Simaudio MOON 610LP with Lyra Kleos

Can't think of too much. I'm assuming you are using the single ended inputs and outputs on the 610 and that the balanced jumpers are inserted?

Apart from that I would be setting the gain initially at least at the 56 dB setting as the Kleos appears to have a relatively high output of around .5 mV.

It also has relatively low internal impedance around 5.5 ohms so I would initially experiment with the loading in the 75-150 range. But Lyra has a very wide range spec'd for loading (supposedly based on the capacitance of your phono cable) so you may end up experimenting with much higher ranges than that.

What what do you think about using a step-up transformer? Bobs Devices have couple of models all with a ground post and use the Moon in MM mode?

So..a new issue? Can you be more specific as to when you first noticed this issue?

It is a new issue. But each one of these components have been used in other combinations, including cables. 

Just an idea, I had a hum problem with my center channel and mono amp for driving it. I inserted a Jensen Iso-Max isolation transformer in the interconnect, and 90% of the noise went away. It might be something to try. I have a two-channel analog set up (using the same main speakers, separate tube preamp and SET 300B amp) with no noise issues.

Hope you get it sorted out.
Regards,

Dan