Introducing: Submissive Volume / Source Control Kit
We felt that an “ultimate” attenuator needed to be done to a higher standard and we felt that it would be reasonable to make the kit similar in price to the other high end attenuators on the market. So we got very high quality rotary wafer switches with silver plated contacts and PB put his math degree to work coming up with a very useful thirty-six 1.5dB steps, yielding a total -52.5db of attenuation. Yes, you read that right, 36 steps. We accomplish this with two six position switches, one a stereo coarse control with 9db steps and the other a stereo fine control with 1.5 db steps. Simply set the coarse control in the general range you want to listen and then use the fine control to get the level perfect.
This became the BeeQuiet stepped attenuator upgrade for the BeePre. The natural extension of this attenuator concept was to create a passive volume control combined with a source selector for those who wish to experiment with the use of a passive control (for the record we think the term”passive preamp” is rather contradictory). So we adjusted the impedance from that used in the BeeQuiet upgrade for the BeePre 300B preamp to a more optimal range for passive use and we put the attenuator into a chassis with a three position source selector.
The switches for the attenuator are populated with Vishay Dale 1% metal film resistors, a resistor that has remained a favorite of ours over the years for attenuator use. The coarse and fine stereo switches mount on a custom aluminum sub-chassis, and we provide a neat overlay for the top of the 10″x 6″ chassis, with attenuation settings, input selector setting and a cool vintage look. Three pairs of gold plated RCA jacks compose the inputs and a single pair are the output jacks. A ground post is included to assure low noise connections between the sources and load.
Input impedance varies from 20K ohms at the lowest end of the range to to 40K ohms at the highest end. Output impedance varies from 140 ohms at the lowest end of the range to 10K ohms at the highest step. Insertion loss is -4dB. As with any passive control, bear in mind that there is some attenuation of the signal even at the highest setting. And be sure to use a load (that would be your amplifier) with an impedance of at least three times the 10k output impedance of the Submissive for the very best performance (though we have run the Submissive into a 25K load and it sounded quite good). Short cables will always be the best bet between a passive control and an amp. We suggest a half meter or less as ideal, with a maximum of about 1 meter. This control will work best with fairly high output sources with low output impedance and amplifiers with a relatively high input impedance and fairly senistive input. The combination of a low source output level and an amp with low sensitivity may require an active preamp.
As always the kit comes with an extensive, detailed manual. Assembly is probably a one or two evening affair.
Impressions:
Built! Burning in but the controls are very nice to use…I like the course/fine adjustments. It is more intuitive than I thought it would be. The sound is very clean (yeah, not much there to color anything)…exactly what I was hoping for!
Best,
John