Amp gain matching

Hey gang, I watched a couple of Paul’s videos talking about gain matching different power amps. As in for example a 300 watt amp for mids/bass and a 25 watt amp for tweets. How exactly does one go about doing that? I assume it’s not just measuring VAC at the terminals.

Hi Jedi, Paul did a good job of explaining it. In most cases for bi-amps, you can ignore the amps power rating. You want the higher power for the bass drivers and typically lower power for the tweeters. When it comes to gain matching, this should be fairly easy to do. Most amp manufacture will spec the gain because it is very important number. Both our Stellar amps and BHK amps have 30.5 dB of gain. If you’re going to gain match amps, I’d try to not exceed a discrepancy in gain of about 1.0 - 1.5 dB. 1.5dB is really stretching it. If it’s only +/- 1dB I’d be really hard pressed to hear the difference.

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Ok, so it’s not actually a measurement I can make - I have to rely on manufacturer’s specs. Correct?

It is something that you could measure based off the voltage at the terminals. You’d want to play some pink noise through the system at slightly above listening levels. If the two amp’s voltage out are similar, then you’re fine. Keep in mind that 6dB is double. So if one measure 1v and the older 2, this is a 6dB spread and is MASSIVE!

I’m measuring AC voltage at the terminals correct?

To go a bit further, not every amp’s gain structure is linear. Keep everything else consistent but set the pre to 20 and measure the amp’s output… If the amps measure the same voltage, it doesn’t mean they will have the same voltage if the pre is set to say 60. Yes, measuring from the terminals.

Right on. Thanks.