Actually Dario's build thread answers this nicely:
(...)
Didn't see it until now. Duh. Very nice thread Dario!
I'm happy you found it useful
How critical is the value of this resistor - will either 180R or 200R do?
Better 180R
Thanks Bob.
What I do need a hand with is buying C1 & C2 (220uf 50V Elna RJH). The BOM says "Can be ordered from Elfa-Distrelec" but they want 45 Euros for shipping! Did you use these or something else?
Thanks
P.S.
Just read that there was a elna and ero capacitor kit available. Dario: do you have any left?
What I do need a hand with is buying C1 & C2 (220uf 50V Elna RJH). The BOM says "Can be ordered from Elfa-Distrelec" but they want 45 Euros for shipping! Did you use these or something else?
Thanks
P.S.
Just read that there was a elna and ero capacitor kit available. Dario: do you have any left?
Today I sent some caddocks all the way to Jordan and it only cost $3.00. Let me know if I can help.
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A possibility - 6PCS ELNA 220uF 50V SILMIC II RFS Silk Hi-Fi Audio CAPS | eBay
Or maybe this one: 4x 470uF 63V 105C ELNA RJH series radial capacitors | eBay
Just read that there was a elna and ero capacitor kit available. Dario: do you have any left?
You have a PM
WARNING - Dario pointed out the caps in post #1488 are not the correct spec. Those are Silmic II and not RJK. Not sure how much difference there is but, be aware they are not what is in the BOM. They are quite usable in those positions, just not the same. I ordered some so I'll try them out and report back.
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Soon,
the input DC blocking capacitor and the negative feedback, DC blocking capacitor locations, both have a DC offset. This is usually checked for during design and checked again at assembly time.
Have you never bothered to measure the offset on your polarised capacitors?
the input DC blocking capacitor and the negative feedback, DC blocking capacitor locations, both have a DC offset. This is usually checked for during design and checked again at assembly time.
Have you never bothered to measure the offset on your polarised capacitors?
Which polarised (electrolytic) capacitors are you referring to?polarized caps for a position that does not have DC offset
PSU, Decoupling, Coupling, DC blocking?
As far as I can see, all of these locations in the MyRef have a polarisng voltage applied to the capacitor.
that is not a requirement.DC voltage needs to be such that polarized caps are never reverse polarized in operation.
Prevention of excessive reverse polarity is a requirement.
As far as I know electrolytics can tolerate 1000mVk to 1500mVpk of reverse polarity without suffering any degradation.
If you apply a 1Vac signal to an electrolytic coupling cap and it has 200mVdc offset then the worst case short term reverse polarity is ~1200mVpk.
But the capacitance of the capacitor does it's best to drag the undriven plate along with the voltage on the driven plate. That 1Vac signal can't actually apply anything like a 1200mVpk reverse polarity between the plates.
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