Cave Dweller Debug Help

[otsismi]

Been troubleshooting a cave dweller I built the other day. I'm getting very low guitar signal through the effect but no delay. Pots do nothing except raise and lower volume somewhat.

Using an audio probe I followed the signal from the input to LPF1-in on the pt2399, from there I can't find the signal anymore. LPF1-out does not have a signal. Is the chip fried? Maybe a solder bridge to ground? I've inspected the board extensively and can't find anything visible.

Solder joints are good. Will post voltages soon

Help!

[das234]

On my Sea Urchin, I had to solder a jumper between pins 3 and 4 to get the PT2399 to give me delay.  I don't know if that applies to the Cave Dweller as well but it's possible. 

[otsismi]

3 and 4 are bridged. No changr

[jimilee]

Have you tried different chips? Have you reflowed everything? What do your voltages look like? This is an easy build but it's tiny so it's easy to create a solder bridge.

[otsismi]

I left my volt meter at work so I can't give voltages till tomorrow. Reflowed and checked for solder bridges. I think my tantalum was in backwards but there was no change.

[otsismi]

Only have one pt2399. More on the way from tayda. Should have used a socket. I'm so discouraged

[jimilee]

Also you may want to post pictures. Can you get sound if you leave the IC out?

[jimilee]

Only have one pt2399. More on the way from tayda. Should have used a socket. I'm so discouraged

It's all part of the learning process. This isn't the first pedal you'll have to debug. They will be fewer and farther between, but they will still happen.Be patient and down melt anything down.

[otsismi]

So during another reflow strafing run, I found that one of the traces on the regulator had lifted off of the board under the solder. I proceeded to smash my face into the table for continuing to use rat shack copper blank boards. Jumped it and plugged it into my amp.

I have delay!!! BUT....

Attached to each echo is a static noise or a distortion. Almost like white noise. I only hear it through the echoes and the noise follows time with the echoes. Strange and still not working correctly but I feel great that I'm that much closer.

[otsismi]

I read that the CD will get noisy if controls are not set proper. But I'm getting this terrible distortion/noise with the echoes wherever the pots are set.

[jkokura]

Not all PT2399s are created equal. Some will sound better than others. That said, it probably sounds like it should, you just weren't expecting it to be as noisy as it is. If you really feel it's too noisy, try some other PT2399s, and see if it gets better. If not, and you still don't like it, you could try posting a video or a soundclip and we'll tell you what we think.

Jacob

[otsismi]

Will do. Sound clips coming tonight. stay tuned

[flanagan0718]

What ever happened with this? I just finished one (Cave Dweller) and I'm getting the same issue. I thought it was a crappy capacitor I had salvaged from another build but That wasn't it. I also tried changing these and it didn't help
-R1 changed to 15K (filter noise)
-R2 changed to 20K (filter Noise)
-C2 changed to 10nf (compensate for R1 & R2 change)
- I also replaced all the Resistors (originally used 1/4 watt) with 1/8 watt.
My next idea is to, I guess, try a different PT2399 chip. Stupidly I didn't socket it but lesson learned. Just wondering what your outcome was. Thanks in advance.

[ggarms]

As stated above, not all PT's are created the same. Some are definitely lower in noise than others, however at longer delay times you'll likely have artifacts. I typically try 3 or 4 chips until I find the one that suits the pedal. In addition, I'm usually messing with the repeats level so I can find that happy balance.