Underhill Bass Guitars

11/13/2025

Wiring Diagram Update - There are now 17 wiring diagrams on the web site that cover all of the ready-made Preamp configurations.

10/07/2025

Wally Barnum demos the new Moonshot jazz-plate filter preamp. Direct in, with no post processing. '74 J with DiMarzio DP123s.

09/12/2025

Announcing The Moonshot!

Exactly 63 years ago today, Kennedy announced the moonshot. While it's not as big a deal, today Underhill announces the "Moonshot" jazz-plate preamp, featuring:

- Stacked volume and tone control for each pickup.
- Large knurled k***s with original k**b spacing.
- Original style non-magnetic brass control plate.

So what is different? Under the hood, this preamp is a sophisticated "dual filter" preamp, using active filters to electronically isolate the volume and tone controls. When you change the bridge tone, it doesn't affect the neck tone, and the volume controls allow precise mixing of the pickups over the entire range.

In short, like the Apollo Program, it actually works! You can achieve an endless variety of subtle tones with your Jazz-style bass, and like all Underhill preamps it has an ultra-quiet and natural sounding signal, enabled by some fundamental technology pioneered in the Apollo era.

09/01/2025

This video shows how individual modules are tested before being sold or built up into preamp systems.

08/21/2025

Part 6 of 10 shows the soldering of through-hole components, which include terminal blocks and potentiometers.

08/15/2025

This video shows the important (but perhaps dull!) step of sorting and prepping potentiometers.

08/06/2025

In Part 4 the boards are baked in an oven to solder the surface mount parts.

08/01/2025

Came across this video of the Fastbacks, featuring Kim Warnick with her Underhill bass!

A rare knock out reunion of the punk-pioneering rock band (1979-2001) Fastbacks! Kurt Bloch, Kim Warnick, Lulu Gargiulo and Michael Musburger pull it togethe...

07/31/2025

Swearless Installation! Underhill preamps feature pots and pot hardware designed for mounting in any situation, and now include a precision screwdriver ideal for securing screw terminals and fine-tuning trim pots.

07/29/2025