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Enclosure not stated · 1 knob

Revolution Deux

Keeley Katana Boost

Based on the Keeley Katana· 11 other boards clone it

Category
Boost
Controls
Volume
Price
see vendor
Tags
freestompboxes.org trace
Read the post at Revolution Deux Schematic imagefreestompboxes.org threadPCB layout by RYANUKPCB transfer by RYANUK

From the vendor

Keeley's Katana clean boost: two cascaded 2N5458 common-source JFET stages run at 18V from an ICL7660S charge pump, which doubles the gain of the same circuit at 9V. A push-pull switch on the volume pot adds a 10uF bypass cap across the first stage's source resistor and a 15n cap to ground at the output for a fatter, overdriven mode. The post says the bypassed mode brings in its own clipping and the author prefers it without.

Use a smaller cap than 10uF across the first source resistor for a treble and mid boost instead of a full one. Replace the 4.7K drain resistors with 10K trimmers and bias each JFET's drain to about half the supply (about 9V).

Schematic

The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.

Parts list 23 rows

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RefValueNormalizedTypeNotes
Resistors 7
R11M1Minput; read from the schematic by eye
R21M1Mread from the schematic by eye
R34.7K4.7kdrain; 10K trimmer suggested; read from the schematic by eye
R4680680source; read from the schematic by eye
R51M1Mread from the schematic by eye
R64.7K4.7kdrain; 10K trimmer suggested; read from the schematic by eye
R7680680source; read from the schematic by eye
Capacitors 9
C1100p100pread from the schematic by eye
C2220n220nread from the schematic by eye
C310u10uelectrolytic, switched by S1A; read from the schematic by eye
C4220n220nread from the schematic by eye
C5220n220noutput; read from the schematic by eye
C615n15nswitched by S1B; read from the schematic by eye
C71n1nread from the schematic by eye
C810u10uelectrolytic, charge pump; read from the schematic by eye
C910u10uelectrolytic, charge pump; read from the schematic by eye
Diodes 2
D11N58171N5817Schottky; read from the schematic by eye
D21N58171N5817Schottky; read from the schematic by eye
Transistors 2
Q12N54582N5458JFET; read from the schematic by eye
Q22N54582N5458JFET; read from the schematic by eye
ICs 1
IC1ICL7660SICL7660Scharge pump; or MAX1044; read from the schematic by eye
Potentiometers 1
VolumeB250KB250kPotentiometerread from the schematic by eye
Switches 1
Pull boostDPDTDPDTS1, push-pull switch on the volume pot; read from the schematic by eye

Other boards based on the Keeley Katana