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Hi, gang!
For this post, I present a mystery! I have a fully populated FX PCB w/ connected pots that I would like to identify. The only marking is JCW (or perhaps JCW II), and 1983. As you can see in the pictures, the board features a couple NE5532 dual op-amps. I think the two nice sealed pots (both 10K-S, 1/8" shaft) might be original, but the two dual 100K pots probably aren't. I seem to remember Radio-Shack selling that exact same dual 100K (41-step detent, 40% tap). Let me know what you think, and thanks in advance for your help!
Tony

Hi Tony

I am starting this PCB clone.
Please could you fill in the missing component values?

I believe those components you have marked as a diodes are actually axial ceramic capacitors in a glass housing. I have a few different values and they look just like the ones in the photos here. They are actually SMD parts in hermetically sealed glass.... Could be wrong, but that's what it looks like to me...

Lani wrote: ↑14 May 2023, 02:56 I believe those components you have marked as a diodes are actually axial ceramic capacitors in a glass housing. I have a few different values and they look just like the ones in the photos here. They are actually SMD parts in hermetically sealed glass.... Could be wrong, but that's what it looks like to me...

Thanks Lani for the hint.

Tony, can you find out using an ohmmeter with diode test function?

No problem man.... Have a look here,
https://theelectronicgoldmine.com/colle ... ts/g23938a
I'm pretty sure that's what they are the more I look at it. I can't make out the number, but it's there so Tony should be able to identify them for ya once he gets around to it. Any idea what it is?

Lani wrote: ↑14 May 2023, 03:44 No problem man.... Have a look here,
https://theelectronicgoldmine.com/colle ... ts/g23938a
I'm pretty sure that's what they are the more I look at it. I can't make out the number, but it's there so Tony should be able to identify them for ya once he gets around to it. Any idea what it is?

Great, you never stop learning.
I have never seen this type of capacitor in more than 50 years of electronics practice.

I gave identifiers to the components as well as the potentiometer and wire connections and finished the layout.
Please check the values and fill in the missing ones.
Next I will draw the circuit structure.
Template for entering the values:

EDIT: Potentiometer connection designators corrected.

Corrected layout, one Capacitor was missing, right next to IC1.

This is the circuit structure I found by tracing.
I guess that this is a filter circuit.

Man, you guys are ON it! I was just expecting somebody to go, "Yeah, it's a blah-blah-blah." Here are some more detailed pics...

Thanks for the shots I will continue with entering the values in layout and schematic.

Here is the layout and the schematic with the added values.
The printed values of C3 and C6 are not to interpret for me, but these are not important for the function.
These are only high frequency interference suppression capacitors for the supply voltages.
At C10 the imprint is scratched away.
Could you please measure the value of R3 with an ohmmeter?
Next, I will do a simulation of the circuit to figure out the function.

Nice co-op guys. This is the way to live!
I can agree with a Filter effect. No pot on FB loop so fixed gain for every op-amp (I guess R3 is 10k).
P4 seems a Mix
P2/P3 signal regulation of two sources of P4
P1 seems a general FB loop dependant on P3

R3 measures 4.8K ohms. I will unsolder C10 and measure its value...

C10 measured 100nF. C3 and C6 had more markings on the side we couldn't see: .10 and 50-V (C3 actually measured 84nF, but they are both probably meant to be 100nF).

Okay, it's done.
Here are all the completed and corrected documents.
Ready-to-print PDF files: Sprint-Layout6.0 file: Gerber & drill files:

The circuitry round P3a&b is a wein bridge but everything round that seems backwards, with my understanding at least Does this work at all?

TWSpedals wrote: ↑28 May 2023, 23:09 The circuitry round P3a&b is a wein bridge but everything round that seems backwards, with my understanding at least Does this work at all?

Yes, it works.
I ran a circuit simulation, first with all potentiometers set to center position.
I will run more simulations with different potentiometer settings.