Dampening factor

[sfogg]

"check out the numbers on my favorite all time sweetest sounding SS amp, IMHO, the McIntosh 250. Its dampening factor is 10, thats right TEN."

Transformer on the output... right?

BTW, for anyone that wants to try listening to how a different output impedance effects the sound here is an old trick. Get a high DF SS amp. Spend some time listening to it. Then insert a 1 ohm power resistor (10w is fine for horns) in series with the positive feed to the speaker. In effect you just reduced the amps DF to about 8 and you will be able to hear how/if the sound changes.

Shawn

[MrMcGoo]

"check out the numbers on my favorite all time sweetest sounding SS amp, IMHO, the McIntosh 250. Its dampening factor is 10, thats right TEN." Transformer on the output... right? BTW, for anyone that wants to try listening to how a different output impedance effects the sound here is an old trick. Get a high DF SS amp. Spend some time listening to it. Then insert a 1 ohm power resistor (10w is fine for horns) in series with the positive feed to the speaker. In effect you just reduced the amps DF to about 8 and you will be able to hear how/if the sound changes. Shawn

The Sunfire amps use the same "trick" as Shawn recommends. The voltage outputs have no resistor in series while the current outputs on the same channel have a 1 ohm resistor in series. Bob Carver recommends that the current output be used to run the high frequency drivers and the voltage output should drive the low frequency drivers. I use that setup on my center channel.

Bill

PS: Sunfire does not advertise the damping factor of their amps. B

[Duke Spinner]

Duke,

"my K-2 ... has a Damping factor of 20,000 ......"

I thought it was 10,000... and that was below 300hz or so. As the

frequency rises in the K2s the output impedance goes up. Higher up I

think it is 'only' around 1000.

Either way though obviously the K2 has an extremely low output

impedance. Shawn

Ha ...we're both Wrong , Shawn ...

i was thinking of my Macro Reference @20,000.

the 'K" is 3000 @10 - 400 hz

[dragonfyr]

At the risk or offending everyone, this is another topic that ultimately is 'much ado about very little.'!

And unfortunmately any significant advantages are normally negated by the use of speaker cables and passive crossovers!

...there are a great many more factors of greater import!

[][][6]

[Speedball]

Any input about what to look for or is it too technical? The only things I'm familiar with are power rating...DF...does it double in power as the ohms are halved. What I read on these forums is a big one too about how happy people are with their equipment and that's about it. [8-)]

............Thanks!

[Duke Spinner]

At the risk or offending everyone, this is another topic that ultimately is 'much ado about very little.'!

And unfortunmately any significant advantages are normally negated by the use of speaker cables and passive crossovers!

...there are a great many more factors of greater import!

[][][6]

no way to get around the highest resistance in the circut ....

the one that Skews the calculation all to hell ...

the Voice Coil ....

[Deang]

Hee hee, ain't that the truth.

[CONVERGENCE]

George Augspurger wrote an article on this subject. With scientific calculations. Here is what his conclusion was.

"used an 8-ohm loudspeaker with a d.c. resistance of 6 ohms to prepare the chart. The exact figures are not particularly significant - the point is that the resistance of the speaker voice coil is the limiting factor.

Amplifier R (ohms)< td>

Amplifier DF

Actual Over-All DF

8

1

0.57

4

2

0.80

2

4

1

1

8

1.14

0.5

16

1.23

0.25

32

1.28

0.125

64

1.30

0.05

160

1.32

0.025

320

1.33

0.0125

640

1.33

0.0000

8

1.33

Table 1: The actual damping factor (with loudspeaker connected) is limited by the speaker voice-coil resistance. Figures are for 8-ohm output terminals to which speaker having nominal 8-ohm impedance and 6-ohm voice-coil resistance is connected.

Note that changing the amplifier damping factor from unity to 8 makes a substantial change in the actual damping factor, though it is not a 1:8 change but a 1:2 change. But changing the damping factor from 8 to 16 makes very little difference in the actual damping factor, and anything more than 16 has very little effect indeed. If we increase the damping factor from 16 to 160, the change is effectively less than 10%, not 10 or one.

[MrMcGoo]

The damping factor is a surrogate for amplifier output impedance. Low output impedance helps attain better frequency response, since a speaker's impedance varies with frequency. Unfortunately, a high daming factor may be obtained with poor amp designs, so it may be of little value in understanding an amp's capabilities.

Bill

[djk]

Calling Mac bass 'warm' is being charitable, 'muddy 'is more like it.

My McIntosh MC2120s have a DF of 14, and they sounded 'muddy'. After adding about $4 worth of caps at various spots in the circuit it would pound your guts out. The DF didn't change.

Crown made the Delta Omega with negative output impedance sensing (to compensate for the resistance of the speaker wire). The DF measured in excess of 1000.

The modified Mac has much better 'slam'.

If your speakers have wide impedance swings (as do some Klipsch speakers), and the amplifier you are considering has a DF of less than 20 (because it has an output transformer), it is a good idea to audition the exact components as a system.

It would be nice if the Tin Eared Meter Reader types actually came up with a test for sound quality, I would be all in favor of such as it would save me the agrevation of auditioning horrible sounding equipment.

Until then, I guess I am forced to listen to the music.