Akashic Guitar effects circuit lookup
BOOSTVOLUME

Enclosure not stated · 2 knobs

Revolution Deux

Tycobrahe Octavia

Based on the Roger Mayer Octavia· 27 other boards clone it

Category
Octave / Pitch
Controls
Boost · Volume
Price
see vendor
Also as
Vero layout · from Revolution Deux
Read the post at Revolution Deux Schematic imageOriginal schematic Vero layout

From the vendor

The Tycobrahe Octavia, said to have been traced by a Tycobrahe employee from one of Roger Mayer's hand-made Octavias brought in for repair. A high-gain three-transistor fuzz drives a small center-tapped audio transformer and a pair of germanium diodes that rectify the signal into the octave-up. The post calls it an evil-sounding fuzz with swells and bloom, heard on Hendrix's Purple Haze and Band of Gypsys tracks.

To cancel the octave-up effect, switch one of the two germanium diodes out of the circuit. The vero layout by Dr Tony Balls is an NPN negative-ground version (2N5087 for Q1, 2N4401 for Q2 and Q3, 42TM002 transformer), unlike the PNP positive-ground original, so it can share a daisy-chain supply.

Schematic

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

Parts list 25 rows

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RefValueNormalizedTypeNotes
Resistors 10
R1180K180kread from the schematic by eye
R2820K820kread from the schematic by eye
R3680K680kread from the schematic by eye
R41K1kread from the schematic by eye
R5220K220kread from the schematic by eye
R6220220read from the schematic by eye
R747K47kread from the schematic by eye
R822K22kread from the schematic by eye
R91.2K1.2kread from the schematic by eye
R10470470read from the schematic by eye
Capacitors 7
C133u33uelectrolytic; read from the schematic by eye
C2100n100nfilm; read from the schematic by eye
C3150p150pceramic; read from the schematic by eye
C41n1nceramic; read from the schematic by eye
C5100u100uelectrolytic; read from the schematic by eye
C633u33uelectrolytic; read from the schematic by eye
C7220u220uelectrolytic; read from the schematic by eye
Diodes 2
D11N2701N270germanium (1N34A or any Ge diode); read from the schematic by eye
D21N2701N270germanium (1N34A or any Ge diode); read from the schematic by eye
Transistors 3
Q1MPSA18MPSA18fitted backward in the original unit; read from the schematic by eye
Q2MPS6519MPS6519PNP; BC327-16 or -25; read from the schematic by eye
Q3MPS6519MPS6519PNP; BC327-16 or -25; read from the schematic by eye
Inductors 1
TR142TU01142TU011180 ohm / 16 ohm center-tapped audio transformer (or 42TM022); read from the schematic by eye
Potentiometers 2
BoostA1KA1kPotentiometerP1, 1k log; read from the schematic by eye
VolumeA500KA500kPotentiometerP2, 500k log; read from the schematic by eye

Other boards based on the Roger Mayer Octavia