psycho lfo assistance needed!

jacobian · Joined: Oct 14, 2008 Posts: 10 Location: san fran

Hi!

So I finished this module about a week ago and it seemed to work...i plugged it into a simple 4046 vco the results were, psychotic. Definitely not a standard lfo output.

However, last night after finishing the vcs, which works like a charm, the pyscho lfo seems to not work anymore. In the original build I added an led and last night it lights up like it normally did but when plugged into the same 4046 vco I get nothing. Any thoughts? I checked all the traces and don't see any solder blobs, so I'm a bit at a loss.

Also, can someone please describe how their pyscho lfo "sounds" just so I can compare to see if it really was working properly to begin with?

Thanks!

Adam-V · Posted: Wed Mar 24, 2010 3:53 pm Post subject:

Hi,

Just a couple of questions:

Is this the Psycho LFO or the Super Psycho LFO?
Do you have something other than the new VCO to plug the LFO into?
Where on the LFO circuit did you connect the LED?

Cheers,
Adam-V

jacobian · Joined: Oct 14, 2008 Posts: 10 Location: san fran

Hey Adam!

This is the psyscho lfo (non super)

have only tried it on the 4046. I tested a different lfo with the same 4046 which worked fine.

the led was connected with the positive terminal soldered to the signal banana jack, and the ground terminal soldered to the available ground pad.

thanks for the taking the time to respond!

andrewF · Posted: Wed Mar 24, 2010 7:46 pm Post subject:

Possibly the way you have connected the led is most likely the cause of your problem. It is fine if you just want a led, but won't work if you want led and an output signal. Basically all the current will go thru the led rather than into the input of your VCO.

have a look at Kens page for connecting a led to an output:
http://www.cgs.synth.net/modules/cgsld.html
this way the led is turned on/off by the output signal but draws its power from the power supply so the output signal is not affected.

have fun Very Happy

Adam-V · Posted: Thu Mar 25, 2010 3:33 pm Post subject:

I agree with what Andrew said. The LED will be loading the output. You will need an LED driver circuit connected to the output.

Cheers,
Adam-V

jacobian · Joined: Oct 14, 2008 Posts: 10 Location: san fran

hey guys,

I was really hoping the led was the problem, but apparently it's not. I disconnected it last night and still got the same non working results.

might it be the ferrite beads? it was my first time using them and perhaps I got the wrong ones. does the type of ferrite bead matter?

thanks for all the input regarding the lack of output.