I have a Kawai and a Schimmel, I'd say they're also competently designed as regards the sound. But the Schimmel (upright) has really cheap engineering on the pedals which squeak from time to time. So that aspect is not really competent.
I'd say an amplifier is more like a photographic lens than a piano. Its not the originator of the sound, it merely passes through. So if the amplifier is heard, then that's a sign of its lack of perfection. A 'textbook perfect' amp will sound as the source sounds but louder (of course!), adding no colouration of its own.
Then you must accept you've allowed yourself to be conned.
Its definitely the enjoyment factor for me, and more enjoyment always corresponds to more transparency in my experience.
Just a sign that the right measurements are not being taken. Don't rely on them, rely on your ears!
Can't tell if you're being ironic or serious here in your meaning of 'perfect'...
Hmmm... I have a Chappell, and used to have a Roland too. I'd take the Chappell anytime over the electronic. Mine used to have a squeeky pedal too lol. Think a mouse lived in there.
We can go round in circles with threads like this. I accept Jans definition, and yours too in saying that the amp should add nothing to what passes through it. But then you say trust your ears, and my ears prefer technically less "perfect" offerings. Offerings that have that "Wow" factor, that just seem to push all the right buttons musically. So again it becomes subjective. The measurements would show high levels of distortion (relatively speaking) probably of a predominance of 2H and so on as well as other non linearities.
We can go round in circles with threads like this. I accept Jans definition, and yours too in saying that the amp should add nothing to what passes through it. But then you say trust your ears, and my ears prefer technically less "perfect" offerings. Offerings that have that "Wow" factor, that just seem to push all the right buttons musically. So again it becomes subjective. The measurements would show high levels of distortion (relatively speaking) probably of a predominance of 2H and so on as well as other non linearities.
Overview arround Perception and Emergence of Distortion
Perception & Thresholds of Nonlinear Distortion using Complex Signals
http://projekter.aau.dk/projekter/files/9852082/07gr1061_Thesis.pdf
Nonlinear perception of hearing-impaired people using
preference learning with Gaussian Processes
http://www.sps.ele.tue.nl/members/b.vries/papers/groot08-Nonlinear-perception-JASA-EL.pdf
Operational Amplifier Distortion
SG-Acoustics · Samuel Groner · IC OpAmps
http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf
http://www.diyaudio.com/forums/solid-state/129202-amazing-opamp-measurement-shoot-out.html
A NEW METHODOLOGY FOR AUDIO FREQUENCY
POWER AMPLIFIER TESTING BASED ON PSYCHOACOUSTIC
DATA THAT BETTER CORRELATES WITH SOUND QUALITY
BY Daniel H. Cheever
http://www.tubesville.com/cheever_thesis.pdf
small signal distortion NFB amps
http://www.its.caltech.edu/~musiclab/feedback-paper-acrobat.pdf
The influence of schematics on power amplifier parameters
The influence of schematics on parameters
The influence of schematics on parameters - part 2
Auditory Perception of Nonlinear Distortion - Theory
Perception
http://www.gedlee.com/downloads/Distortion_AES_I.pdf
http://www.gedlee.com/downloads/Distortion_AES_II.pdf
http://www.diyaudio.com/forums/solid-state/109147-geddes-distortion-measurements.html
http://www.diyaudio.com/forums/multi-way/121253-geddes-distortion-perception.html
Reduction of Transistor Slope Impedance Dependent
Distortion in Large-Signal Amplifiers
http://www.essex.ac.uk/csee/research/audio_lab/malcolmspubdocs/J10 Enhanced cascode.pdf
Perception & Thresholds of Nonlinear Distortion using Complex Signals
http://projekter.aau.dk/projekter/files/9852082/07gr1061_Thesis.pdf
Nonlinear perception of hearing-impaired people using
preference learning with Gaussian Processes
http://www.sps.ele.tue.nl/members/b.vries/papers/groot08-Nonlinear-perception-JASA-EL.pdf
Operational Amplifier Distortion
SG-Acoustics · Samuel Groner · IC OpAmps
http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf
http://www.diyaudio.com/forums/solid-state/129202-amazing-opamp-measurement-shoot-out.html
A NEW METHODOLOGY FOR AUDIO FREQUENCY
POWER AMPLIFIER TESTING BASED ON PSYCHOACOUSTIC
DATA THAT BETTER CORRELATES WITH SOUND QUALITY
BY Daniel H. Cheever
http://www.tubesville.com/cheever_thesis.pdf
small signal distortion NFB amps
http://www.its.caltech.edu/~musiclab/feedback-paper-acrobat.pdf
The influence of schematics on power amplifier parameters
The influence of schematics on parameters
The influence of schematics on parameters - part 2
Auditory Perception of Nonlinear Distortion - Theory
Perception
http://www.gedlee.com/downloads/Distortion_AES_I.pdf
http://www.gedlee.com/downloads/Distortion_AES_II.pdf
http://www.diyaudio.com/forums/solid-state/109147-geddes-distortion-measurements.html
http://www.diyaudio.com/forums/multi-way/121253-geddes-distortion-perception.html
Reduction of Transistor Slope Impedance Dependent
Distortion in Large-Signal Amplifiers
http://www.essex.ac.uk/csee/research/audio_lab/malcolmspubdocs/J10 Enhanced cascode.pdf
To be prices not all music recorded through opamps
TACET-Website - english
Also there are very interesting debates among sound engineers what kind of mic preamps tube or transistor works better in studios.
I like OPA2134 / 134 very much by the way, however cannot justify expensive opamps. IMHO for DIY discreet transistor design works better then pricey opamps like BF862 preamp mentioned earlier.
Agreed. Than you for the link.
measurements vs music
Well, this is getting interesting. My point was that I have 3 amps of different technologies and two (discrete, op amp) sound better, the tired tube one sounds worse. Good electronics have no characteristic sound. The one measurement that is easily done it voltage into 8 ohm resistor- the ST70 with bad caps and output tubes is more of a ST20 (twenty watts), and you can hear it on piano hits. I find THD and IMDistortion measurements are useful down to 1%, which most people on this forum have pushed way past. I'm old enough to remember when the audio standard of most people was the six foot long wooden console record player, with the more expensive wood the better. These produced maybe 5% THD at their peak 5 watts per channel output, and can mostly be found now in the craigslist "free curb alert" listings. At the time when these were popular, my band director was touting the Altec-Lansing VOT's and tube amp at the local movie theater- a reference standard that has held up over the years. The shibboleth of today is the MP3 player- I find nobody on this forum touting them, while the whole rest of the world is fascinated. I've dispaired of finding J Curl's favorite "Kind of Blue" on vinyl LP at the charity resale shop, and will probably have to do with buying a new CD. Anyway, below 1% THD, speaker imperfection and room effects dominate amplifier imperfections in my opinion. To point out systems that don't sound good without a distortion analyzer to analyze it, my new HDTV is "pretty good", but not great, with it's 3x6" speakers and maybe 3 watts output. The point of having multiple amps, is that one of them is going to the TV room, along with the T-300 HF projector speakers that have only one "sweet spot", which will be aimed at the TV chair. Room effects can really dominate electronic imperfections, and I"ve (pardon italics, I don't know how I did that) recently moved the Steinway to a less than ideal spot to prove the point. I'm sorry I don't worship the goal of .01% distortion, but I find that amps that are great in that respect in my price range tend to go up in flames and take your speaker with it, or pass lightning straight through to the speaker, of which we have a lot here. The whole point of tubes in my opinion is their indestructability-The ST70 and PAS2 have taken several lightning strikes over the years, with power switches being the main casualties, whereas the ST120 went up in a ball of flame under the podium at a choir rehearsal that went on too long, and has only recently been revived and better output fused.
Well, this is getting interesting. My point was that I have 3 amps of different technologies and two (discrete, op amp) sound better, the tired tube one sounds worse. Good electronics have no characteristic sound. The one measurement that is easily done it voltage into 8 ohm resistor- the ST70 with bad caps and output tubes is more of a ST20 (twenty watts), and you can hear it on piano hits. I find THD and IMDistortion measurements are useful down to 1%, which most people on this forum have pushed way past. I'm old enough to remember when the audio standard of most people was the six foot long wooden console record player, with the more expensive wood the better. These produced maybe 5% THD at their peak 5 watts per channel output, and can mostly be found now in the craigslist "free curb alert" listings. At the time when these were popular, my band director was touting the Altec-Lansing VOT's and tube amp at the local movie theater- a reference standard that has held up over the years. The shibboleth of today is the MP3 player- I find nobody on this forum touting them, while the whole rest of the world is fascinated. I've dispaired of finding J Curl's favorite "Kind of Blue" on vinyl LP at the charity resale shop, and will probably have to do with buying a new CD. Anyway, below 1% THD, speaker imperfection and room effects dominate amplifier imperfections in my opinion. To point out systems that don't sound good without a distortion analyzer to analyze it, my new HDTV is "pretty good", but not great, with it's 3x6" speakers and maybe 3 watts output. The point of having multiple amps, is that one of them is going to the TV room, along with the T-300 HF projector speakers that have only one "sweet spot", which will be aimed at the TV chair. Room effects can really dominate electronic imperfections, and I"ve (pardon italics, I don't know how I did that) recently moved the Steinway to a less than ideal spot to prove the point. I'm sorry I don't worship the goal of .01% distortion, but I find that amps that are great in that respect in my price range tend to go up in flames and take your speaker with it, or pass lightning straight through to the speaker, of which we have a lot here. The whole point of tubes in my opinion is their indestructability-The ST70 and PAS2 have taken several lightning strikes over the years, with power switches being the main casualties, whereas the ST120 went up in a ball of flame under the podium at a choir rehearsal that went on too long, and has only recently been revived and better output fused.
music production equipment is in a different category from music reproduction equipment.
Gordy... May I suggest you wire some opamps up (use point to point wiring, it takes minutes), use a couple of PP3's and see what you think. Use a socket and make your own mind up whether you feel they are worth pursuing or not.
Try a 4558, a TL072, a 5532 and something else... I would still say a 2604 and tell us what you think.
What does it matter what commercial equipment uses what... it doesn't make it a good or bad product on that alone.
Mark Levinson, if "very" still applies.
To name a few models ; No 38, 38S, 380S, and the current 326S.
Most of the typical German opamp camp have gone fully discrete or out of business.
The thing with opamps is that some concepts are easily managed with a handfull of opamps, while as completely discrete becomes a magnitude more complex.
The either-or stand is not a big help.
SYN08 does very interesting stuff by combining ICs and various discrete components, imso.
Edit : me forgots the No 32 flagship, $28k with phono boards overhere at the current $-rate.
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Likewise, I used to have a Yamaha (Clavinova, not acoustic) and would never go back.
I feel sure that such 'technically perfect' amps must measure poorly given the right measurement stimulus. Just as one example, an AP generates a near perfect sinewave stimulus but its differential mode only, by design. Real world sources have a common mode component too and less competently designed amps respond in different ways when given common mode signals.
Those amps would be ones which are able to ignore common mode signals on their inputs and outputs I would reckon. Having an output transformer helps enormously with this. So there are good 'objective' reasons for your subjective preferences but the distortion spectrum measured with a pure tone is a red herring I think.
Sorry, this is not correct. An amp that doesn't add or subtract from the signal will measure perfect, however you measure it.
The AP can generate all kinds of signals, single ended, balanced, common mode, what have you. And all of that is routinely measured (if the tester is worth his money). A routine measurement is with ISO-31 signals which contain 31 different frequencies that are spaced in a specific way so that their harmonics do not overlap. This is a more stringent signal than music.
jd
Yes, but we (Mooly and I) are not talking here about one of those perfect amps which is merely a straight wire with gain. We're talking about an amp which is claimed to be 'technically perfect' but does add and subtract from the signal. How I know this is because he found it unsatisfying to listen to. A truly perfect amp would sound perfect too, not merely measure perfect. So your 'this is not correct' is tilting at windmills.
How about a low distortion sinewave signal which is riding on broad band common-mode RF in the band 500kHz to 10MHz? Certainly when I was using an AP1 it did not have this plug-in, but perhaps AP2 has the feature? If so, please enlighten me.
You said very recently not to take you too seriously. This is a case in point - all symbols/text on a page/monitor are just symbols/patterns and inherently valueless. Your words, my words - all valueless.
Seems to have struck a raw nerve there with you abraxalito. Valueless but still worthy of a response. Interesting that you don't respond to my points, just try to rubbish me on a personal level. I can live with that.
You're not a closet subjectivist masquerading as a tweak (sorry, scientist), are you?
Until science reclaims audio engineering we're all trying to operate in a fog.
janneman, talking out of his surface hopelessness, thinks that this will never happen, but the scientist in him hasn't give up hope, and keeps on popping up in rebellion.
w
Oh, don't take me too seriously, I was kidding about the Turner prize.
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Do you have any evidence of that? Some words of mine indicating that I got emotionally affected by your words? If so, which ones please? If you indicate them, I can help you see where your perception has gotten distorted.
Did you miss my saying that my words are just as valueless as your own? I wasn't particularly targeting your latest post in my statement that all words are valueless, its just how life is.
Interesting that you don't respond to my points, just try to rubbish me on a personal level. I can live with that.
Evidence please that I'm trying rubbishing you on a personal level? And what points are you making which you'd like me to respond to - I didn't see anything that I felt needed a rebuttal but I could have missed some, so help me out here if you're dying for a reply.
I'm fairly open about being a subjectivist so nothing 'closet' about that. I wouldn't want to associate myself too closely with the term 'scientist' as Jan has some valid points there.
Actually here's a statement which is worth a rebuttal. Science (in terms of what's actually practiced, not the methodology which is basically sound) needs to be radically rethought, more along the lines of subjectivist audio. That is, perceptions (observations, auditions and the like) need to be brought back centre stage and speculation moved into the wings.
I'm happy to let other readers make up their own minds in this case without further comment from me.
w
No it cannot. It can also not generate infrared signales. But that was not the issue.
You thought (or at least said so) that the AP only does sines, and then only diff mode. Clearly, you have no experience with modern audio testing or you should not have said that. Yet your ignorance did not prevent you to make judgements.
jd
BTW Here is a representative ISO-31 signal frequencies in Hz, magnitude only; of course the phase relationships also have to be set for worst-case signals
17.575
23.450
29.300
41.025
52.725
64.450
82.025
99.600
123.050
158.200
199.225
252.000
316.500
398.500
498.000
632.750
802.750
1,002.000
1,248.000
1,599.500
1,998.000
2,502.500
3,152.500
4,002.500
4,997.500
6,352.500
7,997.500
10,002.500
12,497.500
16,002.500
19,997.500
Cool, I'll just add one remark for guidance if anyone's really interested in making up their minds. The scientist historically has relied on evidence first, and from the evidence builds up theories. So observation precedes hypothesizing. If you believe wakibaki is a scientist in that tradition, you'll want to see how many of his statements cite his observations.
Hi Gordy... try something like the OPA604 or OPA2604 if you have been used to valves. OpAmps do have their own sound, the fact that we seem able to pick up on these tiny differences always amazes me, but we do. The 604 has the "right" kind of distortion spectrum to sound pleasing I find.
Edit... whats wrong with opamps ? Nothing, it's the way they are implemented that's often wrong
I also like the OPA604. However, the LM4562 provides exceptional performance and has gotten a good reputation.
Cheers,
Bob
These are good points. JFET op amps are less susceptible to RFI, and that is one reason why they are often preferred. It is also wise to bias the output stage into class A if there is any concern that it is entering class B in the circuit in which it is being used.
Cheers,
Bob
These are all very good points, especially about the aural exciter.
However, bear in mind that many well-designed push-pull tube amplifiers do not produce a lot of second harmonic distortion, since they can be made symmetrical. Single-ended tube amplifiers are a different animal, and do produce lots of second harmonic.
Cheers,
Bob
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