I do not think there is anything else you need to do except set the input on RCA and play with Crystallock, narrow and wide to see which you prefer. Of course, the preferred would be Crystallock for its non-upsampling mode with jitter rejection.
Originally Posted by BrianS i was wondering if the lavry can drive hd650 directly out of xlr ports if I went that route? is the volume software or hardware dealt?
Yes, The Lavry can definitely drive HD650's from the XLR outs. All you need is a proper 2x female XLR to Senn connector cable, the likes of which are available from Moon Audio, and other fine purveyers of cables 'round here.
The results are quite stunning, and worth the investment in the afore mentioned wires and connectors, at least to these ears. As usual, ymmv.
<edit> btw, and with all due respect to slwiser, he is needlessly quoting the Lavry manual. That reference is for how to drive a single ended (unbalanced) device from the Lavry's balanced outs. In our case, we want balanced output to the Senn's (with proper cable, of course). </edit>