PHOBOS GERMANIUM FUZZ
6
BUILD NOTES, CONT.
Variants
There were a number of other variants of Mk III that each had minor changes. Start with the original
Sola Sound Tone Bender parts list on page 3-4 of this documentation and make the following changes.
Vox Tone Bender Mk III
•
R1:
100k
•
R2:
680k
•
C4:
6.4uF (nearest standard value today is 6.8uF)
•
C6:
2n (doesn’t make much of a difference; just use 2n2 here like the Sola Sound version)
This is also identical to the Park Fuzz Sound (3-knob version), except the Park uses
2n2
for C6.
Park Fuzz Sound (2-knob)
•
R1:
100k
•
R2:
680k
•
R10:
470k
•
C2:
200pF
•
C4:
25uF (nearest standard value today is 22uF)
The 2-knob version omits the Fuzz control and hardwires it full-on all the time. If you’re building this
variant, it’s recommended to keep the Fuzz control in place. If it’s turned all the way up, the unit is stock,
but this way you still have the option to turn it down.
Prescription Electronics Yard Box
•
C4:
4.7uF
•
Fuzz:
250kB
The Yard Box also changes R10 from a 220k fixed resistor to a 250kB pot. Most people do not find this
to be very useful since it essentially just increases the maximum volume, acting as a secondary volume
control rather than causing any major tonal changes. It’s recommended to instead use the output
volume mod in the next section.
Output volume
The 220k resistor before the volume control (R10) reduces the maximum available output volume.
While the circuit isn’t lacking in available volume, if you’d like to get a little more out of it, you can
reduce this resistor to
68k
and then increase the volume control to
250kA
. This gives you the same
total resistance (~320k) so the tone and output impedance is unaffected, but available output volume is
increased.
