Another of my vintage Bottlehead units, my Foreplay II amp.
I was trying to eliminate some hum today and to help me trace the source I swapped the left & right the tubes on the Foreplay. The source of the hum turned out to be something else. However I noticed that the Foreplay had suddenly become extremely microphonic. The tubes rang, dinged if I gently tapped the top, if I touched any metal part there was sizzle of squeaky noise from the speakers even if the volume was at zero.
I swapped them back and the noise has gone, back to normal. However, the right channel has been slightly lower volume for awhile. I had presumed it was my phono stage tubes. But having recently put in a new solid state phono stage, the problem persists. Could it be time for new tubes in the Foreplay? The unit has been running at least 15 hours a week for over 20 years.
Any thoughts? Does it sound like an aging tube of could it be something else? Any recommendation on buy new tubes?
The current tubes are 5965s. I guess a like for like replacement is easiest.
Thanks
Simon