New system/room, upgrade amp or preamp first?

I found success with both components from the same manufacturer. You get the company's preferred sonics and no surprises. Get them at the same time.

Installed the Pre1 tonight, running y-adapters from the line out section to both the B&K and both subs. So far, so good. So, so good :) The soundstage feels like it's a foot deeper and maybe I'm just imagining things but I swear I'm hearing more detail now than before. Little things like a guy hitting his guitar with his hand (or something that sounded like that) and increased instrument separation, even in complex/loud passages. I always like to crank the opening of Money for Nothing (SACD) as a simple test. If I can play it loud, as in 90-95 dB (guessing here) and still here all of the individual sounds during the opening sequence, I feel good. No regrets there at all.

I think I'm good now for awhile. I'll save up my coins for a SET amp, most likely. That's the nice thing about having such a small room, it won't take much :)

Thanks again for all the feedback!
Todd

Update!

So it's been nearly a month now since I got everything up and running. Where to start... first of all, these DIY speakers are something special. They are hyper-resolving, tonally they are very accurate. Drums sound like drums, pianos sound crisp but not sharp or glaring, bass guitars sound incredible. Playing a 35 Hz test tone, these things have prodigious output down that far. Turn on a 20Khz test tone? I can hear it plain as day. They paint a deep, wide, and rock solid stereo image, dare I say 3D-like. They are faithful to the source, now that I've upgraded my DAC and Preamp. Still rocking a bargain-bin, used B&K amp too! And yes, I did end up finding a used power cable, plugged directly into the PS Audio outlet. The rest of the gear runs through a Tripp-Lite ISOBar.

The room. I've done a lot since my last post. Put in rear absorption just behind my listening position, put up a curtain over the wall to the right of my listening position to tame some reflections that liked to collect back in that corner, and threw down an area rug. All of which have made steady improvement, resulting in the imaging and spacing I alluded to in my first paragraph. The room seemed quiet enough with everything turned off. I used an app on my phone to see just how quiet - 18 dB is the final number. As soon as I turn on the TV and PC, that number goes up to 26 dB. Obviously the TV is simple - turn it off and pick my music from my phone, duh. The PC, I thought, was going to be a challenge. Turns out, going back to integrated video (bye bye PC gaming, hello future new console?!), turning off both case fans (don't worry, temps are fine), and spinning the HSF down a little resulted in a huge decrease in noise. It doesn't sound like much, but I'm now at 18 dB noise floor with the computer on, so that's good. Next up is a fanless PSU.

I can't overstate this - the quieter the space, the better everything sounds. Little details in music you've never heard suddenly come to life. This is across every recording I've tried. I just had on Wish You Were Here and thought... "Is that someone breathing?" during the intro. Turns out, yes it is. I'm not talking about the cough or the sniff, it's someone breathing. Maybe others have heard it, but I hadn't, even on this exact same system three days ago. It's there now, though. Little guitar notes during solos, performers hitting their hands on the guitar unintentionally, it all comes through.

So, to sum up, I'm enthralled, and enjoying the shit out of this room and system. My new routine is to kiss the wife and daughter goodnight around 10, then go downstairs and enjoy a little bourbon, some tunes, and a very dark room. It's enriching, I assure you. Money and time very well spent, and I've learned an unbelievable amount about sound and playback systems in the last month.

Oh, and from someone who had not given Radiohead - OK Computer a fair shake in my previous attempts to listen to it, it is now one of my favorite albums to turn on. Also, Black Sabbath - War Pigs, in the right system, is a lesson for how to record drums.

Edit - thought it would be fun to list some of my favorite stuff to listen to in here:

Dire Straits - Brothers in Arms (the song, but the whole album is good too)
Pink Floyd - Time, Comfortably Numb, anything from Wish You Were Here
Rush - YYZ, Vital Signs
Jethro Tull - Aqualung
Hank Mobley - Soul Station
Rodrigo y Gabriela - *
Yo-Yo Ma plays Enio Morricone
Radiohead - Paranoid Android, Let Down, Lucky, Karma Police
Black Sabbath - War Pigs, Paranoid, Planet Caravan, Iron Man, Rat Salad
Titanic Score - Death of Titanic
Hans Zimmer - Gladiator - the long one, it's 10:30 seconds, don't remember the name
John Williams - Duel of the Fates
Pearl Jam - Ten.*
Parkway Drive - Atlas.*

There are more, but those are my gotos.

Edit 2 - shit I knew I'd forget a bunch. My favorite part of the room? Listening at low to mid volume. On a scale to 100 with 85 being *loud*, I do most of my listening between 48 and 60. Doesn't wake up the ladies of the house but the sound is full and rich. This is a direct result of a much better preamp than what I was using initially. Also, I took the metal/glass stand out of the front of the room and all of the equipment sits on the floor. Well not really, I can go into detail if anyone wants to hear about that whole setup.