ac coupling

[abbey road d enfer]

i know the 1% works because that's the only type i use.
the 0.1% is roughly 0.44€ (single price) a piece, about 10x the amount of a 1%.
Buying 100 of them drops the price and they will get used, like the other smd components i have used and are almost to be replenished.

Since you already have made your choice, in consideration of your preferences, why do you ask?
I believe you're going to piss off wear out the patience of members who take the time to give you advice.

I have beaten more than 21.000.000 people (people with or close to having a University degree) in a ongoing hardcore coding competitions, no i dind't reach the number one spot, but well below the 10.000 rank.

So, you're a great coder. Good for you. Some members here are successful artists, producers or businessmen, but when it comes to audio electronics, they listen for advice, because they know that being an ace in one domain doesn't mean they are in all domains.

 

[abbey road d enfer]

In Cyril Bateman's capacitor study bipolar electrolytics showed lower distortion than all configurations of polarized electrolytics. Good reason to make them the preferred choice in audio paths.

I'm not so sure. Considering the progress in electrolytic capacitor technology in the past 20 years, the difference is probably much less than it was.
I think the same work should be conducted today with modern types.
Looking at the spec sheets of non-polar 'lytics, I don't see such a difference.
Anyway, I know it should be confirmed by experimentation, but I don't have access anymore to the right test equipment, and I don't have the patience.
Now, one must remember that the capacitors had to be put in extreme conditions in order to produce clearly identified results.
Today, most designers understand that minimizing the voltage across the cap, by increasing the nominal capacitor value or the load is the Nr one fix for reducing distortion.
That was not always possible in the 60's and 70's, but now it is, unless one is constrained by miniaturization.

 

[user 37518]

I'm not so sure. Considering the progress in electrolytic capacitor technology in the past 20 years, the difference is probably much less than it was.
I think the same work should be conducted today with modern types.
Looking at the spec sheets of non-polar 'lytics, I don't see such a difference.
Anyway, I know it should be confirmed by experimentation, but I don't have access anymore to the right test equipment, and I don't have the patience.
Now, one must remember that the capacitors had to be put in extreme conditions in order to produce clearly identified results.
Today, most designers understand that minimizing the voltage across the cap, by increasing the nominal capacitor value or the load is the Nr one fix for reducing distortion.
That was not always possible in the 60's and 70's, but now it is, unless one is constrained by miniaturization.

If I remember correctly, Douglas Self reported some tests, if a regular electrolytic being used as a decoupling cap is large enough, the distortion is negligible and the difference between a premium electrolytic, bipolar or a cheap one is also negligible.

 

[abbey road d enfer]

If I remember correctly, Douglas Self reported some tests, if a regular electrolytic being used as a decoupling cap is large enough, the distortion is negligible and the difference between a premium electrolytic, bipolar or a cheap one is also negligible.

Yes. Decoupling is a different and much more complex case study than a simple CR, because it involves the rest of the circuit, the PSU characteristics and how currents circulate. And of course a one-transistor common-emitter circuit (zero PSRR) reacts very differently than an opamp with NFB.
And I'm not talking about the rail-to-ground vs. rail-to-rail controversy...
Member Ricardo has very strong opinions about electrolytics for rail decoupling. He suggests the low-ESR types may result in oscillations; he has the credentials for sustaining his opinions.
That's another subject that may trigger experimentation.

 

[FIX]

i did a second test ...
View attachment 94113

i tested:
Wima: 1nF / 1000pF fail.
Wima: 10nF fail.
Wima: 47nF fail
Wima 100nF fail
Wima 330nF could work
Wima 680nF could work
Wima 1uF works

electrolytic:
4uF7 works
10uF works

On the centuria Wima caps the amplitude only drops at high frequency, above 20kHz, but so does the VCO.
It's hard to see the difference between the 1uF Wima and the electrolytic caps with my scope.
Only a current generation digital scope could tell you and if there is a difference it would be in the range of 50mV.

You need a resistor from PIN 5 to GND, or the op-amp will drift, then clip, then latch. An electrolytic probably had enough leakage to keep it stable. 100K is plenty.