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VOLUMEDRIVEBASS CUTTREBLE CUT

Enclosure not stated · 4 knobs

Revolution Deux

Paul Cochrane Timmy

Based on the Paul Cochrane Timmy· 17 other boards clone it

Category
Overdrive
Controls
Volume · Drive · Bass cut · Treble cut
Price
see vendor
Also as
Vero layout · from Revolution Deux
Tags
freestompboxes.org trace
Read the post at Revolution Deux Schematic imageAlternate schematicfreestompboxes.org thread Vero layout

From the vendor

Paul Cochrane's Timmy transparent overdrive: a JRC4559 op-amp gain stage with 1N4148 clipping diodes in its feedback loop (a DIP switch selects symmetric or asymmetric pairs), a passive Bass cut control ahead of the gain stage, a Treble cut low-pass after it, and a second op-amp stage with fixed 2x gain driving the Volume pot. It has been cloned widely, by the Danelectro Cool Cat Transparent OD and the Lovepedal Amp Eleven and OD Eleven among others.

Feedback mod (image 3): a 47K resistor and a DPDT on/off/on toggle choosing 2.2n or 220n from the output back to the input, as in the BJF Honeybee and the author's Hummingbird, lowers the overall gain and brightness. Clipping options (image 4): a 2PDT footswitch and an on/off/on toggle between the op amp's inverting input (point A) and output (point B) choose among 1N4148, 1N270, 1N34A, 1N5818 and BS170 MOSFET clippers. Paul Cochrane advises that with other diodes, LEDs or no diodes the output stage should be turned into a unity-gain buffer (or have its gain switched with the diodes) to avoid rail clipping; with no diodes the first stage swings from a gain of 2 to about 304 with the 1M Drive pot. twangquack found nearly every op amp works; he liked a TL072 with an OPA2134 stacked on top, and an RC4559 alone sounded darker with nice drive.

Schematic

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

Parts list 30 rows

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Check before you build · 2 values the reader of this schematic was not sure of
  • The Volume pot is drawn as 10K on the schematic, while the vero layout's parts list gives Level as 100K.
  • The Timbre Reamer schematic does not mark pot tapers; the feedback-mod drawing marks Drive 1M A, Bass and Treble 50K A, and Volume 10K A.
RefValueNormalizedTypeNotes
Resistors 9
R18.2K8.2kVref divider; read from the schematic by eye
R210K10kVref divider; read from the schematic by eye
R33.3K3.3kread from the schematic by eye
R42.2M2.2Mread from the schematic by eye
R5510K510kread from the schematic by eye
R63.3K3.3kin series with Drive; read from the schematic by eye
R71.5K1.5kread from the schematic by eye
R83.3K3.3kread from the schematic by eye
R93.3K3.3kread from the schematic by eye
Capacitors 8
C147u47uelectrolytic; read from the schematic by eye
C247u47uelectrolytic; read from the schematic by eye
C31u1uread from the schematic by eye
C439n39nread from the schematic by eye
C547n47nread from the schematic by eye
C6100p100psilver mica; read from the schematic by eye
C710n10nread from the schematic by eye
C81u1uread from the schematic by eye
Diodes 7
D11N40011N4001polarity protection; read from the schematic by eye
D21N41481N4148read from the schematic by eye
D31N41481N4148read from the schematic by eye
D41N41481N4148read from the schematic by eye
D51N41481N4148read from the schematic by eye
D61N41481N4148read from the schematic by eye
D71N41481N4148read from the schematic by eye
ICs 1
IC1JRC4559JRC4559read from the schematic by eye
Potentiometers 4
Volume10K10kPotentiometerread from the schematic by eye
Drive1M1MPotentiometerread from the schematic by eye
Bass cut50K50kPotentiometerread from the schematic by eye
Treble cut50K50kPotentiometerread from the schematic by eye
Switches 1
SW12-way DIP switch2-WAY DIP SWITCHclipping diode select; read from the schematic by eye

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