aion VULCAN Handbuch - Seite 5

Blättern Sie online oder laden Sie pdf Handbuch für Musikanlagen aion VULCAN herunter. aion VULCAN 11 Seiten. Effect type octave fuzz; based on foxx tone machine; a classic untamed fuzz from the 1970s that adds an octave-up overtone

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BUILD NOTES

Version 1.1 updates

Version 1.1 of the PCB (April 2020) adds two new resistors, R23 and a second R9. (The second R9 was

labeled by mistake—it should have been labeled R24.) The top R9 is 12k and the bottom R9 is 100k. R23

is 100k. These are the only changes to the circuit board.

Tracing notes: early vs. late version

Since releasing the Vulcan initially, Aion FX had the opportunity to trace two original Tone Machines, an

early blue one and a later red one. The early version is identical to the commonly available schematics.

The differences in the red version are very minor:

1. 12k series resistor added to the Sustain control to drop the maximum amount of sustain slightly.

2. The treble-side tone capacitor, normally 3n3, has been reduced to 2n7.

3. The transistors (still 2N3565) are sorted for higher gain, 400+.

In addition, another thing we noticed in tracing is that the C8 capacitor measured right around 22uF

(nominally 10uF). This did have an impact on the bass content of the tone, so if you want it to sound like

a real vintage unit then use 22uF.

Tone capacitor

The red version of the Tone Machine used 2n7 for the tone capacitor instead of 3n3. Due to the

midrange switch in the Vulcan, the corresponding tone capacitor is a combination of C10 + C11 (1n

+ 2n2 = 3n3). So, if you want to use the red value, we recommend using a 1n8 capacitor for C11 for a

combined value of 2n8.

Transistor selection

While the 2N3565 was the only transistor used throughout the run of the Tone Machine, the gain of

those transistors was very different. Early units had gains around 230-250 while later units were over

450. Here is a chart of the gain (hFE) of the transistors that we measured in two vintage units:

PART

BLUE (EARLY)

245

230

240

230

If you are building to "early specs" then 2N3904 is a good option, though it's typically a little lower gain

than these. For "late specs", the 2N5089 or 2N5088 will get you there.

VULCAN OCTAVE FUZZ

RED (LATE)

549

451

456

455