DOD - 230 ( Noise Gate )

floris · Post by **floris** » 05 Apr 2014, 09:05

shalebridge wrote:I haven't built this one yet, but I already know I don't need the switch. How would I leave it out without screwing with the rest of the circuit?

Just leave it out and use a regular true bypass.

tarbush · Post by **tarbush** » 14 Feb 2022, 18:28

I've got this DOD 230 that was disassembled by someone else. I'd like to put it back together. I'm an amateur and not exactly certain how to rewire it. The schematic I found online doesn't seem to match, so I'm going to try to create a schematic in order to deduce the interface points on the board. I know i need to get a pot. Does anyone have any insight into what the transformer is doing and where the wires from it go? Red wire on left is not attached, but I assume it was attached on the lower left. I assume on of the red wires goes to the 9v+. Thinking audio in may be on the lower right of the board. Also, anyone have any idea of the age of this pedal? Thanks.

Manfred · Post by **Manfred** » 14 Feb 2022, 18:44

I will make a PCB clone to trace the circuit. The imprint on the 14-pin IC is hard to read,
the values of the blue electrolytic capacitor and the blue diode are not visible. Can you tell me the IC type and the two values.

tarbush · Post by **tarbush** » 14 Feb 2022, 19:11

IC - CD4066BCN
cap - 2.2uf
diode - looks like it says 751.

Thanks.

ppluis0 · Post by **ppluis0** » 14 Feb 2022, 19:56

1N751 is a 5.1V 400mW zener

Manfred · Post by **Manfred** » 14 Feb 2022, 23:25

tarbush wrote: ↑14 Feb 2022, 19:11 IC - CD4066BCN
cap - 2.2uf
diode - looks like it says 751.

Thanks.

Thank you, I forgot to ask for the board size, the dimensions would be helpful for me.

tarbush · Post by **tarbush** » 15 Feb 2022, 03:39

Manfred wrote: ↑14 Feb 2022, 23:25
tarbush wrote: ↑14 Feb 2022, 19:11 IC - CD4066BCN
cap - 2.2uf
diode - looks like it says 751.

Thanks.
Thank you, I forgot to ask for the board size, the dimensions would be helpful for me.

5.5cm x 5.5cm

Thanks.

Manfred · Post by **Manfred** » 17 Feb 2022, 01:55

The PCB layout is in progress.
The resistor and transistor cover the traces, can you please check the traces between the IC connections and the transformer and draw in the missing ones.
BTW the one lead of the diode is not soldered.

: DOD 230 PCB Solder Side.jpg (100.21 KiB) Viewed 2365 times

tarbush · Post by **tarbush** » 17 Feb 2022, 20:17

Manfred wrote: ↑17 Feb 2022, 01:55 The PCB layout is in progress.
The resistor and transistor cover the traces, can you please check the traces between the IC connections and the transformer and draw in the missing ones.
BTW the one lead of the diode is not soldered.
DOD230 Layout.JPG
DOD 230 PCB Solder Side Detail.jpg
DOD 230 PCB Solder Side.jpg

I think I got it right. I added a couple additional closeup pictures.

I did see the missing solder joint.

Thanks.

Manfred · Post by **Manfred** » 17 Feb 2022, 21:14

Thanks for adding the pictures and drawing in the missing conductor.
please check the component values I have entered.
Next, I will start tracking the circuit.
I already see some confusing things about the power supply, I am curious.

storyboardist · Post by **storyboardist** » 18 Feb 2022, 00:05

Had a go at the schematic based off Manfred's pcb recreation. That 510k has me scratching my head a little...

Manfred · Post by **Manfred** » 18 Feb 2022, 09:58

Had a go at the schematic based off Manfred's pcb recreation. That 510k has me scratching my head a little...

Thank you for taking some work off my hands.
R9, R10 and R11 are the reference voltages for the comparator IC1_A, which changes with the state of the output voltages at pin 1.
To get clarity I will recalculate the comparator circuit and also run a circuit simulation.

Manfred · Post by **Manfred** » 20 Feb 2022, 00:09

storyboardist wrote: ↑18 Feb 2022, 00:05 Had a go at the schematic based off Manfred's pcb recreation. That 510k has me scratching my head a little...

I recalculated the comparator circuit and ran a circuit simulation, with and without the 510k resistor.
The voltage at the comparator output pin 1 is 7.76 volts when the voltage at the comparator input pin 2 is less than the reference voltage at pin 3 and 0.32 volts when the voltage at the comparator input pin 2 is greater than the reference voltage at pin 3.
The 510k resistor obviously shifts the switching points only slightly so that it could be omitted.
This would have to be tested in practice.

Manfred · Post by **Manfred** » 21 Feb 2022, 07:40

The value of C3 is 50nF not 5nF.

storyboardist · Post by **storyboardist** » 21 Feb 2022, 19:31

Fixed.

tarbush · Post by **tarbush** » 23 Feb 2022, 22:01

Sorry for the delay. Values seem correct to me. So, based upon the schematic, is this correct? 2 & 3 go to their respective xlr pins. Would pin 1 on the xlr go to the unlabeled interface point in the diagram? Thanks.

Manfred · Post by **Manfred** » 24 Feb 2022, 00:13

Sorry for the delay. Values seem correct to me. So, based upon the schematic, is this correct? 2 & 3 go to their respective xlr pins. Would pin 1 on the xlr go to the unlabeled interface point in the diagram? Thanks.

Is the value of the threshold potentiometer known?

tarbush · Post by **tarbush** » 24 Feb 2022, 00:54

Manfred wrote: ↑24 Feb 2022, 00:13
Sorry for the delay. Values seem correct to me. So, based upon the schematic, is this correct? 2 & 3 go to their respective xlr pins. Would pin 1 on the xlr go to the unlabeled interface point in the diagram? Thanks.
Is the value of the threshold potentiometer known?

Unfortunately, I don't have the pot. Was thinking it might be 500k but not certain.

Fender3D · Post by **Fender3D** » 24 Feb 2022, 12:06

sorry guys I don't get the purpose of injecting DC to output...
And again isn't output level too much high when you crank treshold pot? It's the same gain in MXR D+ or DOD 250 distortion, furthermore won't D1 and D2 clip signal?

Scruffie · Post by **Scruffie** » 24 Feb 2022, 12:38

Fender3D wrote: ↑24 Feb 2022, 12:06 sorry guys I don't get the purpose of injecting DC to output...
And again isn't output level too much high when you crank treshold pot? It's the same gain in MXR D+ or DOD 250 distortion, furthermore won't D1 and D2 clip signal?

That's the envelope section, seems the audio is dealt with passively and the output is pin 2 of the 4066.