D-PRE is based on London Power’s Mini-Marshmallow amp, which was a tribute to Alexander “Howard” Dumble. The basic topology is here with typical values. Although many amp designers used the “overdriven Fender amp” as the basis for the preamp in a master-volume amplifier, Dumble’s is the most famous.
D-PRE provides two distinct sounds: classic warm clean and late-over-drive distortion. We’ve added an extra ‘Drive’ control to the Dumble topology, making it more useful to a wider range of players. Two 12A_7s provide all functions in a pure tube audio path.
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.
• Clean Volume
• Mid-shift (sw)
• Jazz-Rock (sw)
• Over-Drive Level
• Early Drive
• Late Drive
Use two RLY kits for basic mechanical relay switching, to switch between the two sounds.
Power requirements: 12V-300mA; 160-450V-5mA
Use our PSU-PRE Power Supply Kit for Tube Preamp or similar to build a stand-alone preamp.
Combine with AMP-25 to build an integrated amp.
The Standard DIY Kit is item includes PCB, tube sockets and components, and helpful installation notes including layout and schematic diagrams of the kit.
Configurations available for purchase:
Standard DIY Kit (PCB + resistors + tube sockets + caps + notes) (D-COMP)
Pre-assembled kit – Internal tubes (D-BLT-N)
Pre-assembled kit – External tubes (D-BLT-X)
Hard parts + notes only (D-HP)
PCB + notes only (D-PCB)
For more info on London Power Preamp Kits, see our Selecting a Preamp Kit page.
PCB size: 7.2 x 1.5″, 183 x 38mm