3 Legged Dog problem

black mariah · March 17, 2007, 06:45:02 AM

Just finished the 3 legged dog from ROG and came up with some rather weird noises. It's a great little noisemaker... but I just want it to distort.

The sound is gatey and there's a constant squeal. I checked all my connections and nothing is in the wrong place or touching something it shouldn't be. I know how to troubleshoot opamps but the CD4049 I'm totally at a loss on. It sounds like something is just misbiased... but what if anything biases this chip?

black mariah · March 17, 2007, 03:04:12 PM

Freakin' BUMP. Did I mention it's overheating? $:-\$ Time to octuple-check all the connections.

black mariah · March 17, 2007, 04:09:12 PM

Fixed. Moral of the story is DON'T BUILD WHILE TIRED. I missed the 220k resistor. Didn't put it in. How's THAT for misbiased?

stumper1 · March 17, 2007, 04:38:49 PM

Doh!

black mariah · March 17, 2007, 04:48:04 PM

I didn't realize how much gain this thing has available.

This will DEFINITELY do what I'm planning on using it for... but that's a secret.

Short Circuit · March 17, 2007, 08:11:18 PM

Congrats on getting it working.
This schematic was my first build with an opamp and I couldn't get it to work right.

If you look on the schematic the opamp says 4049 on it and that was the way it was on the drawing so that's the way I installed it...with the numbers facing up.
After a few days of getting bugged eyed I looked at the picture that accompanies the schematic and then realised that I had installed the 4049 upside down(the indent that I never noticed was opposite what it was in the pic). I turned it around and it worked.
I won't make that mistake again !!!

It does have tons of gain!!!

Is your # Legged Dog noisy with the guitar plugged in but not playing

Mine is.

Mark

black mariah · March 17, 2007, 08:34:09 PM

Yeah, it is. That's to be expected with such high gain.

ambulancevoice · March 18, 2007, 12:39:38 AM

Quote from: black mariah on March 17, 2007, 04:48:04 PM
I didn't realize how much gain this thing has available. This will DEFINITELY do what I'm planning on using it for... but that's a secret.

a cover of metal machine music!?
hahaha

black mariah · March 18, 2007, 12:44:07 AM

It won't work for the idea I had. Or rather, the other half of the equation won't.

Back to the drawing board..

StephenGiles · March 18, 2007, 08:43:32 AM

Well, we're just off to walk our 3 legged dog Bonzo!!

tcio · October 10, 2007, 12:08:15 AM

I had this thing sounding pretty good (3 Legged Dog) except for the constant extreme hiss. Don't know if I had it all wired right or not but I absolutely love the guts and high gain this thing has. I started replacing the resistors that went to ground with all metal film and I started getting that shrieking squealing noise. Now I cannot get rid of it. I went over the circuit dozens of times, even replaced ALL of the components in case one was fried. If anyone has any advice please let me know. I cannot for the life of me see anything wrong with the connections yet I can no longer plug into it as it currently is due to the horrible squealing sound. As of right now I only have it all wired on a breadboard. I was hoping to tweak it just a little before I soldered to the PCB. Is there a way to tame this beast a little? Out of all the pedals I have built I like this by far the best for shedding but wouldn't mind simmering it down now and then when not playing metal but just Rockin' out or playing heavy blues.

I am pretty new at building pedals so please bare with me. Any help would surely be appreciated.

Thanks in advance

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3 Legged Dog problem