The SP-1B showed a clear preference for expensive analog front ends. It really took a liking to my Kuzma Stabi Reference turntable setup with the Clearaudio da Vinci II MC cartridge and the Sound Traditions MC-10 step-up transformer. In this context, the SP-1B delivered a cavernous spatial impression, admirable resolution of massed voices, and luxurious midrange textures. Images were tightly focused and stayed stable while scaling a recording’s full dynamic range. Next on the agenda was a confrontation with the Conrad-Johnson PV5. Introduced in 1984, the PV5 was highly regarded during the 1980s and became a reference preamp for quite a few audio reviewers. Its phono section is still competitive with modern designs. I have kept it around as a benchmark for phono preamp reviews. Any phono section in-house for review needs to pass the PV5 gauntlet. You would be surprised to know how few preamps under $4K actually surpass the PV5 when it comes to sound quality. For the record, the SP-1B easily surpassed the performance of the PV5. This is a big deal, especially for an affordable preamp.
At this point I was beginning to wonder just how good this preamp was relative to my current reference preamp, a DIY collaborative effort with Jonathan Noble of South Africa. Dubbed the Nouveau Flamingo, this might best be described as a crazy, over-the-top affair featuring a massive tube-rectified-and-regulated power supply replete with glow tubes, a 6J4 mu follower phono input stage, passive RIAA equalization, and a vintage 27 triode-based linestage. OK, so the Flamingo’s textures were distinctly more luxurious, and it also bested the SP-1B in the treble and bass ranges. In particular, it highlighted the latter’s lack of presence-region finesse. Still, the SP-1B is a preamp I could live with for the long haul. Low cost is often the enemy of the good. Not so in this case. The SP-1B is both affordable and sonically damned good, and that’s because good engineering and execution don’t have to be expensive. If you’re searching for an affordable tube preamp with a killer phono section, the Brown Audio Labs SP-1B is it. It may well be the best $850 audio investment you’ll ever make.
SPECS & PRICING
Gain: 45dB (phono); 16.5dB (line)
THD: <0.5% at full output
RIAA response: 10Hz–20kHz +/- 0.4dB
Line-level frequency response: 5Hz–100 kHz, +/- 0.1dB
Input impedance: 250k ohms
Output impedance: 350 ohms
Dimensions: 17.75" x 4.5" x 11.5"
Weight: 13 lbs.
BROWN AUDIO LABS
145 Springwood Dr.
Graham, TX 76450
Analysis Audio Omega planar speaker and Basszilla Platinum Edition Mk 2 DIY loudspeaker; VTL Manley reference series 100/200 and First Watt SIT-1 monoblock amplifiers, First Watt F7, Futterman H3, and Atma-Sphere S-30 stereo amplifiers; Kuzma Stabi Reference, Revox B795, and Sony PS-X600 turntables; MacBook Pro laptop running Amarra V3.03 software, April Music Eximus DP1 DAC; ModWright-modified Sony XA-5400ES SACD player; FMS Nexus-2, Wire World, and Kimber KCAG interconnects; Kimber KCAG speaker cable; Monarchy Audio AC-Regenerator; Sound Application power line conditioners