Electronic – How to identifiy this “2222 063 90025” vintage capacitor


I am restoring an old stereo valve amp and would like to test (and replace if needed) some components. I don't know the history of the amp, but it's made in New Zealand and looks to be from the 1960's or 70's, but I could be wrong.

There are a couple of capacitors that need identifying. The first and larger one is clearly marked 50 \$\mu\$F, however, it has three legs. What I would like to know about this capacitor is:

  • Do the three legs signify a 2-in-1 capacitor?
  • What does the product code of 2222 063 90025 signify (tried here, but no luck)?
  • What do the triangle, square and circle symbols indicate?
  • How do replace this capacitor?

Capactior product code:
Capacitor product code

Capacitor from below, with 3 pins:

Capacitor from below

Best Answer

It's a three section electrolytic capacitor, with the three symbols indicating which pin is associated with each capacitor positive lead. The three capacitors share a common negative terminal (the can) which you will observe is grounded by virtue of being bolted to the chassis. I see soldered lugs on the can to reinforce that connection.

Commonly used as the power supply reservoir capacitor in a vacuum tube amplifier.

Note that one section has a lower rated voltage : you'll see it's connected to the others via a high-ish resistance, to provide a well filtered (quiet) supply to the sensitive preamp stages.

Circuitry will be easy to trace out and will look roughly as below...


simulate this circuit – Schematic created using CircuitLab

If you can't find a replacement, you can use three separete 50uF 450V capacitors. Bonus points for assembling them into a lookalike can...

(A bit more reading suggests this was a Philips part number)