Quiet switching

[nickbungus]

hi guys.  Haven't posted anything for ages.

I've always used true bypass switching but recently made a pedal for a friend but the switching is dead noisy.  There's a real thump when engaging/ disengaging.

I tried the millennium bypass 2 circuit from tagboard effects website and still had noise.

Anyone recommend any alternatives? Fewest parts and less noise would be ideal.

[antonis]

Any pedal schematic availiable..?? 

[nickbungus]

Just a fOXX phaser

[nickbungus]

And heres the Millenium Bypass 2 switching I tried

[antonis]

Millenium bypass is used for utilizing 2PDT switches with indicator led..

Wire your 3PDT switch for IN + OUT grounded when bypassed..
(with LED anti-pop also.. just in case..)

[amz-fx]

There is a dc path from pin 13 of Z2 to the output, so the output is going to have a dc bias of up to 1.8v

Since the input will be close to 0vdc bias, the pedal will make a thump when the switch is toggled as the dc rapidly alternates between 0v and 1v+

This pedal could also make other pedals down the chain thump because of the dc it is injecting into the signal path.

You could add a capacitor between the Q control and the output, and probably a pull-down resistor on the output since you are making it true bypass.

regards, Jack

[idy]

I don't see a pulldown on the input.

[nickbungus]

There is a dc path from pin 13 of Z2 to the output, so the output is going to have a dc bias of up to 1.8v

Since the input will be close to 0vdc bias, the pedal will make a thump when the switch is toggled as the dc rapidly alternates between 0v and 1v+

This pedal could also make other pedals down the chain thump because of the dc it is injecting into the signal path.

You could add a capacitor between the Q control and the output, and probably a pull-down resistor on the output since you are making it true bypass.

regards, Jack

Sorry - I should have noted I add a 100nf in the feedback loop to stop this

[nickbungus]

I don't see a pulldown on the input.

Should have said I do this too.  Usually add a 1M or 2M2.  I'm sorry

[amz-fx]

Sorry - I should have noted I add a 100nf in the feedback loop to stop this

6 Reasons Guitar Pedals Pop When Switched: http://www.muzique.com/lab/pop.htm

regards, Jack

[nickbungus]

Millenium bypass is used for utilizing 2PDT switches with indicator led..

Wire your 3PDT switch for IN + OUT grounded when bypassed..
(with LED anti-pop also.. just in case..)

I will give this a shot!

[deadastronaut]

that was taken from jacks site above.....thanks jack . 

[Rob Strand]

will give this a shot!

The problem is the circuit not the switching.  Replies #5 & #6 cover both issues.
You need to mod the circuit.
- 2m2 resistor from ckt input to gnd
- Add cap in series with R2 or R7.  Then say 10k to 100k to ground on output; IIRC lower the better for millenium.

[R.G.]

And then there's the whole series or articles on quiet, effective pedal switching at geofex.com.
Just sayin'   

[nickbungus]

will give this a shot!

The problem is the circuit not the switching.  Replies #5 & #6 cover both issues.
You need to mod the circuit.
- 2m2 resistor from ckt input to gnd
- Add cap in series with R2 or R7.  Then say 10k to 100k to ground on output; IIRC lower the better for millenium.

Thanks Rob

Sorry, I just put the original schematic on but I always implement these 2 points.  Haven't tried a 10k to 100k to ground on the output though.

[amptramp]

There is a thread here:

https://www.diystompboxes.com/smfforum/index.php?topic=120006.msg1122294#msg1122294

that has suggestions for noiseless switching that do not appear anywhere else.  This takes you to one post but the entire thread is about the same topic.

[Rob Strand]

Sorry, I just put the original schematic on but I always implement these 2 points.  Haven't tried a 10k to 100k to ground on the output though.

If you can easily tell the difference between 10k and 100k I'd be thinking the JFET on the millenium is leaking.  For a mechanical switch the 100k should be enough.