Thanks for your clarifications Al. Let me add one too.
Most ARC amps use negative feedback and have "low'ish" output impedances, especially off the nominally denoted 4 ohm taps. Al .. as we have discussed many times before, this means that ARC amps with low'ish output impedances perform somewhat like SS amps -- i.e., like voltage Paradigm amps.
As I recall, the ARC Ref 75 has a robust power supply (520 joules) and low'ish output impedance off the 4 ohm taps (1 ohm off the 8 ohm taps; probably less than that off the 4 ohm taps). Ergo, it might not be a bad amp to consider.
That said, if the SF speakers in question (a) present very low impedance plots and highly negative capacitive phase angles in the bass spectrum, and (b) are not very sensitive, then a safer bet might be a high current SS amp with lots of watts. Or, a bigger ARC tube amp such as the Ref 150.
(P.S. J Atkinson measured the Ref 75's output impedance off the 4 ohm taps to be .75 ohms at 20 Hz and 1K Hz. See: http://www.stereophile.com/content/audio-research-reference-75-power-amplifier-measurements)
Most ARC amps use negative feedback and have "low'ish" output impedances, especially off the nominally denoted 4 ohm taps. Al .. as we have discussed many times before, this means that ARC amps with low'ish output impedances perform somewhat like SS amps -- i.e., like voltage Paradigm amps.
As I recall, the ARC Ref 75 has a robust power supply (520 joules) and low'ish output impedance off the 4 ohm taps (1 ohm off the 8 ohm taps; probably less than that off the 4 ohm taps). Ergo, it might not be a bad amp to consider.
That said, if the SF speakers in question (a) present very low impedance plots and highly negative capacitive phase angles in the bass spectrum, and (b) are not very sensitive, then a safer bet might be a high current SS amp with lots of watts. Or, a bigger ARC tube amp such as the Ref 150.
(P.S. J Atkinson measured the Ref 75's output impedance off the 4 ohm taps to be .75 ohms at 20 Hz and 1K Hz. See: http://www.stereophile.com/content/audio-research-reference-75-power-amplifier-measurements)