What do you look for in damping factor?

Guidocorona, you may be thinking of the INPUT impedance of the Rowland 312. Usually, power amps’ output impedances are very low, hopefully below that of the speakers--especially for SS amps.

If the Rowland 312 is a Class D or switching amp--and I believe it is, the manufacturer may be quoting the figure in a different way because of the different topology. The Rowland site does not list the impedance figures of the 312 under products, 300 series---unless I missed it.

Typical tubes amps use transformers to lower their output impedance below that of the 4-8 Ohm speakers they usually have to drive. Atmasphere amps are, of course, different (being OTL's) and do necessitate being mated with a bit higher impedance speaker than most “normal” amps do. SET amps also have their impedance limitations.

A 100K Ohm amplifier output just sounds wonky to me.

Ralph, I am slightly confused. Are you trying to say that:

A. The perceivable synergy of the Rowland 312 and the Mahlers exists in spite of the amps high damping factor?

B. The 312's damping factor is immaterial to its synergy with speakers in general.

C. The perceived extreme degree of synergy between the two devices cannot be, and is likely a case of self delusion on my part?

By the way, if I recall correctly, the output impedance of the 312 is 100K Ohms.

Guidocorona, the answers are yes, yes and no. The synergies you hear have nothing to do with 'damping factor'. BTW the impedance you refer to is input impedance, not output impedance.

Negative feedback is not normally a problem unless the device is unstable or is over driven (bad design, misuse). Excessive damping factors may be indicative of a design that is not balanced with regard to other factors, such as stability, distortion at clipping etc.

Extremely low damping factors will cause frequency response to vary with speaker impedance.

Audio is represented by a voltage signal. In order to preserve this you should have low ouput impedance compared to the speaker input impedance, which equates to a high damping factor (at least greater than a nominal value of 10 in order to be inaudible when matched with a load that varies significantly with frequency,such as most speakers).

A solid state amp with a damping factor of 25 or lower will sound more tube-like. I have a Onkyo A-9555 Integrated amp and the damping factor is only 25.......sounds very tube-like too!

I'm not sure you can equate a high damping factor with large amounts of global feedback in all instances. Digital amps may be the exception in that they have a high DF of a 1000 but they don't seem to suffer in sound quality, the lack of openess or transparency. I know for sure when a conventional amp is designed with large amounts of global feedback it is usually involves a poorly executed circuit design. So it is my opinion that if your looking for an amp with a high damping factor that results in visegrip control of the low frequency drivers without sacrificing sound quality you may want to go digital.

For example I have used the McCormack DNA-1 Rev B. This amp uses no global feedback, has a low damping factor of 150 and seems to have unlimited power reserves. Because of the low damping factor the bass at times can be a bit mushy & loose depending on the preamp used but definately excels in soundstaging & sound quality, one of my all time favorites.