Amp damping factor?

Keep in mind that many amps with extremely high damping factors achieve that by means of large amounts of feedback, which results in several well-recognized negative side-effects. These include transient intermodulation distortion, which results in sloppy handling of sharp transients.

Regards,
-- Al

In amps with output transformers, damping factor is limited by the magnetic hysteresis (lag) of the output transformers, to usually not more than 16. This includes all tube amps with output transformers, and certain ss amps with 'auto-formers' (like McIntosh ss amps.)

The main advantage of higher damping capability is in providing cleaner bass in cone woofers and subwoofers. I think 100 is plenty, unless your speaker cables are 50 feet long! Speakers with big voice coils and strong magnets (woofers) create a strong 'reactive load' (a counter-current back to the amp.) Damping is a measure of an amp's ability to overcome this reactive load; to make the cone follow the music signal precisely and reversing its direction of travel instantly when the polarity of the signal changes.

This is why subwoofer makers use ss amps, as well as why people who biamp their speakers use a ss amp for the bass, and a tube amp for the mid/highs. (A tube amp has plenty of damping to control midrange drivers and tweeters, while, many believe, offering a more nuanced presentation of the music, especially the midrange.)

Speaker Q (actually woofer Q) becomes an important issue primarily when it has a resonant peak at a certain (audible) frequency; because the cone becomes hard to control when excited by musical information at that frequency. Adequate damping can help keep the woofer's response flat, but more important IMO, good damping results in better bass transient response (detail.)

Vintage Mac gear (tube) has the lower damping associated with tube amps, although Mac's tube amp damping is always a couple of points better because of their unrivaled output transformers. Their ss amps, (except for a couple of models - can't remember which) all use autoformers, and although they have a bit better damping than their tube amps, I wouldn't buy one, new or vintage ;-) As for what the folks at Krell said: well, if you're using a Krell, you don't need to think about damping ;-)
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Too high of a damping and the bass is thin, lacking in authority, and not very musical. Too high is relative depending on the speakers it is matched to. My tube amp has a damping factor of about 11, and the bass on the Legacy Whisper is stunning, better than the SS 600wpc Legacy amplifier also used with the Whisper. Damping is also like a "brake" on the woofer and too much braking and the woofer will not be able to move enough to get some body in the bass. A speaker and amplifier need to be matched with regard to damping and then magic occurs....I also use Bryston amplifiers and they match well with my speakers and their damping is over a hundred, and the bass is great. Numbers don't tell all the story....The biggest mistake is thinking that the higher the number, the better the control of the bass....not necessarily....jallen

Inductor in-series with the woofer has resistance approx. 0.08 ohm limiting DF to 100.

Truthfuly, I have not heard a quality sound produced by an amplifier whose damping factor is rated more than 200. Specs don't reveal any secrets how musical and enjoyable an amp will sound, so believe your ears. Digital amps seem to be the exception which normally have a damping factor of up to 1000.