Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Smash => Topic started by: Raser on November 12, 2014, 08:03:16 AM

Title: Hum and microphonics
Post by: Raser on November 12, 2014, 08:03:16 AM

Hi! Im considering that the smash would be my next preamp. There is a lot of posts about hum and that 4P1L tube being very microphonic. My speakers are 96db efficient so im a little bit afraid. But whats the real deal here, are the tubes really that microphonic what everybody all over the internet are saying?

Title: Re: Hum and microphonics
Post by: Paul Birkeland on November 12, 2014, 08:11:56 AM

If you set your speakers and Smash on a table, then play them loudly, you'll experience issues with micrpohonics most certainly.  All our DHT preamps need about the same precautions as a turntable, which generally doesn't end up being a problem.

Additionally, if you have 96dB speakers and a high power (high power=high gain) amplifier, this will irritate the issue without some padding at the amplifier input. 

-PB

Title: Re: Hum and microphonics
Post by: Raser on November 12, 2014, 08:20:08 AM

Thank you for the quick reply. my power amps are Tsakiridis Devices Achilles. shouldnt be a problem i think? Well i got all kinds of antivibration and dampening tweaks so no problem :)
Also another question if i put a stepped attenuator to the smash what value should it be 10K 25K 50K or what?

Title: Re: Hum and microphonics
Post by: Grainger49 on November 12, 2014, 08:35:22 AM

Stock should be 100k Ohms.  If you can only get 50k Ohms it should not present problems.