A minor problem with GAT

[begli occhi]

Just wanna ask other owners if they have experienced tube hiss with their GAT as I do. Changed the stock 6922s several times ( with the same brand EH) and could not eliminate the hiss. In fact it grows louder and louder over time. Should I try other brands? I already tried NOS and cryo tubes but could not get the zest that the stock EHs deliver. Got my GAT brand new almost 2 years ago and the hiss was there from the start.

[vintage_tube]

Just wanna ask other owners if they have experienced tube hiss with their GAT as I do. Changed the stock 6922s several times ( with the same brand EH) and could not eliminate the hiss. In fact it grows louder and louder over time. Should I try other brands? I already tried NOS and cryo tubes but could not get the zest that the stock EHs deliver. Got my GAT brand new almost 2 years ago and the hiss was there from the start.

Approximately how high is the volume set when your first hear the hiss? Very low (less than 10% volume), Low (25% volume), between low and 50%, around 50%, a bit higher than 50%, etc.

Bob

[ronenash]

This is a problem with the tubes. There was a defective batch of EH tubes that are known to have this problem. You can try to get some NOS tubes or other brand tubes. The Matsushita 7DJ8 worked great for me and sounded much better.

[begli occhi]

Hi Bob, even at very low levels the hiss is there and grows progressibly louder as you crank up the volume.

ronenash, thanks for the tip.

[ronenash]

Hi Bob, even at very low levels the hiss is there and grows progressibly louder as you crank up the volume.

ronenash, thanks for the tip.

One more thing. You can call CJ and they will tell you if your tube is from the defective series. They will also send a replacement if needed. I will still try to get a good tube to replace the EH, it will sound better.

[begli occhi]

Thanks ronenash but FYI, I have a lot of EH 6992s which I got from different sources but with the same result.

[Rayooo]

Thanks ronenash but FYI, I have a lot of EH 6992s which I got from different sources but with the same result.

so in my case, not an apples and apples comparison....but.

ET5 with various tubes installed over the ages....

A few are definitely more "hissy" than others. In a few cases a new tube would go bad and become audibly noisy in some amount of time.

However, in general, with my system, if I crank the volume on the ET5 to 99, (no music playing!) only then do I hear a slight amount of hiss and hum. Anything below about 97 is dead quiet, and this test is "ear-against-the-speaker" Even at 99, from my listening position, it'd be hard to hear anything at all.

Are you literally hearing hiss, at typical volume settings, at or near your listening position? Do you have EXTREMELY sensitive power amp+speakers?

I'd definitely give CJ a call if you've not. I think the GAT is rated, S/N wise even better than ET5. and my ET5 absolutely hiss-less.

[ronenash]

Thanks ronenash but FYI, I have a lot of EH 6992s which I got from different sources but with the same result.
You can check if the date codes on the tubes are the same. If so they are from the same batch.

[Puma Cat]

so in my case, not an apples and apples comparison....but.

ET5 with various tubes installed over the ages....

A few are definitely more "hissy" than others. In a few cases a new tube would go bad and become audibly noisy in some amount of time.

However, in general, with my system, if I crank the volume on the ET5 to 99, (no music playing!) only then do I hear a slight amount of hiss and hum. Anything below about 97 is dead quiet, and this test is "ear-against-the-speaker" Even at 99, from my listening position, it'd be hard to hear anything at all.

Are you literally hearing hiss, at typical volume settings, at or near your listening position? Do you have EXTREMELY sensitive power amp+speakers?

I'd definitely give CJ a call if you've not. I think the GAT is rated, S/N wise even better than ET5. and my ET5 absolutely hiss-less.

So are my CT-5 and Premier 17.

[Coppy]

Running EHs in the GAT here and no hiss.

[joeinid]

Running EHs in the GAT here and no hiss.

+1

[aldinohiend]

Your is not a problem of tubes but power. You definitely an issue to the power house. Try changing the socket to which the pre attacks.

[begli occhi]

Running EHs in the GAT here and no hiss.

In that case, maybe we can solicit the opinion of Mr. Lew Johnson on this.

[Coppy]

I'd be glad to contact the c-j folks but not sure what my intervention accomplishes. This is likely not a single question issue and will require some discussion with the GAT owner. Wouldn't it be better and more effective for the person with the issue to contact them? They respond to both e-mail and telephone requests... my guess is that GAT customers will certainly be responded to quickly.

Bob

[begli occhi]

Hi Bob,

I emailed them over a year ago and followed up several times but never received a reply. Highly unusual, as prior to that, any inquiry of mine was replied to very promptly.

[Coppy]

Maybe I can help you contact them. I didn't find your e-mail address in the profile here. Please send it to me here or on a PM. Whoops, looks like you haven't subscribed yet, you might want to; so maybe you can't PM. My e-mail is rbc7@verizon.net. Thanks.
Bob

[begli occhi]

Hi Bob,

You've got mail. Thanks.

Bert

[medward0]

I'm not in the GAT league (:drool:), but have observed a similar set of issues with my ET3SE over the past year or so.

Hiss in one channel, in both channels, with no variation with volume, crackling in one channel...maybe this is just what tubes do.

I think that I am on my 4th tube in the rig with only 500 - 600 hours play time on the pre. Right now, no hiss and a blissfully silent pre.

I've tried stock EH (original), gold EH, Gold Lion...all 6922s.

At this point, I'm beginning to think that my pre just eats tubes somehow. I've considered sending it to CJ, but I know I'd have withdrawals and tubes aren't all that expensive.

Is this worth sending to CJ for repair? Or perhaps I just buy a set of tubes from CJ and see if any improvement.

In constrast, my ET250s amp is still on its original set of EH 6922 tubes that were shipped with the unit from CJ almost a year ago.