damping factor

[mtrycrafts]

but when amps have factors below 100 there are differences to be heard.

Who has replicated this under proper DBT??? I'd be interested in that publication.

As the output impedance increases, the frequency response will follow the speaker and that is not a DF induced issue but output impedance issue, period.

 

[mtrycrafts]

all amps do not sound or perform the same.

No one has said this. Many distort what has been said.
If there is a difference, it will be well know issues, FR issues, clipping, etc. Not DF but high output impedance that alters the frequency response. That is a poor amp design, no matter what.

 

[mtrycrafts]

In general unless you have some exotic load, a damp factor >10 will sound the same as an amp with a factor of 10000000. .

Not convincing to some around here I am with you though, again
What is this world coming to.

 

[highfihoney]

Who has replicated this under proper DBT??? I'd be interested in that publication.

replicated are you serious,the main goal of most dbt testing is to prove that there are no differences to be heard not to find the performance point that the differences become audible.

the reason that im a nay sayer to all the google links is because i believe that most of them are shill posts & not science at all,how can testing of anything be subjective when the testing methods have an agenda before the testing ever starts,its easy as pie to prove anything you want if you pick the requirements & have an agenda,the testing methods that many covet as being the tell all are extremely biased & misleading.

im not suprised that bob carver used this type of testing to try & prove how his amps could perform as well as any other,i owned quite a few carver amps when i was younger including the silver-7-t monoblocks(top of the carver line),i was so dissapointed in those amps that if i were super rich i'd have thrown them in the fire place & roasted marsmallows over the flames.

the other reasons you are saying could be the root of the differences are not part of the equation,all specs are the exact same between the 2 amps except damping,here are the specs for 2 amps that i own that have different bass response that can be easily heard.

mc300 specs taken from my manual.

freq response, 20-20khz

distortion, 0.005 % maximum at all levels.

noise & hum, - 105 dba.

dynamic headroom, 2.1 db.

damping factor, 40.

input impendance, 20k & 40k

output impendance, N/A

clipping, N/A
.........................................................

mc402 specs taken from my manual

freq response, 20-20khz

distortion, 0.005 % maximum at all levels.

noise & hum, -105 dba.

dynamic headroom 2.1 db.

damping factor, 100.

input impendance, 20k & 40k.

output impendance, N/A.

clipping, N/A.

your saying that output impendance will be the cause when that is the biggest non issue there could possibly be,the same with clipping,both of these issues are not in the equation right from the start.

 

[highfihoney]

Nothing will happen. If that DF was so important, there would have been an awful lot of positive outcome from DBT tests of amps over the years. There are no such data and the ones where there are audible differences, it was not the DF that caused the differences, but other issues.

the outcome has been decided right from the start in these tests due to the extremely flawed & biased testing methods.

there is no data because the tests are not set up to find the truth they are set up to prove or disprove & are worthless.

 

[mtrycrafts]

the outcome has been decided right from the start in these tests due to the extremely flawed & biased testing methods.

Which tests are you referring to here?

I see, from the below response. The outcome is never decided, especially when the golden ears are so eager to find audible differences.
As to flawed and biased testing, your evidence may be found where??? Everyone has opinions. Some are better than others though.

there is no data because the tests are not set up to find the truth they are set up to prove or disprove & are worthless.

You may have this flawed opinion.
Your tests are set up to find the truths??? Or, perhaps it is even more flawed? and worthless.

 

[highfihoney]

the outcome has been decided right from the start in these tests due to the extremely flawed & biased testing methods.

Which tests are you referring to here?

I see, from the below response. The outcome is never decided, especially when the golden ears are so eager to find audible differences.
As to flawed and biased testing, your evidence may be found where??? Everyone has opinions. Some are better than others though.

there is no data because the tests are not set up to find the truth they are set up to prove or disprove & are worthless.

You may have this flawed opinion.
Your tests are set up to find the truths??? Or, perhaps it is even more flawed? and worthless.

hi mtry,the tests im refering to are every dbt test ive ever read,its constantly the underdog $300 amplifier against the champion $10,000 amplifier,dont this seem odd to you,smells like marketing to me

you asked where is my data,there are no published dbt tests where the goal was to establish if there are differences between amplifiers with extremely low damping & amps with damping above 200,in order to do a dbt that deals with damping factors as the only possible issue both amplifiers would need to be made to exact specs except the damping with instantainous a/b switching,any time delay (even one second) makes any results void,no such tests will ever be done & published.

you responded in an earlier post that issues such as output impendance & clipping are the reason differences can be heard & not damping factors,please explain what you are basing those statements on & why you say that they are issues.

you also questioned my motive behind testing amplifiers,i am a collector of audio gear weather it be pro gear,economy or high end i collect it all & use it all,i own & use amplifiers costing from $300 up to $18,000 & i enjoy them all, my only motive is to match the best amp with the rig its going to power nothing more.

crown audio has published their findings in dealing with damping factors if anybody cares to read them they are all over google.

 

[mtrycrafts]

hi mtry,the tests im refering to are every dbt test ive ever read,its constantly the underdog $300 amplifier against the champion $10,000 amplifier,dont this seem odd to you,smells like marketing to me

Thanks. I wasn't sure and took a gamble and payed off. Too bad it wasn't that powerball, then I would have set up a DBt team

Marketing??? By whom? What do they have to gain? The folks who started the development of the DBt equipment were indeed 'golden ears' but things changed when the DBt data started to come in.

Why would that $300 Yam integrated be audibly different from that $15k pair of monoblocks? Why couldn't the 3 'golden ears' differentiate?

One thing is for sure, anyone can try it, replicate it. The only issues com up when others mess up the protocol. A number of years ago, someone from Toronto posted a long experiment of wire, supposedly under DBT. There is no way he can get 48 of 50 correct answer on comparable wire, under DBT. And these kinds of results with a whole slew of wires. That is fishy. I offered him to repeat his testing with 3rd party presence and be published.

you asked where is my data,there are no published dbt tests where the goal was to establish if there are differences between amplifiers with extremely low damping & amps with damping above 200,

Low damping is an amp with high output impedance. High output impedance affects frequency response, plain and simple. this can be measure very easily. That is an inhering part of the design as best I know. Hence, that would ride on top and exaggerated by the speaker frequency response. Not so with an amp with low output impedance. If that FR is not leveled, that is what you hear if it exceeds the threshold of detection. No different from an amp that has poor FR already. This can also be achieved by adding a resistor external to the amp. Bob Carver did this to give that tube sound.



in order to do a dbt that deals with damping factors as the only possible issue both amplifiers would need to be made to exact specs except the damping with instantainous a/b switching,any time delay (even one second) makes any results void,no such tests will ever be done & published.


Well, it would be published someplace if it was done and written up

If, the high output impedance caused Fr deviation not accounted for, that is what anyone may detect. Just like an amp with poor Fr in the first place. It would also depend on where in the spectrum this happens as the JND at 10kHz and above increases to 3 dB spl at 16kHz, under the most sensitive conditions.

Florentine, Mary, et al 'Level Discrimination as a Function of Level for Tones from .25 to 16khz. Journal of Acoustic Society of America, 81(5) May 1987, pg 1528-1541.

you responded in an earlier post that issues such as output impedance & clipping are the reason differences can be heard & not damping factors,please explain what you are basing those statements on & why you say that they are issues.

Clipping need no explanation. You cannot hear clipping? that is a dead give away of differences.

High amp output impedance affects FR. That AES paper Mac lambasted measured it, Fig 8. Bob Carver demonstrated it on some of his amp lines having a resistor switched in the speaker output.

you also questioned my motive behind testing amplifiers,

I seriously doubt this. Most likely I questioned your results, but not knowing the full specs of the amps you test, and seeing that many may be older tubed amps, high output impedance, you might have heard real differences, who knows, without a DBT and one that preferably been replicated. But then we would also know with proper measurements of those amps what is causing those differences as it would not be a mystery.





crown audio has published their findings in dealing with damping factors if anybody cares to read them they are all over google.

Yes, they have and others have analyzed DF, one example is the DF tech paper here at AH which is the same as this one.

http://groups.google.com/group/rec.audio.high-end/msg/1a35b2da043f01d5?q=author:DPierce@world.std.com+and+damping+factor&hl=en&lr=&rnum=1


Controlling speaker movement is well explained in this link, how much and how low of a DF.
One also have to include the JND of the human hearing. At the low and high fr band, the threshold is rather high, several dB and more(3dB at 16kHz per the above citation)
FR deviation can be audible, if above the JND.

supplemental:

http://www.mastersonaudio.com/audio/20020901.htm

He has conducted many amp DBT in his lifetime. Not sure how many were with tube, probably not many. This is why tube is usually excluded from amp sound debate But, some well designed, those that are able to have low output impedance, is different.

 

[highfihoney]

Low damping is an amp with high output impedance. High output impedance affects frequency response, plain and simple. this can be measure very easily. That is an inhering part of the design as best I know. Hence, that would ride on top and exaggerated by the speaker frequency response. Not so with an amp with low output impedance. If that FR is not leveled, that is what you hear if it exceeds the threshold of detection. No different from an amp that has poor FR already. This can also be achieved by adding a resistor external to the amp. Bob Carver did this to give that tube sound.

If, the high output impedance caused Fr deviation not accounted for, that is what anyone may detect. Just like an amp with poor Fr in the first place. It would also depend on where in the spectrum this happens as the JND at 10kHz and above increases to 3 dB spl at 16kHz, under the most sensitive conditions.

Clipping need no explanation. You cannot hear clipping? that is a dead give away of differences.

good morning mtry.

i would agree that clipping & output impendance could be issues if these 2 factors had not been dealt with from within both amplifiers used.

clipping in the amps i use is not a factor for many reasons,these amps have a built in device called "powergaurd" that will not allow the amp to clip & automatically lowers the gain just enough to keep the distortion from ever reaching above 0.005% at any time then automatically returns the gain at the blink of an eye,this affect never becomes audible,both of the amps also have wattage meters that show true output & they show any power draws caused by hard hitting dynamic peaks,both amps also have highly accurate warning lights to show if any distortion at or above 0.005% is present in the signal,for these reasons clipping is eliminated from the picture.

output impendance has been accounted for also within both amplifiers,both amps have "autoformers" that keep the impendance at a constant no matter the circumstances or the load,at no point will the output impendance be affected by the signal or by the speakers,no matter what the output impendance remains a constant & will not variate.

i think its safe to say that clipping & output impendance can be eliminated from the picture & the only other spec to look at why these differences in performance are audible is the extremely low damping factor of 40 in the amp compared to the amp with a damping factor of 100.

have a great day.

 

[WmAx]

.....output impendance has been accounted for also within both amplifiers,both amps have "autoformers" that keep the impendance at a constant no matter the circumstances or the load,at no point will the output impendance be affected by the signal or by the speakers,no matter what the output impendance remains a constant & will not variate......

.....the only other spec to look at why these differences in performance are audible is the extremely low damping factor of 40 in the amp compared to the amp with a damping factor of 100.....

Damping factor is a product calculated from output impedance and load impedance. Output impedance is much more useful value, because you can calculate damping factor with any load if you know the output impedance. But damping factor is a final calculation of a specific load and means nothing without very specific information. (Note: output impedance varies with frequency, but in the majority of solid state amplifiers it has no variance of substantial magnitude to be audibly relevant).

Here is how damping factor is calculated:

Damping Factor = (Load Impedance) / (Output Impedance )

For accurate results, this must be analyzed at a specific frequency. Even if output impedance if flat across the bandwidth, the load impedance of any real speaker certainly will not be, thus the variable will change. You need to go ahead and add in the series resistance of the speaker cable used if you want to know the actual damping factor as used, so:

Damping Factor = (Load Impedance + Speaker Cable Resistance) / (Output Impedance )

-Chris

 

[highfihoney]

Damping factor is a product calculated from output impedance and load impedance. Output impedance is much more useful value, because you can calculate damping factor with any load if you know the output impedance. But damping factor is a final calculation of a specific load and means nothing without very specific information. (Note: output impedance varies with frequency, but in the majority of solid state amplifiers it has no variance of substantial magnitude to be audibly relevant).

Here is how damping factor is calculated:

Damping Factor = (Load Impedance) / (Output Impedance )

For accurate results, this must be analyzed at a specific frequency. Even if output impedance if flat across the bandwidth, the load impedance of any real speaker certainly will not be, thus the variable will change. You need to go ahead and add in the series resistance of the speaker cable used if you want to know the actual damping factor as used, so:

Damping Factor = (Load Impedance + Speaker Cable Resistance) / (Output Impedance )

-Chris

hi chris,i understand that a damping factor is subject to change for the reasons that you posted but they still dont have large affects on the output impendance of the amps i used,the autoformers keep the load that the amplifier is being presented with at a optimum level allowing the amps to produce a constant rate of power & impendance at all times.

if both amplifiers have the exact design & output impendance plus both amps are using autoformers to keep the load a constant then any affects that might be caused by wire resistance or from the speakers would be transfered equally to both amplifiers then transfered equally to the speakers.

 

[WmAx]

hi chris,i understand that a damping factor is subject to change for the reasons that you posted but they still dont have large affects on the output impendance of the amps i used,the autoformers keep the load that the amplifier is being presented with at a optimum level allowing the amps to produce a constant rate of power & impendance at all times.

The autoformer does not eliminate the output impedance and load impedance interaction because the autoformer itself is going to have an output impedance value. From what I can gather from 3rd party references, a McIntosh 'autoformer' appears to be an inductor with multiple taps to provide maximum power output to a specific load impedance and to reduce load impedance varation to the output transistors.

-Chris

 

[highfihoney]

The autoformer does not eliminate the output impedance and load impedance interaction because the autoformer itself is going to have an output impedance value. From what I can gather from 3rd party references, a McIntosh 'autoformer' appears to be an inductor with multiple taps to provide maximum power output to a specific load impedance and to reduce load impedance varation to the output transistors.

-Chris

you are correct about the autoformer & its functions which take away drasticly from the equation by keeping power output at its maximum & severely limiting any varaitions to the output,both amplifiers have the same autoformers therefore when using the same ohm taps both amps autoformers would have the same impendance so the autoformers impendance is constant between the two amps,correct?

both amps are the same design,both amps have the same impendances,both amps autoformers are the same,both amps are not clipping,both amps power output is monitored,both amps are running the same speaker.

the load that the manufacturer used to determine the damping factors of both amps is the same & that is where their rated damping factor was derived from,this would also apply to any variables in the chain as long as they remain constant to each amplifier which they have.

im not trying to figure out what the damping of either amp is while its in the system,there is no need to,i allready have a fixed starting point from the manufacturer & any variable that would effect one amp would surely effect the other.

im still not sure where you are going with all of this,both amps share the exact same everything including the same set of variables that determine damping while the amps are in & out the system.