Whats up with this?…..perfect dac sounds inferior allthough math says otherwise..

[Speedskater]

Long cables, or some super high capacitance cable.

If a unit's output impedance is 200 Ohms or less, then the cable wound need to be hundreds of feet long to matter.
Hard to make a reasonable super high capacitance cable. (coax or Shielded Twisted Pair)

 

[DVDdoug]

I recall seing a list in some thread the other day with some models from same manufacturer did have diffrent output resistance values. some araound 2K while others could be 10K.

That's probably not the output impedance but the minimum recommended load impedance. Solid state electronics have "naturally" low impedance outputs and it not easy to get 10K unless you add a series resistor. Even 2K would be unusually high.

...Sometimes there is a resistor to limit current in case the output is shorted but 1K or less would be more typical (for a line level output).

 

[fpitas]

If a unit's output impedance is 200 Ohms or less, then the cable wound need to be hundreds of feet long to matter.
Hard to make a reasonable super high capacitance cable. (coax or Shielded Twisted Pair)

Agreed, it's probably not an issue IRL.

 

[Deleted member 35357]

Anyone ever done a test on the output impedance from a DAC where they varied it with regard to frequency response measurements down the line?

A frequency sweep would be preferred at the end line.

Just asking because it had an effect for HP AMP output with regard to headphones at the last stage and got curious if there is a similair effect in other parts of the chain with the same thing, if there is a compounding effect or it's so small it shouldn't matter with short distances on cables used and it's really only at the AMP output stage it only matters, and then only if the headphones/drivers are sensitive to it in the first place.

 

[TimW]

Watched the video. Only difference I could concern was higher volume with the D400EX.

 

[fpitas]

Watched the video. Only difference I could concern was higher volume with the D400EX.

The isolators are a clue someone isn't playing with a full deck.

 

[Ken Tajalli]

It could be down to the differing Isolators being used?

Are you referring to the rubber legs?

 

[TimW]

The isolators are a clue someone isn't playing with a full deck.

They're probably just misguided. Someone should explain how easy it is to level match using a voltmeter and test tones available on streaming platforms.

 

[fpitas]

They're probably just misguided. Someone should explain how easy it is to level match using a voltmeter and test tones available on streaming platforms.

It may be worth a try, in any event. Of course, they may want the "test" to come out a specific way.

 

[Blumlein 88]

Anyone ever done a test on the output impedance from a DAC where they varied it with regard to frequency response measurements down the line?

A frequency sweep would be preferred at the end line.

Just asking because it had an effect for HP AMP output with regard to headphones at the last stage and got curious if there is a similair effect in other parts of the chain with the same thing, if there is a compounding effect or it's so small it shouldn't matter with short distances on cables used and it's really only at the AMP output stage it only matters, and then only if the headphones/drivers are sensitive to it in the first place.

Without going into the full explanation it's reasonable output impedance with hp amps could matter on phones. With dacs the answer is almost never. We can explain further if you want.

 

[fieldcar]

I aligned, trimmed, and normalized to -23dB LUFS in audacity.

I say there are some BS wonkery going on.


M400 on top and D400EX on the bottom


Some parts look similar


Then, there is this crap. What the hell is with the D400EX on the bottom? I CALL SHENANIGANS!



Here are the FLAC's to verify.

asr - Google Drive

drive.google.com

 

[Oukkidoukki]

Hey, just came back, lot of conversation, good, thanks.....Could it be because its louder? I don't know....even thru youtube for me there is clear difference. Weird. This thing remains mystery for me.

 

[fpitas]

Hey, just came back, lot of conversation, good, thanks.....Could it be because its louder? I don't know....even thru youtube for me there is clear difference. Weird. This thing remains mystery for me.

As many people here pointed out, the test has several fatal flaws and lots of unanswered questions.

 

[Deleted member 35357]

Without going into the full explanation it's reasonable output impedance with hp amps could matter on phones. With dacs the answer is almost never. We can explain further if you want.

It would be nice if anyone knows a test with results on this. I would expect it's been tried before at some point.
Results speak for themselves so would be nice the see someone having done a comparison or show that there is nothing to make note off or be concerned about it there.

Just want to see more details about it.

 

[DonR]

It would be nice if anyone knows a test with results on this. I would expect it's been tried before at some point.
Results speak for themselves so would be nice the see someone having done a comparison or show that there is nothing to make note off or be concerned about it there.

Just want to see more details about it.

If the DAC is line out then the expected load would be purely resistive and likely > 10K in which case the effect of the output impedance vs frequency would be the frequency response curve.

 

[Joachim Herbert]

Something is really wrong if there is a clear difference via YouTube.

 

[Oukkidoukki]

Clear but ofcourse very minimal. But enough to make me wonder what the hEck..

 

[VintageFlanker]

Could it be because its louder?

That's part of it, as @pkane said.

But anyway, we have absolutely zero information about circumstances, how these two samples could have been recorded. Did the mic move between both captures? Is the YouTuber himself maybe standing nearby? Did he care for level match after recording? How?

So many unanswered questions...

...We cannot, in any shape or form, use this video as a valid A/B comparaison.

 

[Blumlein 88]

It would be nice if anyone knows a test with results on this. I would expect it's been tried before at some point.
Results speak for themselves so would be nice the see someone having done a comparison or show that there is nothing to make note off or be concerned about it there.

Just want to see more details about it.

It has been done, and could be done again. This is really trivial stuff electronically. Output impedance of 300 ohms or less and an input impedance of 10kohm or more there is just nothing going to happen. You are good for a 100 feet of interconnect.

Go look at Amir's tests on DACs. What you'll see if the upper frequencies vary a bit from different output filtering methods. Otherwise, nothing to see. Same with Stereophile DAC measurements.

One could add resistance to the output and remeasure. This is such a trivial effect you can just use the very simple equations involved and calculated results will match with high precision the measured results. One of those things not really worth doing again.

With headphones, and low impedance phones (ie 32 ohms or less) you will get predictable frequency response effects. Once again you can look at Amir's HP amp tests and see what output impedance is and know if it is an issue or not.

 

[krabapple]

Clear but ofcourse very minimal. But enough to make me wonder what the hEck..

The video is garbage as 'proof' of anything. We've explained why. No need to keep wondering.