Zombie Chorus odd LFO shape

Started by lazerphea, October 02, 2012, 02:45:36 AM

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lazerphea

Hi!
I built for the second time a Zombie Chorus (sweet, btw... :): this time, the LFO seems to have a triangular shape instead of sinusoidal; I didn't have the tools to measure this, but I can clearly hear the difference between the two choruses; the first one is really pleasant and smooth in its oscillations, while the last one I built rises, reaches a peak and suddenly lowers again. I'm not @ home right now, so I cannot take measures on the ICs pins, but I'm hoping someone could however give me some hint on where to search for some mistakes.
Thanks

P.S.: if this could help, I remember I had the same (I think) issue when I wired wrong one of the two pots, but I can't remember which one... anyway, this time they seem to be wired correctly.

Mark Hammer

The Zombie HAS a triangular LFO output.  I don't know where you got sinusoidal from.

oldschoolanalog

#2
Quote from: Mark Hammer on October 02, 2012, 08:44:10 AM
The Zombie HAS a triangular LFO output.  I don't know where you got sinusoidal from.
+1
>... I'm hoping someone could however give me some hint on where to search for some mistakes.<
Look at the LFO section. First check that all the components/values are the same as the first build.
Then compare the V's of the 2 units for differences. Is the LFO high and low V the same?
If you have or have access to an o'scope you could see the differences.

Mystery lounge. No tables, chairs or waiters here. In fact, we're all quite alone.

lazerphea

Mark, Dave, thanks: you were right, I rememer wrong about the lfo... I don't know why, but I convinced myself the two choruses sounded different... the I recorded myself playing the same riff through the first and the second chorus, and I couldn't notice any difference... auditory hallucination? :)