Suggestions needed for an SS Stereo Amp w/+175wpc

Mapman, in my opinion you've offered some really excellent, valuable comments.

The one thing I would add in the way of clarification is that your item 4 really equates to your item 3 + item 5. In other words, the reason that the ability to progressively double power as load impedance is halved is significant, is that it signifies that the amp has both high current capability (relative to its power rating) and high damping factor (which is the same as low output impedance).

"Efficiency" is probably not the best term to use for these capabilities.

Best regards,
-- Al

Bob_reynolds: Do you have any idea what the output impedance is for the Carver amp? In the Sunfire amp Bob placed a 1 ohm resistor in series with the output and labeled those "Current" to provide a more tubish sound. I wonder if what you experienced with it versus the MF amp was the frequency response modification caused by the interaction between the amp's output impedance and the speaker's impedance.

Good point, Bob. I'm just about certain that the M4.0t was designed to emulate the sound of Carver's exotic Silver Seven tube amp. So it most likely did have a highish output impedance/low damping factor, with probable adverse effects on the bass, and increased sensitivity to variations in the speaker's impedance vs. frequency characteristics. And I don't think that on the M4.0t there was a choice of "voltage output" or "current output" as I believe was the case with the Sunfire's you referred to.

Mapman: It could be that the lower bass levels were just more noticeable as deficient at lower volumes. At high volumes, the rafters could be shaken by the 360 w/ch without any major tonal balance issues that I can recall. The differences in specs between Carver m4.0t and MF A3CR I recall that I could attribute this to were the power rating into 4 ohms, the damping factor, and/or the current levels available.

This strikes me as very likely. The bass weaknesses of the Carver would have been more noticeable at lower volume levels because they would have been accentuated by the Fletcher-Munson Effect, which GREATLY reduces the sensitivity of our hearing to deep bass frequencies (and also very high frequencies) relative to mid-range frequencies, when the overall volume level is low.

Martykl: I don't know ... whether there would be any impedence matching issues with their power amp and your preamp (though I don't know why there would be).

There wouldn't be. The preamp's 25 ohm output impedance is very low, and I suspect would be fully compatible with the input impedance of any power amp known to man (or woman). It's provisions for adjustable sensitivity on each input should also make it possible to avoid gain mismatches that might otherwise result in having to use the volume control near the bottom or top of its range.

Regards,
-- Al