Review: Sadowsky SBP-1 & SPB-2 Bass Preamps

A nowadays the bass gear marketplace is so flooded with technology that it’s easy to forget just how primitive the instrument was a few decades ago.
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Nowadays the bass gear marketplace is so flooded with technology that it’s easy to forget just how primitive the instrument was a few decades ago. From its invention in the early ’50s through its late-’70s adolescence, the bass guitar’s essential characteristics remained largely unchanged. That changed with the introduction of active electronics, and New York luthier and repair guru Roger Sadowsky, along with co-designer Alex Aguilar, made the most lasting and influential impact. Inspired in part by his close relationship to Big Apple bass-god Marcus Miller, Sadowsky landed on a circuit that’s been in the signal chain of innumerable hits. The latest outboard iterations of his iconic design, the SBP-1 and SBP-2, feature an identical circuit, but add a couple of useful features for the modern age.

The benefits of an active circuit are two-fold. First, a preamp buffers a bass signal, converting its output impedance from high to low. A buffered signal preserves a signal’s fidelity as it travels down an instrument cable and as it hits the high-impedance input of the average amp. Buffered signals are much less susceptible to the “tone-suck” associated with multi-stompbox signal chains or long cable runs. The second and more obvious advantage of an active preamp is that it can offer frequency-selective volume control, a.k.a. equalization or EQ.

The Sadowsky design is slightly iconoclastic. First, it uses discrete JFETs for buffering and amplification; of all the solid-state amplification devices available, JFETs are the most tube-like in their linearity, transient response, and clipping behavior. Second is its boost-only EQ circuit. Boost-only EQ, while not as effective a corrective tool as boost/cut circuits, can still be a potent tone sculptor; a boost to any part of the frequency range leads to a perceived cut to neighboring frequencies outside the filters’ effective bandwidth.

The SBP-1 & SBP-2 are largely the same circuit, with the SBP-1 offering additional features like a balanced DI output, footswitchable mute, and tuner out for silent tuning. Both pedals are ruggedly constructed, with high-quality pots, switches, and jacks. Peeking inside each stompbox revealed an exceptionally orderly layout. Circuitry is mostly surface-mount, with a few larger through-hole components.


I’ve spent a fair amount of time with Sadowsky basses over the years, and I’ve long been a fan. Few basses have as distinctive a sonic signature to my ear. They tend to be clearly steeped in the Fender Jazz tradition, but with a buoyancy and solidity in the lows and sizzly, but never harsh, sheen in the highs that’s immediately beguiling. I’m also fortunate to have a pair of vintage Fender Jazz Basses on hand, a ’66 and a ’75, so of course I turned to them first for testing. I’m happy to report that the Sadowsky vibe is easily achieved with either pedal. When it came to the vintage Fenders, being able to easily switch in a more modern and aggressive sound for a slap passage, or a tune that demanded more sheen, immediately made itself indispensable. There is something singular about the Sadowsky sound that works especially well with J basses. Having one in your signal chain means you essentially have two instruments: the lovely and organic passive bass you love, and a new, more authoritative, fatter-sounding alternative.

If you have a passive bass that you’re loathe to modify with an onboard preamp (and if it’s an old Fender, please don’t), a Sadowsky preamp will give you the quickest route to one of bassdom’s most essential sounds. It’s smooth and satisfying, well built, and distinct from its competition.



SBP-1 & SBP-2 preamps
SBP-1, $190; SBP-2, $290
Pros Excellent, definitive tone; slappers’ delight; superb construction
Cons None
Bottom Line Two takes on a legit bass-tech classic, the Sadowsky preamps are a quick route to fantastic tone.


Input ¼"
Frequency response 5Hz–50kHz
Input impedance 1MW
Outputs SBP-2: unbalanced ¼"; SBP-2: unbalanced ¼" out, unbalanced ¼" tuner out, balanced XLR
EQ bass, +18dB @ 40Hz; treble, +18dB @ 4kHz
Power 18 volts @ 250mA, adapter included

Made in USA