Low damping factor but fast& high current SS amps?

OH, one other thing.....Kirkus speaks about the relation of enclosure size, TS parameters and where the term Damping Factor may come from. Good stuff.

I would add that many years ago, as watts became less expensive with the start of the SS 'era', speakers also changed....a lot, to the small, sealed boxes we know today.

Large enclosure speakers still exist, and they are still generally best with low power tubes, which also have a minimal measured damping factor....

And, for no particular reason....My panel also has an inductor in series with the woofer. In this case, Magnepan uses a 16ga iron core inductor of about 0.4 ohms DCR. This is one of those DIY items which causes some minor controversy in panel discussions. Some will put a monster aircore of as little as 0.2 ohms in the stock inductors place. This will have the effect of changing the speakers freuquency balance a little more bass-wards.

Looks like this thread go side-tracked into a 101 on definitions. LOL! :-) Anyway, it was an interesting read & a good refresher for me as well.

Now, to address Zuio's issue: I'm not sure that low damping factor (DF) & fast + high current can co-exist. DF is an indirect measure of an amp's output impedance so if you assume 8 Ohms nominal speaker impedance then higher the DF, the lower the amp's output impedance.
An amp's output impedance is a function of the amp's bandwidth - the higher the bandwidth, the lower the amp's output impedance will remain. If the amp's bandwidth decreases, the amp will not be able to follow the music signal & we get distortion & increased output impedance.
If output impedance increases, it will limit the amount of current that can be delivered to the load as more will be dissipated as heat in the output impedance.
So, I believe that high DF indirectly let's us know that the amp is trending towards high bandwidth (fast) & will be capable of high current delivery (if it's power supply is able & the music signal demands it). Correct me if I'm wrong. Thanks.

"So, I believe that high DF indirectly let's us know that the amp is trending towards high bandwidth (fast) & will be capable of high current delivery (if it's power supply is able & the music signal demands it)."

High current demand is at lower frequencies where amplifier's output impedance is usually very low. High DF doesn't tell us anything about amplifier's bandwidth. Amplifier might have bandwidth limited at the input (to avoid TIM) while output is wide bandwidth with low output impedance. In addition output impedance might or might not change a lot with frequency. For instance Rowland 625 has DF=200@20Hz-20kHz while my class D Rowland 102 has DF=8000@20Hz and DF=8@20kHz.

If I may, a question more related to the original post, and Kij's comments, above.

Doesn't high damping factor also indicate high feedback? I know, right now, that though I am a satisfied 'd' owner, I'd swap it out for a Pass amp. Low feedback, reasonable output while remaining in class 'a' and a minimal number of gain stages. Simple, perhaps, and direct?

Feedback may be even more controversial than damping factor!

Magfan - Deep feedback lowers output impedance (also lowers THD and IMD). Amplifier's configuration affects initial output impedance. Class D amps for instance connect speaker to power supply and GND (zero impedance points) all the time, only polarity changes. Without feedback output impedance would consist of Mosfets' resistance (in order of 0.1ohm) and zobel network's impedance (common mode choke + capacitor and resistor to filter out carrier). Inductance of this choke is the reason of class D higher output impedance at high frequencies. On the other hand this choke has only few turns of wire and very low resistance (high DF at low freq.). I would estimate that since 0.1ohm is reduced to 0.001ohm feedback is at least 40dB deep but it is not too bad.

There is nothing wrong with feedback, if you know how to use it. Amplifier has to be as linear and fast as posible to start with. Small amount of feedback should reduce THD only to about 0.2-0.5% while bandwidth at the input should be limited to one that amp had without feedback (to prevent TIM).

I'm trying to make sens of it and so far I've learned that things are extremely complicated. Very high DF means deep feedback but Soulution 700 amp has DF=10000 and bandwidth of 1MHz with no feedback. If I would only know how to do it I would build such amps and sell them (for $100k) myself.