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Red llama problem

Started by suregork, April 21, 2008, 07:44:41 AM

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suregork

Hi,

I've built another red llama using dragonfly's vero layout, but this time no sound. I've traced the problem down to pin 14 and 15 of the 4049ub which both give 0V, even though they should be ~2-3V (all other pin voltages are fine compared to values others have given on the forum).. I've tried replacing the IC, but no difference, and I've changed the 51pF capacitor jumping the two pins. When I measured the resistance between the pins (to see if the pot was working correctly) I sometimes could here the overdriven signal, but this was with the volume and fuzz pots on max. I haven't tried audio probing, but will try to make one. Any help appreciated.

The IC is a CD4049UBCN.

Thanks in advance.
Successfully built: Mosfet Boost, Red Llama, Crunch Box, SHO, RM Voodoo Vibe, Fuzz Face, Ross Comp, 9V Electric Mistress, Modded Crybaby

MikeH

More info would be helpful, like the checklist in the "Debugging; what to do when it does not work" thread.  But, first impression, double check that you've put all of the jumpers in place (this design has a lot) and make sure there aren't any solder bridges (vero board is quite prone to them).
"Sounds like a Fab Metal to me." -DougH

suregork

#2
[Problem Solved], wire with loose solder joint..
Successfully built: Mosfet Boost, Red Llama, Crunch Box, SHO, RM Voodoo Vibe, Fuzz Face, Ross Comp, 9V Electric Mistress, Modded Crybaby

OscarMeat

I thought to continue in this thread rather than start a new.

So, my Red llama build is giving me hard time. I first built it on veroboard and had this gating effect.
When i hit strings hard it sounds like it should i suppose but stops very abruptly as the signal loses a bit of strength and then there's only cleanish signal passing thru with low volume.

I got something more inspiring to do so I left it be and gutted the parts. Now I started etching my own pcbs and thought I'd give it another go. Tonepad layout.

So, the same effect again. I've tried it with two different CD4049ube chips and the result is the same. Triple checked part values/polarity, solder bridges/joints, IC voltages are as they should be (Vin, 5.5v, signal in out, about 2.13v).

Any ideas to point my way

Thanks!