Ok here are a few of my notes I've been taking since yesterday:
Just received the Lyr today (Friday, July 27, 2012). Right now I have about 7 hours on the amp, and it's sounding pretty good. Compared to the PS Audio GCHA, I notice that the Lyr has more transparency, which could simply be the result of the amp being less rolled off in the treble than the GCHA. The PS Audio has always been noted by other users as having a rolled off sound. The PS Audio does have a very liquid sound to it, but the Lyr maintains a bit of that liquidity while also bringing more dynamics and control to the table. The two sounds are still very different, however. Right now I'm listening to John Mayer's "Stop This Train", and even at a moderate volume, everything sounds very nuanced and controlled, but you can still hear a bit of that tube magic within the harmonic textures. The PS Audio did have a bit of specialness to the textures, but it wasn't quite like tube sound. There's just something very distinctive about tube sound; it adds an emotional quality to the music. The Lyr seems to provide better "separation" of the instruments, with a more expansive soundstage. The idea of soundstage when describing headphones seems a bit ridiculous, but once you've heard it, it's understandable. I'm trying to avoid gushing too much right now, simply because the amp is new, and new things have a tendency to sound fantastic at first. But I cannot deny the additional emotion that this amp seems to portray. I will see how this develops even further as the amp burns in. I read people describing the amp as running hot, but I didn't expect it to run this hot. I was disappointed to discover this, as this office room already can get a bit warm during the summer with our computers running. Even though the amp is relatively hot to the touch, it doesn't seems to warm up the room too much overall. I chose to get the amp with the NOS GH 6BZ7 tubes. I don't know how these compare with the second option, which is the JJ E88CC tubes. I may hear just a tad of midrange emphasis from this amp right now, which would also be the result of the tubes. I can't say that I mind it. I have a set of Beyerdynamic T1's on the way coming from the Cable Co. I'll be curious to hear these, but I'm most excited about the Hifiman HE-6 and HE-500s, which are next up after the T1.
I've also read people describing the Lyr as having a "high noise floor", but I'm not just not hearing that with the HD650. The noise floor sounds very low to me, and sounds seem to emerge from a fairly dark background, at least as dark as the PS Audio Amp.
I should also note that at this point, I'm using the PS Audio Digital Link III DAC, the PS Audio UPC-200 power conditioner, and Audience Conductor E interconnects. Power cables are PS Audio and Van Den Hull.
------------------------------------------------------------------------------
Listening to the Lyr again now after it's been burning in overnight. Rage Against the Machine's Bombtrack is full of energy, with strong, tight, impactful bass. I'm hearing the qualities of a good strong solid state amp, but yet things like guitar strings still have that tube lushness to them. I find that it's dangerously easy to crank up the volume on this amp, just because the sound is so exciting; but I need to be careful with my hearing. But ironically, it's not to say that this amp doesn't sound good at low volumes. In fact, I find the Lyr to do a much better job at lower volumes than the GCHA.
Wow, Killing in the Name just came on, and I'm getting chills. The guitars have such grunge and bite to them, but have that fantastic tube bloom when it comes to harmonics. I can't say that I've ever heard a sound like this before; it's pretty hard to describe. I'm getting very excited to start trying out some good orthyodynamics (or Planar Magnetic, as the kids call them these days).
One thing that I've noticed with this pairing of the Lyr and HD650 is that the gain does seem to be too high. I can barely get the volume knob to 9 o clock, and if I take it any higher, I feel like I'm going to start doing damage to my hearing. In fact, at 8:30, I'm already playing at levels that should not be sustained for long periods. This could also have something to do with the output voltage of the PS Audio Digital Link III. I remember in the past some people discussing how it has a slightly higher-than-average output voltage.