Akashic Guitar effects PCB lookup
SUSTAINTONEBALANCEVOLUME

125B · 4 knobs

Aion FX

TethysGermanium Fuzz

Based on the Baldwin-Burns Buzzaround

Category
Fuzz· Germanium fuzz
Controls
Sustain · Tone · Balance · Volume
Difficulty
Easy
Price
$12.50in stock

From the vendor

An early version of the Tone Bender Mk. III with a completely different voicing and transistor bias control, sold by the Baldwin-Burns company in London.

The Tethys Germanium Fuzz is an adaptation of the Baldwin-Burns Buzzaround, a germanium transistor fuzz first sold in 1966 and best known as Robert Fripp’s fuzz of choice in the late 1960s.

The Buzzaround is very similar to the third version of the Tone Bender (3-knob, often called the Mk. 3) and for that reason it’s often believed to have been a clone. However, the Buzzaround actually came earlier and the Mk. 3 was the derivative circuit, not releasing until 1967.

Despite persistent rumors that the Buzzaround was designed Gary Hurst (the inventor of the first two versions of the Tone Bender), it was discovered more recently that it was probably copied from an earlier effect called the Harmonic Generator from G. P. Electronics in Devon. No known examples of the Harmonic Generator survive to know for certain, but the control layout is the same and the advertising copy makes the similarities very clear.

The major difference between the Buzzaround and Tone Bender is the volume control, called Balance. This is actually a bias control on the third transistor and changes the tone throughout the travel, not just the signal level. Because of this, builders will generally add a true volume control in DIY Buzzaround implementations, which we’ve included here. You can use either of the controls or both in combination.

The two other notable differences from the Tone Bender Mk3 are in the gain and tone controls. The Buzzaround’s gain control is set up as a voltage divider (inter-stage volume control) rather than a variable resistor as in the Tone Bender, and the tone control is also voiced differently. These changes along with the Balance control make it a very different pedal, even though at first glance the schematics appear almost identical.

Schematic

The schematic is in the vendor's build document, page 6. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 44 rows

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RefValueNormalizedTypeNotes
Resistors 10
R1100k100kMetal film resistor, 1/4W
R2470k470kMetal film resistor, 1/4W
R31k1kMetal film resistor, 1/4W
R410k10kMetal film resistor, 1/4W
R53k33.3kMetal film resistor, 1/4W
R615k15kMetal film resistor, 1/4W
R727k27kMetal film resistor, 1/4W
R810k10kMetal film resistor, 1/4W
RPD1M1MMetal film resistor, 1/4WInput pulldown resistor.
LEDR10k10kMetal film resistor, 1/4WLED current-limiting resistor. Adjust value to change LED brightness.
Capacitors 11
C1100n100nFilm capacitor, 7.2 x 2.5mm
C2100pF100pMLCC capacitor, NP0/C0G
C34.7uF4.7uElectrolytic capacitor, 4mm
C44.7uF4.7uElectrolytic capacitor, 4mm
C5100n100nFilm capacitor, 7.2 x 2.5mm
C61n1nFilm capacitor, 7.2 x 2.5mm
C7100uF100uElectrolytic capacitor, 6.3mm
C810uF10uElectrolytic capacitor, 5mm
C947uF47uElectrolytic capacitor, 5mm
C10470n470nMLCC capacitor, X7R
C11100n100nMLCC capacitor, X7R
Diodes 3
Z11N4742A1N4742AZener diode, 12V, DO-41
D11N58171N5817Schottky diode, DO-41
D2GermaniumGERMANIUMGermanium diode, DO-07Original uses 1N270, but part number isn’t important. Just use any NOS germanium diode.
Transistors 3
Q1GermaniumGERMANIUMGermanium transistor, PNPRecommended to buy a selected set. See build notes.
Q2GermaniumGERMANIUMGermanium transistor, PNPRecommended to buy a selected set. See build notes.
Q3GermaniumGERMANIUMGermanium transistor, PNPRecommended to buy a selected set. See build notes.
ICs 1
IC1TC1044SCPA VoltTC1044SCPA VOLTage inverter, DIP8
Potentiometers 4
SUSTAIN100kBB100k16mm right-angle PCB mount pot
TIMBRE100kBB100k16mm right-angle PCB mount pot
BALANCE10kBB10k16mm right-angle PCB mount pot
VOLUME100kAA100k16mm right-angle PCB mount pot
Trimmers 1
Q1-2B50k50kTrimmer, 10%, 1/4"Bias trimmer for Q1 and Q2. See build notes.
Switches 1
FSW3PDT3PDTStomp switch, 3PDT
LEDs 1
LED5mm5MMLED, 5mm, red diffused
Jacks & sockets 7
Q1-STO-5 socketTO-5 SOCKETTransistor socket, TO-5
Q2-STO-5 socketTO-5 SOCKETTransistor socket, TO-5
Q3-STO-5 socketTO-5 SOCKETTransistor socket, TO-5
IC1-SDIP-8 socketDIP-8 SOCKETIC socket, DIP-8
IN1/4" stereo1/4" STEREO1/4" phone jack, closed frameSwitchcraft 112BX or equivalent.
OUT1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X or equivalent.
DC2.1mm2.1MMDC jack, 2.1mm panel mountMouser 163-4302-E or equivalent.
Hardware 2
BATTBattery snapBATTERY SNAP9V battery snapOptional. Use the soft plastic type—the hard-shell type will not fit.
ENC125B125BEnclosure, die-cast aluminumCan also use a Hammond 1590N1.