RING FROBNOBICATOR QUESTION is this working?

[slotbot]

Hi.

I recently perf boarded a frobnobicator by John Hollis. I am not sure if it is working correctly. I have a few questions....

1. There is always and output even when there is no input. im not sure if this is supposed to be liek this.

2. I could only find a ca3080E by RCA not a CA3080A is there abig deffernce? (if there is does anyone have some ca308a's i could buy?)

3. The TRIM control dosnt seem to do much. It says on the schematic "adjust for minnimum breakthrough" breakthrough of what?

im hearing 2 signals when i play. the synthesized signal from teh 062 that can be adjusted with the FREQ and DEPTH control (both of which seem to work fine) and a sound simalr but not exactly the original tone being fed into it.

ANY HELP IS MUCH APPRECIATED!!!

Also any suggestios on more synth / distortion type pedals i could make would be appreciated. And i HAVE already built the ugly face.

scott.

[brett]

1. There is always and output even when there is no input. im not sure if this is supposed to be liek this.

2. I could only find a ca3080E by RCA not a CA3080A is there abig deffernce? (if there is does anyone have some ca308a's i could buy?)

3. The TRIM control dosnt seem to do much. It says on the schematic "adjust for minnimum breakthrough" breakthrough of what?

1. The output is the modulation signal.  Likewise, I found that I couldn't trim it out.  I *think* there's a big resistor to the wiper of the trimpot.  Reduce that, or use a larger value trimpot and you're laughing.
2.  CA3080E is the correct part
3. See 1, above.

PS you'll only be able to get down to a certain level of modulation signal in the output.  For a *slightly* better modulator, try the modulatron at my website.

have fun

[slotbot]

I upped the trim to 1 Meg. Seems to work fine now. And you are right you cant get rid of the signal entirely but you can get pretty close. Also i will check out yor ring mod after i box this one up.

THANKS FOR THE HELP!

As a side note, on your site theres a White Noise genereator. Is white noise that staticy hiss? or what sort of sound is white noise?


scott.

[brett]

No worries about the help.  Crikey, I've had heaps from the forum.

Is white noise that staticy hiss?

Yes.  It's useful for checking the operation of filters, etc, because it contains a wide range of frequencies.  You can also get it by tuning a radio in between the stations.

cheers