No part that exists in reality is perfect. Even a Teflon capacitor, so knowing your part and use is wise is the best recipy i know of. A lot of modern desigers use what i call "boutique" parts in not very inspired topologies and the result is one circuit more that does not bring us any further in our goal to amplify the original signal without alteration. Still a lot of what i call "mechanical" problems exist like limited dynamic range and extention in microphones, Room-Loudspeaker interface etc. For the purpose of extracting the optimum subjective result in a non perfect world my " Niceness Extractor" or call it a modern equalizer could help. Somtimes adding something nice makes a flawed product digestable allthough this has nothing to do with the current paradigm of "Input = Output plus Distortion free Amplification ". I rather whould like that as a seperate and bypassable entity to not violtate the first paradigm " Do no Harm".
Adding a small amount of intentional distortion to pop music recordings to "improve the sound" has been done for decades in the recording industry, and not just on electric guitars with guitar amplifiers and "stomp boxes." One piece of popular processing equipment that works along the lines you're discussing is the Aphex Aural Exciter, which adds intentional distortion at a low level to "brighten up" dull tracks.
Yes, i know that. I play the guitar in a small band and do recordings. I have an SPL unit that does that. Anyway, i found that when i inserted my version of the Salas Buffer behind an Audio Aero CD player the sound got more spacious and dynamic. We talk here about much less then 0.1% second harmonic. The Buffer is wideband and very low in noise so it alters the sound only very supple, still it is very audible to our surprise. The listening panel consists of 5 audiophiles with each more then 20 years of experience with expensive gear.
Its true I did snip some choice words out of your post.
But I feel I got your meaning correctly because I did take into account what the previous poster said. He was purporting to speak for more than himself by saying 'everybody knows...' which I agree is a step too far in that he's not speaking for you at the very least and certainly there are others who agree with you. Yet you did not disagree with that aspect of his statement, you seem to be disagreeing with the 'knows' bit by changing that word to 'believes'.On a more philosophical note, I would say that for someone who hears differences its perfectly fine for them to say 'I know amplifiers sound different'. When there's perception of something, beliefs about that thing are irrelevant. For example, I perceive I'm sitting in front of my monitor typing - its not necessary, indeed totally redundant for me to believe that I'm sitting in front of my monitor typing.
But we agree basically I BELIEVE
You're saying you BELIEVE amplifiers sound different? I take that to mean that you believe others hear differences in sighted listening which disappear when tested? Or have you heard differences yourself in sighted listening?
Yes, totally agree. At the risk of taking this thread way way off the original topic, I wonder why this is. For people who upgrade resistors to bulk foil or non-magnetic types, or caps to Black Gate and the like without first checking that the layout is sound, they're spending a fair amount of money but not getting a great return because their circuit remains layout limited. Whereas those who work on the layout spend very little money but lots of time and in my experience get a good bang for the buck.
But working on the layout requires intuitive understanding of how currents flow which many people don't have - when I was working in the industry grounding to me was pretty much a black art. Swapping opamps though is quick and easy so I can understand the appeal.
Do you have measurements of the differences in distortion between an optimally grounded amp and one that's not? If you do, I'd be very interested to examine them and probably Jan will be too
. Not talking here about non-optimum feedback take-off points or haversine currents induced into the output by poor output stage wiring - just grounding.I have seen up to 1 KOhm in series with well regarded CD player outputs - in some situations buffering need not add magic euphonic distortion to make double blind ABX-able audible difference depending on the interconnect C and next stage input Z
I have messed up wiring several times, grounding in particular, when doing amp measurement. The FFT/THD measurement showed suspicious result, e.g. very high third harmonic.
I am glad a few of you noticed my post.
And real thank those who remember me.
This way I can see what people are positive towards me.
And this may be of use when I try to communicate onwards here.
Those that not are FOR you are AGAINST you.
This is often very true, when it comes to it.
I am happy for small things
even if not a single chap bothers to comment my post.
But I can take it. When somebody will not and can't argue,
not either way,
my point may stand as a good point.
With no flaws.
And an opinion ignored, I can take.
Because is the common way among most and specially selfish, egoistic people
and att my age (soon 60) I am used to this state of things.
The state of people.
-------------------------------
To the discussion.
Regarding what can effect the outcome
when we deal with small signals, like pre- and linelevel
is defenitely Grounding + Power Sppply.
(True also for the input stage of Power Amps)
And of course with this goes a proper layout and wiring
as a whole.
AKSA is know to understand and implement these things well.
When layout, grounding, wiring and power supply
is done properly
comparatively very simple and clean circuits can be good used
to acheive great performance.
Have a look at Nelson Pass preamplifiers!
Many modern 'audio' op-amps has got extremely good PSRR.
(how insensitive they are to be effected by power supply)
But if we look att the figures, diagrams they present i datasheet
we can see those figures are taken from a test signal at a point
that is not very demanding.
Which says we should not challenge an op-amp too much
but we should go for proper power supply, regulated psu
and good ground/wiring.
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Hi all
There are op-amps and op-amps! You have to choose your op-amp with care. Many op-amps got a bad press (for hifi) with the original 741 because it had a really rotten frequency response. It had a classic Miller capacitor stabilisation, and whatever anyone says about transient distortion it certainly is a real effect which you can see in simulations. The debate as far as I am concerned is whether real signals are ever fast enough to cause transient distortion, whether the amplifier input is suitably filtered and so on.
Modern op-amps built with faster transistors are a lot better. You can use lots of feedback without TID if you ensure that the overloading is suitably handled. Or at least, you should ensure that the amplifier can handle transients without overloading.
So scrutinise the data sheets closely. Check to see if the distortion figures quoted (such as 0.0006%) apply only to unity gain - which won't help you much if you want higher gain, unless you accept higher overall distortion. Consider shunt capacitor input stabilisation to minimise TID effects.
Cheers
John
There are op-amps and op-amps! You have to choose your op-amp with care. Many op-amps got a bad press (for hifi) with the original 741 because it had a really rotten frequency response. It had a classic Miller capacitor stabilisation, and whatever anyone says about transient distortion it certainly is a real effect which you can see in simulations. The debate as far as I am concerned is whether real signals are ever fast enough to cause transient distortion, whether the amplifier input is suitably filtered and so on.
Modern op-amps built with faster transistors are a lot better. You can use lots of feedback without TID if you ensure that the overloading is suitably handled. Or at least, you should ensure that the amplifier can handle transients without overloading.
So scrutinise the data sheets closely. Check to see if the distortion figures quoted (such as 0.0006%) apply only to unity gain - which won't help you much if you want higher gain, unless you accept higher overall distortion. Consider shunt capacitor input stabilisation to minimise TID effects.
Cheers
John
Most of the recordings you listen to have instruments that were recorded or amplified through op amps. Some basses even have op amps inside them.
I build preamps for electric basses, and use both discrete and op amps, and if properly designed, you can't hear the difference, and when you can, it's apples or oranges, not good or bad.
Check out this double blind test that was done on a music instrument preamp:
Lutherie Myth/Science: A Listening Evaluation
of Discrete vs Integrated Circuit Audio Preamplifiers in Stringed Musical Instruments
Op-amp comparisons
I started futzing with op-amps way back in the 80's when the early CD players were using what were then considered higher-fi devices.
I've long lost count of the many, many types experimented with in upgrading op-amp circuits. To this day I still routinely search for samples of new developments in op-amp design. 
My current favorites are National Semiconductor's LME49710 and LME49720. A/B comparisons done on my own in various types of equipment have these li'l guys soundly trouncing the competition. I always install the necessary sockets/adaptors on the circuitboard to accommodate a DIP or SMD package to easily swap out devices under test.
In an actual system set-up the listener can then decide for himself whether or not there's an audible difference in hearing the different op-amps in a familiar setting. So far, 4 of 4 in-system demo's have had the listener upgrading a piece of gear using the Nat's.
I've had no issues with the duals when substituting the Nat's for the factory original. The result is always a huge upgrade in audio performance. If there's anything better out there right now I haven't heard it yet. But I'd like to!
Atom
If you want also deal with various OP-Amps for the aim of compare, prefer the types AD797, OPA604, OPA134, NE5534 oder LME49710.
Avoid in all cases dual or quad OP-Amps (no perfect ground management possible)....
I started futzing with op-amps way back in the 80's when the early CD players were using what were then considered higher-fi devices.
I've long lost count of the many, many types experimented with in upgrading op-amp circuits. To this day I still routinely search for samples of new developments in op-amp design. My current favorites are National Semiconductor's LME49710 and LME49720. A/B comparisons done on my own in various types of equipment have these li'l guys soundly trouncing the competition.
I always install the necessary sockets/adaptors on the circuitboard to accommodate a DIP or SMD package to easily swap out devices under test.In an actual system set-up the listener can then decide for himself whether or not there's an audible difference in hearing the different op-amps in a familiar setting. So far, 4 of 4 in-system demo's have had the listener upgrading a piece of gear using the Nat's.
I've had no issues with the duals when substituting the Nat's for the factory original. The result is always a huge upgrade in audio performance. If there's anything better out there right now I haven't heard it yet. But I'd like to!
Atom
Hi,
two days ago,I red an article,by Thorsten Loesch,trying a modification of the output stage of a Marantz CD80, old cd player,with a kind of a "universal" tubed one.
At the end of the presentation,he describes in nearly 3000 words,the reasons why,he believes that op amps are at the dark side of the road.
Just google Marantz CD80 ,search a little bit,and you will see, why opamps for audio is a loosing end.
Best regards
B.L
two days ago,I red an article,by Thorsten Loesch,trying a modification of the output stage of a Marantz CD80, old cd player,with a kind of a "universal" tubed one.
At the end of the presentation,he describes in nearly 3000 words,the reasons why,he believes that op amps are at the dark side of the road.
Just google Marantz CD80 ,search a little bit,and you will see, why opamps for audio is a loosing end.
Best regards
B.L
I read it, and what he's talking about as far as distortion has to do with design as well as application.
As I said, the CDs you listen to were recorded and mastered through op amps at some point. For a simple well designed circuit, and using high quality parts, you wont hear any more distortion as you would with transistors.
Tubes? A lot more distortion than from op amps. But we happen to like the way the distortion sounds, since the tube tends to smooth things out. But it's far from accurate.
Its probably instructive to get a view from a professional on this issue - Douglas Self. In his book he says he always has a laugh when people start hitting on op-amps because (to paraphrase him) almost every piece of recorded music on the planet has gone through about 100 NE5534's and about the same number of electrolytic capacitors between the mic and the cutting head or the final A-D on the CD recording process. I believe him. There is just far too much b.s. about op-amps and discrete circuitry floating around in the audio firmament. If, to some ears, discrete sounds better, or tubes sound better, then its because they impart a specific sonic signature to the the signal in the final stages of amplification. Thats ok if this pleases your ear - but, recognize it as such. This is not accurate reproduction. An op-amp like the NE5432, or the new nat semi LME49xx series are incredibly accurate devices - which is exactly what recording engineers are looking for - zero distortion and as close to zero noise as possible. My son is a college educated recording engineer and a musician and appreciates the special qualities of tubes and various other amplifying devices, but in the recording signal chain, he told me he wants accuracy. In my system, I want accuracy as well.
We should be very happy, that the recorded signal has not gone through
100 Tube Triodes without any negative feedback.
Or 100 single ended JFETs without any error correction.
Because if, then the accumulated distortion in such recording
would be totally horrendous!
DavidSchwab - Bonsai
Yes and Yes. Hundreds of cheaply implemented op amps, some miles of plain wires,often out of phase wiring,lots of drained electrolytics,and so and so and so...
And we,reproducers,designers and users,tied in a whirlpool,seeking accuraccy.
It is a factual acceptance,that some material and components,(tubes,transistors opamps,caps,resistors etc.)for reasons that no one knows, perform better.under certain circumstances,so why not use them instead.
Distortion and noise are cumulative parameters,and once imprinted they are part of the information.As you said some distortions are more easily processed,by our auditory channels,so it is plain unwise to ignore the faulty nature of them just because someone says so.(Self)
You are aware of course of Ben Duncan,that in the mid 80's,wrote a series of articles in Hi-Fi News,comparing opamps for a preamp.He measured the industry standard 5534,and found some groundbreaking results,as far as noise,hidden somewhere,undetected,by the common measuring procedures.
What I'd like to say is ,that holding various opinions,mostly market driven, as shields in front of the truth ,that our ears "tell "us,is childish and ostrich behaviour.
Both of you strive for accuracy.Accuracy compared to what? Badly recorded signals,rightly recorded signals, live, amplified or acoustic music? What accuracy means to you? The sound of a Bossendorfer or a Steinway piano. Lively or dead venues?
Omni microphones or directional? Blumlein or Mark Levinson?,and so on...
Obviously,by accuracy,you do mean, the standards and the opinions formed into our brains,after all those years of listening and trying to perfect an imperfection.Recorded sounds.
We all know that live music is an event that takes place in a certain window of time and space.Even if we have the means to record it and replay it, with 0% distortions,we haven't,it will never be the same. Simply because that window of time and space there is no more.
B.L.
9
Yes and Yes. Hundreds of cheaply implemented op amps, some miles of plain wires,often out of phase wiring,lots of drained electrolytics,and so and so and so...
And we,reproducers,designers and users,tied in a whirlpool,seeking accuraccy.
It is a factual acceptance,that some material and components,(tubes,transistors opamps,caps,resistors etc.)for reasons that no one knows, perform better.under certain circumstances,so why not use them instead.
Distortion and noise are cumulative parameters,and once imprinted they are part of the information.As you said some distortions are more easily processed,by our auditory channels,so it is plain unwise to ignore the faulty nature of them just because someone says so.(Self)
You are aware of course of Ben Duncan,that in the mid 80's,wrote a series of articles in Hi-Fi News,comparing opamps for a preamp.He measured the industry standard 5534,and found some groundbreaking results,as far as noise,hidden somewhere,undetected,by the common measuring procedures.
What I'd like to say is ,that holding various opinions,mostly market driven, as shields in front of the truth ,that our ears "tell "us,is childish and ostrich behaviour.
Both of you strive for accuracy.Accuracy compared to what? Badly recorded signals,rightly recorded signals, live, amplified or acoustic music? What accuracy means to you? The sound of a Bossendorfer or a Steinway piano. Lively or dead venues?
Omni microphones or directional? Blumlein or Mark Levinson?,and so on...
Obviously,by accuracy,you do mean, the standards and the opinions formed into our brains,after all those years of listening and trying to perfect an imperfection.Recorded sounds.
We all know that live music is an event that takes place in a certain window of time and space.Even if we have the means to record it and replay it, with 0% distortions,we haven't,it will never be the same. Simply because that window of time and space there is no more.
B.L.
9
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