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impedance mismatched ?

Audio Aero Capitol Mark 2 running directly into amplifiers via balanced outputs has a output impedance of 100 ohms.
My VTL 750 REFERENCE amplifiers balanced input impedance is 137 ohms. Is this a impedance mismatch which could possibly cause a audible [20 feet away] hum to result when using 1 meter balanced Interconnects? when using the RCA outputs and RCA inputs with same components as above [same impedance specifications for RCA also] their is absolutely zero hum. And yes the XLR pin configuration has been confirmed as being correct on my balanced Interconnects for these components. was suggested could be a ground loop causing the hum but when plugged all 3 components into a power strip the hum still remains, even if floating all the grounds with cheater plugs.
mejames
herman
1,974 posts
 
The input impedance is actually 137,000 ohms, which is typical for a tube amp. The high ratio of amp input to source output that you have is what you want in this situation.

I suspect you have a broken connection inside your balanced cable at the connector since the RCA doesn't hum.
mejames OP
986 posts
 
hello Herman I believe your correct I checked the information again the specifications actually says input impedance 137kw is this actually same as 137k ohms? Thanks
ivanj
640 posts
 
What brand of cables are they? I've had a number of balanced cables that really weren't balanced and hummed like crazy. They were just coaxs with XLRs stuck on the ends.
mejames OP
986 posts
 
they are XLO SIGNATURE 2 they don't hum when used in my friends system. Interesting note when I connect from the balanced players outputs using a XLR to RCA adapter and a RCA terminated Interconnects to the amplifier their isn't any hum problem?
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