Ideally matching preamp output to a power amp
Are there any best practices when matching pre-amp output gain/impedance to power amp inputs? I know next to nothing about this topic...
I have a Schitt Ragnarok, integrated headphone/speaker amp, with pre outs. As an amplifier, it has three gain settings:
20 (26dB), 5 (14dB), 1 (0db) via front panel switch (copied from web page).
I recently purchased a Schiit Vidar for evaluation, with another coming for use in mono-block mode. In SE mode, the Ragnarok into Vidar is able to push my speakers to better aural satisfaction - seems an improvement. Hoping that two > one.
What surprised me (again, my ignorance) is that the front-panel gain settings also affected the pre-amp outs, and the overall power amp output. So far, with limited listening, I prefer the high gain of the Ragnarok into the (one) Vidar.
Is there an optimal gain setting that a power amp likes to see? Can too much gain cause power amp distortion, or some other harm? The Vidar specs say:
Gain: 22 (27dB); Input Sensitivity: AKA Rated Output (Vrms)/Rated Gain. Or, 28V/22. You do the math; Input Impedance: 22k ohms SE, 44k ohms balanced (copied from web page).
I'm not wedded to the Ragnarok, but since I already own it and occasionally like to use headphones, I'm not in a hurry to shed it unless I can do significantly better.
Thanks -- Todd