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Hum with VTL's

I have a Wadia 7 & 9 Transport/DAC/Preamp and a pair of VTL 450 monoblocks all fed by a PS Audio P600.Using the balanced connections there is a very loud hum coming through each channel (does not vary with volume). It does not accur using the RCA connections and also stops when using the balanced connections (toggle switch on bal) but
the RCA cables also plugged in. I read somewhere about checking the continuity from the earth pin to the phono ocket body and both my amps have continuity. I would be grateful for any advice on where to go next with this. Having both the balanced and RCA cables plugged on stops it but I'm not sure if I'm curing the problem or the symptom.
128x128adecook7

Showing 2 responses by adecook7

adecook7's avatar
adecook7 OP
5 posts
 
Herman Thanks for advise.
I've tried different cables and they are the same so it's not them. Does this mean the balanced sockets should all have a grounding to the chassis of each commponent and I have one or more that does not have this connection ? Could this be a design issue or would it be a defect ?
Similarly as all my components have 3 pin mains have I lost earth continuity to mains on a component. If I have a design conflict between components which my bridging with he RCA solves then I can live with that I just don't like the idea of having something that is not right or has a defect !!
On the P600 it normaly shows an output reading of 450-500 Watts as it's supossed to be a 600 watt unit I thought it should be OK ? Mind you it does get a bit warm !
Many Thanks Ade
adecook7's avatar
adecook7 OP
5 posts
 
Herman
Thanks again, I've done some more checking and I'm getting more confused ! I've found that the wadia 7 has no chassis continuity to earth, while this can't be right I'm not sure how it would effect things as the link from the wadia 7 to 9 is optical. Also one of the amps has a poor earth connection as you have to wiggle the socket to get the continity ! again I'm not sure this is relevent as I still get the hum with this earth path there though it does reduce it. There is no continuity between the wadia and amp chassis with either the XLR or RCA cables .
I guess I should sort out the faulty earths I've found and check again Regards Adecook
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