Previous preamps I have owned in the past 30 years: (before this it was always integrateds)
NAD $110 entry level preamp (from same dealer i bought the Bryston!)
Hafler Dh110 I built from kit new (loved it, sound was excellent for a $275 kit built with phono...sorry i traded it in)
Sony scrapheap first digital preamp POS.new (Liked it for the gizmos, stopped listening to music as soon as the novelty wore off...I guess you can see it was not as great as advertised?)
Counterpoint 2000 Used (loved it, but it broke down too much, also sorry i ever let it go. Another pre that I really loved the sound of, too bad it never would keep working.)
Adcom ??750 New (the 'audiophile' Adcom. was good, sold it. no problem, Sound was OK, I used it for many years. decent preamp)
Denon Receiver for 5.1 4806 model Demo uber cheap good deal(still have and enjoy, with the Canton 300/360 speakers and a Furman Power conditioner, magical PRAT, the screen functions remote sucks)
Audio Research Sp-10 used (noisy tubes, sold for way more than i paid for it, bought it on a whim locally. was OK, but noisy cheap tubes in it. selling after also got Sp-15 and found the Sp-15 was way more of what i want in a preamp, sold the Sp-10 for more than I paid plus the then free Sp-15 and $300 cash. And i didn't even ask a top price, i knocked $800 off for new tube purchases!)
Audio Research Sp-15 used (basically got for free with extra cash from sale of Sp-10, and the good part is the Sp-15 is way better sounding than the Sp-10. Still use the Sp-15 for a second phono section and keep around for it's cool factor. This is only slightly below the Bryston BP-26 in performance. a bit less clarity, a little more grunge $7,000. when new...)
Bryston BP-26 and Bp 1.5 phono (current preamp, great! only problem too much gain in BP-26 for digital.. IMO I was spoiled by the Audio research with two gain controls!)
VAC Standard tube preamp (expensive tube buffer for digital otput from my DAC to the Bryston The VAc is below the Sp-15 in clarity and PRAT. It is perfect for the use i have it for at this time. Used and a decent deal. The VAc would be better with a better power cord, actually took the best cord off because it was too good for my use as a grunge hiding device for digital. Still it lacks clarity and a solid focus)
So I have owned a variety of preamps
The three preamps i have currently all have a dedicated separate power supply. (VAC, ARC, and Bryston)
The one additional thing that affects the sound of a preamp IMO is a power conditioner. i have used several, but currently use a $3,500 Furman REF20i for all the analog stuff including the Bryston BP-26 and Bryston 4B-SST2. The conditioning clears up a bit of grain in the top end of any preamp i have used, and really allows the bryston to shine. (i use a Monster 7000SS for the digital, bought it before the Monster lawsuit garbage.. no more Monster for me!)
As for the sound of the Bryston, and why i decided to buy it. It has a great clarity. This is my personal #1 thing I want. The Bryston is neutral beyond other stuff i could afford. i only thought seriously about an Audio Research REF 3, but used it was still a few thousand more than the Bryston new (and i would have hated to leave a REF 3 on 24/7, tubes and all, and then the Bryston warranty, vs no warranty, and buying new sets of $400/$600 tubes every two years..forever..
So i am happy with what i bought. Hope to keep the Bryston for a LONG time. (Unless i win $200,000,000. lotto! then i would buy a 40th annv ARC preamp!)
As for the Bryston Bp 1.5 phono. the one i kept is magical. i wept onceI sat down and really listened to it with a bit of music i knew really well. Beautiful. Wonderous. Glad i got the Bryston BP-26 and 1.5 phono. Well worth the price of entry.