Please give me a hand with this ULTRA FLANGER......

[brokenstarguitar]

Hey guys, I need some help if yous don't mind giving me a hand. I've built an etched version of the Hollis Ultra Flanger from the Geofex layout ( http://www.geofex.com/pcb_layouts/layouts/ultrafln.pdf ) and it doesn't seem tobe doing anything at all.

The first one I built was the Sabrotone layout on vero and I had some issues with that one as well. Luckily I got alot of help from you guys and it ended up being the led pair/diode that controls the LFO/Rate, it wasn't reaching the specified 3.8v. So I thought that might be the problem here. I checked the output voltage and it was only reaching 3.1v with the specified 1N4730 so I put a (4.3v) 1N4731 zener in and it brought it up to 3.9v but I'm still getting nothing.

Here's some pictures of my build and my voltages. The Geofex layout can be found at the link above. Thanks guys!!!

Power Supply - 9.52v

U1 (LM358N)
1. 5.29
2. 5.32
3. 5.25
4. 0
5. 4.97
6. 5.04
7. 4.74
8. 9.52

U2 (MN3007)
1. 9.52
2. 4.74
3. 5.30
4. 0
5. 0
6. 4.73
7. 5.02
8. 5.02

U3 (CD4049UBE)
1. 9.48
2. 4.73
3. 4.74
4. 4.72
5. 4.74
6. 4.72
7. 4.72
8. 0
9. 4.73
10. 4.74
11. 4.73
12. 4.72
13. 0
14. 4.72
15. 4.74
16. 0

U4 (CD4046BE)
1. 0
2. 4.75
3. 4.73
4. 4.73
5. 0
6. 1.49
7. 1.47
8. 0
9. .63
10. .63
11. 0
12. 7.96
13. 0
14. 9.48
15. .60
16. 9.48

U5 (LM358N)
1. 3.6 - 4.2
2. 3.95
3. 3.71 - 4.10
4. 0
5. 3.95
6. 3.9
7. 3.78 - 3.82
8. 9.2

Diode 3 - 3.95

[GGBB]

You will need to go over your board and compare it to the layout carefully making sure all connections between components are good. I spotted 1 broken trace almost right away - bottom left at U4 pin 9 - at least it looks broken. And what happened to D3? If you've deliberately done these things or others, we would need to know those things in order to help troubleshoot.

[bloxstompboxes]

You will need to go over your board and compare it to the layout carefully making sure all connections between components are good. I spotted 1 broken trace almost right away - bottom left at U4 pin 9 - at least it looks broken. And what happened to D3? If you've deliberately done these things or others, we would need to know those things in order to help troubleshoot.

It looks to me like he had a bad etch and just went with it. Several pads on some of the ICs and maybe other places are missing and the leads bridged with solder. I have tried this before in the past and it usually causes more trouble then it's worth. If I had just made another board and chucked the other one, then it would have been a hole lot easier. I would check all your traces for continuity if you haven't already and make sure that all those missing pads/pins are jumpered or bridged to were they need to be.

[anotherjim]

Missing D3 doesn't look like a problem, it's got a Zener instead of the LED/Diode ladder for the LFO reference which is correct voltage.

U5 pins 1 & 7 are not showing the full voltage swing, but it may be the LFO rate was set too fast for the DMM to follow...
...make sure LFO rate is set slowest. You won't hear an obvious effect if the LFO isn't sweeping the delay time - you need to see it working. Also turn the depth controls up, you need to see the LFO voltage sweep on pin 9 of the 4046.

Ideally, an oscilloscope would be available when working on this type of effect, but at least an audio probe should be used, then you can tell where the signal is getting through and where it isn't.

All the voltages look about right. The 2 clock signals through the 4049 chip might be ok, because the DMM is showing the average voltage of the clock pulses (about half of supply volts), but unless you can check them on an oscilloscope or frequency counter, you'll only know they're correct when you hear flanging!

The BBD bias voltage set by TR3 cannot be pre-set exactly, you do have to make small adjustments either way until you get a good, clear signal passed through the BBD. You won't hear much if TR3 is too far off.

[brokenstarguitar]

You will need to go over your board and compare it to the layout carefully making sure all connections between components are good. I spotted 1 broken trace almost right away - bottom left at U4 pin 9 - at least it looks broken. And what happened to D3? If you've deliberately done these things or others, we would need to know those things in order to help troubleshoot.

Pin 9 on U4 wasn't soldered. You're correct. Somehow I missed that. Now, I have went over the board with my dmm checking for continuity and everything is as it should be. I removed the 2 led and diode for the lfo ladder and replaced with 2 wires to swap out zeners to get the correct 3.9v so that is why nothing is in the place of the leds and d3, that part is on my breadboard with the correct zener.


[/quote]

I would check all your traces for continuity if you haven't already and make sure that all those missing pads/pins are jumpered or bridged to were they need to be.
[/quote]

I've went over everything numerous times, even using a microscope looking for anything out of the ordinary.

The BBD bias voltage set by TR3 cannot be pre-set exactly, you do have to make small adjustments either way until you get a good, clear signal passed through the BBD. You won't hear much if TR3 is too far off.

How would I go about checking TR3 for the correct bias? I replaced the resistors as the build doc said to do if I wanted to implement it (maybe I shouldve done with it?) Could it have something to do with my pots? I did realize that a few (maybe 2 out of 25) showed no life after soldering to the circuit (not this build).

[anotherjim]

Correct bias for the BBD chip varies from device to device. The voltage given on the build document is a suggested starting point. It is a very small step in bias voltage between working and not working which is why a multi-turn trimmer pot is best for the job.

If your only way of testing is to hear the effect working at the effects output, you have the problem that you cannot clearly hear if the BBD is carrying a signal because the dry sound from the input is always present. What you can do is remove R12 which will stop the dry sound being heard, and what you can hear at the output is only whatever signal is coming from the BBD chip.

[brokenstarguitar]

I tested the pots and 3 of them were dead, I changed them and it's a lot different. It wants to flange, I can hear it trying when I turn the trimmers. The issue now is a high pitch whine. Does that mean it isn't biased correctly? This is sort of the same issue I had with the Sabrotone vero layout at first. Maybe it's the LFO? How do I check that? I now pin 9 of U4 should be oscillating but it isn't......HHMMMMMMMM

I did set TR3 so that pins 1,2, and 3 on U1 was at 4.9v.........

[anotherjim]

Whine may not be the circuits fault. It could be heterodyne noise created by interaction between the flangers clock and another , external, high frequency source. That could be noise picked up from lighting etc which might be solved when it's boxed up in a grounded enclosure. It could also be from a switched mode power supply - you should always use a standard transformer based power supply for this type of effect. It could also happen if you are plugging into an amp with a digital dsp in it.

The circuit has no protection against high frequency noise reaching the bbd which is the cause of heterodyne whine. With a well screened guitar and cables and good grounding from the amp, rf shouldn't get in. The popular Electro Harmonix Electric Mistress flanger didn't have any Rf protection either. However, you can add a modest amount of rf filtering by adding a 100pF to 220pF capacitor in parallel to R4 to create a low-pass filter. 150pF or 180pF are probably the best values if you have them. Similar action has helped cure Electric Mistress designs from whining.

I repeat my last post, if you need to make sure the BBD has best bias, disconnect the dry signal by lifting one end of R12 and adjust TR3 for the loudest and clearest signal. If that doesn't help, it probably isn't a bias problem.