Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Smash => Topic started by: boyanb on April 07, 2017, 04:29:09 AM

Title: passive preamp with remote volume before smash
Post by: boyanb on April 07, 2017, 04:29:09 AM

Hi all,

I am considering adding a passive preamp with volume control before the smash, for example khozmo ( http://www.khozmo.com/stereo_selector.html (http://www.khozmo.com/stereo_selector.html) ).
But I don't know what resistance to choose. Do you have any suggestions? I can choose between 5K ... 250K Ohms.
Thank you.

Title: Re: passive preamp with volume before smash
Post by: fullheadofnothing on April 07, 2017, 06:12:27 AM

This one. (http://bottlehead.com/product/smashquiet-attenuator-upgrade-for-the-smash-preamp/)

Title: Re: passive preamp with volume before smash
Post by: boyanb on April 07, 2017, 11:30:38 AM

I have the smash preamp. I would like to add a passive preamp with remote volume control between the sources and the smash preamp. My question is what resistance of the attenuator of the passive preamp should I choose? If anyone knows.
Thank you.

Title: Re: passive preamp with remote volume before smash
Post by: Paul Joppa on April 07, 2017, 03:14:20 PM

The impedance of a preamp attenuator - or at least the minimum impedance - is set mostly by the source components. The maximum is set by the preamp itself, through the input capacitance (Miller capacitance of the 4P1L in this case). We have usually chosen around 100K for Bottlehead products, as a reasonable compromise that hardly ever causes any problems.