... how important is Damping factor in determining what amp to buy

... oh man! - was looking for abit more clarity about how important it is in the voicing and control of a speaker; I understand what it is and what it supposedly does and that all amps must have it to some degree... stringreen's approach ( which to me seems to be more financially-based) would have me all over town, listening to not in my space, or with my components...
MOre pointedly: I'm wondering if my vintage Onkyo A7 (65w/c) or Nikko DC Alpha 230 (120w/c) has enough DF to adequately control the woofer in a new-to-me pair of vintage Gershman Avant Garde RX-20s (before 2000) I've got on the way; I've been lead to believe that if a speaker is underpowered that you can damage a woofer, and I assumed this had to do with DF...

It appears that your Onkyo has a damping factor of 50, and the Nikko has a damping factor of 70. Both of those damping factors will be suitable in terms of sonics with any speaker that is suitable for use with a solid state amplifier.

I’ve been lead to believe that if a speaker is underpowered that you can damage a woofer, and I assumed this had to do with DF...

An amplifier that is underpowered relative to the application, and therefore may be frequently driven into clipping, can cause tweeters to be damaged. I am not aware of any means by which an underpowered amplifier can damage a woofer, or of any relation between damping factor and the likelihood of speaker damage.

Regards,
-- Al

Who wouldn’t want better control of the bass drivers? Wouldn’t that yield tight and accurate bass

Actually no. It **might**. Any loudspeaker can be overdamped- IOW, you can have too much damping. The result is 'punchy' bass without much in the way of definition (also called 'body' when low frequencies are being described). The correct bass will have punch and definition at the same time.

If you have too much damping, the speaker can't make the excursion it should to reproduce the waveform- which is why you loose definition. On top of that, the **amount** of 'punch' you get will not be correct (punchy, but not enough). A lower damping factor can allow for more bass excursion. Too much excursion of course and you have muddy bass, but IME that is actually pretty rare- most acoustic suspension speakers are internally damped already, while most bass reflex, horn and open baffle designs (which includes magnetic and electrostatic planars) really don't need that much.

If I knew absolutely nothing else about two amps, except that one has a damping factor of say 4 and the other had a damping factor of 1,000, I would take the amp rated 4 (it would most likely be a tube amp, and perhaps a single-ended triode with only one output tube).

As the owner of a pair of VTL MB 450 III with adjustable damping factor (4 settings) I can attest to the fact that damping factor matters. Obviously it's an interaction with the rest of your system but as I got my room resonances under control I could lower the DF on my Magico Q3s and now have it at the lowest setting. The effect of lowering DF is to lose some immediate "punch" in the bass but replace it with greater air, scale and overall body which is much more preferable. My suspicion would be that too many amps (especially solid state) are over damped but that's just my preference and I'm surprised more manufacturers don't offer adjustable DF

ps I can't find any specs on what the VTL damping factors actually are for the four settings, anyone know?