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RCA 6K3 Preliminary Capacitor/Resistor Research
#30

You only need 500V for the firts cap and rarely for the second.
YOu do not need that for the rest: many will do just fine with 300V or so, but you have to know the voltages they are being kept at; if you do not, eveything being 450V takes that question off your mind.

The first cap charges first and his is worse with the 80 tube as it is direct-heated and starts rectifying fast while the rest of the tubes are still warming up; this way the 1st and 2nd caps are not loaded, and even with the choke in between the 2nd cap can get some signifcant voltage; however it is a filter and the voltage there is an average whereas at the 1st cap it is peak-to-peak ripple. So most times the 2nd cap is OK with 450V. But since I use the same capacitances, I buy them all with the same 500V rarting.

Now with the 84 and the likes of it, it warms up slower, almost in sync with the rest of the tubes, so the voltage even across the 1st cap might not reach 500V or even 450V.

But then again, since the capacitors should be of ths same type and quality to work well in the rectifier, rather than keeping several WV, it is easier to keep them all the same.

I think I bought bunch of Panasonic 450V ones, the reason being the earlier radios had 10uF (or sometimes 8uF) value and I get it by serializing the caps I have, so 22uF gets me 11uF which is fairly close. And the voltage is 2x450V (and even without equalizing resistors it is still much higher than 450V).

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.


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RE: RCA 6K3 Preliminary Capacitor/Resistor Research - by morzh - 05-02-2026, 03:08 PM



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