Eliminating the Pops

[Means2nEnd]

Gentleman I didn’t find a clear cut answer in the search. I have recently done some Duncan preamp installs and separated the contour slap from the push pull on the volume and added an active/preamp bypass switch. I do have the cavity shielded with copper foil and wired correctly and grounded correctly.

My issue is the active/bypass switch the first time you switch either way there is a loud pop I can’t seem to get rid of. I know how to add two resistors on a push pull mid knob but this has me perplexed. Anyone know what to do…?

[Stealth]

Is the A/P switch wired like this?



If it's not, it should be - this is the proper way that grounds the input and floats the output when you're in passive mode, so the preamp shouldn't receive any switching transients.

[Means2nEnd]

No it isn't I will try that thank you!

This is what I used below..

[Means2nEnd]

Hey Stealth do you have a better way for doing a 3 or 2 way mid shift switch that will hep with grounding? I am using the diagrams from the Aguilar site. I don't have an issue but wondered what or how you do it. Seems you got it.

[Stealth]

What you used has a big flaw - the preamp input is left floating ungrounded and that's the source of the pop.

As far as the mid-shift switch, I have no idea as I'd never used an Aguilar preamp (I'm guessing you have an OBP-3). However, the mid switch impacts the preamp internally and has no connection to the ground.
Personally, I'd go with a push-pull on the mid knob just for the sake of having a smaller footprint (fewer separate controls).

[Means2nEnd]

Thank you Stealth

[walterw]

Originally Posted by Stealth

What you used has a big flaw - the preamp input is left floating ungrounded and that's the source of the pop.

stealth beat me to it!

these are both "true bypass" schemes, but the one he posted is what you want, the newer method.

the exact same thing applies to effects pedals, where the "old" wiring can cause pops and even allow the effects circuit to oscillate or otherwise induce noise while bypassed.

[Means2nEnd]

This was awesome you guys really helped me the bass is killing thanks to you guys and TB!