What am I missing? Pre/power gain and input sensitivity.


I’ve read a few posts about power amps with lower gain needing a pre with additional gain, but no one seems to mention input sensitivity in those conversations. If my source outputs 2V and my power amp input sensitivity is only 1.2V then whether the power amp gain is 16dB or 26dB my pre amp is attenuating the signal and the amount of gain on the pre doesn’t matter at all. With a given set of speakers, to get the same SPL with 2 different amps they should just need to output the same voltage, regardless of how they get there.

Am I missing something?

cat_doorman

Showing 1 response by dentdog

I’m a prime example of what Ralph has stated above. For about 6 years I owned a well thought of phono pre and just thought the tics and pops were part of the vinyl. Couldn’t believe the difference and improvement when changing phono preamp. If playing a clean copy can’t hear anything but the music.
As to the gain/voltage equation, the purchase of an amp with only 18db of gain negated the use of my preamp, which had only 12db of gain. To add to the imbalance, the amp requires 2.5 volt input to reach full power. Purchased a preamp with 20 db gain that definitely pushed the amp to full power. The preamp manufacturer actually mentioned that the amp’s lower gain would be a plus in combo with his preamp. All in all things are matched up very well. And I’m done for the foreseeable future.
Posters like Ralph (AtmaSphere) and Almarg are very valuable to this forum. The technical info they provide can guide you to make sound purchases.