VAC owners, sound off

Tholt, what you describe sounds like a bad match between the VAC pre and
your amplifier (despite assurances otherwise). It doesn't seem to me the sound
you are describing is typical of VAC, nor does it sound like anything that tweaks
will resolve.

Sometimes, you have to accept that the match is not ideal and move on to
another preamp.

Why not try something like the Audio Horizons TP2.1 that can be auditioned
with a 30 day home trial? Listen for an improvement/change versus the VAC.
If there's no definite and immediate change in the sound, then perhaps
something else is amiss in the system.

I surmised the same thing. Outside of impedance matching, is there any other specs to check between pre and amp for compatibility before rolling the dice?

Impedance and gain. Gain will dictate how quickly things get loud in relation to how far you turn your preamp's volume control. Basically, if things get loud with only a quarter turn of the knob, then you have too much gain. Too little gain is almost never an issue.

don't know if that contributed to the issue in this case, but gain was exactly as you described -- loud at about a quarter way or less on the dial. Is there a spec to determine if gain on a pre will match up well with your amp?

Sometimes it's referred to as output gain (and input gain on the amp). Sometimes it's spec'd by output and input sensitivity.

Gain would not be the cause of the issues you described.

Generally, preamps don't require more output gain than about 12dB, although most have output gain of 18dB - 25dB depending on the unit. Gain is easily adjusted on a preamp by the manufacturer (if required).