I never had an issue with my GAT or ET5 for that matter. I am actually thinking about replacing my GAT with another one, because I liked it so much.

Joe, you never had your cj components in your system long enough to have anything go wrong

[Coppy]

Originally Posted by joeinid

I never had an issue with my GAT or ET5 for that matter. I am actually thinking about replacing my GAT with another one, because I liked it so much.

Good move...

[joeinid]

Originally Posted by turntable

Joe, you never had your cj components in your system long enough to have anything go wrong

I was waiting for that

Originally Posted by Coppy

Good move...

[ronenash]

I had the same problem. CJ mentioned that there was a bad stash of tubes from EH that were turning noisy. They can identify them by the dates. Once I replaced the EH tubes with the Matsushita 7DJ8 I had it working for over a 1000 hours with no problem whatsoever. A friend of mine received a replacement EH6922 from CJ and also worked with it for over 500 hours without a problem.

[turntable]

Originally Posted by vintage_tube

That's ashame -- hope you or the fine folks at cj gets to the bottom of the issue -- they are great components.

Best in your troubleshooting/resolution.

Bob

I am sure they will. Lew and the cj team are amongst the nicest in the business.

[joeinid]

Originally Posted by turntable

I am sure they will. Lew and the cj team are amongst the nicest in the business.

+1

[vintage_tube]

Originally Posted by turntable

I am sure they will. Lew and the cj team are amongst the nicest in the business.

Let's hope it is a specific 'bad' tube batch as ronenash mentions. Now, that would be nice & sweet (for an easy resolution).

Best

Bob

[ronenash]

Originally Posted by turntable

I am sure they will. Lew and the cj team are amongst the nicest in the business.

The nicest I have ever met that's for sure. This is one of the reasons for over 20 years now I keep coming back.

[ronenash]

Thought I would provide a bit more information on this one.

I am guessing the noise you are hearing in this case is just white noise with no crackling or breakage noises. The white noise will get stronger as the tube ages until the tube becomes useless. If the noise you are hearing does not match this description then you are looking at a different problem.

Tube noise that matches the above is in most cases a result of disintegration of the coating on the tube filament (the heater wire inside the tube). I believe the scientific explanation for this is that once the coating goes bad stray electrons from the filament are interfering with the normal operation of the tube and causing noise.
This problem with the filament coating can be a result operating the tube at higher filament voltages then the 6.3v the tube is designed for or a defect in the manufacturing of the tube.
I have checked the voltages inside CJ preamps and they are spot on so that leaves us with the manufacturing defect as Lew Johnson mentioned. I think Reflector had this problem for quite a while since I have seen it on Gold Lion tubes as well (GL's are premium EH tubes manufactured at the same factory).
The problem is more noticeable when the tube is used in high gain application such as that in a CJ preamp where no feedback is used which reduces the gain. Using these tube in as driver tubes in a power amp will not be a problem in most cases as the tube is configured to driver the output tubes and not to amplify the signal.

This is a rather technical explanation. I hope I have not gone overboard
Anyway, I hope this helps understand what we are experiencing.