who's up for an experiment?

[stj]

it seems to me that the thing about audio caps is pretty unsettled.
it also seems to me that it's easy to settle.

does anybody have a scope and a frequency generator that can sweep a sinewave from 15Hz to 20KHz ?

the idea is to slowly sweep through the audio frequency range with a cap between the generator and scope to see how much distortion and signal loss is incurred across the sweep.

i know they arent uniform across the range, but we are looking for a relativly flat response.
and i am wondering how well a poly would work as an audio dc-blocker - because i'v not seen anybody try with poly's before!

[eccerr0r]

Re: who's up for an experiment?

If only I could read in the waveforms from my DSO... my crappy DDS can be computer controlled...

However I think it'd be more than just the cap. The input impedance of the scope is typically 1M but amplifiers do not usually have it as high...

[budm]

Re: who's up for an experiment?

Lots of info out there, just need to find the time to validate it.
http://sound.westhost.com/articles/capacitors.htm
You also need the equipment that can check the distortion easily.
http://conradhoffman.com/cap_measurements_100606.html
https://cdn.badcaps-static.com/pdfs/...578c335e37.pdf
https://linearaudio.nl/cyril-bateman...sound-articles
http://www.reliablecapacitors.com/pickcap.htm
https://www.youtube.com/watch?v=xfAgOdOrJ1c

[Khron]

Re: who's up for an experiment?

If only I could read in the waveforms from my DSO... my crappy DDS can be computer controlled...

However I think it'd be more than just the cap. The input impedance of the scope is typically 1M but amplifiers do not usually have it as high...

That's no biggie - just add a 10k or something, in parallel with the scope input

[stj]

Re: who's up for an experiment?

i really am seriously curious about using poly's - the esr is next to nothing - i wonder how flat it is though?

[montemcguire]

Re: who's up for an experiment?

it seems to me that the thing about audio caps is pretty unsettled.
it also seems to me that it's easy to settle.

does anybody have a scope and a frequency generator that can sweep a sinewave from 15Hz to 20KHz ?

the idea is to slowly sweep through the audio frequency range with a cap between the generator and scope to see how much distortion and signal loss is incurred across the sweep.

i know they arent uniform across the range, but we are looking for a relativly flat response.
and i am wondering how well a poly would work as an audio dc-blocker - because i'v not seen anybody try with poly's before!

The typical distortion of a capacitor itself is really low, well below 1 part per million even with a faulty cap. Better caps are on the order of dozens of parts per billion - essentially residual for some of the best distortion measurement setups.

So, an oscilloscope, or even a plain-jane spectrum analyzer is pretty much useless - there is no way at all to resolve distortion on this scale. The best analyzers, e.g. an Audio Precision APx-555, can measure the distortion of faulty caps, but you still have to scrape the residual of the machine. Pricey gear though, but it does work!

[eccerr0r]

Re: who's up for an experiment?

One could say that tube vs transistor is pretty unsettled but people already settled it the way they feel like, anyway, despite much lower THD in one...

[stj]

Re: who's up for an experiment?

it's not a matter of distortion, it's about checking the amount the signal exiting the cap rises and falls as you sweep through the frequency range.

[kaboom]

Re: who's up for an experiment?

it's not a matter of distortion, it's about checking the amount the signal exiting the cap rises and falls as you sweep through the frequency range.

Which is determined by XC (in series with the feed/source) and load impedance.

Even a 1u cap will be flat from 10Hz to 20+ kHz into that 1meg scope input.

[Logistics]

Re: who's up for an experiment?

This is one of those topics which always comes down to very core facts: Everyone hears differently, and no matter what math on paper tell you, (which is that a properly functioning capacitor should not sound different than another) in actual practice, capacitors of different materials sound different. I've seen it first-hand by replacing electrolytics in the signal path of my sound-cards with new, low-impedance electrolytics, bipolar electrolytic, and finally, film capacitors. And film capacitors are hand-down superior sounding to any electrolytic.

[jiroy]

Re: who's up for an experiment?

STJ ; Someone should start the experimenting ..from somewhere , and here , it's you the starter ..

By the way i never seen big size polymers , but i'll assume there should be , at very high prices , right ?

[stj]

Re: who's up for an experiment?

i dont have the equipment - i do digital work.

as for big poly's - i know you can get 2000uf because i used one to upgrade a motherboard the other day.
https://www.rapidonline.com/w-rth-pt...0x12-5-61-2954

[jiroy]

Re: who's up for an experiment?

i dont have the equipment - i do digital work.

as for big poly's - i know you can get 2000uf because i used one to upgrade a motherboard the other day.
https://www.rapidonline.com/w-rth-pt...0x12-5-61-2954

Me too , due to lot of projected projects ..
Imagine a motherboard fully polymer ! , or even an Amp with 4700mf polymers, that would be something .
Thanks man .

[Logistics]

Re: who's up for an experiment?

So much easier to just complete the experiment by installing said polymers, and giving it a listen. In my opinion, most people who worry about "distortion" are listening on gear that has much more to worry about than distortion. But I believe this is because people mistakenly conclude that if their music sounds like crap, on their current listening setup, it must be due to distortion.

While a polymer cap may bring something beneficial to the table which a normal electrolytic will not, it's still not the correct solution for audio.

[Th3_uN1Qu3]

Re: who's up for an experiment?

Before you go all crazy on capacitor tests for audio, remember the RECORDINGS that you are listening to have been done thru a mixing console where they went thru 10s if not 100s of electrolytic capacitors. Just some food for thought. I will not even go thru the whole mixing/mastering process when sometimes distortion is added intentionally to "color" the mix.