Coupling capacitor and bypass choices

[PauloPT]

Hi,
I need some advice about a cap, please.
I know, the best cap is no cap and the second best it's a Black Gate. Unfortunately those are not options for me.
I need to choose a dc blocking cap of 100uF and I pay special attention to the treble, which I'd like to be detailed and good with female voices. I'm thinking about Elna Silmic II and Nichicon Muse ES. Which of these would be better to the task? Are there other possible choices? About bypassing - should I or not bypass? I have some Ero MKP1837 22nF in my parts bin. If i should bypass the 100uF electro would these do a good job?

Thanks,
paulo.

[EchoWars]

I use the Silmic caps, and I love them. If you want to bypass the cap with a film, I typcally use some 0.22µf stacked film caps for the job. Seems to me your 22nf is a bit small to have any real effect.

[AndrewT]

read Rane.
They specify the coupling cap and it's bypass for both halves for the balanced output socket.

I'll see if I can find the doc.

[AndrewT]

Not Rane.
Jensen Application Note 003
www.jensen-transformers.com/an/an003.pdf

we recommend Panasonic 16 volt bi-polar electrolytics, part number ECE-A1CN221S,

I used a 1uF polypropylene as the direct signal route and 150uF as the LF bypass.

[PauloPT]

Thank you for your answers. What would be the best value for the 100uF bypass? 0.22uF?

Thanks again,
Paulo.

[AndrewT]

You got what I said back to front.
The 1uF polypropylene couples the audio signal by the most direct (shortest) route.

The extreme low frequency bypasses the poly via the 150uF bipolar electrolytic. This route is slightly longer.

[PauloPT]

If I understand correctly you have 2 caps in parallel, one of 1uF and the other of 150uF. Isn't it relative to say which is bypassing which?

[AndrewT]

they are different depending on location and orientation and trace routing.

I want the poly to pass the best Audio Signal that it is capable of.
The Electro is there just to bring back the bass and routing is not so important for the LF that will bypass the main audio route.

[PauloPT]

You're saying the length of the capacitor wires has influence in sound quality? I didn't know that, I mean, if the wires are short I thought it's indifferent which capacitor has the longer wires.

[AndrewT]

The trace inductance and the lead inductance combined with the ESR & ESL of the capacitor will affect the way the amplifier passes/amplifies the Audio Signal.

Setting the electro as the main coupling cap completely defeats attempts to maintain good audio quality through the system.

Set the best Audio cap in the best location using the best layout for best transmission of the Audio Signal. Then tag on the bypass electro using any traces & lead lengths that gets it to fit conveniently on the PCB. The LF does not mind about a bit of extra inductance.

Does this explain why I differentiate between an electro coupling cap with a poly bypass and a poly coupling cap with a LF electro bypass?