The JHS Fumble is a JFET clean boost in a compact enclosure, a production version of the Dumble BBC-1 circuit JHS cloned for John Mayer. That circuit traces back to a 1970s Barcus Berry acoustic preamp, the same JFET stage Dumble later used as the FET mode inside his amplifiers.
It has two knobs. Output is the master volume. Input attenuates bass and input gain together at the front of the circuit: fully right leaves the signal alone, and turning left gives a thinner, tighter response. Run it as an always-on sweetener at the front of the board, in front of an overdrive such as the Morning Glory, into an amp that is already breaking up, or as a solo boost at the end of the chain.
Its job is clean volume and shape, and it makes whatever comes after it sound bigger. It shares the AT Mini's compact enclosure size.
SPECIFICATIONS
SPECS
Country of Origin: United States
Type: True bypass JFET clean boost
Circuit: Dumble BBC-1
CONTROLS
Input: bass and gain attenuator; fully right is no cut
Output: master volume
POWER
Power: 9V DC center negative
Current Draw: 5mA
Maximum: do not use more than 9VDC center negative
DIMENSIONS
Dimensions: 1.96" x 3.93" x 1.21"
