Hacyon, I do not have the most recent EW article yet - what were his conclusions ?.
Regarding effects other than SNR, THD, IMD etc, I think that the resultant 'sound' comes down to effects caused by the actual materials used.
Ime, different conductor materials cause different sounds, as do different encapsulating materials, metallic, conductive or insulating.
These effects are low level but do add in the total equation, and further modulate the standard explanations of thd, imd etc.
Currently I do not have explanations for these field effects (quantum physics question I'd say), but I have found them to be real and repeatable.
As part of a repair job on a 30 yo furniture radiogram recently, I did a blanket replacement of electros (signal and decoupling) with some low esr smps caps that I have found to be sonically very acceptable previously, and the result was radical improvement all round.
Much lower audible thd and imd, and overall much more pleasant presentation, and the customer is very pleased.
On closer listening to that radiogram, the flavour of those caps is evident, with a similar character to that imbibed to other bits of audio gear that have had the same cap replacement treatment.
Eric.
Regarding effects other than SNR, THD, IMD etc, I think that the resultant 'sound' comes down to effects caused by the actual materials used.
Ime, different conductor materials cause different sounds, as do different encapsulating materials, metallic, conductive or insulating.
These effects are low level but do add in the total equation, and further modulate the standard explanations of thd, imd etc.
Currently I do not have explanations for these field effects (quantum physics question I'd say), but I have found them to be real and repeatable.
As part of a repair job on a 30 yo furniture radiogram recently, I did a blanket replacement of electros (signal and decoupling) with some low esr smps caps that I have found to be sonically very acceptable previously, and the result was radical improvement all round.
Much lower audible thd and imd, and overall much more pleasant presentation, and the customer is very pleased.
On closer listening to that radiogram, the flavour of those caps is evident, with a similar character to that imbibed to other bits of audio gear that have had the same cap replacement treatment.
Eric.
Sound of Polycarbonate Caps
Hi,
I have tried polycarbonate caps in loudspeaker crossover and as coupling caps. They make the sound less harsh but you also loose information. Kind like metalised paper caps, same effect.
The ones tried are ERO MKC1862 100V DC, purple/pink color. Same as in old Mark Levinson equipment. Mark Levinson used polycarbonate a long time from the start with the JC-2. I switched to polypropylene.
Anyone interested in these caps? I have some 22 of 10µF and a few1 µF and 2.2µF. Will post at the trading section.
Hi,
I have tried polycarbonate caps in loudspeaker crossover and as coupling caps. They make the sound less harsh but you also loose information. Kind like metalised paper caps, same effect.
The ones tried are ERO MKC1862 100V DC, purple/pink color. Same as in old Mark Levinson equipment. Mark Levinson used polycarbonate a long time from the start with the JC-2. I switched to polypropylene.
Anyone interested in these caps? I have some 22 of 10µF and a few1 µF and 2.2µF. Will post at the trading section.
Re: Sound of Polycarbonate Caps
Hi Elso,
You are absolutely right with your comments on the sound of polycarbonate caps, which seem to me to be less fashionable nowadays than they were say 30 years ago.
About that time, I conducted a great many trials of the then available plastic film caps, and came to some very definite conclusions, almost irrespective of their individual makers and values.
During some private discussions with John Linsley Hood, I advised him of my (then) 'Ranking Order', which I will never forget.
Beginning with the best: polystyrene, polypropylene, polycarbonate, and lastly, polyester.
There wasn't then much in the way of Mylar, as far I can recall, and I didn't 'listen' to other types like silver micas, these (sil micas) being about on a par with polystyrenes, provided they don't have magnetic leads.
Where appropriate, a film and foil construction would also outperform an otherwise similar metallised film construction, and generally, higher voltage rated caps sound better than the lower voltage ones.
JLH used to be employed by British Cellophane, before he retired, and they manufactured many different plastic films suitable for use in cap manufacture.
Interestingly, at a later date, John notified me that my 'sonic' choices coincided precisely with the differences in the DA factors of these caps, so my ears had probably been quite faithful in my earlier trials.
Regrettably, it seems from what John told me, that in an attempt to reduce costs, certain cap manufacturers were buying inferior grade 'packaging quality' polypropylene at one time to use in their caps, which would certainly have an adverse affect on the sound of them, even though perhaps, 'electrically', they were satisfactory!
Regards,
Elso Kwak said:Hi,
I have tried polycarbonate caps in loudspeaker crossover and as coupling caps. They make the sound less harsh but you also loose information. Kind like metalised paper caps, same effect.
The ones tried are ERO MKC1862 100V DC, purple/pink color. Same as in old Mark Levinson equipment. Mark Levinson used polycarbonate a long time from the start with the JC-2. I switched to polypropylene.
Anyone interested in these caps? I have some 22 of 10µF and a few1 µF and 2.2µF. Will post at the trading section.
Hi Elso,
You are absolutely right with your comments on the sound of polycarbonate caps, which seem to me to be less fashionable nowadays than they were say 30 years ago.
About that time, I conducted a great many trials of the then available plastic film caps, and came to some very definite conclusions, almost irrespective of their individual makers and values.
During some private discussions with John Linsley Hood, I advised him of my (then) 'Ranking Order', which I will never forget.
Beginning with the best: polystyrene, polypropylene, polycarbonate, and lastly, polyester.
There wasn't then much in the way of Mylar, as far I can recall, and I didn't 'listen' to other types like silver micas, these (sil micas) being about on a par with polystyrenes, provided they don't have magnetic leads.
Where appropriate, a film and foil construction would also outperform an otherwise similar metallised film construction, and generally, higher voltage rated caps sound better than the lower voltage ones.
JLH used to be employed by British Cellophane, before he retired, and they manufactured many different plastic films suitable for use in cap manufacture.
Interestingly, at a later date, John notified me that my 'sonic' choices coincided precisely with the differences in the DA factors of these caps, so my ears had probably been quite faithful in my earlier trials.
Regrettably, it seems from what John told me, that in an attempt to reduce costs, certain cap manufacturers were buying inferior grade 'packaging quality' polypropylene at one time to use in their caps, which would certainly have an adverse affect on the sound of them, even though perhaps, 'electrically', they were satisfactory!
Regards,
Pan
Well probably and unforunately that is the case.
But still (of course) a necessary evil to get the results we want.
However, if the processing that is done to the signal could be done without any bad side effects I´m sure we would have much higher fidelity in our listening rooms.
The best/most realistic recordings and reproduction systems is to my ears thoose who use the simplest signal path. Guess most agree on that one
/Peter
Well probably and unforunately that is the case.
But still (of course) a necessary evil to get the results we want.
However, if the processing that is done to the signal could be done without any bad side effects I´m sure we would have much higher fidelity in our listening rooms.
The best/most realistic recordings and reproduction systems is to my ears thoose who use the simplest signal path. Guess most agree on that one
/Peter
***
Hi Fmak,
Regrettably, and very disappointingly, as I have found out 'in spades' (and very surprisingly in this DIY Forum), not all of us have progressed very far at all.
I had the good old "LCR Rules, and nothing much else matters" quoted to me by an 'expert' only a couple of days ago!
Regards,
***fmak said:
Hi Fmak,
Regrettably, and very disappointingly, as I have found out 'in spades' (and very surprisingly in this DIY Forum), not all of us have progressed very far at all.
I had the good old "LCR Rules, and nothing much else matters" quoted to me by an 'expert' only a couple of days ago!
Regards,
And assuming that even the most marginally acceptable quality gear is used then the weakest link is always going to be the transducers (mic and speaker).
Distortion in direct radiating subs commonly reaches 10%. Even high quality horn subs will often have 1% distortion. And that's before you consider the effects of the room. I agree with making our electronics as accurate and noise free as possible, but if you are going to trot out the "weakest link" theory at least acknowledge that there are links that have at least 2 orders of magnitude more influence on the sound than the electronics do.
Phil
Distortion in direct radiating subs commonly reaches 10%. Even high quality horn subs will often have 1% distortion. And that's before you consider the effects of the room. I agree with making our electronics as accurate and noise free as possible, but if you are going to trot out the "weakest link" theory at least acknowledge that there are links that have at least 2 orders of magnitude more influence on the sound than the electronics do.
Phil
Pjotr,
please tell me one/some GOOD recording that used 12bit AD!
haldor,
Yes, the transducer are (within balance) the least perfect links in the chain, but.....
that does not mean that there can not be a HUUUUGE audible difference between the electronics.
Some people seem to think that just because a speaker driver has let´s say 1% THD,
going from 0.5% - 0.1% to 0.1%-0.01% in electronics would not matter, but it sure does many times. This is because of several reasons, phase relationship of the distortion being one of them which does not show up in simple standard measurements.
/Peter
please tell me one/some GOOD recording that used 12bit AD!
haldor,
Yes, the transducer are (within balance) the least perfect links in the chain, but.....
that does not mean that there can not be a HUUUUGE audible difference between the electronics.
Some people seem to think that just because a speaker driver has let´s say 1% THD,
going from 0.5% - 0.1% to 0.1%-0.01% in electronics would not matter, but it sure does many times. This is because of several reasons, phase relationship of the distortion being one of them which does not show up in simple standard measurements.
/Peter
Load Impedence Matters.....
":that there are links that have at least 2 orders of magnitude more influence on the sound than the electronics do."
I agree that the most damage is done at the source (mic), and final replay (speakers/amp) ends, and not nearly so much in the intermediate stages.
I expect that the explanation is that typical line level stages, even though containing 'supspect' amp stages like 741, 4558 etc although prone to harmonic distortion, are not prone to the infinitely more sonics damaging effects of IMD.
The fact that the final power amplifier/loudspeaker combination can give such wildly varying sonics results is the clue.
The amplifier/cable/crossover/drivers final chain is prone to intermodulation and comb filtering and resonance effects because of reactive loads, and negative feedback.
In my experience, if measures are taken to run a very low inductance coupling (cable) between amp and loudspeaker, and the drivers/crossover combination is impedence compensated to present as a resistive load, then the IMD cause is vanquished, and a standard NFB amplifier will sound as clean as it's measured specs would suggest.
Line stages remain clean because they drive clean resistive loads, and the same can result if the final transducer stage (loudspeaker) appears as a clean resistive load too.
This is not rocket science, but it seems that far too many designers and constructors do not have a handle on this simple fact, and on closer inspection this distortion mechanism is to be expected.
In my experience on a system configured as above, the system goes straight to the master tape, and very good recordings sound very good, standard recordings sound good, and very bad or distorted (very old recordings mainly) present as clean and perfectly listenable, except that recording faults like line level clipping, THD and noise are revealed but do intrude, as happens on a typical non load compensated system.
By definition, reactive load means a load that stores and returns energy and this causes typical NFB amplifiers to act up.
The cure is simplicity itself.
Eric.
":that there are links that have at least 2 orders of magnitude more influence on the sound than the electronics do."
I agree that the most damage is done at the source (mic), and final replay (speakers/amp) ends, and not nearly so much in the intermediate stages.
I expect that the explanation is that typical line level stages, even though containing 'supspect' amp stages like 741, 4558 etc although prone to harmonic distortion, are not prone to the infinitely more sonics damaging effects of IMD.
The fact that the final power amplifier/loudspeaker combination can give such wildly varying sonics results is the clue.
The amplifier/cable/crossover/drivers final chain is prone to intermodulation and comb filtering and resonance effects because of reactive loads, and negative feedback.
In my experience, if measures are taken to run a very low inductance coupling (cable) between amp and loudspeaker, and the drivers/crossover combination is impedence compensated to present as a resistive load, then the IMD cause is vanquished, and a standard NFB amplifier will sound as clean as it's measured specs would suggest.
Line stages remain clean because they drive clean resistive loads, and the same can result if the final transducer stage (loudspeaker) appears as a clean resistive load too.
This is not rocket science, but it seems that far too many designers and constructors do not have a handle on this simple fact, and on closer inspection this distortion mechanism is to be expected.
In my experience on a system configured as above, the system goes straight to the master tape, and very good recordings sound very good, standard recordings sound good, and very bad or distorted (very old recordings mainly) present as clean and perfectly listenable, except that recording faults like line level clipping, THD and noise are revealed but do intrude, as happens on a typical non load compensated system.
By definition, reactive load means a load that stores and returns energy and this causes typical NFB amplifiers to act up.
The cure is simplicity itself.
Eric.
I have tried NFB and non-NFB amplifiers with a variety of speakers (including such known "difficult loads" as the Wilson Audio WATT), and I have not necessarily found NFB amplifiers to be any more sensitive to non-NFB types. The point of differentiation seems to be in whether the NFB amplifier was designed with adequate phase margins or not. Many NFB amplifiers appear to be designed without adequate phase margins, and if you ask them to drive a difficult load, they may show signs of overshoot, ringing, or outright oscillation. Let us not confuse a technology with improper application of the same.
Line-level amps can be more problematic than you may think, and I believe that a major reason is that the load of a long interconnect can be fairly capacitive. Another common triggering mechanism is RF from the environment. Different countries have different wireless communication bands, and a circuit that works flawlessly in one country may not always work well in another country because of this.
regards, jonathan carr
Line-level amps can be more problematic than you may think, and I believe that a major reason is that the load of a long interconnect can be fairly capacitive. Another common triggering mechanism is RF from the environment. Different countries have different wireless communication bands, and a circuit that works flawlessly in one country may not always work well in another country because of this.
regards, jonathan carr
Hi Jonathon,
You state good and valid points.
My point is that if the speakers are compensated and exhibit a flat impedence characteristic, then just about any amplifier will work at it's optimum, and correlate with amplifier measurements driving resistive test dummy loads.
When driving a clean resistive load, the importance of factors such as phase margins diminish.
Regarding line level stuff, I mainly meant situations like a mixing desk where the audio signal may easily pass through a dozen or more op-amp stages, each resistively loaded, and the resultant audio damage is reasonably minor.
I fully agree that long interconnect lines can be significantly capacitive, and that this is another cause of errors.
Very good point about RF conditions differing around the world (or suburb even).
Eric / - not reacting, just resisting.
Eric.
You state good and valid points.
My point is that if the speakers are compensated and exhibit a flat impedence characteristic, then just about any amplifier will work at it's optimum, and correlate with amplifier measurements driving resistive test dummy loads.
When driving a clean resistive load, the importance of factors such as phase margins diminish.
Regarding line level stuff, I mainly meant situations like a mixing desk where the audio signal may easily pass through a dozen or more op-amp stages, each resistively loaded, and the resultant audio damage is reasonably minor.
I fully agree that long interconnect lines can be significantly capacitive, and that this is another cause of errors.
Very good point about RF conditions differing around the world (or suburb even).
Eric / - not reacting, just resisting.
Eric.
Hi,
Yes…. You got it! This is also why impedance compensated speakers usually sound better: The speaker is part of the feedback loop. And in some amplifiers the driving impedance of the pre-amp + cabling also is.
A lot of power amps are SOA (Safe Operating Area) protected. That means that when voltage and current are largely out of phase, the protection mechanism comes in at much lower currents. This can result in clipping at relatively low power output.
When an amp clips for even very short periods, the NFB is not effective anymore. You end up with the open loop gain in such occurrences. The whole amp is driven hardly in saturation. The way an amp recovers from such situations makes a huge difference how the amp sounds. This is damm important with dynamic material like CD and DVD-Audio.
All amps have NFB, also the SE triodes. But the SE triodes have a very large loop bandwidth and a huge phase margin. That’s part of their secret. Also they are very difficult to drive into saturation. They have a build in “limiter” mechanism, called “soft clipping”. The result is that they recover very quickly from saturation. Much, much faster than a BJT amp.
Yes…. You got it!
This is also why impedance compensated speakers usually sound better: The speaker is part of the feedback loop. And in some amplifiers the driving impedance of the pre-amp + cabling also is.A lot of power amps are SOA (Safe Operating Area) protected. That means that when voltage and current are largely out of phase, the protection mechanism comes in at much lower currents. This can result in clipping at relatively low power output.
When an amp clips for even very short periods, the NFB is not effective anymore. You end up with the open loop gain in such occurrences. The whole amp is driven hardly in saturation. The way an amp recovers from such situations makes a huge difference how the amp sounds. This is damm important with dynamic material like CD and DVD-Audio.
All amps have NFB, also the SE triodes. But the SE triodes have a very large loop bandwidth and a huge phase margin. That’s part of their secret. Also they are very difficult to drive into saturation. They have a build in “limiter” mechanism, called “soft clipping”. The result is that they recover very quickly from saturation. Much, much faster than a BJT amp.
Hi all,
The CD of Mr. Cyril Bateman is availlable. I have a copy.
Inlclude enlarged versions of the series of articles about capacitor distortion, also other articles published in EW&WW for Mr CB, All the designs with schemes and pcb´s, and also any non published stuff.
The cost is 15 Sterling, included post, if interesting please contact with Mr. CB in:
cyrilb@attglobal.net
Happy days,
Raúl Couto
The CD of Mr. Cyril Bateman is availlable. I have a copy.
Inlclude enlarged versions of the series of articles about capacitor distortion, also other articles published in EW&WW for Mr CB, All the designs with schemes and pcb´s, and also any non published stuff.
The cost is 15 Sterling, included post, if interesting please contact with Mr. CB in:
cyrilb@attglobal.net
Happy days,
Raúl Couto
driving cables
"Line-level amps can be more problematic than you may think, and I believe that a major reason is that the load of a long interconnect can be fairly capacitive. Another common triggering mechanism is RF from the environment. Different countries have different wireless communication bands, and a circuit that works flawlessly in one country may not always work well in another country because of this."
Mega-Dittos. For more on this.........
http://www.diyaudio.com/forums/showthread.php?postid=161789#post161789
"Line-level amps can be more problematic than you may think, and I believe that a major reason is that the load of a long interconnect can be fairly capacitive. Another common triggering mechanism is RF from the environment. Different countries have different wireless communication bands, and a circuit that works flawlessly in one country may not always work well in another country because of this."
Mega-Dittos. For more on this.........
http://www.diyaudio.com/forums/showthread.php?postid=161789#post161789
Hi all,
I have just buy the version 3 of the CD about sound in capacitors.
Have new articles, that appeared in october, november and december, about measurements in power amplifiers, opamps and also potentiometers and resistors.
I think that this is a very recomended read for all interesting in audio, as the book of Walter Jung or Douglas Self.
The price is 15 Sterling, sending and handling included.
Please contact with Mr Cyril Bateman all interested.
Happy days,
Raúl Couto
I have just buy the version 3 of the CD about sound in capacitors.
Have new articles, that appeared in october, november and december, about measurements in power amplifiers, opamps and also potentiometers and resistors.
I think that this is a very recomended read for all interesting in audio, as the book of Walter Jung or Douglas Self.
The price is 15 Sterling, sending and handling included.
Please contact with Mr Cyril Bateman all interested.
Happy days,
Raúl Couto
I haven't read every input on this thread, but this is the ongoing record from my perspective. About 30 years ago, Tektronix made a modification to their 577 component analyzer in order to measure caps. This showed BIG distortion problems with typical ceramic caps. They showed this to me in Mar '74 at the factory. I modified my own 577 and ran tests. Ceramics can be AWFUL! Worse than anything else, but the TEK test procedure did not show much with anything else.
Over the years I tested caps with harmonic and IM distortion. I published this in an IEEE paper in 1978. Here, I also showed that tantalum caps (very popular at the time) had bigtime distortion when not biased with DC, as well as ceramic caps. About this time, Richard Marsh then at LBL, wrote a LTE to 'The Audio Amateur' about DA. I completely missed this potential distortion mechanism at the time, even though I had many papers on it, because it did NOT measure as non-linear distortion.
In the early '80's Walt Jung showed me a differential test procedure developed by Scott Wurcer of Analog Devices, (designer of the AD797 and many other designs) that easily measured DA in caps down to .001%. I measured 100's of caps, and found up to 6% deviation in aluminum electrolytics. Only teflon, styrene, and propylene caps were close to my residual. The rest spread out from .01%-.5% or so for film, and much more for ceramic, tantalum or aluminum caps. We published or results in 'The Audio Amateur' 4/85, and later in 'HFN'. Martin Colloms took this test and applied further measurements to caps and published several articles around this time. We have found that caps sometimes had excessive inductance, physical self resonance, and steel leads, as well as lousy contacts inside the cap itself.
Yes folks, there are differences in caps and they can be audible.
The latest work by Cyril Bateman is excellent, however he took a couple of cheap shots at Walt, me, and anyone else, who did all the preliminary work 25 years earlier. Still, he has done a lot of good work and his measurements are more sensitive, because of FFT analysis that was not cost-effective 25 years ago. I highly recommend it, with the warning that MOST ceramics are really bad, and COG or NPO ceramic caps, recommended by Cyril Bateman are the exception, rather than the rule.
Over the years I tested caps with harmonic and IM distortion. I published this in an IEEE paper in 1978. Here, I also showed that tantalum caps (very popular at the time) had bigtime distortion when not biased with DC, as well as ceramic caps. About this time, Richard Marsh then at LBL, wrote a LTE to 'The Audio Amateur' about DA. I completely missed this potential distortion mechanism at the time, even though I had many papers on it, because it did NOT measure as non-linear distortion.
In the early '80's Walt Jung showed me a differential test procedure developed by Scott Wurcer of Analog Devices, (designer of the AD797 and many other designs) that easily measured DA in caps down to .001%. I measured 100's of caps, and found up to 6% deviation in aluminum electrolytics. Only teflon, styrene, and propylene caps were close to my residual. The rest spread out from .01%-.5% or so for film, and much more for ceramic, tantalum or aluminum caps. We published or results in 'The Audio Amateur' 4/85, and later in 'HFN'. Martin Colloms took this test and applied further measurements to caps and published several articles around this time. We have found that caps sometimes had excessive inductance, physical self resonance, and steel leads, as well as lousy contacts inside the cap itself.
Yes folks, there are differences in caps and they can be audible.
The latest work by Cyril Bateman is excellent, however he took a couple of cheap shots at Walt, me, and anyone else, who did all the preliminary work 25 years earlier. Still, he has done a lot of good work and his measurements are more sensitive, because of FFT analysis that was not cost-effective 25 years ago. I highly recommend it, with the warning that MOST ceramics are really bad, and COG or NPO ceramic caps, recommended by Cyril Bateman are the exception, rather than the rule.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.