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

Can you hear a difference and which file do you prefer

  • I can hear a difference but have no ABX result

    Votes: 4 14.3%
  • I cannot hear a difference but have no ABX result

    Votes: 14 50.0%
  • I can hear a difference and have an ABX result

    Votes: 2 7.1%
  • I cannot hear a difference and have an ABX result

    Votes: 4 14.3%
  • I prefer witch1 file

    Votes: 1 3.6%
  • I prefer witch2 file

    Votes: 8 28.6%

  • Total voters
    28
  • Poll closed .

pkane

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If I look at the PK Metric of original vs amplifier recordings for a given track, they look similar no matter which amplifier. So it seems difficult to identify a better amplifier this way. Maybe that is just what we are up against when the differences in direct amp to amp comparison are small.

Maybe that's because the differences are barely audible, if at all? ;) You can always find a measurable difference between two analog devices if you look deep enough. The question is, at what point do you stop looking and decide that they are pretty much equivalent?
 
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pma

pma

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I admire the patience. At some level, I am unable to do so and to spend the time.
 

pogo

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This is news to me - thank you! I just sent him an email asking if I can download it after the site seemed to indicate it was going to mail it to me from Germany! : )
Do you have any news regarding the test suite for your device?
 

Jimbob54

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If I look at the PK Metric of original vs amplifier recordings for a given track, they look similar no matter which amplifier. So it seems difficult to identify a better amplifier this way. Maybe that is just what we are up against when the differences in direct amp to amp comparison are small.
I think that is the point. Within the ideal operating parameters of any electronics, why should there be significant differences.

I don't think we are trying to pick the best amp. I think we are trying to prove there isn't a big difference until you start stressing the electronics.
 

Langston Holland

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Do you have any news regarding the test suite for your device?

Not yet. I ordered it that evening and haven't heard back other than the immediate automated "we got your order" reply. I will try anything in the attempt to quantify perception as much as possible. : )

In other news: DeltaWave rocks if you really study it, but you need to feed it good data (so what's new?). For example, I've yet to find it helpful with the various witch files in this thread, but on my files it shows some real differences that coorelate with what I hear. My hypothesis at present is that it's important to use very high quality A/D and D/A with stable clock rates between each reference and comparison file (a flat horizontal line on the Clock Drift plot after adjustment by DW). Equipment used in measurement should be an order of magnitude better than the DUT in the area of interest. DeltaWave is going to be included in my comparison measurements going forward. Thank you Paul!
 
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pjug

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I think that is the point. Within the ideal operating parameters of any electronics, why should there be significant differences.

I don't think we are trying to pick the best amp. I think we are trying to prove there isn't a big difference until you start stressing the electronics.
I agree that was the point of the test since this was set up to look at audibility. But still I think it is interesting to see if the recording can show if one amp is better than the other. In the other forum @Langston Holland looked at spectrograms to do this so maybe that is the best way. Here are Witch1/Witch3 and Witch2/Witch3 delta spectrograms. I am assuming Witch3 is the original track. So maybe Amp2 is slightly more faithful?
1629233504123.png
 

pogo

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My hypothesis at present is that it's important to use very high quality A/D and D/A with stable clock rates between each reference and comparison file
This is an important basic requirement. It's simply a matter of time ;)
In witch3, when the drum decayed, I heard textures that I hadn't heard so clearly before. That could also point in the direction of ADC.
 
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Jimbob54

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This is an important basic requirement. It's simply a matter of time ;)
In witch3, when the drum decayed, I heard textures that I hadn't heard so clearly before. That could also point in the direction of ADC.
Any of this listening blind?
 

Blumlein 88

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Okay had some quiet unbusy time to try and abx the latest couple files. Did not manage it. My best score was 7/10 along with 3/10 and 6/10. 16 of 30 with an apparent regression to the mean on view. While the rms null isn't that deep between these two, the PK metric is -62 db. Whenever the PK metric goes 60 or better I think I have failed. With a bit more experience with more types of music it could be a real time saver. If the metric is -60 db, don't even bother with abx trials on it.

Thanks to the OP for providing these files for us to fuss with and get some common experience listening to them.
 
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pma

pma

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Okay had some quiet unbusy time to try and abx the latest couple files. Did not manage it. My best score was 7/10 along with 3/10 and 6/10. 16 of 30 with an apparent regression to the mean on view. While the rms null isn't that deep between these two, the PK metric is -62 db. Whenever the PK metric goes 60 or better I think I have failed. With a bit more experience with more types of music it could be a real time saver. If the metric is -60 db, don't even bother with abx trials on it.

Thanks to the OP for providing these files for us to fuss with and get some common experience listening to them.

Thank you for trying the files and for your sound comments.
 

pogo

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Any of this listening blind?
No, and it is not necessary, since it is clearly audible. This should actually be easily recognizable for anyone who uses a NAD M33 (SPK & HP). Also a RME ADI-2 DAC FS should be able to do this, since its converter section is probably built similarly. Can anyone confirm my perception on such devices?
 

Geert

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This should actually be easily recognizable for anyone who uses a NAD M33 (SPK & HP). Also a RME ADI-2 DAC FS should be able to do this, since its converter section is probably built similarly.
What do you mean with similar, as the NAD M33 DAC uses an ESS Sabre chip while the RME ADI-2 uses an AKM chip? I also expect the analog sections of these DAC's to be different.

And what would be so special about these specific devices that they allow you to more easily recognise differences?
 
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Geert

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In witch3, when the drum decayed, I heard textures that I hadn't heard so clearly before. That could also point in the direction of ADC.
Can you provide the timing of that drum decay section so we know what to listen for, and can analyse that specific section with DW.
 

pogo

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What do you mean with similar, as the NAD M33 DAC uses an ESS Sabre chip while the RME ADI-2 uses an AKM chip? I also expect the analog sections of these DAC's to be different.

And what would be so special about these specific devices that they allow you to more easily recognise differences?

M33 converter section:
ADC Chipset
AKM AK5578 (8 channel ADC with 4 channels used per stereo channel to improve SNR and distortion)

DAC Chipset
Dual ESS ES9028QM (each run in mono mode)

The new version of the RME has now also switched to the ESS Sabre and since both are probably similar in design, they should also be similarly transparent.
 

pogo

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Can you provide the timing of that drum decay section so we know what to listen for, and can analyse that specific section with DW.
Any drum event at the beginning.
 
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