Gain staging

[steveau]

I'm appreciating the newly completed Moreplay mod daily.
But I have a question... is there an optimal volume setting for the preamp?
since upstream there can be volume adjusting for digital sources, DAC's, etc.
What's the general practice/philosophy with these variables in play, according to the Bottlehead sages.

 

[Paul Birkeland]

For the Moreplay, I would try to keep your source voltage below 6V, though that can be stretched a little in the stock configuration. 

The typical problem you'll experience with too much source voltage is a very sensitive volume pot that races to full volume in your system from barely being turned, and this is certainly to be avoided. 

Both the Moreplay and the BeePre 2.0 will put out a pretty constant amount of THD relative to output signal level, so there isn't really a sweet spot for the volume control in that regard.  There is better performance relative to signal-to-noise ratio if you keep the signal going into the Moreplay up around the typical line output levels of 1.5-3V. 

-PB

 

[steveau]

I apologize for my technical naivety, are these Voltages per channel?
can I try to get an average with a MM off a RCA cable feeding the Moreplay?

 

[Paul Birkeland]

Yes, that's signal voltage on either channel. 

If you know the nominal output voltage of your MM cartridge and the gain of your phono preamp, then the source voltage of your vinyl setup can be calculated.

 

[pboser]

I apologize for my technical naivety, are these Voltages per channel?
can I try to get an average with a MM off a RCA cable feeding the Moreplay?

Am I right that you meant a multimeter?

 

[steveau]

Yes, multimeter is what I should have typed out-

 

[2wo]

If you look up the specs on your cartridge, it will list an output voltage in millavolts. With this you can calculate the gain.