RCA Caps

@bdp24 

Thank you very much for that info. That pricing is good. Although you purchased them years ago and we know prices only head north as time marches on :)

I'll give them a call. In my case I only have phono inputs as I don't have an analog turntable. I would imagine if shorting plugs make any difference at all, shorting the phono inputs should make the greatest, so I'm intending to short those (as any other input).

I can’t envision a design in which a shorting plug applied to an RCA **input** would cause any problems. Consider the fact that the essentially zero ohm impedance presented to the input by a shorting plug is not greatly different than the very low output impedances (e.g., 10 ohms or perhaps even less in some cases) of some components that might be used to drive that input.

@almarg

Sorry to belabor this. I’m merely operating out an abundance of caution in this regard :)

I take your statement to *include* an LFE subwoofer RCA input as well as a phono input. Therefore, *any* type or kind of RCA input where audio is concerned would fall under the same umbrella where RCA shorting of input jacks are concerned.

And, I surmise the most benefit (if any benefit can be realized at all), would or should be from a phono input, which in the case of my amp has a phono input impedance of 47k Ohms, according to manufacturer spec.

EDIT: 
I also realize that operating out an abundance of caution might mean do nothing in this regard :)

Thanks for the follow-up, Hal, as it reminds me of one situation in which a shorting plug on an input could conceivably be harmful.

That would be on some power amplifiers which provide both XLR and RCA inputs, the intent being that only one of those inputs would be used. In some of those cases the signal pin of the RCA connector is wired directly to one of the two signal pins (usually pin 2) of the XLR connector. So if the XLR input is being used in those cases and a shorting plug is put on the RCA connector, the output circuit of the preamp or other component providing the balanced signal pair to the amp would have one of the two signals on its XLR **output** shorted to ground.

And I suppose a similar situation could conceivably arise in the case of some subwoofers, if both RCA and XLR input connectors are provided for a given signal type (i.e., for either an LFE input or an input that is intended to receive a full range signal).

And, yes, I agree with your statement about phono inputs.

Best regards,
-- Al

You're welcome @almarg  

And, thank you too!

I don't believe the RCA/XLR input scenario applies in my case. I'm using a Musical Fidelity M6si (which has phone RCA in) and Golden Ear Triton Reference (which has LFE RCA in).

I believe the scenario you are speaking of, where the RCA and XLR input is "shared" (i.e. one or the other) would be, for example, a Pass Labs INT-250. It's 1 and 2 inputs support RCA and XLR, however, it doesn't appear as though that unit wants both RCA and XLR connections in its 1 and/or 2 inputs simultaneously.

Yes, exactly, @gdhal . From the manual for the INT-250:

There are four inputs, two with XLR and RCA and two with RCA only. The XLR and RCA inputs on INPUT 1 (and INPUT 2) are connected so use XLR or RCA but not both. When using INPUT 1 & 2 with RCAs you should have the XLR shorting jumpers in place.

It’s unusual, though, for inputs of an integrated amp to be configured like that. Typically that situation arises with power amplifiers. But I suppose Nelson wanted to provide users with some added flexibility, by making it possible for those inputs to be used with either type of connection. While another designer might have simply made inputs 1 and 2 XLR only.

So with the INT-250 a shorting plug should not be put on the RCA connectors of inputs 1 and 2 if the corresponding XLR connector is being used.

Best regards,
-- Al