Acoustic Pop stop

[Drumennut]

I am fairly new to pedal building and still learning, I have about 10 pedals under my belt and am learning as I go.  I am having a problem with my acoustic pedal board, My signal chain is Polytune, Reverb, Echo base, Tap Tempo Tremolo, ART Tube preamp.  Since my acoustic has an active pickup I get quite a loud pop when I engage my tuner or other True bypass pedals.  To solve this problem I found that by putting a Boss metal zone in front of the chain it almost eliminates the pop.  I assume this is because the Boss is a buffered pedal?  Since I don't really want to run my acoustic through a Distortion pedal I was hoping to get this off of my board.  Is there a good buffer I can build that would simulate what the Boss does? Can I just build a buffer pedal, no effect, is this possible?  or Is there a better solution?

Thanks,

Mike   

[Mike Burgundy]

Sounds like your experiencing DC offset. It shouldn't do that, although for some reason unknown (to me) this seems to happen sometimes with active acoustics - my double bass suffers from the same problem. Haven't chased it down yet, guess I'm lazy ;P
Your signal (say 1V peak-peak)swings around "0" - "0" as a DC level being equal to the voltage level at Ground. Signal goes from -1V to +1V. If there is an offset, your signal is swinging around (for example) 0.5V, so signal goes from -0.5V to 1.5V. No signal =0.5V DC.
What happens with that DC offset  is when you switch a TB pedal (the Poly is MOSFET/CMOS switched true bypass), the DC level is suddenly yanked from one voltage (0.5) to another (0) - for the electronics this is the same as an audio spike, and so you'll hear it. Buffered pedals work around this, but that still leaves you with a DC offset that shouldn't be there. Sometimes you can measure it (with a DMM with very high impedance - if too low measuring will bleed away the charge and it seems like there's nothing there). Most of the time it's a process of elimination - see if you can figure out where the offset is coming from, next install a (temporary) pull-down resistor to see if that helps. Replace the output cap and/or input cap, etc. Keep in mind it can be the guitar, a pedal, even the amp intoducing the offset!

So, a buffer *between whatever introduces the offset and the rest* will work, but is a band-aid. The real solution is finding the cause and fixing that.

[Drumennut]

Thank you for the reply.  I give it a go and see if I can find the source of the problem.