Aion Obelisk O-scope build issue

[bal704]

I'm currently building an Aion Obelisk overdrive pedal.  This is an adaptation of the Lovetone Brown Source OD pedal.

https://aionfx.com/project/obelisk-vintage-drive/

I've got it built.  I'm using an O-scope to check functionality.  I'm injecting a 1kHz sine wave into the input jack, and looking at the output at the output jack.  In bypass mode, I get the 1kHz sine wave.  When I engage the pedal, I see the 1kHz wave but it is a bit distorted.  When I adjust the gain pot, the sign wave changes shape as I sweep thru the pot range.  The volume knob changes the size of the wave.  The tone and mode knobs change the shape of the waveform as I sweep thru them.  So far so good.

When I plug in my guitar and amp, in bypass mode, everything sounds fine.  When I engage the pedal, I get no sound. 

I've tried different cables/amps/guitars, and they all work fine when the effect is bypassed.  No sound when engaged.

The instructions for the build say to check the orientation of the transistor if you get no sound.  I have changed the orientation, but I still get no sound, and the using the o-scope shows no output. 

Any thoughts on why it works with the o-scope and not my guitar/amp?

[antonis]

Have you tried to inject 1kHz signal with output connected to amp..??

[r080]

Grounding issue perhaps? Is it possible your scope connection is completing a ground that is missing without it?

Is it already in an enclosure?

[MikeA]

Could in & out jack wiring possibly be swapped?
If not, where on the out jack are you attaching the scope?  Can you run a TS cable from the output jack on the bench, inject a tone, and probe the other end of the cable for a signal?
What's your bench signal level?  50 - 150 mV RMS or so is reasonably close to guitar pickup output.

[bal704]

It is now working....

It is in an enclosure.  This board has a spare daughterboard card with a 4 position rotary switch.  I hooked it up with short wires, but basically it is hard to remove and put back in.  I would be easier to work with, IMO, if he had put the mounts for the rotary on the main board, with hard wired traces.

I hadn't thought of hooking the output jack to an amp running a 1khz signal, but that did indeed work!  Thanks for the tip.

I found one resistor that may have had a bad solder joint. It felt a bit looser than I like, but I couldn't see the solder side of the board since it's installed.  I hit it with some solder from the top side.  I then hooked up the 1khz output to a small practice amp and I got sound.

Thanks for the tips!

[idy]

The daughter board is a solution to the eternal conflict: the pots and rotary switches we are mostly using have different heights off the board! Crazy but true. Other solutions involve long pin pots, component leads to pots. Aion has a new trick for this apparently.

Isn't there a line of rotaries that doesn't have this issue?

[ElectricDruid]

Isn't there a line of rotaries that doesn't have this issue?

It's kind-of amazing that no manufacturer of rotary switches has thought to produce them in similar form factors to common pots - 9mm, 16mm, 24mm etc. A choice of vertical and horizontal mounting? Hey, why not?!?

Jeez, I mean all the work has been done for you...