Alas Carlos, I've tried my best but haven't been able to get rich on my name. Apologies to whomever I "borrowed" this card from on the 'net, but maybe this is what you had in mind!
As I said, "rules of thumb" tend to be dangerous in audio. I find very little that there isn't some important exception to, so I'm only comfortable saying that in such and such a circuit I had good success with Brand P capacitors under such and such conditions. I know that's limiting but the good engineer is usually conservative, since the public only remembers the bridge that collapsed, not all the ones that are trouble free.
As I said, "rules of thumb" tend to be dangerous in audio. I find very little that there isn't some important exception to, so I'm only comfortable saying that in such and such a circuit I had good success with Brand P capacitors under such and such conditions. I know that's limiting but the good engineer is usually conservative, since the public only remembers the bridge that collapsed, not all the ones that are trouble free.
unfortunately we won't know if it's relevant, until we saw the paper.
but if it contains some info on electrolytics, I think it serves the topic.
maybe stormsonic can tell us more about the content.
As you have acces to the paper homemodder, can you check wether it is on topic and if so ask for permission to show it here?
but if it contains some info on electrolytics, I think it serves the topic.
maybe stormsonic can tell us more about the content.
As you have acces to the paper homemodder, can you check wether it is on topic and if so ask for permission to show it here?
Its not fully on topic but I think a lot of members would like to have a look at it, not only electro are compared but other caps too, its a 3MB download so I dont think we can post such a large file here.
I am surprised at Destroyer X and his assertions. We have measured cap differences for decades. I first published cap non-linear distortion in hi Q ceramics and tantalum caps back in 1978, or 32 years ago. Walt Jung and Dick Marsh followed up with other factors, especially Dielectric Absorption, that showed many measurable differences between caps in 1980. We did our research in order to understand the differences that we heard in caps when we put them in our audio designs, even before we ever tried to measure them in a special way.
If one chooses to ignore cap differences, so be it, but that does not remove their measurable and potentially audible differences.
If one chooses to ignore cap differences, so be it, but that does not remove their measurable and potentially audible differences.
Just curious, when you use electrolytic caps as coupling caps (e.g., the input cap to a power amp), can you measure any differences in overall amp performance compared to (say) polypropylene film/foil? I haven't done this, but I remember Bongo claiming that it made no difference at all.
IMO Sy, you've asked the question in the one place where the comparison is really good to make. Given the fairly high input impedance of most power amps, there's a good overlap in the values of suitable capacitors. You can get all manner of 10 uF electrolytics, films and even Teflon, that won't muck with the bandwidth of the amp. In almost every other location except maybe interstage in tube amps, some compromise invariably has to be made when choosing film caps due to size or availability. I've made some great taped up groups of caps for speaker crossovers, but they're less than practical. No idea of a film cap solution for the DC blocking cap used on the ground leg of feedback networks. 500+ uF of film caps? What I'm getting to is that IMHO many so-called comparisons are sabotaged from the start because a different value was used and considered "close enough", usually a Teflon that's a bit small. Unless the LF curve of the amp is preserved, even if it's seemingly too low to matter, I think even the perception of rumble, bearing noise or whatever, will cause a change in the overall perceived sound.
To a previous poster- no, I only use the high voltage electronic fly swatters. I like to hear them scream, see the little flash and watch the smoke!
To a previous poster- no, I only use the high voltage electronic fly swatters. I like to hear them scream, see the little flash and watch the smoke!
Yep...i use to have problems to perceive such kind of sonic details.
the ones that think they can perceive (maybe ilusion....maybe not) use to say i am not listening very well (old bugger i am maybe), that my speaker are not good enought, or my audio source is not good...well...they say a lot of things... basically that i am unable to perceive.
Well...i do comparisons..without that i cannot feel differences....these ones say that can listen, usually ...not all..not ever.... do not compare...they use to say they do not need..because this whole thing is obvious.
This king of behavior, seems to me alike someone persuading me they can see electrons:
- "Can't you see Carlos?, the third in the strip... the tall electron one, can't you see he is using a boot instead of a shoe?"
Well.....well..... welll.....that's it folks!
regards,
Carlos
the ones that think they can perceive (maybe ilusion....maybe not) use to say i am not listening very well (old bugger i am maybe), that my speaker are not good enought, or my audio source is not good...well...they say a lot of things... basically that i am unable to perceive.
Well...i do comparisons..without that i cannot feel differences....these ones say that can listen, usually ...not all..not ever.... do not compare...they use to say they do not need..because this whole thing is obvious.
This king of behavior, seems to me alike someone persuading me they can see electrons:
- "Can't you see Carlos?, the third in the strip... the tall electron one, can't you see he is using a boot instead of a shoe?"
Well.....well..... welll.....that's it folks!
regards,
Carlos
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This is fairly straight forward with modern designs. Most people do not use input coupling caps in their power amps. None of mine do, anyway.
However, if I did, it would be possible to measure an inferior cap compared to a polystyrene, polypropylene or Teflon cap used as an input cap for a preamp or a power amp, and Walt Jung and I published one result in our cap paper published in the 1980's. In our example we used a 10 uF electrolytic cap and a 50K load. Fair enough?
Of course, the problem with feedback caps in the ground leg are even more problematic, and why I use servos. I don't need any coupling or DC feedback caps in my designs.
Parasound makes a number of inexpensive preamps that use coupling caps between stages. If anyone is content with their overall audio performance, they should use them and not waste their time with the much more expensive JC-2 preamp. Why waste money?
However, if I did, it would be possible to measure an inferior cap compared to a polystyrene, polypropylene or Teflon cap used as an input cap for a preamp or a power amp, and Walt Jung and I published one result in our cap paper published in the 1980's. In our example we used a 10 uF electrolytic cap and a 50K load. Fair enough?
Of course, the problem with feedback caps in the ground leg are even more problematic, and why I use servos. I don't need any coupling or DC feedback caps in my designs.
Parasound makes a number of inexpensive preamps that use coupling caps between stages. If anyone is content with their overall audio performance, they should use them and not waste their time with the much more expensive JC-2 preamp. Why waste money?
Servo(s) is the way to go for sure. I haven't even played with a DC blocking cap design in years. Although I still use a small 1uf polypropelyne input cap.
John, you are one of the best we have in this forum..one of world's best
guys...not only me, but also you, are becoming old... the litlle bit i have learned in this forum, from you, Douglas Self and some others, i am teaching Brazilians inside small groups in Orkut and now a days in the Brazilian forum.
We are slowly getting old John.... we have to let this information for others and not to carry these things with us to the grave.
My knowledge is ridiculous (because small, just scratching the surface) compared to yours... even this way i could perceive it is even bigger than some guys in my place.
We need you...to our progress, only having skilled men talking in an open way what they know for us, we gonna progress...otherwise we gonna be marching in the same place.
Several times i felt angry and decided to go away and leave this forum...good friends told me, and was not once:
- "Carlos, this is the only place on earth, you can talk and listen people alike John Curl"
So, despite you should have being bombed by envy guys, you should know you are the reference..alike Nelson Pass and some others..... a reference!...because of this reason, from time to time was attacked, some guys cannot stand for your superiority......this way...you have a huge responsability, because people have enormous respect by you.
Alike me you may have 20 or more years ahead of you...use it to left the best heritage someone can left.... knowledge!
Please, give us these informations John Curl.
regards,
Carlos
guys...not only me, but also you, are becoming old... the litlle bit i have learned in this forum, from you, Douglas Self and some others, i am teaching Brazilians inside small groups in Orkut and now a days in the Brazilian forum.
We are slowly getting old John.... we have to let this information for others and not to carry these things with us to the grave.
My knowledge is ridiculous (because small, just scratching the surface) compared to yours... even this way i could perceive it is even bigger than some guys in my place.
We need you...to our progress, only having skilled men talking in an open way what they know for us, we gonna progress...otherwise we gonna be marching in the same place.
Several times i felt angry and decided to go away and leave this forum...good friends told me, and was not once:
- "Carlos, this is the only place on earth, you can talk and listen people alike John Curl"
So, despite you should have being bombed by envy guys, you should know you are the reference..alike Nelson Pass and some others..... a reference!...because of this reason, from time to time was attacked, some guys cannot stand for your superiority......this way...you have a huge responsability, because people have enormous respect by you.
Alike me you may have 20 or more years ahead of you...use it to left the best heritage someone can left.... knowledge!
Please, give us these informations John Curl.
regards,
Carlos
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Servos or integrators still use caps, except now they are usually wrapped around the feedback path of a 100 dB opamp. This will magnify any defect of this smaller value cap or even the added complexity of the opamps circuitry noise, offsets etc. You're just trading off one problem for a whole set of new ones. Servos are mostly used to counter act DC and LF drift over a limited low value range and thus are not too good at DC fault protection either.
Maybe of topic:Just finished succesfull with CRT TV set repair, found just one electrolytic capacitor fail(47uf/16v).After 30 year doing this job always the same:dry electrolytic capacitor and bad solder joint on TV set PCB.My conclusion about electrolytic capacitor for Audio apllication:Chose the best elkos manufacturer(Rubycon,Panasonic,Iskra....),And always double check new electrolytic capacitor for`leak before instalation,the best way for this `check` is Analog ohm meter (once check normaly polarized and once inverse),if capacitor`leak` throw him away and start with new one.The smaller value of electrolytic capacitor the great chance for bad one(special with capacitor `No Name Manufacturer`).Good luck for Eweryone
An another approach I have see by repair of an Italian power amp (brand name: AES, Model TWO test in Germans "Stereoplay" 3/95)
Here are to see jFET inputs. Thus the NFB network was with high impedance resistors. Instead an electrolytic cap was a 10uF WIMA MKP cap in use.
BTW - If I want to avoid a big cap between amp output and speaker, what kind of speaker protect would you prefer?
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the problem with high impedance feedback networks is said to be noise
It does not really need fet inputs for a suitably high Z feedback network that allows the use of a plastic cap. That could be done just as well or maybe even better with a BJT input.
many ifs and maybes, I should read up on...
It does not really need fet inputs for a suitably high Z feedback network that allows the use of a plastic cap. That could be done just as well or maybe even better with a BJT input.
many ifs and maybes, I should read up on...
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