Can you hear a difference between 2 solid state preamps?

[PMA]

After some time, there is a listening test again. This time, 2 solid state preamps based on opamps and JFET transistors are tested. The test files can be downloaded from

http://pmacura.cz/worldstring.zip

The question is if you can hear the difference between the two files and of course the ABX result would be appreciated, as always, but is not mandatory.

Your comments telling which of the files you prefer by listening will be appreciated as well.

============================

Nov 8, 2019: for those who might be interested, there are new samples

http://pmacura.cz/claire.zip

Now, it is a contemporary recording issued by a highly regarded record label. To make it not so easy, there are 3 sample recordings now. The same preamps were used in the test as for Sinatra files. Please comment and bring your sound impressions of the new samples.

 

[Max Headroom]

On laptop quick listen yes clear differences.
Do you want subjective descriptions yet ?.


Dan.

 

[mountainman bob]

I can tell a big difference even on my shop KLH’s

 

[Nico Ras]

Hi Pavel, yes the difference is easy to spot. In fact, I prefer the second sample more than the first, it sounds less thick if that might be a description.

 

[PMA]

On laptop quick listen yes clear differences.
Do you want subjective descriptions yet ?.


Dan.

Yes Dan, please. As I said, this time subjective descriptions are welcome. I only will not disclose anything about preamps before the poll is closed.

 

[PMA]

Hi Pavel, yes the difference is easy to spot. In fact, I prefer the second sample more than the first, it sounds less thick if that might be a description.

Thank you Nico.

 

[mountainman bob]

Yes, the worldstring 1 is way cleaner, better bass, I can’t tell if it’s too bright as my main system is boxed up; my shop system is a little ‘bright’ anyway.

 

[PMA]

I can tell a big difference even on my shop KLH’s

Thanks for your impressions.

 

[PMA]

All, let's call the "1st sample" the one named worldstring1 and "2nd sample" the one called worldstring2, OK? Interesting how this recording from 1953 makes a difference.

 

[Speedskater]

Did you do any basic measurements on the pre-amps?
From the measurements, would you call either pre-amp 'Accurate' or 'Euphonic'

 

[PMA]

Did you do any basic measurements on the pre-amps?
From the measurements, would you call either pre-amp 'Accurate' or 'Euphonic'

As you would probably guess, I have a full set of measurements of both units. However, I am not going to show any plot before the poll is over.

As to your specific question, both preamps may be described as accurate, very linear, with wide frequency range and low distortion.

 

[PMA]

Several technical notes on the test files - the files are recorded in 24-bit resolution and they are in 96kHz/24bit format, however the music signal limit is 20kHz, due to test music sample used. DAC/ADC path is the same in both cases with same settings and levels. The 2 preamps under test have volume level matched within 0.04dB only by use of the preamp's volume control pots. No digital volume matching was used, no frequency equalization was used. Switching spectra (at the same time point) of the recorded files shows they are almost identical. The main difference is in quiescent noise level, which can be seen in the attached spectral plots, but only at frequencies above 20kHz, as this difference is completely masked, in the plots, by the music signals, in the audio band. The plot images are named apple and pear, to exclude relation to the test samples.

 

[ginetto61]

Hi sorry are they mic preamps ?

 

[PMA]

No, one is an "audio" line level preamp and the other is an "instrumentation" preamp that I use to measure audio. Both are my designs and production, so there is no parallel to commercial products.

 

[ginetto61]

No, one is an "audio" line level preamp and the other is an "instrumentation" preamp that I use to measure audio. Both are my designs and production, so there is no parallel to commercial products.

Thanks !

 

[PMA]

In a sighted test, I have a feeling that I can quite clearly tell the difference in sound of both preamps. When doing ABX test, I get permanently results between 3/8 and 5/8, so just random results. I will try harder .

 

[scottjoplin]

I imagined I heard a difference too. I'm experimenting with self induced bias.......not to be confused with Self-serving bias - Wikipedia

 

[PMA]

With my best concentration on sound:

foo_abx 2.0.2 report
foobar2000 v1.4.8
2019-11-05 12:29:21

File A: worldstring1.flac
SHA1: dd4095af5322127d4db4220fcb35696161b23e70
File B: worldstring2.flac
SHA1: 74034a929c8176706e3fc5e9d44a315084e9c54f

Output:
ASIO : Creative Sound Blaster ASIO
Crossfading: NO

12:29:21 : Test started.
12:30:55 : 01/01
12:31:10 : 02/02
12:31:36 : 03/03
12:31:55 : 04/04
12:32:03 : 05/05
12:32:28 : 05/06
12:32:42 : 05/07
12:33:02 : 05/08
12:33:02 : Test finished.

 ---------- 
Total: 5/8
Probability that you were guessing: 36.3%

 -- signature -- 
71ae3bf697b0f34e08c1e5ca304feb80d2d6d3d0

a following one:

foo_abx 2.0.2 report
foobar2000 v1.4.8
2019-11-05 12:45:53

File A: worldstring1.flac
SHA1: dd4095af5322127d4db4220fcb35696161b23e70
File B: worldstring2.flac
SHA1: 74034a929c8176706e3fc5e9d44a315084e9c54f

Output:
ASIO : Creative Sound Blaster ASIO
Crossfading: NO

12:45:53 : Test started.
12:47:07 : 01/01
12:47:22 : 02/02
12:47:37 : 03/03
12:47:52 : 04/04
12:48:08 : 04/05
12:48:23 : 04/06
12:48:38 : 05/07
12:48:54 : 06/08
12:48:54 : Test finished.

 ---------- 
Total: 6/8
Probability that you were guessing: 14.5%

 -- signature -- 
4147cb7f8d3e7a9342bac70ac14fecc29715b376

 

[Max Headroom]

Yes Dan, please. As I said, this time subjective descriptions are welcome. I only will not disclose anything about preamps before the poll is closed.

Ok, I find with quick not paying 100% attention with 4 x listen to the pair (looped playlist) that WS1 is 'harder' sounding and gets 'messy' on the brass solos and vocal is not right, sort of a buzz tracks with the program, WS2 is overall 'friendlier' and clearer and does not get so 'upset' by program, I could live with WS2 maybe, certainly not WS1.
I can take more careful listen tonight and take written notes, I can A/B all I like then without driving my housemate nuts lol.


Dan.

 

[PMA]

Thank you Dan for your comments.

I think I could reveal the biggest (probably) difference between the preamps under test, and this is the frequency response. Though they are both well within 0.1dB in 20Hz-20kHz range, there is quite a remarkable difference when we extend the range to 1MHz. This also reflects, of course, in 10kHz square response and corresponding rise/fall time of the leading/falling edges. Frequency responses shown without revealing which one belongs to which preamp.