My new BeePre

[Thermioniclife]

Hey folks,
I just got my new BeePre up and running tonight. No problems with the build other than a little problem mounting the  the ux4 sockets and standoffs. Resistance and voltage checks were spot on with variac set to 120Vac. Powered on and let warm up for about 20 min. and ran output to my crack on my bench, crossed my fingers and gave it a listen. Nice and quiet even with an isolation trans and a variac running in close vicinity, bravo. But holy smokes it's microphonic yikes! But I knew that going into this project. Overall I am happy but will need to mitigate the microphonic nature of the 300b's . I am Quite happy with the low noise floor besides the aforementioned issue.
here are some obligatory pics.
thanks Bottlehead.
Regards,
Lee

[grufti]

I have found a few ways to tame the microphonics: suspend the base plate on a few pieces of neoprene from an old wetsuit or something similarly squishy, it's important that the base plate doesn't make direct contact with the base - that made the most difference for me - next you can suspend "heavy" weights from the bottom of the base plate with silicone or in some other fashion that's decoupled - next you can put dampers on the 300B tubes themselves - that didn't make much of a difference for me - next you can put the BeePre in a soundproofed enclosure - guaranteed to work, but I haven't found a need to do that.

Enjoy

[grufti]

Some day I am going to try the Thomas Mayer approach and use flexible suspensions for a section of the base plate around the tube sockets. You can see it in most of his amps on vinylsavor[dot]com.

[Paul Birkeland]

The Bel-art 18307-0005 flask rings will make a huge improvement with the microphonics.

[Thermioniclife]

Thanks fellas, I'll look into these solutions.

[Thermioniclife]

Hey grufti as fate would have it, I just sold my sound proof booth. I had no use for it anymore after I broke up with my last girlfriend.