I've just obtained some Amperex orange globe tubes (Holland, A-frames) for the Lyr and I cannot believe how much they've elevated this amp and consequently the HD650. I always thought the Fun's discrete amp section conveyed most the HD650's capabilities and the slight improvement the stock Lyr provided reinforced this belief. My first impressions of the HD650 matched with tubes were positive with the improvements in imaging and weight, but the initial tubes I tried in the Lyr sacrificed the transparency and resolve of my solid state amp for the musical presentation I craved.
The orange globes on the other hand are magical, and I encourage anyone with these cans and the Lyr to hear the great synergy at play here. The separation, width and depth of soundstage destroys the containment of the headphone listening experience. It's not a huge reverberated hall type soundstage, but it's certainly outside the head space, and the depth allows each instrument to occupy its own space. Imaging is elevated to another level as a result, and I now understand why this characteristic of the HD650 is talked up by those who've heard these cans perform at this level.
The bass is the most balanced and controlled I've heard from the HD650. It's organic and rich, and steps to the fore with authority when required. The smooth high end creates an expansive ceiling and accentuates the transparency and resolve being presented.
I don't usually listen to instrumental pieces but as I type this my internet radio stream is interrupted and it switches to the next available stream where Hans Zimmer's "King of the Pride" is playing and is followed by Ennio Morricone's "On Earth As It Is In Heaven". Epic. And fitting.
I tell ya, it's amazing just how much scale ability the HD650 have. With the right equipment, one can have sound quality that rivals almost any dynamic headphone available. So for now ,are you no longer interested in the LCD-2 or HE-500?