So i plugged another piece into the la610 and it sounds fine. this leads me to believe theres something wrong with my moog. any ideas?

Hi Clinton welcome to RO,

If your cable run from the synth to the LA610 isn't any longer than 15ft. - 20ft., I'd use a standard unbalanced TS instrument cable out of the Moog to the LA610's Hi-Z input and try both impedance settings on the LA610 to see which matches the Moog best. You might like the way the big fat analog synth loads the input with one impedance setting over the other. Without downloading the Moog manual to be sure, I can say very few keyboards have balanced 1/4" (TRS) outputs. And by using the TRS to XLR cable to try to create a pseudo-balanced connection I think you're introducing a variety of mis-matched levels. And more importantly, likely sending what should be the shield from the synth to pin-3 on the XLR input of the LA610. And at that point certain combinations of your phase switches in the LA610 could really create some unpredictable problems with cabling that isn't truly balanced properly. For instance, if your phase switch on the front panel is set to Out of Phase, you could be sending the shield of the synth to your LA610 output. I would also expect the "Line Level" input to be designed to accommodate a much more amplified signal than a typical synth output. Not that it wouldn't work, but I seems like it might not be optimal.

I'm curious about post #2, what other "piece" you plugged in that gave you a better result. Was it another synth? Different manufacturers use different methods to wire 1/4" jacks. Depending on how they dealt with the Ring of the 1/4" you can get a variety of results using TS and TRS connectors. A) Some remove the contact to the Ring, when it's intended to be unbalanced - so no matter which you use TRS or TS only the Tip and Sleeve make contact. B) Some leave the Ring, but short it to the Sleeve, when it's intended to be unbalanced. C) Some equipment will leave the Ring for true balanced. and D) Some equipment provides auto-sensing circuitry to send (or receive) unbalanced signal when you short the Ring and Sleeve by using a TS cable, and send a balanced signal if you use a TRS cable. But that last one (D) is usually something you would find in a mixer, I don't think I've ever personally seen a keyboard that did that.

If I manufactured keyboards they would have a built-in DI split with a ground lift - so I could use the balanced XLR for recording or to the snake for the FOH mixer and an unbalanced 1/4" to my keyboard amp or mixer on-stage in a live set-up. In the meantime, I build my own keyboard cases and built the DIs into the case.

I hope that helps.

Thanks for the reply dvdhawk,
I would have never tried the hi-z input, I figured that was reserved for guitars.

The other "piece" is an Arturia Minibrute. I also tried my mpc1000 through it as well. Though I might add about the mpc, the right channel output is busted so I use the headphone jack. To test the mpc with the LA610, as with the Minibrute I used a balanced 1/4". I had no problems with the hum Ive described with either mpc or minibrute.

Im going to let my Moog warm up and give the hi-z a shot! Ill let you know...

Thanks for your help,
Clinton

It works, thanks dvdhawk!

I would have never thought to use the hi-z input. I cant really hear the difference in the impedance switch though.

Glad you're happy with the results.

Although FYI, using a TRS to XLR cable from the headphone output to a mono XLR input can really cause a whole new set of problems.
I'd be happy to bore you with the details on why that's a bad idea if you're really interested.