AionFX Heliodor (BOSS OD-3)

[MichaelW]

Build Rating

5.00 star(s)

Last one of my series of Boss overdrives.

Really glad I did this (thanks to @Guardians of the analog for the inspiration!)

None of these drives ever made it onto my radar but they're all great sounding overdrives, each with their own thing going on.

This is another of Boss's Discrete OpAmp topology drives like the OD-2 and BD-2, although this one does also use silicon clippers for soft clipping and has a 4558 but it doesn't contribute to the clipping or gain sounds.

I found some T0-92 2SK184-GR JFETS at Smallbear but I'm pretty sure any J201's would work equally well.

Like the "Aurum" (Boss OD-1) this is a tight and busy build. The 1uf film caps need to be small footprint ones. The only ones I've ever been able to find are the WIMA ones and I just happened to have some on hand for these two builds.

I also remembered to shift the knob drill holes down 6mm so it doesn't look so scrunched to the top of the pedal like my OD-2.
I went with the Pink Viola Tayda enclosure and of course "Boss style" knobs as a nod to the originals.

Planning to record a demo comparing the whole series of drives. Stay tuned......

 

[geoffrey]

Man, you made that AionFx build CLEAN! The last (and only) one I've done from them had wires everywhere lol.

 

[MichaelW]

Man, you made that AionFx build CLEAN! The last (and only) one I've done from them had wires everywhere lol.

Yah, the Aion wiring layout can be a bit obtuse, which is why I use buss wire to connect the daughterboard then hide all the wiring behind the board. You should see the first Aion project I built.....it was a mess....hahaha

 

[jhaneyzz]

I like your "hard wired" consolidated ground. I've been doing that just because it looks cool but you really thought through the wire management!

great call on shifting the board placement down. that looks great.

And, I really dig the choice of the non-skirted tone (I assume) knob.

 

[MichaelW]

I like your "hard wired" consolidated ground. I've been doing that just because it looks cool but you really thought through the wire management!

great call on shifting the board placement down. that looks great.

And, I really dig the choice of the non-skirted tone (I assume) knob.

That's the way Boss did it, I thought I'd just copy it

 

[geoffrey]

Yah, the Aion wiring layout can be a bit obtuse, which is why I use buss wire to connect the daughterboard then hide all the wiring behind the board. You should see the first Aion project I built.....it was a mess....hahaha

Obtuse is the right word for it. I bought that buss wire you suggested and it’s been a huge help. Thanks for that!

 

[Route14]

I've been waiting for you to get to this one. One of the best Boss OD pedals in my opinion.

Buss wire??? I've been using resistor lead trimmings!!!

 

[MichaelW]

I've been waiting for you to get to this one. One of the best Boss OD pedals in my opinion.

Buss wire??? I've been using resistor lead trimmings!!!

I used to do that but decided there was just too many different thickness leads. Buss wire is much more uniform.

 

[Guardians of the analog]

I really like this one Michael, you did a good job on it. I don't think that this is scooped sounding, but if you look at it on a spectrograph, the frequency response is actually more flat. It still has a slight mid bump but the bass and treble isn't cut like in an SD-1. The BD-2 on the other hand is definitely more scooped in the mids.

 

[MichaelW]

I like them all, they each have their own voice. I think the BD-2 is probably the most scooped. My fave is still the OG OD-1.
There's something lo fi and gnarly about that I like

 

[eh là bas ma]

I modded my OD-3 unit a few days ago.

The choice of diodes is a good start to get different gain textures.

I added an extra toggle allowing to choose between two D9E in series instead of anti-parallel at D9-D12 and D10-D11 (4 ge diodes total), and original boss diodes. I used an other toggleswitch to choose between stock 1N4001 and 3mm red leds at D6-D7.

With both ge diodes and 3mm red leds, the saturation feels somewhat less processed, less sophisticated, unleashed at max gain.

I also tried to lower R51 value (10R and 330R) but it always resulted with a brighter sound, a bit like a Presence control. Not what I was looking for, so I left the standard value.

 

[Route14]

I used to do that but decided there was just too many different thickness leads. Buss wire is much more uniform.

What gauge and where are you getting it from?

 

[MichaelW]

What gauge and where are you getting it from?

22AWG from Amazon.

one spool lasts a long time....even for me.....

 

[andare]

You're unstoppable! Single-handedly keeping the Build Reports section alive.