S-PRE – London Power Spectrum Bass Preamp Kit

CAD $46.00CAD $218.00


Our S-PRE bass preamp kit is based on the preamp sections of London Power’s SPECTRUM bass amps. The front end is gain controlled and accommodates high-output active basses as well as low-output passives – and even piezo pickups. Clean sustain or over-driven sounds can be achieved, or just natural tube compression as the player desires.

The three-way EQ has a traditional and familiar feel. The second stage adds warmth and provides another route to modern and traditional tonal textures. The output buffer assures that the tone generated will not be altered driving long cables. If you would like transformer-isolation and an XLR or TRS jack, see our LTX Line Transformer kit.

Two 12A_7s (not included) can be used to provide an all-tube path. The front-end is optimized for 12AT7 but accepts any type. Local supply decoupling is included.

The board has silk-screening on both sides which allows you to stuff the components appropriately for INTERNAL or EXTERNAL TUBES. For INTERNAL, all the components are on the same side of the board; for EXTERNAL the components are on the opposite side from the tube sockets.

• Gain
• High
• Mid
• Low
• Volume
• Output

Power requirements: 12V-300mA; 320V-4mA
Use PSU-PRE or similar to build a stand-alone bass preamp.
Combine with AMP-25 (PA66-25 + PSU-25) or AMP-50 (PA66-50 + PSU-50) to build an integrated bass amp.

This item’s “Standard DIY Kit” configuration includes PCB, tube sockets, resistors, and caps. Also includes installation instructions including schematic and layout diagrams of the kit.

PCB dimensions: 5.9″ x 1.5″,  150 x 38mm

Configurations available for purchase:

Standard DIY kit (PCB + resistors + tube sockets + caps + notes) (S-COMP)
Pre-assembled kit – Internal tubes (S-INT)
Pre-assembled kit – External tubes (S-EXT)
Hard parts only (S-HP)
PCB + notes only (S-PCB) 

For more info on London Power Preamp Kits, see our Selecting a Preamp Kit page.

Need a chassis for your preamp project? See our Rack-Mount Chassis page, or browse under Building Supplies.