RCA or XLR iInput Shorting Plugs or Pins

Hi Audiobrian,

Actually my VAC preamp and amp each have selector switch for preamp inputs and amplifier input. So no shorting plugs needed if I fully understood your remarks.

It’s conceivable, although perhaps unlikely, that putting shorting plugs on unused inputs of the preamp might provide a small benefit. In any event, doing so won’t cause any harm. Without knowing more about the design of the power amp, though, I would not apply a short to its unused inputs.

... my Audio Note Kits Interstage Monoblock amps (with RCA and XLR inputs) do not have such a selector switch. Would you recommend trying shorting RCA plug on RCA inputs as I routinely use transformer coupled XLR inputs?

Again, when it comes to power amps I wouldn’t short any inputs without being familiar with the design of the specific amp. I took a look at the schematics for the Interstage Monoblock SET amps that are shown at the ANK website, but they don’t show the amps as having XLR inputs (yours must have been specially configured to provide them). It seems very possible, though, that the RCA center pin is connected to XLR pin 2, and if that is the case you would definitely not want to short the RCA input.

The distinction between shorting preamp inputs and shorting power amp inputs derives from the fact that a preamp is designed to accept and select between inputs from multiple source components, while a power amp usually is not. A power amp providing both XLR and RCA inputs is usually designed based on the expectation that just one of those inputs will be connected to a preamp or other component.

Regards,
-- Al

Cardas makes covers to be used on all unused inputs (made absolutely no difference in my system)

Those Cardas RCA jack covers are just cosmetic---if the plugs aren’t shorting, they do nothing except keep dust off the RCA’s. Why does Cardas (and others) offer such a useless, ineffective product, if not to simply make money off vain, insecure audiophiles? I found genuine RCA shorting jacks on ebay, about a buck apiece. Anyone with a soldering gun can make his own, of course. The cheapest RCA plugs available are fine---no audiophile version necessary ;-). I’ve never seen an XLR version, however.

I've applied shorting plugs to my VAC Ren Sig II's unused inputs, and I sure believe it made it quieter.  Spent all of a $1 a piece off of Ebay, just as bdp24 notes above, so I haven't sweated it much to make dead sure of it...