Questions about Intelligent Relay DPDT module

[Jacco32]

Hi all,

I bought a kit from Musikding. Soldered everything and I think it works properly. The LED clearly indicates the different modes. I connected the soldered PCB to a breadboard with an Envelope Filter Effect on it. When switching the effect on and off I hear a pop sound. Everything else works properly. I bought this module specifically to be able to switch it on and off silently so I doubt if I did something wrong.

IN = guitar tip
+ = +9V Boss PSA 230S Power Supply

IN = board in
GND = not used
SW = cathode 3mm LED --> 390R --> +9V
OUT = board out

- = GND Boss PSA 230S Power Supply
OUT amp tip

Guitar and amp sleeve are connected to GND.
Breadboard circuit is also connected to the same Power Supply as the module. When I connect the Board in wire and Board out wire directly to each other (so without EF effect) the pop is less but it is still not 100% silent. Leaving the LED out of the schematic has little effect.

- Am I doing something wrong or is it supposed to be that this is not 100% silent?
- Is it correct that the circuit and the module can use the same +9V connection?

Thanks!

Jacco32

 

[Robert]

You should be able to switch relatively silently but since there is no form of muting built into the relay module that is going to depend on the circuits being used and the wiring scheme.

You should be able to power the relay modules and effect from the same +9V connection, but if noise is induced between them you might try decoupling them by connecting each PCB to the DC jack with a low value resistor instead of wire. (10 - 100R)

 

[Jacco32]

Now that's what I call a quick response! Thanks Robert!

- Is there a way I can add that muting option to the existing PCB? Or is that too complicated?
- Is this what you mean by the R between PCBs and DC jack? I guess I can leave the 220uF out from the image below while there is already a 100uF used?

I also noticed that the pop sound gets worse when the string vibrates. In other words, when the amplitude of the wave has to go to zero during switching. I read an article about that somewhere too, although I can't remember where. But even when I keep the strings are muted, the pop is still present.

Maybe using a breadboard causes noise? I'll see if I can test it in an enclosure with another PCB.

Jacco32