Sadowsky Onboard Bass Preamp 4-Knob


7 in stock

SKU: SOBP Category:


NOTE: Free shipping on preamps in the US! You will have an option to choose free shipping on checkout if this is the only item in your cart. Use code “freeshippreamp.” However, if there are any other items in your cart at the time, the free shipping option will be removed. Please email with any questions.  

The Sadowsky 4 knob Onboard Bass Preamp is a completely prewired system offering the same controls and preamp as all Sadowsky Basses.

The controls are: Volume-Pan-VTC-Treble/Bass. VTC stands for Vintage Tone Control (pull up the knob for total bypass).

The preamp can be installed either with the included control plate or mounted through a rear control cavity in either a 4-in-line or diamond pattern.

Your pickups attach via solderless connectors at the pan pot. The direction of the pan pot can be easily reversed by which pickup terminals are used.

Installation requires a side jack and a battery compartment. We recommend shielding the control cavity and pickup cavities at the time of installation. We also recommend installation by a professional guitar technician or builder if routing and drilling for a battery compartment and/or side jack is required.

This system is not compatible with EMG or any other active pickups requiring anything other than a 250K or 500K volume pot. For these applications, please custom order a parts only preamp kit and use your original volume pot.

NOTE: if you want to order more than one preamp, please contact Roger:

Additional information

Weight 0.8 lbs
Dimensions 9 × 4 × 4 in


  1. Michael O’Brien

    I purchased the “drop-in” Onboard Bass Preamp about a year ago based on having purchased previous preamp kits from Sadowsky Guitars as well as having owned several Sadowsky basses since 1996. Have been playing bass for 50 years, and because I’m a Sadowsky fan, I’m admittedly biased. This said, for J-type basses, the drop-in preamp is a brilliantly conceived and executed product. The installation was as much a “no-brainer” as this (perhaps cliched) term implies. I swear you could attach this preamp to a strung 2×4 and get good results. I put mine into a fretless “Frankenbass” made up of parts I’ve had laying around (Sadowsky pick guard, older Fender J-bass body, All-Parts lined ebony neck, Hip-Shot brass bridge, Lollar J-PUs). The results are stunning. I feel completely comfortable saying that I can wholeheartedly recommend this peramp to anyone looking to upgrade a J-bass (or a 2×4). Best regards… Michael

  2. STEVE FURR (verified owner)

    I am a bass player and a craftsman with limited electronics experience. Not a Luthier. However, I installed this preamp into my Jazz Bass with great success. There’s a wealth of info on YouTube for this kind of work. My JB sounds awesome!

  3. fuhlbrugge_robert

    This pre-amp, because it has VTC and is boost only, is exactly what I need. The push/pull active/passive bypass switch also is a nice touch, I almost never use it in passive mode though. I run straight from my wireless Rx output into a power amp (and a DI), so all of my tone settings are done on my basses. This pre is clean, and really easy to install. The modular engineering approach, with the connectors is so easy to install that a relatively handy person could easily install it themselves. I’ve put a few of these into various basses (including a very early Sadowsky bass), with various PUPs including Sadowsky, EMG,Nordstrand, and Fender, all with great success. Yes, there are other pre’s, some with more EQ bands, but this one lets me get the tone I want with the least amount of difficulty, and it’s by far the easiest to install, super clean and quiet.

    Cant go wrong with this one, in my book.

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