DuoVibe

[VanDerchuck]

I'm not sure where this should be posted. The Duovibe isn't a current project or an old project and I don't think it's an extra project either. But I think the origins are from this forum. So here it goes.

I'm wondering if someone can help me. I've built one from the Effectslayout blog on perf board. My signal passes through fine. But it doesn't vibe at all. The led lights and if I touch the led with a jumper to the positive 9v it warbles like it's supposed to.

Now, I know. I should post a big picture of the perf board if I really want help. But what I really want is to know how the LFO works so I can better understand where my mistake can be found.

I've looked at the LFO on the Tremulus Lune because it's very similar and there are a lot of of posts on other forums about it. But I haven't found a good explanation as to how it works.

One thing I've noticed is that my voltages are not similar and I'm not sure if they'd be much different. In the Lune the second side of the opamp voltages are much lower. Should the DuoVibe LFO voltages also be lower for the second stage?

I've tried new pots, and new caps in the LFO. I've looked for bridges and missed solder joints. The mistake isn't obvious.

Here are my voltages;

1. 7.6v
2. 7.6v
3. 7.8v
4. Ground
5. 8.25v
6. 8.14v
7. 8.54v
8. 8.6v

I've attached a copy of the LFO schematic and a copy of the layout for reference.

The layout uses the second side of the opamp in the first stage of the LFO.

Thank you for any help.

Jacob

[VanDerchuck]

Well, anyway. C10 was bad. I found the voltages should be everywhere after bread boarding the LFO. They're only stationary if it isn't working right.

[culturejam]

Don't forget to add a 10n cap to R3 as described in the updated build document: http://www.madbeanpedals.com/forum/index.php?topic=23669.msg231843#msg231843