Tri-vibe popping noise on bypass switch

[psychepool]

I seem to be asking you a series of questions with a popping noise.

Yesterday I made a Tri-vibe with a layout of 1590A size.
It works clean without any hiss or LFO noise.

But every time press the bypass footswitch, there is a lot of popping noise.
Both occur on / off.
All three toggle settings are similar.

I did not have a pull-down resistor on my layout, so I added an 1M pull-down resistor, but it was still there.
I used TL072 in U1. I replaced it with NE5532 but there's no change.

I've maden it with ROG layout about 8 years ago, but it's been a long time ago, so I do not know if there was a popping noise either.

Is it a circuit with popping noise originally?
Or is there another solution?
Or is it due to a tight layout?

Below is the layout I used. Give me advise please.

[jt]

Have you wired the foot switch so when in bypass it grounds the effect input?
if not then check the off board wiring in the link.
It really helps with popping noise.
http://effectslayouts.blogspot.gr/p/gen ... notes.html

[psychepool]

http://www.pedalparts.co.kr/shop/board/ ... %26div%3D0

Wired like this. Input is grounded when bypass.

[marshmellow]

It seems like you don't have a pulldown resistor in front of the input capacitor. Comparing with the original schematic, it isn't there as well. Just put a 1M from the cap to ground.

[psychepool]

It seems like you don't have a pulldown resistor in front of the input capacitor. Comparing with the original schematic, it isn't there as well. Just put a 1M from the cap to ground.

I'm already added 1M Pulldown resistor but there's no change.

[Zokk]

Hi
it is sometimes too difficult to solve this pop while still trying to use a classic 3PDT "true bypass" wiring.
I'd suggest this kind of bypass, few parts, and pop-free guarantee:
http://1776effects.com/wp-content/uploa ... on-BOM.pdf

Another great bypass option is the Millenium Bypass by RG Keen if you don't have opto's laying around.

cheers.

[psychepool]

Hi
it is sometimes too difficult to solve this pop while still trying to use a classic 3PDT "true bypass" wiring.
I'd suggest this kind of bypass, few parts, and pop-free guarantee:
http://1776effects.com/wp-content/uploa ... on-BOM.pdf

Another great bypass option is the Millenium Bypass by RG Keen if you don't have opto's laying around.

cheers.

Thanks for your good recommend. I would like to apply the bypass circuit of the 1776 effect, but I do not know if there is space inside because it is a 1590A case. But I want to consider it as the first priority.

I've heard a lot about Millennium Bypass, but this is the first time I've seen a schematic. However, when I look at the circuit diagram, I can not find a part where pop noise is prevented. Is it for remove the popping noise that caused by the LEDs? If so, it would not suit
for me. There was also pop noise in the test bypass box before put the board to the case

[Zokk]

The pop can occur for several reasons, not only because the indicator LED sucks too much current when engaged.
For example in your circuit you can check for a DC leak at the output, it's a quite comme source of huge pops too.
The ground wiring is also very important, sometimes a bad ground point or a ground loop will create strange problems oscillations, overconsumption, RF noise, and pops.
And sometimes it's just a crappy 3PDT which has bad contacts.

If you make a search in the forum there are plenty of topics about bypass and techniques, from the "vintage" style to µC controlled relay.
You'll find also tons of information about why there is a pop, and how to avoid this (the simple pulldown resistor is not so magic, even if sometimes it works).

Both the Millenium and the 1776 bypasses use a DPDT stompswitch, and the circuit itself is really tiny so it can be stuck on the side of the DPDT. It should not be bigger than a regular 3PDT at the end.
They both have the advantage to be keep the signal independant from the mechanical switch, and some versions of the Millenium do input grounding too ( http://www.geofex.com/Article_Folders/M ... l2plus.htm ).

Edit: you should add 100nF capacitors across the power pins of your ICs too. One cap per IC is ideal, no matter if they're ceramic of film.

[RedViper]

I've been using the true bypass scheme on the tagboard offboard wiring guide. That way of wiring is supposed to eliminate bypass popping without the use of a pulldown resistor. I think I read that in the comments section of the guide. I'm not expert though so maybe somebody else can chime in to verify that.

http://tagboardeffects.blogspot.com/201 ... iring.html