Pre output voltage VS power amp sensitivity

[danilom]

Hello fro Danilo!
I'm trying to best choose a preamplifier that fits the power amp.
I know that the relationship between the impedances should be about 1:10-20.... OK.

There is a question I cannot solve:
What should be the output voltage of the preamplifier in relation to the input sensitivity of the power amp?

I can't find this information on the web.

Thanks a lot!

Danilo

 

[sergeauckland]

As long as the preamp outputs enough voltage to drive the power amp fully, that's all you need.
Equally, this should be achieved with the volume control near maximum, say at 80%, to provide enough control at lower levels. Too many preamps have too much gain, so normal listening levels have the volume control far down, giving coarse control and possible channel balance errors.

Look at the sensitivity figures quoted for each input, and what the nominal output is at full volume, in other words, the gain, and relate that to the power amp's sensitivity for full power. Note that modern digital sources output 2V at 0dBFS, modern phono stages output around the same for most LPs which have peak outputs much more than the nominal 5cm/s recorded velocity. Therefore, most preamps don't need much gain with power amp sensitivities of 0.5-2V.
S