Ummmmm, Craig, I don't think a lot of your criticisms are well-founded. That's ignoring the discrete/vacuum tube rant, which is nonsensical.
The local PSU bypass is more than good enough for line-level (we're not talking power-IC's), and in that location an x7r cap is more than good enough; especially if the voltage rating is generously over-provisioned. Pavel has shown a number of very very high performance circuits over time, so I'd generally trust his ability to lay out a line-level board. Likewise, a big part of his schtick is showing RF effects from opamps -- which highlights some bjt-input opamps that do rectify garbage.
I think it's best we just give the files a good, sincere listen and then see where we stand.
The local PSU bypass is more than good enough for line-level (we're not talking power-IC's), and in that location an x7r cap is more than good enough; especially if the voltage rating is generously over-provisioned. Pavel has shown a number of very very high performance circuits over time, so I'd generally trust his ability to lay out a line-level board. Likewise, a big part of his schtick is showing RF effects from opamps -- which highlights some bjt-input opamps that do rectify garbage.
I think it's best we just give the files a good, sincere listen and then see where we stand.
Oh, I can agree with that 🙂
I can also agree, if somebody states so, that if you play very low level music and there is some residual noise present, you can hear some intermodulation between them, for lack of a better word.
Not sure where this might be caused, if inside the Op Amp itself, an artifact of digitizing or our own ears.
Thank you for your feedback. You might like to check my web page, especially re discrete circuits etc.
Pavel Macura audiopage
Yes OPA627 is a very nice part. I have been using it very often both for instrumentation and audio since about 1993. For example in the circuit as per photo attached (though LT1122 is there). And in many preamps as well.
Do you support your claims about bypass capacitors with measurements as well?
Attachments
Any real recording, even 24-bit one, will have much higher own noise than that introduced by the opamp unity gain buffer even if the worst possible opamp was used. The noise of the microphone, microphone path, microphone preamplifiers is higher than that added by the unity gain opamp buffer. Only an artificial sound artificially digitally generated might be affected by the unity gain opamp buffer noise, and only in the case of ideal electronics used in the analog part of the digital player.
PMA,
That may be, but that is a separate question from whether or not one can hear the contribution of the one opamp, and whether and to what degree it may make things sound better or worse.
If recording and mastering processes have produced an end product that people think sounds good, making it sound less good later doesn't seem like something necessarily to ignore or rationalize away. Then again, some people wouldn't notice or care. But, in this forum we appear to have at least a few people that can notice such things, including Mooly. And, I am pretty sure there are others who may be reticent to speak publicly about it, a few have talked about it by PM though.
That may be, but that is a separate question from whether or not one can hear the contribution of the one opamp, and whether and to what degree it may make things sound better or worse.
If recording and mastering processes have produced an end product that people think sounds good, making it sound less good later doesn't seem like something necessarily to ignore or rationalize away. Then again, some people wouldn't notice or care. But, in this forum we appear to have at least a few people that can notice such things, including Mooly. And, I am pretty sure there are others who may be reticent to speak publicly about it, a few have talked about it by PM though.
SNR at 1W
Maybe, maybe...one key is the SNR at 1W of the amplifiers used to play the files tests.
Maybe, maybe...one key is the SNR at 1W of the amplifiers used to play the files tests.
I agree, but, unfortunately, not a single person published an ABX result here confirming they can hear the difference. Of course between the posted files, because they cover both the almost best IC part available and almost the worst one IC from the seventies. It is impossible to make an ABX test against the original recording, because there would be slight amplitude differences and time/phase differences that are big enough to be distinguishable. I repeat, no one has posted here verified ABX result (newer version of foobar plug-in can make it) to prove he really hears the difference. By now, we have impressions and guesses. This is fine, but no proof.
PMA,
Okay, I will check out the new Foobar and see what I can do with a couple of the non-aa test files.
Okay, I will check out the new Foobar and see what I can do with a couple of the non-aa test files.
I am glad for every vote and opinion. But I would also appreciate if anyone would post a result like this
regardless the result. I know that the ABX is not popular, but it is the only way how to prove audibility.
Code:
foo_abx 2.0.2 report
foobar2000 v1.3.7
2017-06-12 20:29:10
File A: aa.wav
SHA1: 81e0cc3b0146df3562d4421385098251239b3789
File B: bb.wav
SHA1: 4da5d9045285da07488f69c24cda9187be2882c9
Output:
WASAPI (event) : Speakers (Cambridge Audio USB Audio 1.0), 24-bit
Crossfading: NO
20:29:10 : Test started.
20:33:02 : 01/01
20:33:21 : 02/02
20:33:36 : 02/03
20:33:51 : 03/04
20:34:02 : 04/05
20:34:27 : 04/06
20:34:39 : 04/07
20:34:55 : 05/08
20:34:55 : Test finished.
----------
Total: 5/8
Probability that you were guessing: 36.3%
-- signature --
6196d50715e8c2e68ce38a0f0f371d2f7691ba11Not only the SNR at 1W - 10W, the THD at 1W - 10W is very important too. And a clean power in the amp and computer.
My AV Marantz SR4500
-> https://www.soundandvision.com/content/marantz-sr4500-av-receiver-ht-labs-measures
-> micro – iCAN
[Polish] AVR reviews with numbers and graph measures:
-> Amplitunery AV - testy sprz?tu
and the Stereo amps too:
-> Wzmacniacze stereo - testy
My AV Marantz SR4500
-> https://www.soundandvision.com/content/marantz-sr4500-av-receiver-ht-labs-measures
and my iFi iCAN (headphones amp)
-> micro – iCAN
By the way, the new japanese AVR have only 78 dBA (Marantz or Denon) or 81-83 dBA (Yamaha). The music does not sound as good than the films 🙁
[Polish] AVR reviews with numbers and graph measures:
-> Amplitunery AV - testy sprz?tu
and the Stereo amps too:
-> Wzmacniacze stereo - testy
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We weren't professionals and there was no attempt at any room treatment, but I do remember the criticisms were delivered in a very cordial way.
I'd love to use RockBox on DAP for test source but they have a real 'attitude' and don't even try to look at DAC sample rate setting - they just resample, truncate as default:
(most recent post in RockBox forum search for 'resample')
(most recent post in RockBox forum search for 'resample')
Blah, blah, yawn, Jan Didden won the amateur recording contest at this years Triode Fest with an IC op-amp and gobs of feedback with many of the judges total tube heads.
Wow! That's a great story 😀. But never let the audiophile to test the blackbox, to prevent possible heart attack.
You know the folklore about low FB and great tube sound is one of the fragments to get the whole picture 😉.
http://www.diyaudio.com/forums/loun...ars-listen-comments-welcomed.html#post4225334
Still makes me giggle tho. I did like the recordings, but then again I really like redbird even with the motor noise from the DAT recorder in the background (and dog, and cars etc). OT but has SY waded through the rest of those recordings?
Sorry Bill I had the wrong set of recordings. The Southpaw Jones set had some nice comments on how we could have treated the room and/or the area around the mics.
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