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]

Originally Posted by 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.

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]

Originally Posted by 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.

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]

Originally Posted by begli occhi

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]

Originally Posted by begli occhi

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]

Originally Posted by Rayooo

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.