Listening test of 2 power amplifiers - files recorded for download - disclosed

[pkane]

@pkane
It was suggested to me by @Blumlein 88 that the checking the EQ setting in DeltaWave might help improve the matching. I don't really understand what this does. Do you think it is appropriate to use this for such a comparison?

Non-linear EQ settings are designed to compensate for the effects of filters on frequency and phase. It is best not to use these unless you know that you need to correct for these (for example, when comparing two different DACs or same DAC with different filters).

 

[pjug]

Non-linear EQ settings are designed to compensate for the effects of filters on frequency and phase. It is best not to use these unless you know that you need to correct for these (for example, when comparing two different DACs or same DAC with different filters).

OK don't use the EQ for this. So for comparing an amplifier measurement to a reference, maybe use a loopback measurement as the reference rather than the original track? That way any ADC/DAC contributions will mostly zero out?

 

[pma]

I think there is a slight difference in the stereo image between the files, but I was getting tired towards the end. I might be able to ABX this if I try some other time. Or I'm just imaginging things

Btw which song is this? I like it.

Thanks for trying the test. I get similar results, like 4/10, 5/10. Just random flip. I also have amp files against the original data and again unable to get positive ABX result.

The song is The Witch by Rebecca Pidgeon, album The Raven. Chesky Records, files bought from HDtracks.

 

[pma]

OK don't use the EQ for this. So for comparing an amplifier measurement to a reference, maybe use a loopback measurement as the reference rather than the original track?

I even am not able to tell the difference against the original. I will post the original after the poll is over. To "hear" the difference between amplifiers, there must be either:

- clipping
- very poor technical parameters like high output resistance or limited bandwidth
- extremely high distortion
- extremely high noise
- installation errors like groundloops and hum injection

Otherwise, if it is a "normal" amplifier, there are no wiring and grounding errors and the amp is not clipping, it is close to impossible to get the positive ABX result. Of course provided that one does not make wiring and grounding mistakes when capturing the files.

 

[Pdxwayne]

ping @Pdxwayne have you a preference between witch1 and 2?

@pma I would later be interested in some specs of those amps.

With pkmetric of more than -80, unlikely I can hear a difference. Not going to try.
: P

 

[pjug]

I even am not able to tell the difference against the original. I will post the original after the poll is over. To "hear" the difference between amplifiers, there must be either:

- clipping
- very poor technical parameters like high output resistance or limited bandwidth
- extremely high distortion
- extremely high noise
- installation errors like groundloops and hum injection

Otherwise, if it is a "normal" amplifier, there are no wiring and grounding errors and the amp is not clipping, it is close to impossible to get the positive ABX result. Of course provided that one does not make wiring and grounding mistakes when capturing the files.

I am wondering: what were the amplifier output peak voltages? I don't disagree with what you say but it seems that it would be more likely to get differences if the amplifier has to deliver high peaks into a difficult speaker load.

 

[b4nt]

With pkmetric of more than -80, unlikely I can hear a difference. Not going to try.
: P

Just try. I'd like to know your opinion

 

[MarkS]

Ambient noise and room reflections make all the tests with amps captured by microphones absolutely pointless and only a source of many errors.

Is this still true if we replace "microphones" by "ears"?

I think it is.

 

[Pdxwayne]

Just try. I'd like to know your opinion

I am away from home and won't be able to check until about 2 days later. : )

How about you? Any preference?

 

[b4nt]

I am away from home and won't be able to check until about 2 days later. : )

How about you? Any preference?

Currently listening to electro experimental and noises

 

[Pdxwayne]

There are requests to record outputs of two different power amplifiers and prepare a listening test with such recorded files. I have decided to answer the challenge again and recorded files from 2 different class AB amplifiers, loaded with real speakers. One of the amplifiers has about 6 times more power than the other one. The files were recorded at output power up to 20W/4ohm. The level was matched by analog path (blue Alps pot) and the files were time aligned by SW.

The files are in 96/24 format and can be downloaded as a zip file from the link below. Please download and unzip the files before listening to them

https://drive.google.com/file/d/1LUMM5EmNyQt8YBHSp4eujuxArA9e_15p/view?usp=sharing

Please let me know if you can hear the difference between the files and if yes, which one do you prefer. Of course and ABX test result would be greatly appreciated.

Please feel free to use DeltaWave software by Paul @pkane to analyze the files. I will have no problems if you post the results here, for discussion purposes.
https://www.audiosciencereview.com/...test-deltawave-null-comparison-software.6633/

Have fun!

I would love it if you could also do class A vs class AB, using XLR vs RCA inputs, using difficult to drive speakers vs higher efficiency speakers, etc.

 

[Blumlein 88]

Is this still true if we replace "microphones" by "ears"?

I think it is.

The difference is our ears process sound so what we 'hear' filters out much of the early contribution of the room. If you listen to a microphone recording of your system from your listening position it will sound full of echoes and reflections which you don't hear in normal listening. Because your ears/brain are filtering much of that out.

 

[pjug]

The files were recorded at output power up to 20W/4ohm.

I missed this. Sorry about that. So something like 9V peaks? Are you interested in doing higher levels using a voltage divider? I used Tricycle by Flim & the BB's, which has very high crest factor so isn't unbearably loud when played into speakers with more than 40V peaks.

 

[pma]

I would love it if you could also do class A vs class AB, using XLR vs RCA inputs, using difficult to drive speakers vs higher efficiency speakers, etc.

That's a challenge . I will try, but it would be a long path trail. I did, earlier, a test with class A with extremely low distortion (<-120dB) however with not so low output impedance, 0.22 ohm. There was some effect on frequency response with wild complex impedance speakers, but the ABX .......
Maybe an exercise for DeltaWave . BTW, it is an excellent program. I tried to fool it with residual noise signals, but it was able to detect the right things.

 

[pma]

So something like 9V peaks?

RMS. I was talking the real "sine" power, not "peak power". Voltage peaks about 13V.

 

[pjug]

RMS. I was talking the real "sine" power, not "peak power". Voltage peaks about 13V.

OK thanks. Still, any interest in doing higher voltage?

I am listening with Foobar and so far ABX would be pure guessing. I will do it anyway later using NC headphones. Pretty sure it will be pure guessing though.

@Pdxwayne care to try this? You did pretty well on the other ABXs.

 

[shal]

Hi,

Spoiler: abx

I think I prefers the second, more harmonics.
Very very subtle.

I test a abx, and during the test I think I totally failed.
ABx test on the first 3 seconds
But perhaps....

 

[Pdxwayne]

OK thanks. Still, any interest in doing higher voltage?

I am listening with Foobar and so far ABX would be pure guessing. I will do it anyway later using NC headphones. Pretty sure it will be pure guessing though.

@Pdxwayne care to try this? You did pretty well on the other ABXs.

I am away from home and may try tomorrow evening. I see Shal did well in post above me. Don't think I can do any better than guessing based on pkmetric number.

 

[Geert]

You're all biased by the pkmetric number guys, we need some real believers to give it a fair chance

 

[b4nt]

I am away from home and may try tomorrow evening. I see Shal did well in post above me. Don't think I can do any better than guessing based on pkmetric number.

You may perhaps hear something as you were *sensitive* to piano decays in a hissing track.