Akashic Guitar effects circuit lookup
VOLUMETREBLEBASSGAIN

Enclosure not stated · 4 knobs

Revolution Deux

Catalinbread CB30

Based on the Catalinbread CB30· 2 other boards clone it

Category
Overdrive
Controls
Volume · Treble · Bass · Gain
Price
see vendor
Tags
freestompboxes.org trace
Read the post at Revolution Deux Schematic imagefreestompboxes.org thread

From the vendor

Catalinbread's take on a 30-watt British amp (an AC30): two 2N5457 mu-amp stages with the Gain pot between them, a Vox style Treble/Bass tone stack where turning up both scoops the mids, and a 2N5457 source-follower output. It is built like the Dirty Little Secret and Formula No. 5; C6 and R2 form a feedback path that lowers the gain at high frequencies, and the 470p C7 strongly limits the low end leaving the first stage.

For more gain: reduce R1 (to about 10K), increase C4 (47n or more), increase C7 (1n to 10n), remove or reduce R7, or make Q5 a JFET gain stage instead of a buffer. These change the frequency response somewhat. Running the circuit at 18V instead of 9V opens up headroom and adds a little gain; do not exceed 25V, the limit of the 2N5457.

Schematic

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

Parts list 48 rows

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Check before you build · 1 value the reader of this schematic was not sure of
  • R13 (the resistor from the bass leg of the tone stack to ground) has no value on the drawing.
RefValueNormalizedTypeNotes
Resistors 19
R1100K100kread from the schematic by eye
R2470K470kread from the schematic by eye
R3470K470kread from the schematic by eye
R41M1Mread from the schematic by eye
R51M1Mread from the schematic by eye
R6390390read from the schematic by eye
R7100K100kread from the schematic by eye
R8470K470kread from the schematic by eye
R9390390read from the schematic by eye
R101M1Mread from the schematic by eye
R111M1Mread from the schematic by eye
R12100K100kread from the schematic by eye
R13??no value drawn; read from the schematic by eye
R14200K200kread from the schematic by eye
R152.2M2.2Mread from the schematic by eye
R162.2M2.2Mread from the schematic by eye
R174.7K4.7kread from the schematic by eye
R184.7K4.7kread from the schematic by eye
R1947K47kread from the schematic by eye
Capacitors 19
C12.2n2.2nread from the schematic by eye
C2100n100nread from the schematic by eye
C31n1nread from the schematic by eye
C422n22nread from the schematic by eye
C52.2u2.2uelectrolytic; read from the schematic by eye
C6330p330pread from the schematic by eye
C7470p470pread from the schematic by eye
C822u22uelectrolytic; read from the schematic by eye
C9100p100pread from the schematic by eye
C10470p470pread from the schematic by eye
C11220n220ndrawn polarized; read from the schematic by eye
C1247p47pread from the schematic by eye
C1322n22nread from the schematic by eye
C1422n22nread from the schematic by eye
C15100n100nread from the schematic by eye
C1622u22uelectrolytic; read from the schematic by eye
C1722u22uelectrolytic; read from the schematic by eye
C1810n10nread from the schematic by eye
C19680n680nread from the schematic by eye
Diodes 1
D11N40071N4007read from the schematic by eye
Transistors 5
Q12N54572N5457read from the schematic by eye
Q22N54572N5457read from the schematic by eye
Q32N54572N5457read from the schematic by eye
Q42N54572N5457read from the schematic by eye
Q52N54572N5457read from the schematic by eye
Potentiometers 4
VolumeA100KA100kPotentiometerread from the schematic by eye
TrebleA1MA1MPotentiometerread from the schematic by eye
BassA1MA1MPotentiometerread from the schematic by eye
GainA500KA500kPotentiometerread from the schematic by eye

Other boards based on the Catalinbread CB30