System Plateau--Help Me Take The Next Step

I need a hand. My system seems to have plateaued and I need to bump it up a notch. In the name of completeness (and trying your patience) I’ll provide as much info as possible. Bear with me.

A recent wire upgrade to my headphones made it painfully clear that the main rig needs some work. For context, I have always preferred speakers to the cans in nearly all regards. Then I bothered to upgrade the cords on my Sennheiser HD600’s to the Cardas stuff. The cans are driven by a Headroom Home (and fed by a Meridian 508.24) and, with the upgrade, now sound much better than the speakers. Much. I’ve had a couple of complete neophytes over (you know the type, folks who’s benchmark music playback system is the stock stereo in their VW) and, while they have begrudgingly -- and a bit woefully -- admitted that the main system sounds better than they had imagined possible, they have both proclaimed that the cans were simply mind-blowing and in a whole different league. (The girlfriend, after months of making fun of me and some particularly pointed jabs for a $250 cable upgrade for headphones, listened to one track, took off the cans with a blank look, proclaimed “that’s f-ing amazing,” put them back on and didn’t speak again for at least an hour). Now I won’t claim that the cans are the best ever, but they certainly sound a lot better that the speakers -- though it’s tough for me to say exactly why. They are certainly more detailed and intimate, but, to some extent, I expect that from cans and do not really expect to reproduce it with a speaker system. They are also a lot more vibrant, engaging, vivid and all around compelling. The main rig is just not keeping up. How can I correct that?

The main rig (as per the system below, but again for ease) is, from start to finish: Richard Gray 400s, Meridian 508.24, Rogue 99 Magnum, Bryston 4b-st, Thiel 2.3, Home Grown Super Silver IC’s throughout, Kimber Monocle XL speaker cable, and assorted vibrapods on a Salamander rack (and a partridge in a pear tree). All power cords are currently stock, but I am expecting a full battery of upgraded cords this week. I sincerely hope the new power cords will be a step in the right direction. The room’s a rental, so the RGPC and the cords are the extent of what I am prepared to do as far as power goes. As for the room, it’s roughly 14x20 with an irregular cathedral ceiling sloping gently away from the “speaker end” of the room (the 14ft wall) and with the steep side being all glass. Speakers are about 3ft off of the back wall and roughly 3ft from the sides, eight feet apart and form, more or less, an equilateral triangle with the listening position (slightly toed in). Room treatments are currently haphazard and very unsystematic, but it would be very impractical to implement much more. Due to good-neighborly concerns, most of my listening is far from loud and low-level warmth and resolution is therefor far more important than stability at ear-bleading SPL levels. There it is.

As I mentioned, I am hoping for big things from new power cords. We shall see. Baring satisfaction there (and recognizing that any satisfaction, if satisfaction, will ultimately cede and fall prey to the upgrade demons anyway) where should I look next? The cheaper and easier the fix, the more enthusiastically and quickly it’ll happen. I still haven’t drilled the Rogue power supply and filled it with sand. I mean to. I’ve considered experimenting with new IC’s, but the price to performance ratio on the Homegrown stuff is hard to part with. Thoughts? Finally, my gut instinct (though yet unexplored) is to think about parting with the Bryston. I’ve recently become fascinated with the likes of a pair of bridged Rowland Model 1’s, possibly a Model 2, or perhaps a Plinius SA-100 (likely the ideal, but for the fact that they are just too darn big and run too hot to fit in my rack and would thus require a separate stand and be considerably less than ideal from a logistical standpoint). Q: is amplification the place to look? If so, what should I look at? Without more aggressive room tuning am I spinning my wheels? I might have accused the Meridian of being too polite, but judging from the performance with the cans that's clearly not an issue. Any thoughts or comments would be welcome. Many thanks.