[capwkidd]

I have noticed, when I tried my Digital NuForce amps on a pair of Tannoy's, the bass was way too much, as I understand they are designed for amps with minimal damping factor. Put an SET on them, and they are fine. I have heard, that if you put a 1 to 2 ohm resistor on the (pretty sure I heard it was the + side) output to the speaker, the damping factor will be affectivity reduced, and the bass will not be so pronounced.... I have not had the chance to try this yet, has anyone else? Thanks.

[TerryO]

I have noticed, when I tried my Digital NuForce amps on a pair of Tannoy's, the bass was way too much, as I understand they are designed for amps with minimal damping factor. Put an SET on them, and they are fine. I have heard, that if you put a 1 to 2 ohm resistor on the (pretty sure I heard it was the + side) output to the speaker, the damping factor will be affectivity reduced, and the bass will not be so pronounced.... I have not had the chance to try this yet, has anyone else? Thanks.

You heard right, except you got it backwards. The resistor in series with the positive terminal of the speaker is for Solid State push-pull amplifiers to allow you to achieve extended bass, while a tube amp, especially a SET doesn't need it. Reducing the damping factor will normally give you a bit extra bass extention, not less.

High Damping Factor numbers are more of a biproduct due to the use of negative feedback, than any type of real feature. It is perhaps one of the most worthless specs available, only trailing THD by a nose.

Best Regards,
TerryO

[Wayner]

Typically, amps with low damping factor (like 20) do not have good control of the speaker. Actually the speaker may be controlling the amplifier, simply because of over-shoot. Amps with a damping factor of 100 are generally a better performer because they control the speaker thru the hills and valleys of impedance variations (like at resonance frequencies) and the like.

Wayner

[kgturner]

[avahifi]

I always thought that "damping factor" meant that the amplifier should not get wet.

Unfortunately some amps, even with a high damping factor, still sound like they are playing under water.   

Seriously, damping factor is the ratio of the output impedance of the amplifier to the load impedance. It was typically only an issue years ago when tube amp output transformers were not really great.

If, for example you had a tube amp with a so so output transformer resulting in an output impedance of 8 ohm, then your damping factor would be one into an 8 ohm load.  This would result in the amplifier dissipating half of its output power directly into its own output transformers, and very poor control of the woofers and lower real output power than advertised.

With almost any modern solid state amplifier, the output impedance will be very high, thousands of ohms.  Thus the so called damping factor will be a huge number and essentially meaningless as a measurement of value to predicting audio musicality.

With tube power amps, the output impedance can still be quite high, and this will cause some tube amps to react strangely with random speaker loads.

We suggest good electronic design is to build equipment that minimizes any load interaction both at its inputs and outputs.  Good engineering is to design so that it will work well no matter what the rest of the system is that it is dropped into.

Regards,
 
Frank Van Alstine

P.S.  If you are going to install a resistor in series with your speaker terminal, make sure you use a resistor with an adequate power rating for the task. 40 volts across an 8 ohm resistor generates 200 watts across that resistor!  Be careful. Power equals voltage drop squared divided by load resistance.

[Speedskater]

With almost any modern solid state amplifier, the output impedance will be very high, thousands of ohms.

I hope that we have a small typo here.

"thousandths" not "thousands"

0.001  not  1000

[srb]

With almost any modern solid state amplifier, the output impedance will be very high, thousands of ohms.

I hope that we have a small typo here.

"thousandths" not "thousands"

0.001  not  1000

As well as "low" not "high"
 
Steve

[avahifi]

Yah yah yah, I meant very low, of course, and thousandths, not thousands.  Just another bad day here.

Frank

[*Scotty*]

capwkidd, the problem you are having with too much bass is only partially caused by the amplifier you are using.
 In all likelihood you are sitting in the middle of a zone of maximum pressure caused by standing wave coinciding with your listening position. In fact, depending on your room size and the cone area of your Tannoys every bass node in your listening room may be being energized in a way never before possible with bass capability of a SET amplifier.
 I would suggest moving your speakers further away from room boundaries to lessen the room gain at low frequencies they receive as well as moving your listening position forward or backward with an ear to lessening the amount of bass you hear at the listening position.
 Just repositioning your speakers in the room and moving your listening position may solve most of your problems
Scotty