Balanced Grounding Pins

I have a Krell amp that has both balanced and unbalanced connections. When not using the balanced connections, you have to install a U-shaped grounding pin or you get hum in those channels. The amp came (used) without the grounding pins, and I want to find some replacements. Anyone know if these are unique to Krell (I can't imagine) and if not where they can be purchased? I went to some local stores and they looked at me like I was from Mars.
You can easily make your own grounding connectors: get two male XLR connectors (try Radio Shack) a.k.a. Cannon plugs. Solder in a short jumper to ground the unused input. I used to have a Krell so I made mine, but don't I recall which pin you need to ground (call Krell & ask if you don't have a manual). I think you ground the inverting (-) input, which would be pin 3 to ground pin 1. If it's the non-inverting input, then that would be pin 2 to ground pin 1. If the XLR's are not available at The Shack, try any music instrument shop (these connectors are found on microphones too). Or go upscale, to Micheal Percy Audio or Kimber's WBT, but no need to get fancy as these connectors are not carrying audio signals.
email Krell, they may send you some.