AionFX Cygnus

[VanWhy]

Build Rating

4.00 star(s)

Lately I'm a sucker for the "hybrid" Ge/Si transistor fuzz based pedals. This is compared to the Cornish G-2. My plan for this one is to do the stock version and the version with the mods suggested by AionFX. This one is stock. And I can echo all the other reviews that say it's super dark and low output. I still think it sounds good with all controls maxed but just not great. I'm excited to build the modified one.

I also don't know why I built this one instead of the PPCB version. But I did. I bought the P-2 from PPCB and am looking forward to that build since I heard very good things about it.

Easy build. 4/5 for the circuit.

 

[Laundryroom David]

That’s one slick looking build!

 

[Brett]

Very nice!

 

[ac30irons]

@VanWhy did you do the resistor mod on this ? I am on a constant G2 journey but just cannot get a pedal to sound like demos on the internet. No issue with the darkness, it’s more the lack of drive.

 

[VanWhy]

@VanWhy did you do the resistor mod on this ? I am on a constant G2 journey but just cannot get a pedal to sound like demos on the internet. No issue with the darkness, it’s more the lack of drive.

The only resistor mods I did was for R18 (15k to 18K) and R19 (680R to 100R). This is supposed to help the gain stage prior to the diodes. From what I hear the diodes are pretty critical. If the forward voltage is too low it's not going to drive properly.

 

[darwin999]

If you don't have gain, then you need check those Germanium diodes (D2 thru D5 on Aion Cygnus v2.0.0 doc) - you absolutely need low leakage diodes (in reverse bias) plus forward voltages >0.3V, or you'll have low gain. This has been discussed elsewhere here, e.g., here:

https://forum.pedalpcb.com/threads/aion-cygnus-cornish-g-2-low-volume.11728/​

I measured my Ge diodes before mounting them in the PCB, and I have no gain problem at all. There are also several threads on the PPCB Forum on measuring diode leakage, search for those by @Chuck D. Bones. And if you don't have the measurement capability, then you can socket the diodes and try out candidate diodes seeking the greatest gain.

Good luck - quality Ge diodes are increasingly hard to find, so the AionFX doc also provides alternative options such as the BAT41 with associated resistor changes. And they also suggest a modification for decreasing the bass output. But first fix the gain.

Here was my Aion G-2 build: https://forum.pedalpcb.com/threads/cornish-g-2-clone.21117/

 

[VanWhy]

This

 

[darwin999]

For completeness, here's the Aion FX build docs for the Cygnus:

• v1.0.2 https://aionfx.com/app/files/2019/03/cygnus_documentation_v1.pdf
• V2.0.0 https://aionfx.com/app/files/docs/cygnus_documentation.pdf

There's useful info on diode requirements and various modifications there, worth reading for G-2 builders.