Has anyone replaced tubes in Aesthetix Rhea ?

Hi Thomas, thanks for sharing your similar experience. It could also be that there was some break in occurring in the tube sockets. I've heard of this happening with a new unit where the connection of the sockets and the tube pins needed some burn in time.
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The intermittent noise I've been hearing I think might best be described as tube "ringing", a high pitched microphonic whistlelike sound. I thought I had the noise licked, but it resurfaced today. It can only be heard at moderate to high volumes. I'm expecting 4 NOS Telefunken 12AX7s this week so I hoping that will wipe out the problem. Any ideas gentlemen?

Sounds like a tube (or tubes), Stew. Only way to know is to swap 'em and see. Let us know how you make out once you change them.
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Rushton, still don't have the new tubes but perhaps you can explain why I would be getting ringing in both channels on some days but not others. For example, last night I had a few friends over to listen to the system. Of course, the ringing was present when I turned the system on and stayed all night without abating. Tonight I'm alone and I turn on the system and other than the usual tube rush one might expect to hear, all is quiet. The night before last quiet too. Like you say, the only way we'll know if its the tubes is to swap 'em out. At the moment, I only plan to swap out the 12AX7s in the first gain stage. Any reason to think these might not be the culprits? This is just too strange.

Stew, I don't have an answer for you. Could be you're getting some sort of power line interference or RF interference. That would account for the intermittance and for hearing it simultaneously in both channels. The interference could be coming from some other appliance running, such as a furnace motor or freezer compressor. One way to check that would be to start turning off circuit breakers the next time you have an occurrence of the ringing.
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