AionFX Spectron

flemming

Well-known member
Build Rating
4.00 star(s)
I'll squeeze in one morereport before the end of the year. There are quite a few build reports on this one with different opinions. The actual build itself I wasn't super excited with. To start with the build docs have the wrong dimensions for the top jacks and the expression jack. The template is mostly okay (though the top jacks are still a bit too wide if you follow the template), but the numeric values in the docs are off. I reported this to AionFX a few months ago and they didn't really seem to care, since I never heard back and they didn't update them. If you're interested, here is a drill template that works:


I hate all the unnecessary wiring, but I guess I've just been spoiled by PedalPCB builds. The grounding on the various jacks could be simplified a bit. Something got screwed up with my UV print and it sits slightly too low and I hate it so much :mad: I'm also annoyed for taking the easy way out and not properly labeling everything. The problem was the build docs were a bit ambiguous with regards to the switch positions and prior build reports had conflicting info. I could have put forth the effort to try and figure everything out, but I took the easy way out and left off the labels and now I kinda hate myself. Why? Well because this pedal is finicky and understanding all the various settings is pretty important. Just trying random things made me think it wasn't working properly. The original user manual was pretty helpful, and once I read that and tinkered a bit, I was off and running. I jumpered 2-3 of the color pot as suggested and I used the suggested LDRs from Amazon, but I went with lower MCD green LEDs from Smallbear rather than the ones from Tayda since some people implied that being too bright was a problem. There's a lot going on with this pedal and it's pretty fun to play with. You can go from quacking to almost phaser like with the right settings.

The enclosure is winked silver and while the photo makes it look a little weird I do absolutely love the look of it (minus the print being too low). I was going for a 1970s van vibe. I did originally want Davies 1400 knobs for it, but the damn pointers smacked into each other since the knobs are too close, so I swapped in some MXR style knobs that I had on hand.
PXL_20221228_014146891.jpg PXL_20221228_013342140.jpg
 
I have this on my queue after I build all the other pedals for which I already have all the parts… yadda yadda. I think the graphics look pretty cool! I can’t really tell that they are misplaced. Is the effect loop useful?

Edit: oh now I see the text sits a bit too low on the switches etc. I would be frustrated with that as well!
 
In my notes I wrote down that Dead End FX also makes a board for this. I wonder if it would be an easier build.
 
Do you have a link to the low mcd LEDs you used? I've got this built up with the Tayda greens, but I'm not in love with it
 
I've built one of these - I ended up liking it, but not liking my enclosure (it was an early attempt) - so I may end up rehousing it some day...
 
Do you have a link to the low mcd LEDs you used? I've got this built up with the Tayda greens, but I'm not in love with it
I bought then from smallbear before they sold. At the time they listed the MCD value, but now I don't see it. I think the ones from Mouser linked from the AionFX BOM are also lower MCD. The settings can be picky. Check out the original manual for some insight:


Also things like the input level, picking dynamics, active/passive pickups, etc all play a part. It's really tricky to dial in. "Up" mode is a bit more forgiving. There are certainly easier to use filters. I'm not in love with it, but it's interesting.
 
I have this on my queue after I build all the other pedals for which I already have all the parts… yadda yadda. I think the graphics look pretty cool! I can’t really tell that they are misplaced. Is the effect loop useful?

Edit: oh now I see the text sits a bit too low on the switches etc. I would be frustrated with that as well!
I haven't played with the loop too much. The docs talk about putting your input signal into the loop return and then adding something like a drum loop, vocals, etc to the triggering input for all sorts of fun and games. I haven't tried any of that stuff yet. The downside to the loop is things in the loop are automatically bypassed when the Spectron is bypassed, so that makes those effects otherwise useless.
 
I bought then from smallbear before they sold. At the time they listed the MCD value, but now I don't see it. I think the ones from Mouser linked from the AionFX BOM are also lower MCD. The settings can be picky. Check out the original manual for some insight:


Also things like the input level, picking dynamics, active/passive pickups, etc all play a part. It's really tricky to dial in. "Up" mode is a bit more forgiving. There are certainly easier to use filters. I'm not in love with it, but it's interesting.
I think I just don't get on with MuTron III type filters. But, I do wanna see what I can do to make the spectron a bit more spectacular. Like, I've been able to find maybe 3 sounds I like which seems ridiculous given the amount of knobs and switches it's packing.

As is, with the Tayda LEDs, it's just kinda meh. I do have the Dead End board on hand, but that one calls for VTL5c3, which I'm currently out of.

Or, maybe I really just don't like optical envelope filters 🤷‍♂️

Would it be possible to get a demo of yours?
 
Great build ! I like these shapes and colors.

Just in case, here is a useful mod to set the global sensitivity of your circuit. It really opens up a lot of possibilities. You may love it...

"100k pot (trimmer) from 9v to pin 3 of 358. Dial it in until LED is just barely off, right at the edge of lighting up the LED. Replace with fixed resistor (next value higher than trimmer.)"

Replies #4 and #50 :
 
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Great build ! I like these shapes and colors.

Just in case, here is a useful mod to set the global sensitivity of your circuit. It really opens up a lot of possibilities. You may love it...

"100k pot (trimmer) from 9v to pin 3 of 358. Dial it in until LED is just barely off, right at the edge of lighting up the LED. Replace with fixed resistor (next value higher than trimmer.)"

Reply #50 :
Just tried this, and.... Kind feel its mandatory. The sensitivity knob actually has a usable range now.

Gonna leave the trim pot in, as it does interact with the different modes, and each one has its own lil sweet spot
bd61e64b-ab8e-4715-9aa1-f4b5f3cac061photo.jpeg
 
Just tried this, and.... Kind feel its mandatory. The sensitivity knob actually has a usable range now.
Nice, I just tried this out real quick as well and I think it certainly helps bring more range. I grabbed ~9v from pin8 of the same chip. I think if you carefully bend the pins of the trim pot you might just be able to tack it to top of the chip with some hot glue and solder the trimmer directly between pins 8 and 3. I need to play with it more before committing.
 
Nice, I just tried this out real quick as well and I think it certainly helps bring more range. I grabbed ~9v from pin8 of the same chip. I think if you carefully bend the pins of the trim pot you might just be able to tack it to top of the chip with some hot glue and solder the trimmer directly between pins 8 and 3. I need to play with it more before committing.
I twisted legs 2&3 of the trimpot together, and soldered them directly to pin 3 of the 358. It has a bit of wiggle, bit it's not like it'll ever be cranked on
 
@DGWVI — Given what you said about different modes, is there any point in making the trimmer an external pot?
Maybe, up/down mode changes might require you to tinker with the cutoff point. I still want to play with this a bit more. From my limited testing this change may actually be a negative for guitars with really hot pickups. There's more variation across the sweep but the actually usable area feels less to me. I'm not about to change out the sensitivity pot but I might try tacking on some resistors to see what happens. If you have one it's certainly worth playing with this mod.
 
Given what you said about different modes, is there any point in making the trimmer an external pot?
It would be useful to have such a control (Input gate or input sensitivity), bringing the circuit in the most effective range depending on the level of the instrument input, and the selected mode. But you need to look at the internal leds to see where is the accurate setting.

So it might need further adjustments :

If i recall correctly, the useful zone in the trimmer rotation isn't very large. It would be interesting to find the effective aera, let's say for exemple between 47k and 75k, and use a lower value than 100k for the pot panning between these values.

This would probably make it easier to dial the settings with the extra pot.

Edit : Probably one resistor on each sides of the pot. According to the exemple, using a 20k pot : 47k between 9V and lug 1, an other 20k resistor between lugs 2 & 3 and pin 3 of 358 ?
 
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@DGWVI — Given what you said about different modes, is there any point in making the trimmer an external pot?
It would be useful to have such a control (Input gate or input sensitivity), bringing the circuit in the most effective range depending on the level of the instrument input, and the selected mode. But you need to look at the internal leds to see where is the accurate setting.

So it might need further adjustments :

If i recall correctly, the useful zone in the trimmer rotation isn't very large. It would be interesting to find the effective aera, let's say for exemple between 47k and 75k, and use a lower value than 100k for the pot panning between these values.

This would probably make it easier to dial the settings with the extra pot.

Edit : Probably one resistor on each sides of the pot. According to the exemple, using a 20k pot : 47k between 9V and lug 1, an other 20k resistor between lugs 2 & 3 and pin 3 of 358 ?
As eh lá bas ma says, the useful range of the trimpot is rather narrow, so I don't feel it'd be worth it as an external control. Though, a toggle switch with two fixed resistors could be useful -one tailored for the down sweep, the other for the up.
Maybe, up/down mode changes might require you to tinker with the cutoff point. I still want to play with this a bit more. From my limited testing this change may actually be a negative for guitars with really hot pickups. There's more variation across the sweep but the actually usable area feels less to me. I'm not about to change out the sensitivity pot but I might try tacking on some resistors to see what happens. If you have one it's certainly worth playing with this mod.
The cutoff frequency needing tinkering isn't a bad idea.
Before adding the trimmer, the only really useful setting on the Sens pot was with it cranked full- with the trimpot in place and tuned, I can have the Sens zeroed out and still get a bit of sweep. Up past about noon, the sensitivity does raise considerably, I haven't tried it with lower output pickups yet, but I think that having that degree of sensitivity might be useful
 
As eh lá bas ma says, the useful range of the trimpot is rather narrow, so I don't feel it'd be worth it as an external control. Though, a toggle switch with two fixed resistors could be useful -one tailored for the down sweep, the other for the up.
I may be a slightly out of my depth here, but looking at the schematic, the sweep switch has 9v coming in on the "A" pins, so if you can figure out what resistors work best for the up/down modes you might be able to tap the voltage from the existing sweep switch at pins 1 and 2.
 
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