You simply hookup the Lyr as you would any preamp, the source (I'm using a Parasound Zdac) goes to the inputs of the Lyr and then the Lyr's outputs go to your amps inputs. Make certain that you turn the Lyr on and wait about 30 seconds before turning on your amp (you'll hear a click inside your Lyr at about 20 seconds)...once your done listening for the day, turn the amp off first and then the Lyr. This way you won't get any turnoff discharge hitting the amp and possibly your speakers.
I wrote to Schiit Audio before I tried the Lyr as a preamp as I was almost certain than with all that gain that I would either have noise once it was feed through my amp OR I would have very little of the volume control that would be usable. If you can only use the very start of our volume control (say from 7 to 9 o'clock) that "can" be a problem as more often than not they don't track as well in the beginning. Well, Mr. Stoddard wrote me back and said that he happens to enjoy the Lyr as a preamp...so I've been giving it a go.
How much of the volume control you'll be able to use before the music is too loud depends on a few things, the output voltage of your source, the input sensitivity and power output of your amp...the A23 only requires 1V for full output power and lastly the sensitivity of your speakers. If you have very easy to drive speakers you may find that the Lyr's volume control barely usable before the music gets too loud.
I'm having no trouble with noise from the Lyr at all and with my less sensitive (sealed box) NHT Classic Threes I can use the volume control up to about 11 o'clock before it get a bit loud. I'm also running a Velodyne DD-10 from the loop outs of the A23 so the smallish office will start to shake if I push it too far. The A21 and A23 have left and right input level controls on the rear near the input jacks that can be used to lower the input voltage from the source if needed. Richard Schram (President of Parasound) advised me that as long as the Lyr was tracking perfectly (balance is perfect all the way down to null <good job Schiit Audio>) that its best to left both control turned all the way up as this keeps them out of the signal path. They're there IF you need them...which is a good thing and they may be needed with easier to drive speakers like the ported B&W's.
For nearly two years I've been using a Creek OBH-22 passive unit in place of a normal preamp and changing to the Lyr seems to give me better dynamics...more jump factor yet still has a quiet background. I can certainly see with its high output that it probably won't work for everyone but thus far I've been pleased and if it didn't work out as a preamp I'd still keep it for its main use as a headphone amp. It made my K701's sounds as good as I've always heard that they're capable of.
Regarding the Parasound Halo A23, I LOVE that amp! For years I'd always used a 250 watt amp (I'm not sure why) but I already had then A21 in my living room when my office amp died and I needed a replacement. A couple friends suggested the A23 so I ordered one and have never looked back. It can drive my Maggie 1.6's with no problem and sounds great (sweet midrange and highs) driving either pair of my B&W's. I've since read that "maybe" its easier to get that sweeter sound from a slightly less powerful amp. Of course, I'm a HUGE fan of Parasound, even more so now that I've bought their new Zdac (best DAC I've heard under $1000) so you may want the opinion of somebody that owns less Parasound gear <grin>.
Best of luck and if I left anything out or you think of something else feel free to ask.
Edited by KLJTech - 6/4/13 at 11:13am