Slow Loris Help Needed now with PICS

[PostPaintBoy]

Ok. When I first plugged in after wiring it up, I got sound only when the input cable was halfway in the input jack. Also, the sound I got was certainly not a RAT sound; the volume and gain were all the way up and it just did not sound like a RAT. After taking some advice from this forum, I rewired and now I only get a loud hum from the pedal. I'm relatively new at pedal building so take it easy on me and I highly appreciate the help.

[9Lives]

are you using the stereo jack and battery snap? What kind of dc jack? I made the mistake of using a metal one and it made all kinds of hum. Also hum seems to also stem from grounding issues. Correct?

[PostPaintBoy]

Now, the issue is that I get tone, but just not RAT tone. My volume is maxed and from my RAT experiences, maxed volume is dangerous. Also, when I attack the strings hard, the effect chops up. What the hell is going on here?

[mgwhit]

The most important thing you can do is follow the instructions in this thread.  The next most important thing you can do is post good, in-focus close-up photographs of your board and wiring.  If you have a multimeter, please post the voltage at each pin of the IC.

Here's my first batch of questions.  Which version of the board are you using?  What did you actually do to clear up your earlier problem?  (I'm assuming it was grounding or wiring related.)  What kind of IC and diodes are you using?  Are your diodes oriented correctly?  Do your controls (pots and switches) work correctly or at all?

Good luck.  Post photos.

[PostPaintBoy]

The IC is the LM308N. The diodes are two LEDs, two 1N914s, and one 1N4001, all of which are oriented correctly. The no effect problem that I began with was a grounding issue and now I only have the lack of substantial RATness and the in and out choppiness I get the harder I play. I attempted to upload photos, but when I do, it tells me that the upload folder is full despite the photos being less than 1000KB. I really appreciate the help, guys. Thanks.

[jkokura]

try going with a photo hoster like imageshack, which lets you upload and then will embed their photos in the forum.

Jacob

[PostPaintBoy]

Uploaded with ImageShack.us

[PostPaintBoy]

Uploaded with ImageShack.us

[jkokura]

That's a crazy mashup of parts!

One thing I know is that clear LEDs don't always work the same as diffused ones. Perhaps that's your problem?

Jacob

[PostPaintBoy]

I initially had red LEDs in and was still getting the same stuttering effect the harder I strummed.

[Scruffie]

I can see quite a few suspect joints on that, i'd reflow the board.

I'd also post voltages.

[mgwhit]

Thanks for posting the pics.  I agree that there are quite a few spots that I would touch up.  A lot of your joints look like the solder is blobbed on top of the pad, but not necessarily flowing down into the pad and around the lead.  Make sure you are using enough heat and touching both the pad and the lead with the tip of your iron simultaneously.

Example: look at the leads and pads at C4 on your top picture.  One has solder flowing through the pad and around the lead, the other looks like there's no solder there at all.  I can't see that joint very well in the lower photo, but I'll bet it's cold.

Based on your description (max volume, but not RAT-like), my best guess is that your clipping diodes aren't grounding properly. You're getting the amplification from the op-amp, but the diodes aren't clipping the signal effectively, which would normally result in (a.) distortion, and (b.) lower volume.  Here are somethings you can do to test this hypothesis:

1.  Does the Gain pot effect the output volume?  If so, your op amp circuit is working (at least somewhat) correctly.

2. Does flipping the clipping diode switch affect the sound and/or volume at all.  If not, they're not clipping, and if neither of them is clipping then there's probably a grounding error from the switch.  If one position is clipping (more distorted, lower volume) and the other isn't, then check out the connections of the other non-clipping diodes.  Bad joints maybe?

3. Do the LED's light up at all when they are selected from the switch and you strum a really hard chord?  If they don't and you're getting extremely loud output, they're not clipping (see above).

Good luck!