[W9TR]

Great question!

The math says that on a McIntosh transformer coupled amp the lower impedance taps will produce the most current for a given output power.

There is another consideration, and that’s the output impedance of the various taps. With a varying impedance load like pretty much every speaker ever made, the output impedance of the amp ends up in series with the speaker, slightly impacting the frequency response of the system. The resulting response deviation is small.

You would expect the lower impedance taps would have the lowest output impedance, but that’s not always true as evidenced in the review link below, where’re the 8 ohm tap of an MC 462 has a lower output impedance than the 4 ohm tap.

https://www.stereophile.com/content/...r-measurements


Some SS amps without output transformers can ‘double down’ when the speaker impedance halves. This speaks to these amps having really hefty power supplies that can supply the current needed to ‘double down’. Do these amps sound better than ones that can’t ‘double down’? Not necessarily. Are the parts required to do this more expensive? Absolutely.

Are these amps better at driving speakers whose impedance drops in the bass region?

Not necessarily.

There are just so many things that go into a power amp design that this one factor does not determine their suitability.

Are McIntosh amps high current? My MC 602 puts out 150 Amps per channel. I’d say that’s high current.


Anyway, sure, a McIntosh amp can drive properly drive a speaker with highly variable impedance.

Compared to an amp that can ‘double down’?

I don’t think it matters.

This is when everyone having an amp that doubles down will say the transformer coupled amp they had before sounded flabby in the bass.