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This is a huge board, let's divide an conquer.
- First, check if everything is correctly grounded, i.e. offboard parts connect to the board ground. That is always my first mistake.

- Check if you get stable voltage readings without the ICs: Are you using a 18V PS or a 9V and a voltage doubler?

- No sound when engaged means you also don't have the clean path working (NE5532, IC1 and 4558, IC2).
Get this part working first.
It would be helpful if you post the voltages at the IC pins, with IC2 and IC1 in their sockets and write them down here. If you can, make an excel table, so you can check changes.

- If it works and voltages are OK, let's move to the tricky part, the BBD circuitry.
With the Reg on 0, Manual, Rate and width about halfway:
1- Add the LFO (IC5) and check voltages. Pins 1 and 7 should oscillate. Write voltages down here
2- Add IC6 (pin 7 should vary when you adjust the Manual control). Write voltages down
3- Add IC7 (4013). Pin 1 and 2 should have a high frequency clock signal. On the multimeter it looks like 1/2 of the supply.
4- Add IC8 (4049). Check voltage at pins 12 and 2. Again, stronger clock signal
5- Add the BBD chip and read voltages, write them down. If you have an audio probe, check if there is signal at pin3 (input ) and pin 7 (output). I once had a fake MN3007 that had weird voltage readings and no signal output
6- Add IC4 (4558). It just adjust and filters the signal after the BBD.

You can check if the ICs have voltage at the supply pin. If one IC affects the voltage after the regulator, you may have a problem around it.

Are those regular size jacks?

Yes, they barely fit. I made the holes a little larger so I could still move them a little bit, while checking the position.

So,
finally finished this one!
First: Added input/output jack and 2PDT switch, then added the LED and the board with potentiometers.
I ran into trouble here.
- I only had the larger jacks, instead of the Lumberg one (KLMB 3) had to sand it a little so that they would fit.
- The LED needs to connect to the second board. It would have been easier if the millenium bypass was on the first board (with the jacks)
- Had to cut some space for the jacks on the board. Fortunately, as you can see by the copper planes, there was nothing on the edges of the board. I also cut a piece of the ground plane where the 9V jack is positioned.

Second board in place, only needed to solder the LED wires, the millenium bypass switch and the inlet, that was fast!

With the lid in place

Front

Would the header sockets and pins you get for things like Arduino be too tall for what you need?  (I tend to use them for stuff, I can do some measurements if you need)

That depends on the type of sockets. I got some, but my pins aren't rounded, and won't fit in it. Next time I am going to buy the proper pair.

Hi,
this time I tried something different inspired by some builds where two boards are used,
one for the pots and one for the rest of the circuit.
To start with something easier and with less components, I made a layout for the rat:



I still have to fit it in the box, but so far it works.
Some things that I still want to improve:
- Mirror the board with potentiometers. The copper layer got loose in some points while soldering the connectors

- Better/Single connectors. I cut mine from connector bars, but as you can see, the plastic is gone.
I will have to find some kind of single connector, or move them around, so that there are more connectors together. 

I saw some people use IC sockets, but in this case a certain distance is necessary to fit the power jack, and the sockets are too short.
Any suggestions?

Cheers,
Thomas

Posted by: danfrank
« on: June 25, 2022, 12:07:48 PM »Insert Quote
I like Scruffie's gain setting instructions from Lectric FX...
Basically,  inject a 1kHz audio signal into the input of your total recall and measure it's amplitude before clipping (in millivolts). Now measure the amplitude of the signal at pin 7 of the compander and adjust "gain 1" to get it as close to the input amplitude. I was never able to get it equall to input amplitude but I can get it close...
Next, take amplitude measurement of pin 15 of the compander and use "gain 2" to adjust so it's equal to input amplitude. You should be able to get it exact.
Doing this, I find that the feedback control has a lot of useful range.
Hope this helps...

Where exactly can I find this Info? Without knowing the setting of the potentiometers it's more difficult to compare to other procedures...
Gain 1 is between BBDs, after the compander. Do you mean Level?

Nicely done! The reversed etch looks good!

very nice!

Now I need a picture of the fix, otherwise it will haunt me in my dreams every time I buy online.

Resistor sounds right.
Is the noise only on one side of C6?
Could it be the capacitor?
I though the green caps are kind of inductive, and try to avoid using them, but it could be just misinformation...

Omg, just came by to praise the wiring.
The plexi lid is a must with such an organized interior

Nice, I also like my builds in layers.
The 3D printed part is a nice touch
Using the lid also helps to get a better view, have to try that one at least once.

Do you think it changes with the speed knob, and could be associated with the LFO?
Or is it more like delay feedback oscillation?

The first case would be leaking LFO. But that would be weird, since it should be there when you remove the BBD.

The second case would be a short somewhere in the wet line to the input or a specific position of the input.
What is weird, is that it should be really fast. Maybe the LFO changes that.

My next suggestion would be AC grounding some places through a cap (anything between 100n to 100 uF, one leg to the signal path, the other to ground). Start from the mixer stage and go towards the BBD. It will short the wet signal and at some point there should be no noise left.

If you are lucky, it is in the region where the signal is shorted to the input. Otherwise, you just cut to much of the signal.

Ok, that changes things a bit.

Distortion can be a result of wrong bias somewhere. Probably at the input of the BBD.

My suggestion would be analysing parts of the circuit:
First, remove the mix resistors (If the MN3207 is socketed removing it will break the signal chain there, and no desoldering is necessary).

Let's hear how it sounds without chorus at all (just the clean sound). If there is something wrong with an OpAmp it should be noticiable.

Second, there should be no distortion (when using the audio probe) until you get to the input of the BBD. Chorus do not have feedback, so there should be nothing returning to the begining of the signal chain.

Third would be to remove everything associated with the BBD (clock, BBD, LFO(TL062)) and see if the clean signal works now.

That should give an idea where the Problem is.

Well, that might be a cold solder joint at some ground in the circuit. Every time I have buzz it's either a bad cable or wiring problem.
Your wiring looks exactly like the one in the PDF, but It could present some lose or cold joints.

How are you using the audio probe? Are grounds connected? There should be no noise at R1.
Noise at R1 means noise at the input jack. Any weird noise caused by the circuit should not be present at the input, unless there is a problem with grounding.

Does it work when bypassed? Or is the noise bleeding through even when bypassed?
Can you check continuity between some ground points and some components? For example, one side of R1 should be grounded.

Which build doc are you using? I have the 2019 one, and voltages seem correct for the MN3007.
Voltages on IC2 depend on the type of BBD that you used, though.
Unfortunately, the image is too dark to identify your IC2. Voltages suggest a **3207. Are you using the correct clock (3102)?

Have you tried checking the signal path with an audio probe?