TT and earthing on NAC 92?

Just testing a NAC 92 with a TT.
Connect L and R channels plus the TT earth to the NAC 92 phono inputs. Only one channel plays out. Disconnect the TT earth from the NAC 92 and both channels play fine.

Why?

Sound like you’ve got a short somewhere between the L + or R + wires and the earth wire. Can you isolate it to which channel is affected and the trace it through ?

Given that the earth wire is normally a separate wire up until the arm base plug then you could have a problem at this connector or in wires going from this connector to the cartridge pins, possibly shorting to the arm tube. I take it you’ve swapped connections at the 92 to end to check the problem channel moves too ?

What TT arm is it ?

It all works when connected to a nac 32.5, so I don’t think its in the arm connection. I have also tried another cart in a separate headshell. I suspect it’s in the 92 somewhere.

Hmm - very strange. If you swap L&R inputs on the 92 is the same channel affected ?

NOw this is strange.

I’ve just re attached the earth for test purposes. All is now working with or without the earth attached.

I’m wondering if the earth attachment point itself is shorting occasionally inside the casing.

Ho hum it’s now working so leave it alone :slight_smile:

and Christy Moore is sounding as sweet as ever.

Thanks for the pointers.

Worth checking it’s not a dodgy connector - if you wobble the cables going into the Phono plugs do you lose a channel ?

No, tried all that.

Deffo only when attaching the earth.

Strange. What TT is it ?

Are we talking Phono connectors, here…? Perhaps more likely to give poor or variable contacts…?

Its a trusty planar 3 mk1 that has been in use for ever and doesn’t give any trouble on a 32.5, Nait or through a a phono stage into the 252.

The only change was to try out a nac 92. I would take a look inside the 92 to see how the phono/ earth inputs run but the 92 has the silly plastic rivets. Meanwhile as long as its working etc.

Try cleaning the 92’s input sockets, maybe…?

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