Aion Comet has no sound

[Linac Guy]

Hi Ya'll any help would be great, new to pedal building. I built an Aion Comet and in bypass mode it works great (I got one thing right!) once I press the 3dpt switch the LED lights up but I get no sound. Any ideas? The attachment option isn't working for the iPad. I will try my laptop so I can load a pic. no option to upload attachment, sorry. I guess I will take help with posting a picture also.

[mth5044]

Welcome to the forum!

Check out the thread sticky'd in this forum: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

To upload pictures, you need to host them somewhere. Imgur is a free service without log in, photobucket works (although you might get some arse complaining), as well as others.

In any case, it's always important to post a link to your project. Most people don't have every project memorized and you'll get a lot more help when people have to just click a link rather than google your project and search for the documents.

A multimeter and audio probe will be very useful in fixing your problem.

[Linac Guy]

Matt,

Thank you very much for your quick reply and tip on how to upload pictures! I will try and get them up this afternoon/evening and I agree without seeing it, it's almost impossible for people to help. I have a DMM, where can I get an audio probe? I also have an O-Scope if that would help me.

Thanks,
Bobby

[duck_arse]

< some arse.

an oscilloscope is an audio probe, but with pictures. they are both used in a similar manner. the o-scope WILL help you.

are you sure your switch is oriented correctly? the solder-tags are most often shown horizontal in wiring diagrams, the switch won't work if rotated.

also, welcome.

[aion]

Photos would be fantastic - also if you could use the DMM to take down the voltages of the IC pins as well as the transistors. Between those two things we should be able to get it figured out!

This is a Boss DS-1, for anyone else who is reading. Documentation link is here: https://www.dropbox.com/s/k3d93su9d48k8cd/aion-comet-ds1-documentation.pdf?dl=0

[Linac Guy]

All,

Here is a link to the build in the enclosure. please let me know if you want any other pictures. http://imgur.com/a/e5Zv2
@ Matt thanks for the tip about Imgur!

I believe the switch is correct, its just like the pic of the diagram @ Aion. This is my first pedal build, my daughter wanted a couple of pedals and I said sure I can build it and bought several PCB's from Aion and here I am.  Some of the parts I bought from my local electronics shop here in Dallas and what they didn't have I bought from Mouser and Small Bear.

@ duck_arse  your right, I'm just used to looking at waveforms of RF signals and some high voltages at work and Clearly I wasn't thinking outside the box. To me my scope only had one purpose up until now.

@Kevin I will get and post voltages of the IC this evening.

Thank ya'll for replying so quickly and welcoming me to the forum,
Bobby

[Linac Guy]

ok, got the voltages. the first set of readings is using the ground connection on the input jack and the 3DPT switch pressed (LED On)

Pin 1 = 3.13v
Pin 2 = 3.13v
Pin 3 = 3.13v
Pin 4 = 0.0v
Pin 5 = 3.13v
Pin 6 = 3.13v
Pin 7 = 3.13v
Pin 8 = 9.45v


These checks are using the case as ground and the 3DPT switch pressed (LED On)
Pin 1 = 0.56v
Pin 2 = 0.56v
Pin 3 = 0.60v
Pin 4 = 0.60v
Pin 5 = 0.63v
Pin 6 = 0.63v
Pin 7 = 0.63v
Pin 8 = 0.63v

Let me know if you need any other readings.
Thanks Bobby

[Linac Guy]

Hi All,

Another note about the build. I went with the modern option and the parts I sourced locally (caps) I was able to get the correct nf, pf and or uf but some of the voltages were higher than called for. I believe 1/4 watt resistors are the norm and if I remember correctly I have one that is a 2 watt which I don't think would be an issue but I could be wrong.

Thanks

[bluebunny]

That second set of voltages looks like you're shorting the power when you throw the switch.  Though I can't see from your photos how this might happen...

where can I get an audio probe?

Find an old guitar lead that you no longer love.  Cut off one end.  Solder a wire and an alligator clip to the screen conductor.  This clamps to a ground point on your project.  Solder one leg of a 100nF cap (value not important) to the other amputated conductor.  The free cap leg is now your probe.  Plug the lead into an amp (volume not too high!) and probe away: trace your signal through the build from the input to find out where it disappears.

Though not sure if probing will tell you much in this case: not if the power disappears to the opamp when you stomp.  (And using the oscilloscope instead will be less injurious to your ears.)

BTW, your parts are fine (over-spec is OK, but may be physically bigger).

[aion]

Biggest issue - it looks like Q1 and Q2 are missing entirely... and looking at the documentation, I left them off the parts list (though they are on the schematic) and in over a year, no one has ever mentioned it! I updated the docs but sorry you had to find it. If you need to get them locally, any NPN transistor will work for these, e.g. a 2N3904. All the other "optional" parts are omitted/included correctly so you're good there.

The voltages are definitely an issue. I think the input & output jacks are wired wrong... I don't see anything wired to the shield lug (the innermost one) - it looks like ground is wired to the ring lug of a stereo jack. If using a mono plug, ground and ring will be shorted together, so it may all come out in the wash - but at the very least, the circuit won't be adequately grounded to the case unless something is plugged in, so voltages wouldn't be correct if taken with the case as a ground reference point. Was anything plugged in when you took the voltages? I would move all of those ring connections to the center ground.

I am also a little leery about the soldering on the switch, especially the center-center and center-bottom lugs. I would re-flow those to get better solder coverage. For those, it helps to wedge the tip of the iron inside the pad since there isn't a lot of top-side surface area.

It could be that the ground issue is OK when something is plugged in, but the signal was stopping at Q1, so the voltage issues are a red herring. But I'd still like to get those worked out as well.

[duck_arse]

you should not get different voltages from different ground points. if you do, it suggests all your grounds are not equal. like aion says, I don't think your jacks are wired quite right. (at least one alternative wire colour always helps a build progress.)

[mth5044]

Your enclosure currently isn't grounded. Like duck said, youre wiring isn't correct. I thought at first they were stereo jacks, which if you grounded the ring, should still work, but they look like mono switching jacks. You have the ground wired to the switch part, not the ground. You need the ground to go to inside lug that connects to the sleeve of the cables.

[Linac Guy]

All,

Thanks for the quick responses from all y'all for things to check.
First I would like to apologize for not using multicolored wire (I had all my parts and was excited to build it) still no excuse. Take pride in your work and make it look good!

The only transistors I have on hand are (2n5008 and 2n7000) would either one of those work?

Ok, The input Jack is a stereo Jack and I used the solder tab for the sleeve to connect all of the ground wires. Better picture posted of the Jack and wires to it.

I did a continuity check as follows: grd tab on pwr Jack to (PCB grd, 3dpt PCB grd and sleeve tab input Jack) all good.
Next checked the others (ctr and tip to grd) to make sure it wasn't shorting out, it's good.

So I rechecked my voltages.
Pin 1 to input Jack sleeve tab (grd conn) = 3.1v same as yesterday.
Pin 1 to input Jack tip tab = 2.6v (checked just because I was curious)
Pin 1 to case = -0.5 the same as yesterday

The output Jack is a mono Jack and I get continuity between the 2 solder lugs that go to the tip and the tip (nothing to the center lug).

I decided to connect a jumper from the grd lug on the input pwr Jack to the case and check voltages again from the case to pins.
Pin 1 = 3.1v
Pin 2 = 3.1v
Pin 3 = 3.1v
Pin 4 = 0.0
Pin 5 = 3.1v
Pin 6 = 3.1v
Pin 7 = 3.1v
Pin 8 = 9.45v

Any ideas why the case isn't grounded or how it should be getting its ground connection?

Thanks!!!!! I feel like I'm sooooooooo close.

[mth5044]

2N5088 will work well (as long as that's what you mean by 2N5008), as it's now the suggested transistor in the build doc!

I'm a little confused about your jack wiring description. Did you change it from the pictures you posted? If not, you need to connect at least one of the jacks to ground (right now you have the ring of the input jack connected to something, possibly ground, but neither jacks' sleeve). If you did fix the wiring, you should be able to measure continuity between the enclosure (stick a probe in a screw hole) and the power jack/ground tabs/sleeve of jacks/etc.

Next step is definitely getting those transistors in there, though.

[Linac Guy]

Matt,

Thanks for letting me know the transistor will work, I will put them in tomorrow morning.

As for the jacks I didn't change where they are soldered to. I will take more pics of them tomorrow and put captions on them so y'all are sure what I am talking about.

Cheers

[bluebunny]

If you've not changed your jack wiring from what we see in the pictures, then I still don't think you have a ground connection on either jack.  It's pretty easy to see which lug you need: it's the one connected to the "inside" of the jack where the plug passes through.  Until your jacks are grounded, the case won't be either.

(FYI, the 2N5088 is - to paraphrase R.G. - about as general-purpose an NPN transistor as you can hope to find and will suit ninety-something percent of all applications.  The 2N7000, on the other hand, is a MOSFET and is an entirely different beast.)

Getting there!   

[duck_arse]

from what I saw of your jax original pix, you have one stereo (ring-tip-sleeve) jack, and one switched mono jack. that switch is normally closed, and opens when a jack is inserted (to break a speaker connection when a headphone is inserted, for instance).

AN earth wire needs to connect to AT LEAST ONE of the jax sleeves, a wire to each sleeve is "better". then, when the jax are screwed up tite to the enclosure, it too is grounded. an alternate method is to groundwire-to-pot, or groundwire-to-solder-lug-to-case is another more foolerproof [foolproofer?], more dedicated method.

more photos.

[jez79]

A good way to ground your box is to solder a wire to the lock washer on the footswitch.
Make sure the lock washer is on the inside of the box (no paint or finish). Then ground it to your GND hub

[Linac Guy]

Guys,

First I want to apologize for not changing the ground wires earlier to the lug ya'll kept telling me to.
I switched the ground wires to the proper lug. posted a pic of it here http://imgur.com/KredFfd

I also put the transistors in, now I get the same voltages from the IC when I ground to the case THANK ALL OF YOU!!

So I plugged it in to the guitar and amp and I still have no sound once I press the foot switch (so frustrating) any more ideas? Bypass its working great lol!

[jez79]

C8 seems missing from the first batch of pictures, but i think it's there on the latest pic.
Q3 appears to be missing