Are these 100V electrloytics marginally rated?

[Chris Wilson]

The guy who devised this circuit knows more than I ever will, yet to me the 100V , 10,000uF electrolytics seem marginally rated, voltage wise. I have genuine Nippon Chemico (or whatever they are called, they are not to hand right now), but 100V seems a bit iffy. Am I worrying needlessly please? Thanks. Also, to get the 14V AC he recommends winding a few turns of 1.5 mm enamelled wire on the outside of the toroidal transformer, as the one specced does not have a 14V secondary. Should I then wrap the winding with some sort of tape? What sort please? Thanks.

[SeanB]

Very close to the full voltage rating, but will work. If you are worried use 160V rated caps, though you will need to have a few in parallel as you will likely only get 4700uF in 160V rating.

As to the 14V winding, you just wind it over the existing toroid, and yes you should use some mylar or kapton tape to provide extra protection to the winding so it does not get damaged. Do not use regular insulation tape as it will go sticky and peel off in a few years.

[Chris Wilson]

My hero, Sean always seems to come to lost soul's rescue Thanks, if they get warm or give issues I'll re-examine things. Apparently the creator's amp has run fine with the exact same caps for years. Call me paranoid, been called far worse! Thanks again.

[SeanB]

Just take the new caps and reform them for an hour or two, using a series resistor of around 10K 10W to charge them to 120VDC. This will reform them, and should be safe enough as they likely were originally formed to 130V in production. Best though is to not operate it at full power setting for long periods in receive, especially at high mains voltage, or to just order 160V or 200V capacitors. I have some 4700uF 450V capacitors NOS here that are not in use, I got them in a dumpster, and am looking to add them to a PSU as extra hold up time.