Isolation grommets for tube sockets?

[JoeK]

I'm looking at some amps that have a small orange grommet? or washer/s that isolate the tube socket from the chassis both mechanically and electrically. Haven't seen these advertised at the usual tube amp suppliers so I was wondering if anyone has had experience using them or seen them for sale. Any thoughts advice would be appreciated and I realize it's a bit over the top but I'm building something that could well be microphonic and it will be hard to go back in after it's built. Cheers Joe.

[NorCalTuna]

I have an ancient rickenbacker combo here at my place that has a pentode preamp tube that has little grommets under it's socket. I have seen them specified on datasheets while i have been working with this amp as well, so perhaps it was common practice back in the day, as pentodes can make a lot of gain- hence microphonic noise.

As long as you're not using any of those bolts as grounds, i'd say go ahead, as long as the socket will be well supported. Is it a head or a combo? worth thinking about- Good luck!

[JoeK]

Thanks for the quick response! I will be building a Vox type pentode preamp later but this current one is a special build for a friend. I'm looking at a high end amplifier and I can see they have a separate earth to ground the socket bolts and centre pin on each of the preamp sockets. I can't see what they used to isolate the hardware but I'm guessing it's a step washer or grommet.

[tubeswell]

You should be able to get those little grommets at any decent electronics supplier.