Why are there no Damping factor specs for these amps ? Is it that bad ? Even my old pioneer lists them in its spec sheet. 
This guy is offering to sell me this for 250 bucks. I might take it for my subs just because i am renting it anyway. Until i hear back from peter Daniel. Its not very good for my top end. NO better then my ancient pioneer.
Is there way to measure the factor with a Meterman 37ZR?
This guy is offering to sell me this for 250 bucks. I might take it for my subs just because i am renting it anyway. Until i hear back from peter Daniel. Its not very good for my top end. NO better then my ancient pioneer.
Is there way to measure the factor with a Meterman 37ZR?
Hi Madmike2,
Use the method Netlist linked. Try to stay low in frequency. Many meters are not accurate above 80Hz - sorry, but you normally do this in the midband nearer to 500Hz or so (1KHz is one test freq. standard). You can measure around 100Hz but avoid 60, 120 and 180Hz as you may get ripple effects from the power supply, and use a dummy load. A speaker's impedance is highly variable with frequency, and level to some extent.
A well equipted shop would use something like Dale non-inductive 8R0 250W resistors and a good meter such as an HP 34401A or Fluke 845 (?). There are others. You need a sine wave generator with reasonably low distortion. Do not drive the amp too hard or other issues will become important.
-Chris
Use the method Netlist linked. Try to stay low in frequency. Many meters are not accurate above 80Hz - sorry, but you normally do this in the midband nearer to 500Hz or so (1KHz is one test freq. standard). You can measure around 100Hz but avoid 60, 120 and 180Hz as you may get ripple effects from the power supply, and use a dummy load. A speaker's impedance is highly variable with frequency, and level to some extent.
A well equipted shop would use something like Dale non-inductive 8R0 250W resistors and a good meter such as an HP 34401A or Fluke 845 (?). There are others. You need a sine wave generator with reasonably low distortion. Do not drive the amp too hard or other issues will become important.
-Chris
They may not mention it because damping factor may not be such a high priority to their customer base. Quite a few writers have opined that SS amps nearly always have far more than adequate dampimg factors without any special attention by the designer. I'm not necessarily concurring but it is not an uncommon point of view.
There is also an article in the latest edition of "AudioXpress" where the factors contributing to loadspeaker damping are analized. In the article the author concludes that the voice coil/magnet interaction is the dominate factor in damping and that an amplifier's constibution is nearly insignificant. I read this very quickly and have not given it deep thought so I'm not in a position to concurr or object to the conclusion. Nonetheless, if ART shares this conclusion that may be another reason why they don't state it.
In any case you can measure output impedance with a signal source and a DMM. DF is then simple calculation. BTW, it is frequency dependent.
There is also an article in the latest edition of "AudioXpress" where the factors contributing to loadspeaker damping are analized. In the article the author concludes that the voice coil/magnet interaction is the dominate factor in damping and that an amplifier's constibution is nearly insignificant. I read this very quickly and have not given it deep thought so I'm not in a position to concurr or object to the conclusion. Nonetheless, if ART shares this conclusion that may be another reason why they don't state it.
In any case you can measure output impedance with a signal source and a DMM. DF is then simple calculation. BTW, it is frequency dependent.
High damping factor is normally achieved through high feedback levels. This is normal in most SS designs and there was a period where "the higher the better". Damping factors from around 50 to 100 are normal and in average situations (no silly loads) is enough. Hollow state ranges from, say 4 to 18 on average (eight is a good average number). Different sound, but good.
My previous post should have indicated a Fluke 45, not 845. Finger trouble.
-Chris
My previous post should have indicated a Fluke 45, not 845. Finger trouble.
-Chris
it just wants to keep giving itself to others while driving walking biking. It is a very giving finger.
Wow amplifierguru , my finger says hi It also wants me to inform you that it has a degree in Criminology 3/4 of a diploma in audio engineering half of one in Stationary Engineering and is now actually trying to complete one in Civil Engineering. But if you will take it i can give you the finger as well, i need it back though as it gets busy during rush hour ala "L.A Stories" the family edition. 
^^ all in fun Mods, all in fun
Michael
It also wants me to inform you that it has a degree in Criminology 3/4 of a diploma in audio engineering half of one in Stationary Engineering and is now actually trying to complete one in Civil Engineering. But if you will take it i can give you the finger as well, i need it back though as it gets busy during rush hour ala "L.A Stories" the family edition. ^^ all in fun Mods, all in fun
Michael
Hi Mike,
To measure DF you simply need a 1999 or 3999 count AC millivoltmeter - set it up on the amplifier output putting out 1.990V say on no load then load it to the minimum itll take, say 2 ohms. If it registers a measurable drop then calculate the resistive divider ratio back to the Z0 at that frequency. Too easy.
Sorry about the
I get incensed by the finger.
Cheers,
Greg
To measure DF you simply need a 1999 or 3999 count AC millivoltmeter - set it up on the amplifier output putting out 1.990V say on no load then load it to the minimum itll take, say 2 ohms. If it registers a measurable drop then calculate the resistive divider ratio back to the Z0 at that frequency. Too easy.
Sorry about the
I get incensed by the finger. Cheers,
Greg
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