[sdiy] Dry/Wet effect relay that makes 'click' noise on changes...

[Simon Brouwer]

Hi,
 
Some things I would try...
 
* connecting a 10k resistor between the input and the output, it will prevent
the output to be floating during transition of the relay contact. As the output
of the effect section is low impedance, it will not significantly affect the
effect :)
* checking the routing of the ground between Q1 and the power supply. It should
go there without sharing any ground traces or planes associated with audio.
 
Using a smaller relay (because less coil current will flow) is definitely a good
idea but I doubt it will completely fix the problem.
 
Best regards
Simon
 
 
 

> Op 10 januari 2016 om 2:17 schreef jpdesroc <jpdesroc at oricom.ca>:
>
>
> Hi everybody,
>
> I just finished my DIY Hammond Vibrato/Chorus effect for guitar this
> week
> and am pretty happy with the final effect it gives to my old
> stratocaster.
> 3 vibrato, 3 chorus effects, very impressive !
> BUT I'm facing a last problem on this project..
> It uses a PANASONIC JQ1P-12 SPDT relay (K1) to switch
> the signal from clean to effect, but every time I switch
> the relay to change its state a big 'click' is heard in the audio
> output.
> I used that relay because I had some on hand to be used.
> I checked for any DC voltage on all of its contacts but there are not.
> All the contacts are at zero volt stable.. no DC.
> I noticed at the scope that its contacts are bouncing a lot on all state
> changes
> and that is what makes that noise.
> Maybe its because this type of relay is rated @ 10amp on its contacts.
> A too big coil 'snap' on the contacts ?
> I'm considering to change the type of relay for a quieter one.
> Maybe a small reed relay would do instead..
> Please have a look at the following schematic where the relay is used:
>
> http://www.arcenson.com/public/Hammond_scanner_main_board_schematic.pdf
>
> This is part of the overall project.
> I need your suggestion on a good silent SPDT relay working at 12VDC.
> Thanks.
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