ERO capacitor with 3 leads?

[Whaam68]

Methodically still working through the capacitors on the late 50’s Harting tape deck and I’ve come across two Ero capacitors that are different from the rest. Two .022uf bridging pins of what look to be the two preamp valves On this stereo deck. These have a clear rather than a white resin core and a single lead out on one end but two leads at the Other which is something new to me. I can’t find a circuit diagram anywhere for this deck but I’m guessing the “third” lead might Tie the shields of the two caps together? On the one I checked Capacitance was about 50nf low and esr 78 ohms. Can anyone enlighten me what these are and what to replace them with. For the rest of the 2 legged Eros I’ve simply used standard 630v polyester film caps.
Thanks
Mike

[turretslug]

These three-terminal capacitors feature on the forum every now and then and it seems that the third connection goes to an overall screening layer over the two foils. It may be that conventional types of the same variety as you've already used may be fine here if carefully positioned- i.e. the usual stuff about being close to the chassis and clear of heater and AC wiring. I suppose that you could wrap a turn of copper slug-repellent tape around the capacitor with a soldered flexible-wire fly-lead added before wrapping and cover with heatshrink (clear if you want to prove that you went to the effort!) if you do have hum, or if you just want to be as thorough as the original. If it's a piece of kit that you want to pamper, maybe polypropylene or polycarbonate capacitors here have a better credibility in audio circles but I suspect most folk would struggle to tell the difference, they'll be slightly more pricey but not disastrously so if you avoid "boutique" brands,

Colin

[Whaam68]

Thanks Colin
That’s helpful info I Will probably Just use what I have for now & see how I get on.
Mike