Discussion in 'General Audio Discussion' started by Noisypot, Jun 24, 2018.
The Stax DMA-X2 lists a sampling factor of over 100 in the users manual.
Kenwood amps M1, M1A, M1D, M2, M2A, KA-990, Ka-990V and others with the Kenwood Super DLD (Dinamic Linear Drive) circuit. Damping factor 50 Hz. = 1000
That's an interesting point. Some of those old amps could be adjusted for positive or negative DF, with an intermediate setting that yields theoretically infinite damping. Negative DF causes the amp to actively drive the woofer cone in the direction opposite to its current motion.
Current VTL amps like the current version of mine offer variable NFB.
The Crown PS400 and PS200s I use in my main system with JBL 4345 and its 18-inch woofer simply say ">400".
The Crown Studio Reference-II I use with my JBL 250Ti's says ">20,000". That's twenty-thousand!
They all sound lovely.
My Rotel RB-990BX supposedly has a damping factor of 1000.
A slew of Yamaha 2-channel receivers in the early to mid 90s had damping factors of 240+ and they weren't even especially high-end models.
JVC A-X9 100wpc 200 damping factor
JVC/Vicror M-7050 150wpc 200 damping factor.
JVC M-L10 160wpc,200 damping factor.
Same with my 980BX, rated 1000. Really takes hold of my 2235H and makes them behave.
DF can be likened to a good shock absorber.
Some like a soft ride, and some like a sporty ride.
Higher DF # = the tighter control of the low frequency driver, less overshoot and the quicker return to the neutral state of the driver after a musical impulse(less smear).
Dynamic Bass impulses, IMHO/E, has always sounded better/natural with tight control, whether it be it FB or low PS impedance, or both implemented.
As an example,I have spent plenty of HQ time mixing live music and if a kick drum doesn`t have the "similar realistic" reproduced impact effect through a decent stereo, then for me, it needs to be addressed, and that`s always been one of my many goals amongst others in a reproducing audio system, at least mine.
However, to each their own tastes.
Kind regards, OKB
The only reason to strive for a high damping factor – which can, after all, do no harm – is the
usual numbers game of impressing potential customers with specification figures. It is as certain
as anything can be that the subjective difference between two amplifiers, one with a DF of 100 and
the other boasting 2000, is undetectable by human perception. Nonetheless, the specifications look
very different in the brochure, so means of maximizing the DF may be of some interest.
"Audio Power Amplifier Design Handbook, Fifth Edition, Douglas Self"
Easy now. Science has no place here!
My Dad's old Bogen RR550 had adjustable damping factor. Don't recall where he set it, but I experimented with it when it was passed to me (50 years ago.
As I recall, lower damping factor resulted in more (although mushier) bass.
My experience as well. sdw54 on my B-I-L`s restored Fisher 100 "Box Car" mono block tube amps.
Once again, don't forget that DF is measured at the speaker terminals. Once you add a length of wire, the DF drops dramatically, like divided by 10 ! The thickest wire would be best for tube amps because of the low DF.
I think you mean to say that DF is measured at the amplifier output terminals, not at the speaker terminals, right?
An elegant solution to this problem would be to drive the speaker through one pair of wires while taking feedback to the amplifier through a separate pair attached to the same speaker terminals. Lab power supplies often provide the necessary four-terminal hookup to guarantee excellent voltage regulation at the load, regardless of cable losses. Every hi-fi amplifier I've seen takes feedback from its output terminals instead, which is the reason that DF can be cable-limited. If I live long enough, I'm going to design and build myself a tube amp with four-terminal load connections.
Yep, in general, that relationship can be heard.
That's a great idea! And you are right, I meant the amp. speaker terminals.
I think Kenwood did something similar in the early 80’s with their sigma drive. Then Onkyo with their super servo.
Separate names with a comma.