Home |
Search |
Today's Posts |
#1
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
Re the performance of aluminium electrolytic caps for audio coupling in a zero
bias situation. I've observed, indeed I first heard of it decades back, that provided the signal *across* the capacitor doesn't exceed about 100mV ac there is no measureable non-linearity. I've confirmed this using Audio Preciosn test gear which measures down to 0.0008% THD (-102dB). Hence if the value of the cap is such that 100mV is never exceeded, there will be no distortion contribution from the cap. I've also confirmed that if the 100mV is exceeded, you do indeed get distortion. The mechanism seems to be electrolytic rectification AIUI. I presume that the absence of any effect below ~ 100mV is due to the 'forward' voltage of this rectifier, and current only flows when it's exceeded. Any more thought on this ? I did find this page about electrolytic rectification btw. http://home.earthlink.net/~lenyr/borax.htm The oscillograms are rather interesting. Graham |
#2
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
In article , Eeyore wrote:
Re the performance of aluminium electrolytic caps for audio coupling in a zero bias situation. I've observed, indeed I first heard of it decades back, that provided the signal *across* the capacitor doesn't exceed about 100mV ac there is no measureable non-linearity. I've confirmed this using Audio Preciosn test gear which measures down to 0.0008% THD (-102dB). Hence if the value of the cap is such that 100mV is never exceeded, there will be no distortion contribution from the cap. I've also confirmed that if the 100mV is exceeded, you do indeed get distortion. The mechanism seems to be electrolytic rectification AIUI. I presume that the absence of any effect below ~ 100mV is due to the 'forward' voltage of this rectifier, and current only flows when it's exceeded. Any more thought on this ? I did find this page about electrolytic rectification btw. http://home.earthlink.net/~lenyr/borax.htm The oscillograms are rather interesting. I have always wondered how much AC across a cap will depolarize it, and exactly how NP caps maintain integrety. greg |
#3
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
GregS wrote: In article , Eeyore wrote: Re the performance of aluminium electrolytic caps for audio coupling in a zero bias situation. I've observed, indeed I first heard of it decades back, that provided the signal *across* the capacitor doesn't exceed about 100mV ac there is no measureable non-linearity. I've confirmed this using Audio Preciosn test gear which measures down to 0.0008% THD (-102dB). Hence if the value of the cap is such that 100mV is never exceeded, there will be no distortion contribution from the cap. I've also confirmed that if the 100mV is exceeded, you do indeed get distortion. The mechanism seems to be electrolytic rectification AIUI. I presume that the absence of any effect below ~ 100mV is due to the 'forward' voltage of this rectifier, and current only flows when it's exceeded. Any more thought on this ? I did find this page about electrolytic rectification btw. http://home.earthlink.net/~lenyr/borax.htm The oscillograms are rather interesting. I have always wondered how much AC across a cap will depolarize it, If it's got a DC polarising voltage applied, basically you can't. and exactly how NP caps maintain integrety. The NP caps work by leaking enough initially to build up a charge on both 'halves' so that they end up 'self-biasing' themselves. They are no diferent to a 'back-to-back' pair of ordinary electrolytics. Graham |
#4
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
Eeyore wrote
Re the performance of aluminium electrolytic caps for audio coupling in a zero bias situation. I've observed, indeed I first heard of it decades back, that provided the signal *across* the capacitor doesn't exceed about 100mV ac there is no measureable non-linearity. I've confirmed this using Audio Preciosn test gear which measures down to 0.0008% THD (-102dB). Hence if the value of the cap is such that 100mV is never exceeded, there will be no distortion contribution from the cap. I've also confirmed that if the 100mV is exceeded, you do indeed get distortion. The mechanism seems to be electrolytic rectification AIUI. I presume that the absence of any effect below ~ 100mV is due to the 'forward' voltage of this rectifier, and current only flows when it's exceeded. Any more thought on this ? I did find this page about electrolytic rectification btw. http://home.earthlink.net/~lenyr/borax.htm The oscillograms are rather interesting. Graham Most of the differences between cap types occurs outside the grasp of your inadequate instrumentation and test methodology. Distortion increases with bias. Bipolar electrolytics can be as good as plastic film for audio purposes. Stop clutching straws and do some proper reading. Ian |
#5
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
Ian Iveson wrote: Most of the differences between cap types occurs outside the grasp of your inadequate instrumentation Audio Precision test equipment is inadequate ? Do tell who makes better ! www.ap.com and test methodology. I haven't said anything much about my 'test methodology'. Not much to say really. Distortion increases with bias. Distortion increases with signal level with unbiased electrolytics. DC biased electrolytics don't distort AFAIK ( I haven't measured to make sure becasue that wasn't my area of interest at the time). Bipolar electrolytics can be as good as plastic film for audio purposes. Absolute garbage. Film caps don't distort at all at any practical signal level. NPs do. Considerably so. Stop clutching straws and do some proper reading. Damn.... you're one cluless ****wit. No one else manages to get everything wrong quite as predictably as you do. Graham |
#6
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
Soundhaspriority wrote: Maybe both of you are wrong. Iveson's an utter idiot. He can't even get basics right ! You both seem to lack humility. You both demand that strangers accept your conclusions. I'm met too many idiots to bother spending any time being humble to them any more. They drive me nuts (almost quite literally once). Idiot is as idiot does. Graham |
#7
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
On Tue, 1 May 2007 22:26:51 -0400, "Soundhaspriority"
wrote: Graham, we should be humble towards everyone. Lack of intelligence is not a reason for disrespect. Sure it is. Disrespect for the person's opinions, at any rate. |
#8
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
On 2007-05-02, Ian Iveson wrote:
Most of the differences between cap types occurs outside the grasp of your inadequate instrumentation and test methodology. Distortion increases with bias. Bipolar electrolytics can be as good as plastic film for audio purposes. Stop clutching straws and do some proper reading. Ian - in a related thread I mentioned that I had done some searching and had found little on nonlinear distortion in capacitors. I would be very interested in some references. -- John Phillips |
#9
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
"Ian Iveson" wrote in
message news Eeyore wrote Re the performance of aluminium electrolytic caps for audio coupling in a zero bias situation. I've observed, indeed I first heard of it decades back, that provided the signal *across* the capacitor doesn't exceed about 100mV ac there is no measureable non-linearity. I've confirmed this using Audio Preciosn test gear which measures down to 0.0008% THD (-102dB). Hence if the value of the cap is such that 100mV is never exceeded, there will be no distortion contribution from the cap. I've also confirmed that if the 100mV is exceeded, you do indeed get distortion. The mechanism seems to be electrolytic rectification AIUI. I presume that the absence of any effect below ~ 100mV is due to the 'forward' voltage of this rectifier, and current only flows when it's exceeded. Any more thought on this ? I did find this page about electrolytic rectification btw. http://home.earthlink.net/~lenyr/borax.htm The oscillograms are rather interesting. Most of the differences between cap types occurs outside the grasp of your inadequate instrumentation and test methodology. And your suggested alternative is? Distortion increases with bias. Absolutely bass-ackwards. Bipolar electrolytics can be as good as plastic film for audio purposes. This correlates with your other statements, how? Stop clutching straws and do some proper reading. Doctor, cure thyself. |
#10
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
"Soundhaspriority" wrote in message
"Eeyore" wrote in message ... Ian Iveson wrote: Most of the differences between cap types occurs outside the grasp of your inadequate instrumentation Audio Precision test equipment is inadequate ? Do tell who makes better ! www.ap.com and test methodology. I haven't said anything much about my 'test methodology'. Not much to say really. Distortion increases with bias. Distortion increases with signal level with unbiased electrolytics. DC biased electrolytics don't distort AFAIK ( I haven't measured to make sure becasue that wasn't my area of interest at the time). Bipolar electrolytics can be as good as plastic film for audio purposes. Absolute garbage. Film caps don't distort at all at any practical signal level. NPs do. Considerably so. Stop clutching straws and do some proper reading. Damn.... you're one cluless ****wit. No one else manages to get everything wrong quite as predictably as you do. Graham Maybe both of you are wrong. You both seem to lack humility. You both demand that strangers accept your conclusions. If irony killed... !!!!!!!!!!! |
#11
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
Soundhaspriority wrote
Stop clutching straws and do some proper reading. Damn.... you're one cluless ****wit. No one else manages to get everything wrong quite as predictably as you do. Graham Maybe both of you are wrong. You both seem to lack humility. You both demand that strangers accept your conclusions. Moi? I suggested he does some proper reading. That's a long way from telling anyone to accept my conclusions. Humble apologies, of course, if it seemed otherwise. And for the intrusion, strangers. I'll go away now. cheers, Ian |
#12
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
John Phillips wrote
Ian - in a related thread I mentioned that I had done some searching and had found little on nonlinear distortion in capacitors. I would be very interested in some references. This may be a useful starting point, and gives a few references: http://sound.westhost.com/articles/capacitors.htm But nothing on the net is error-free and unbiased. The series of articles in Electronics World by Cyril Bateman seems to be widely cited. I haven't found a serious critique of it, unfortunately, because it raised a few questions in my mind. I don't think it's available for free and I've lost mine. I posted a very crude resume to rec.audio.tubes ages ago, only to be savaged by a monkey with a posh machine. I came here by accident. Oops. cheers, Ian |
#13
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
John Phillips wrote: On 2007-05-02, Ian Iveson wrote: Most of the differences between cap types occurs outside the grasp of your inadequate instrumentation and test methodology. Distortion increases with bias. Bipolar electrolytics can be as good as plastic film for audio purposes. Stop clutching straws and do some proper reading. Ian - in a related thread I mentioned that I had done some searching and had found little on nonlinear distortion in capacitors. I would be very interested in some references. From Ian ? LOL ! Graham |
#14
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
Ian Iveson wrote: Soundhaspriority wrote Stop clutching straws and do some proper reading. Damn.... you're one cluless ****wit. No one else manages to get everything wrong quite as predictably as you do. Maybe both of you are wrong. You both seem to lack humility. You both demand that strangers accept your conclusions. Moi? I suggested he does some proper reading. Do please tell me what you read to come up with the nonsense you posted. Graham |
#15
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
Ian Iveson wrote: John Phillips wrote Ian - in a related thread I mentioned that I had done some searching and had found little on nonlinear distortion in capacitors. I would be very interested in some references. This may be a useful starting point, and gives a few references: http://sound.westhost.com/articles/capacitors.htm Please inspect the test method for appropriateness. It tests the capacitors with 90V ac applied across them ! That's about a thousand times more than they will ever receive in an audio coupling application. I find the test method questionable too. Graham |
#16
Posted to rec.audio.tech
|
|||
|
|||
Aluminium electrolytic coupling caps.
"Eeyore" wrote in
message Ian Iveson wrote: Soundhaspriority wrote Stop clutching straws and do some proper reading. Damn.... you're one cluless ****wit. No one else manages to get everything wrong quite as predictably as you do. Maybe both of you are wrong. You both seem to lack humility. You both demand that strangers accept your conclusions. Moi? I suggested he does some proper reading. Do please tell me what you read to come up with the nonsense you posted. Reading Marsh and Jung can have that outcome, it seems. |
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
FA SET OF 2 ELECTROLYTIC CAPS 400V 220uF | Vacuum Tubes | |||
bypassing electrolytic caps | Pro Audio | |||
another question--2n4250/electrolytic caps | Pro Audio | |||
Poly caps or electrolytic caps? Which sound better? (in a guitar tube amp) | Vacuum Tubes | |||
JJ Electrolytic Caps | Vacuum Tubes |