Tonepad A/B switch sometimes makes a loud pop

[rkhanso]

Yes, I've searched for answers, but still have a question. My situation is a little different, I think.

At church, we don't have a reliable sound guy back at the board to mute our instruments on the board when we unplug the guitars. So, when unplugging, a loud pop was heard over the sound system. To fix this problem, I thought that an A/B switch would work. We don't use any other effects pedals, the non-used channel of the switch goes into the ether. So, we're really using it like an on/off pedal. We also use passive DI boxes.

I found the http://tonepad.com/project.asp?id=56 Tonepad A/B switch and built a couple of them. (their website doesn't seem to be dishing out the .pdf files right now).

Here's how we're using them:

Guitar--->>>Tonepad A/B switch A channel------------------->>>passive DI--->>>sound board
                                                    B channel-->>not connected                 \--- >>>guitar amp

The one that the guitar player uses works OK, no popping sound (that I've heard anyway). He's using an acoustic electric.

I play bass and when I plug the guitar in (to the A/B switch) and hit the A/B switch to go to channel A, there's a loud pop - over the PA system. It happens only once.....until I unplug the bass and plug it again, then hit the A/B switch again to go back to channel A. I get a pop the first time only, as long as I don't unplug the guitar again I can swtich back and forth with no noise at all. That's pretty consistantly repeatable. Occasionally, there may be no, or a much quieter pop. This is why I think there may be some other problem. I'm in a cold climate and wonder if they dry air may have something to do with it? We don't receive static shocks in the church building.

Is there some issue with my bass? It has active pickups.
The few parts that are used in the box are all brand new (I read where old LEDs may have had too much current draw and caused the popping noise)

Any ideas?

[Galego]

http://www.diystompboxes.com/smfforum/index.php?topic=70162.0

[rkhanso]

Right, I read that one before I posted....thus why I put at the top of the post, "My situation is a little different, I think."

I don't have any other effects in use. No capacitors to charge/discharge. Nothing. Just as shown in the crude diagram on the original post.

Now, my situation may be exactly the same as that post, but I know there are no other effects in use.

Thus, my question.

[jefe]

Is there some issue with my bass? It has active pickups.

Since the guitarist isn't having problems, I'm thinking it's got something to do with your bass. Does the guitarist's acoustic/electric have active electronics as well?

[rkhanso]

Yes, I do belive so. Though I've never seen the battery, it does have an EQ, volume - so that makes me think it does.
It's an Ibanez PF. Searching the web, I don't find anything that gives me a definite answer. I won't be able to visually check until Wednesday night.

[jefe]

That's true.. from what little I know about acoutsitc/electrics, it's probably got active electronics.. so I guess that was a dumb question on my part. Sorry, I guess I'm not much help.

My (very limited) thinking is that the bass's electronics probably has a capacitor or two in there, and they're charging up every time you unplug, then discharging when you plug back in, causing the pop... or something. TBH, I don't even know if that makes sense. So, consider this post a "free bump", lol..

[rkhanso]

BTW, I know it makes no difference in finding the cause of the problem, here is a picture of the boxes.



They are powder coated. The red one was the first one I made, black is an improved parts placement 2nd version. (parts fit better inside)
The black box has a removable bottom cover to get to the battery, so you don't have to mess with any of the switch wires when replacing the battery.
the top cover plate is for aesthetic reasons only. Right underneath the top cover is the bottom of the box.

They are both single electrical boxes.

[rkhanso]

Is there some issue with my bass? It has active pickups.

Since the guitarist isn't having problems, I'm thinking it's got something to do with your bass. Does the guitarist's acoustic/electric have active electronics as well?

I did check both guitars, and the acoustic/electric never makes a pop noise on either A/B box. My bass does make the pop noise (but not every time).
Any ideas what I could do about this? I replaced the battery in my bass with no change.

Again, it only happens the first time after plugging the guitar into the box, and then switching the A/B output. Subsequent switches of the box don't make the noise.