Tonepad Flanger 301 troubles.

[jrc4558]

Hey people! This is my second topic about Flanger 301 from www.tonepad.com

I finished it today and got it working for about two seconds. It did a bit of this typical over-regenerated flanger swirl sound, and then left me with nothing but the clean sound through the effect, as if the delayed line wasn't even there at all. I checked traces and a capacitor that decouples the delayed signal when it is fed back into the mixing stage, they're fine. Audioprobing does nothing to help, because there's signal through the cirquit already. What would you recommend to check in this case? As I've mentioned in my previous posting, this is my first project of this complexity and with these chips, so I don't yet quite know what to look for...
Also, what voltages should I set the biasing trimmers to? Found no info so far...
Thanks in advance.

[Bill Bergman]

I usually tune trimmers by ear. Have you just twiddled them about to see if it bring the flanging back?

[Bill Bergman]

Also, maybe it's a cap problem since it was there for a couple second be for quiting.

or your sweep is so wide it takes a minite or so to come back :shock: ...sorry

[jrc4558]

One other thing is I couldn't find any TL022, so I used TL062, even in the LFO. Is there a crucial difference between the two for the purpose?

[dj_death]

I have built this flanger and it sounds very well. First adjust all potensiometers at maximum position and adjust the clock trimmer and regeneration trimmer at the middle position. Then adjust the bias trimmer until you hear the effect. Then adjust clock and regeneration trimmers for the best effect. If you don't set the bias trimmer properly you will hear only the clear signal. As for the opamps TL062 work very well in this circuit.  In my flanger all of the opamps are TL062. Good Luck!

John

[jrc4558]

That is probably the reason. Because I went through the whole thing with a multimeter today and there are NO shorts in it, thank god... Will resume tomorrow. Thanks for the input! Eu haristo!

[Joep]

maybe a silly suggestion, but did you noticed it works on 18V? It wouldn't work on 9V.

[Bill Bergman]

Actually at 9vdc it works, but gives a sick warbley sound. Also you can get an almost slapback/echo reverb sound with the knobs set right. This is just a novelty not really the way the pedal should be used.

[jrc4558]

Still no effect. I tried adjusting the trimmer for bias and nothings happening. What other rasons could there be? Also, what's a usual voltage range that a BBD likes to see for bias?
Will try again tonight.
Thank you!

[dj_death]

Gia su, Constantin

Check the voltages of the ics. There should be 12V at pin 8 of IC105,IC101,IC102(tonepad layout) and pin 1 of MN3101, MN3007. The bias voltage in my pedal is about 6V. Check the orientation of the ics and the pinouts of the transistors (What did you use?). Check the orientation of the 78L12. And as i told you before make sure the Width pot is set to max position or you will hear a clean signal. Check the wiring of the pots i usually wire them at opposite positions and when they are turned at the maximum right position, they are at minimum position. This mistake has abused me lot of times. Also if you set the regeneration and speed pots to max you will hear a stronger effect, in case it works and you don't here the effect by mistake.

John