aion CYGNUS Manuale - Pagina 6

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BUILD NOTES

Bypassing the true bypass / buffer switch

The E-Switch EG4208 slide switch used for the true bypass/buffer selector is available from Mouser

Electronics but may not be accessible to everyone. If you are unable to obtain it, you can hard-wire the

switch to either true bypass mode or buffered mode by soldering jumpers to the switch pads.

C14 and C17 capacitors

In both the P-2 and G-2, the coupling capacitors immediately after Q4 and Q5 (C14 and C17) are 4.7uF

electrolytics. Since film capacitors are generally viewed as superior to electrolytic within the audio path,

we used a film capacitor footprint. However, 4.7uF film capacitors are unnecessarily expensive and

large, so we reduced the recommended value to 2.2uF.

There will be no audible difference between 4.7uF and 2.2uF since the output impedance coming off the

transistors is low. Most likely you could go down to 1uF or even further with no change.

If you do want to use electrolytics in these two positions instead, the polarity has been marked on the

PCB. (Film caps have no polarity, so this marking can be ignored if using the recommended caps.)

R7 and R39 resistor values (G-2 only)

The original G-2 trace from 2009 showed a 50k resistor for the output pulldown resistor (R39 in this

project, R40 in the original trace schematic).

This may have been correct for the unit that was traced, but 50k is a non-standard resistor value, and

each of the seven Cornish pedals we've traced has used 51k here. So whether or not it's an error, we're

pretty confident that current-production G-2 units would use 51k.

This makes no practical difference to the finished pedal, only changing the output impedance by around

2%, but we're meticulous!

In addition, R7 (R10 in trace) was shown as a 20k resistor in the original trace. It's possible this was

correct in that particular G-2 unit, but once again, each of the seven that we've traced has used 10k here.

Since the buffer is a separate PCB module shared between all of the pedals, we're confident that the

current-production G-2 uses 10k as well.

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