Aion Dimension C Blueshift - doesn't work

[rschultz]

Hi,

I recently built an Aion Dimension C. Super cool build, double layered PCB, very advanced, lots of parts. The build documentation was excellent, part list from Mouser had most everything... just had to supplement a few parts elsewhere.

I took my time, measured all components, double and triple checked polarity, etc. The LED comes on, but the effect doesn't change the sound... just a slight volume decrease in volume is all. The oscope calibration was exactly like the manual said, no problem - the signal was a perfect sine wave out of my computer but after going through the pedal the tips were rounded over just a bit... just like the manual said. But it doesn't work. I have been going through checking components and wiring, checked the OPTO jumpers, checked the bypass method (standard). I can't figure it out. I highly doubt I put a component in wrong. More likely I wired something wrong or a transistor/op amp is blown or shorted, etc.

Here's a link to a thread from a couple years ago... EXACT SAME PROBLEM!
https://www.diystompboxes.com/smfforum/index.php?topic=120977.0

[rschultz]

Schematic

[Ripthorn]

Have you audio probed it? It would be interesting if the BBD's are putting out signal.

[eh la bas ma]

I wonder if your upper jack (Out B) isn't preventing the second board to fit correctly in the pin headers  (I remember it was a real challenge to get all the pins in their sockets, probably the hardest part of the building process). At least, you should turn it so the jack's terminals are facing the enclosure, not the second pcb, in case there is a short.

On my build I used only open jacks. There isn't much space left in the enclosure with both boards, so I would be surprised if these big isolated jacks could fit in there...

Also, make sure the jumpers on the opto are following the markings on the right side of the board.

You can also post  your voltage readings, as described in this link :

https://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[rschultz]

Have you audio probed it? It would be interesting if the BBD's are putting out signal.

Could you describe how to "audio probe" it? I'm sure I can, just not sure on the details.

[rschultz]

I wonder if your upper jack (Out B) isn't preventing the second board to fit correctly in the pin headers  (I remember it was a real challenge to get all the pins in their sockets, probably the hardest part of the building process). At least, you should turn it so the jack's terminals are facing the enclosure, not the second pcb, in case there is a short.

On my build I used only open jacks. There isn't much space left in the enclosure with both boards, so I would be surprised if these big isolated jacks could fit in there...

Also, make sure the jumpers on the opto are following the markings on the right side of the board.

I have also wondered about the headers not fitting well enough. I'm going to fire it up outside the enclosure and test that. Besides the jacks, the wires also prevent a great fit on the headers. But good suggestion on the jack orientation.

I've triple checked the opto jumpers and wiring for standard bypass.

Checking the voltages on all the IC's and transistors... I can do that. Might take a few days before I get time though.

Thanks for the thoughts!

[Ripthorn]

Have you audio probed it? It would be interesting if the BBD's are putting out signal.

Could you describe how to "audio probe" it? I'm sure I can, just not sure on the details.

Here's a pretty good debugging guide that describes it along with other things to check

[rschultz]

I wonder if your upper jack (Out B) isn't preventing the second board to fit correctly in the pin headers  (I remember it was a real challenge to get all the pins in their sockets, probably the hardest part of the building process). At least, you should turn it so the jack's terminals are facing the enclosure, not the second pcb, in case there is a short.

On my build I used only open jacks. There isn't much space left in the enclosure with both boards, so I would be surprised if these big isolated jacks could fit in there...

Well, it's not the headers. I took it out of the enclosure, made damn sure the headers were fully seated. No change.

[Frank_NH]

I had a similar issue when I completed my build of the Aion L5 Preamp.  I was very careful with every phase of construction but when I fired it up for the first time - no joy.  After days of inspecting the board I finally found the problem.  A very tiny blob of solder was lodged between two pins on one of the IC sockets!  Upon fixing that it worked perfectly.  So inspect all of the solder connections and check to see if there is a solder bridge somewhere.  An audio probe will help.  It only takes the tiniest blob of solder to cause trouble. Good luck.

[rschultz]

So the companders, as I understand it, the first one compresses the signal... then do a bunch of BBD/clock stuff... then the 2nd compander expands the signal back to the original. Right? So since my signal is getting through unaltered, it would seem that the companders are working, probably.

I'm going to focus on the BBD/clock stuff for now.

[rschultz]

It's not the BBD/Clock, I bought some cool audio ones and swapped, no change. I've got new companders to try too. But given that the signal basically doesn't change, it makes me think there's something wrong in the BBD/Clock area. I'm going to measure some voltages on the BBD/clock IC's soon too.

Off topic. The Opto really doesn't do much, right? It's hooked up to the LED. What does the OPTO do? And I can't find Opto_IN and Opto_Out on the board... cant figure out what signal goes in/out of that.

[Nitefly182]

Build an audio probe and work your way through the signal path to figure out where you are getting unexpected results. If you aren't getting effect then the delay lines likely aren't working. This is an extremely complex circuit to troubleshoot. Good luck!

[ElectricDruid]

So the companders, as I understand it, the first one compresses the signal... then do a bunch of BBD/clock stuff... then the 2nd compander expands the signal back to the original. Right? So since my signal is getting through unaltered, it would seem that the companders are working, probably.

No, that doesn't follow, unfortunately.

It's a chorus, so it mixes a dry signal path with a wet (delayed) signal path. In this case, two wet paths. If the signal is passing through unaltered, it most likely means the dry signal is getting through, but the delayed paths aren't working. That could be due to the companders, the BBDs, the clocks, the filters, etc etc. That's where the audio probing comes in. You need to chase the signal in from the input and see how far you get before you lose it. When it disappears, you know you're close to the problem.

[rschultz]

It was the companders, The NE571s that I bought off of eBay. I replaced them with CoolAudio ones and it worked!

[rschultz]

So what does the opto do? It's connected to the LED.

[idy]

The bypass is done with an optotransistor. There are two options, I don't follow the details (schematic doesn't show the options, just shows the points of connections and the build doc guides you) but the idea is the switch activates a visible LED and also one inside the opto unit that turns an optotransistor on. That passes signal.. but I don't get if that is the input to the two channels of chorus or what...

[rschultz]

Finished!

[matopotato]

I have the same problem (https://www.diystompboxes.com/smfforum/index.php?topic=128745.msg1241312#msg1241312)
Struggled, tested, resoldered, but now it is in the "maybe some other time" box.
Will check out your solution for sure. Hope it might be similar reason.

[matopotato]

It was the companders, The NE571s that I bought off of eBay. I replaced them with CoolAudio ones and it worked!

Where were you able to get them from?

[rschultz]

Originally I bought all NOS clock/BBD/companders off of eBay. But when it didn't work, I bought cool audio versions of those 6 chips from stompboxparts.com and returned the other ones.