Zen 9 Cap C6 and C7 Question

[vdi_nenna]

The schematic for the Zen 9 call for C6 and C7 to be 10uF.
The bill of materials (BOM) call for C6 to be .1 uF and C7 to be 1 uF.

Should I stick with the schematic or go with the BOM? Was it decided the smaller values were better after the article was published?
The boards designed by Peter Daniel accomodate the .1 an 1 uF caps much better.

Thanks,

Vince

[Rodeodave]

These two caps are simply bypass caps, so their value mostly depends on what you believe. The amp will perfectly work without either of them. Read up on the subject of bypass caps, f.e. Cyril Bateman's articles on capacitor sound (just google, there are plenty out links to it), and you'll see that it's a subject with many different opinions and approaches.
If you're not sure, just leave them out, listen to the amp, get used to its sound, and then install one or both and see if they make a difference.

[vdi_nenna]

Thanks for the reply Rodeodave,

I was going to try different bypass caps on the large 15k cap anyway. The case won't have the real estate for 30 Silmic IIs. When I swap-out the C1 bypass caps, I'll try different sizes for C6 & 7.

Thanks again,

Vince

[Rodeodave]

For the sake of completeness, here are two links with resources on capacitors and bypass techniques:

Capacitor Characteristics from Rod Elliott (ESP).

Pro Audio Design Forum • View topic - Cyril Bateman Capacitor Sound Archive for pdfs of the Capacitor Sound series.


It would be very interesting to see/hear if a series-parallel configuration would make a better output cap. You'd need four large caps per channel though...