high power tube amps vs ss

I will add this to what Al said: It is generally thought to be a good sign when a typical solid-state amp doubles in power as the impedance of the speaker is halved. A sign of a good power supply, IIRC.

And yes, generalizing about amps based solely on the amp being solid-state or tube is certainly problematic. But this doubling-down into lower impedance is something that applies for the majority of solid-state amps. Your amps happen to be an exception to that rule of thumb.

Al, does the autoformer lower the output impedance of the amp, or increase the perceived impedance load of the speakers. I appreciate the DF math works the same way, but just wasn't sure what changes.

In other the DF of amp is 20:1 if speaker impedance at the test frequency is 20 ohms and the amp's output impedance is 1 ohm. DF is still 20:1 if speaker impedance is 10 ohms at the test frequency and the amp's output impedance is .5 ohms.

Cheers,

Bruce

Hi Bruce,

I suspect that the specified damping factor of 40 for the MC-352 (actually, it is specified as "greater than 40," but I'll assume 40 for present purposes) represents the output impedance of the amp for a given output tap divided into the speaker impedance that tap is nominally intended to be used with.

If so:

The output impedance of the 8 ohm tap would be 8/40 = 0.2 ohms.

The output impedance of the 4 ohm tap would be 4/40 = 0.1 ohms.

The output impedance of the 2 ohm tap would be 2/40 = 0.05 ohms.

The output transistors would presumably see the same load when an 8 ohm speaker (that is truly 8 ohms) is connected to the 8 ohm tap, compared to when a 4 ohm speaker (that is truly 4 ohms) is connected to the 4 ohm tap, compared to when a 2 ohm speaker (that is truly 2 ohms) is connected to the 2 ohm tap.

BTW, thanks for your kind comment earlier in the thread.

Best,

-- Al

Atmasphere, are you comfortable telling us which in your opinion are the 5 ss amps that come close? Just curious.

I'm a big fan of Nelson Pass, Ayre and Ridley Audio. That's my short list... I think there are a few other candidates out there but I've not been able to hear them.