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HI-GAINCRUNCHTONELEVELBOOST

Enclosure not stated · 5 knobs

Revolution Deux

Carl Martin PlexiTone (rev. 3)

Based on the Carl Martin PlexiTone· 6 other boards clone it

Category
Distortion
Controls
Hi-Gain · Crunch · Tone · Level · Boost
Price
see vendor
Tags
freestompboxes.org trace
Read the post at Revolution Deux Schematic imagePCB layoutfreestompboxes.org threadBucksears' PCB transfer

From the vendor

A three-mode overdrive (crunch, high gain and an up to 20 dB clean boost) built on an LF347 quad op-amp: an input buffer, an op-amp gain stage with LED clippers in the feedback loop and switchable Crunch and Hi-Gain pots, a tone stage, and a separate boost stage. The onboard transformer and 7812/7912 regulators give +/-12V, so the op-amp never clips and all the distortion comes from the LEDs.

Values in red on the drawing are from early units (provided by JHS): C7 47p instead of 330p, C13 100n instead of 68n, R7 15K instead of 22K; LED4 is also circled as an early-unit difference. Bucksears' PCB layout (Plexituna) runs from 9V with an LT1054 voltage doubler for +/-18V rails and omits the boost stage.

Schematic

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

Parts list 43 rows

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Check before you build · 2 values the reader of this schematic was not sure of
  • The Level pot value is partly hidden by the watermark; read as 5K log, matching Bucksears' layout (5K-A).
  • The meaning of the red circle around LED4 (present or absent in early units) is not stated.
RefValueNormalizedTypeNotes
Resistors 11
R11K1kread from the schematic by eye
R21M1Mread from the schematic by eye
R347K47kread from the schematic by eye
R44747read from the schematic by eye
R52K2kread from the schematic by eye
R64.7K4.7kread from the schematic by eye
R722K22kearly units 15K; read from the schematic by eye
R822K22kread from the schematic by eye
R922K22kread from the schematic by eye
R10100100read from the schematic by eye
R111K1kread from the schematic by eye
Capacitors 15
C7330p330pearly units 47p; read from the schematic by eye
C8220n220nread from the schematic by eye
C933n33nread from the schematic by eye
C112.2u2.2uelectrolytic; read from the schematic by eye
C10330p330pread from the schematic by eye
C12470n470nread from the schematic by eye
C1368n68nearly units 100n; read from the schematic by eye
C14470n470nread from the schematic by eye
C1522p22pread from the schematic by eye
C1470u470uelectrolytic; read from the schematic by eye
C2470u470uelectrolytic; read from the schematic by eye
C3470u470uelectrolytic; read from the schematic by eye
C4470u470uelectrolytic; read from the schematic by eye
C5100u100uelectrolytic; read from the schematic by eye
C6100u100uelectrolytic; read from the schematic by eye
Diodes 1
B1bridge rectifierBRIDGE RECTIFIERread from the schematic by eye
ICs 3
IC1LF347LF347quad op-amp; read from the schematic by eye
IC278127812regulator; read from the schematic by eye
IC379127912regulator; read from the schematic by eye
Potentiometers 5
Hi-GainA1MA1MPotentiometerread from the schematic by eye
Crunch100K100kPotentiometerread from the schematic by eye
Tone5K5kPotentiometerread from the schematic by eye
LevelA5KA5kPotentiometerread from the schematic by eye
Boost500K500kPotentiometerread from the schematic by eye
Switches 3
SelectSPDTSPDTread from the schematic by eye
DriveSPDTSPDTfootswitch; read from the schematic by eye
Boost switchSPDTSPDTfootswitch; read from the schematic by eye
LEDs 4
LED1LEDLEDclipper; read from the schematic by eye
LED2LEDLEDclipper; read from the schematic by eye
LED3LEDLEDclipper; read from the schematic by eye
LED4LEDLEDclipper, circled in red; read from the schematic by eye
Other 1
TR12x15V 70mA2X15V 70MAtransformer; read from the schematic by eye

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