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Hello,
I'm in the process of building an 18 Watt sIII kit and have a few questions.
1. The diagram shows two 50uF 50V electrolytic capacitors, one in the power section and one in the preamp section, but the BOM lists only one of these capacitors and I only have one, am I missing a capacitor or am I misreading the diagram?

2. The diagram shows a .68uF capacitor on the last two turrets in the preamp section. The BOM lists one .68uF X 600V axial capacitor, I have one .68uF 100VDC axial capacitor, which brings me to two questions: 1. does it matter if the capacitor is rated 100V instead of 600V? 2. There are no obvious polarity markings on this capacitor, how do I determine polarity for it?

3. The instructions say to connect the yellow 5V lead from the PT to a lug on the 5 lug terminal strip (I connected the yellow wire to the first lug on the left), but I don't understand what that accomplishes, from what I can tell the lug is isolated and no other leads are attached to that lug.
Thanks,
Jon

1) That seems weird. Both the layout and the schematic show both. The new and old Plexi versions don't have two, but the sIII and sIII V6 certainly do.

2)

3) I think that's just an easy way of keeping an unused lead out of the way.

_________________
Go Buckeyes!

1)yes from the layout. one on cathode of v1b and one on the cathodes of the power tubes. Did you get an extra electrolytic in the kit like 220uf 50v that's not used

2) the .68 for the cathode of v1 100v is more than enough for this location and there is no polarity on this type of capacitor

RMosack, your answer on the yellow lead makes sense, thanks for your help. I'll have to check with Stephen regarding the presumably missing cap.

Thanks Sazafraz. Unfortunately, I have no more caps, I'll have to check with Stephen on this. Regarding the .68 cap, thanks for your insight, I know some caps can go either way but I didn't want to find out the hard way.

All correct. We switched from 220 to 50 recently, for the power amp. Somehow, the extra 50 didn't get onto the BOM list. We'll send one of each and you can try them both. Yes, the tag strip is a way to keep the leads neat and the .68 can safely go either way.

_________________
Stephen
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