speaker hiss with audio aero capitole mkII


I have noticed a hiss from my egglestonworks andraII speakers that is noticeable from the listening position at the highest volume settings on the audio aero capitole mkII. The hissing comes from both the tweeter and the twin mid-range drivers from both speakers and is equal from both sp's. It gradually increases as the volume is turned up and is not present with the capitole turned off and the Krell fpb 300cx on. I have dedicated circuits with their own main panel and the capitole is connected to a PS audio P-300. The hiss is present also when the capitole is not connected to the P-300. I suspect that this relates to intrinsic noise or distortion in the capitole, possibly from the tubed analog output. Although the system sounds terrific, i am concerned that the hissing may be masking low level detail at moderate to high listening volumes. Has anybody had a similar experience with the capitole? Can this be improved? Any suggestions? Thanks.

Rafael
aponter4
the Capital will exhibit the "pin #1 problem" with some amps with balanced cables only due to grounding issues between the components
Golden ears,

The serial# is 0207/338. I can't tell the # of hrs. on the tubes 'cause i bought it from the original owner. He told me that he had put ~600 on it when i purchased it, but this may be an underestimate. Also he may have not counted stand-by time. In any case, the music is played beautifully by the capitole is just that with the music off and the volume setting at the highest levels a hissing sound is heard, not a hum. Would that be how a "bad" tube present? I really am not that experienced with tubes.

Mejames,

How can i tell if i have a "pin #1 problem"?

Thanks,

Rafael
Are you saying that you only hear the hiss when you rotate the volume know to maximum? If so, I wouldn't worry at all. There are a lot of tubes that have a low level residual hiss - if you can hear it at normal volumes you would either have tubes that were noisy in the first place or tubes that have gone noisy after some use. Neither of these things are unusual and present no electrical problem (but be wary if you're hearing snap, crackle and pop sounds after warm up - this would indicate that you should probably replace the tubes).
Yep, you guys are right . This does not affect the sound quality at normal or reasonable listening volumes and is only noticeable at the highest volume setting into the very powerfull Krell amp which obviously at that volume level is greatly amplified. There are no crackles, snaps or other noises. Krell's answer, in true manufacturer's fashion, was that they weren't familiar with the AA capitole or its tubes, right! I am satisfied, however, that this is not of significance and had a great listening session last night at the volume settings i like! Thanks to all for the great advice!

Rafae