6sn7 and 5u4 tubes

Larryken,

I've only owned two pairs of the clear glass Ken-Rads, so it could just be a case of bad luck on my part...or a good ol' case of Audiophilia Psychosomatica. Heheh.

I am using an RCA VT231 (black glass) in my Dehavilland Ultraverve preamp and am finding it to be very microphonic. Has anyone else found this tube to be microphonic in this application, or is it possible that the tube itself is bad (the Sylvania Chrome top 6SN7 it replaced was not microphonic in this preamp).

Weebeesdad,

I've experienced this a lot in my Blue Circle pre as well. More so with the WWII era tubes.

I'm not sure if it has to do with the age or condition of the tubes [even if they test well], or if it's just my preamp. It could just be that these "big tone" tubes are more susceptible to microphonics than other tubes.

I've never had this issue with any of the 6922 based components I've owned. DAC or preamp.

Gunbei- My Cary monoblocks take two pair of 6SN7's: one each as phase splitters, one each as drivers. When I used the VT-231 Sylvania(driver) and Ken-Rad(phase splitter) in combination, I was able to enjoy the strengths of both, and found no downside at all, as neither tube has an actual fault. I'm now using Tung-Sol JAN CTL roundplates(driver) and Sylvania 6SN7W/JAN CHS tall bottles(phase splitter). Talk about realism!