What causes voltage drop?

[dexxyy]

I've built Harald's  version of the John Hollis ultra flanger, I'm getting clean signal but it flanges if I manually turn the sweep pot. I've quadruple checked placements and values, knifed all the tracks, when I checked the ic voltages they where looking a bit low. I checked Vin and I'm only getting 6.45V, which means Vout is only 3.5V when it should be about 4.9V. Could the lack of voltage be causing it not to flange? And what could be causing it? I'm thinking grounding issue, but everything is connected to ground that should be and there's nothing connected to ground that shouldn't. The circuit uses a cd4049 but I can't  find any info on wether it matters if it's a buffered or unbuffered chip, I'm using unbuffered as its all I have. Any ideas guys?

[Vince]

I've seen people using voltage sag boxes on modulation pedals to slow them down or lessen the effects so It sounds like that could be playing a part. There are plenty better informed than me though so that's just my pennies worth.

[induction]

What are you using for power?  Battery, regulated adapter, unregulated adapter?

[induction]

After a little digging I've found a couple of things.

1. The 4049 should be unbuffered (as far as I can tell, anyway), so you should be fine there.

2. The Sabro layout sends Regen 3 to Vref, when it should go to ground. The mistake was on Hollis own schematic, which was eventually revised. This should be easy to fix, but I don't know if it will solve the problem.

3. You really need to get 4.9V at Vref.  You need a stable 9V for V+, so if your power source is sagging you need to try a different one and see if that helps.

Here is some good information you might want to look at.

Good luck. Let us know if you need more help or if you get it sorted.