Active/Passive Switch Advice
 

I have been playing a cheap Busker's (Japanese brand) precision bass guitar running on stock passive electronics for about a year now, and I figured since I will be stuck with this guitar for a while, I should get to know the inner workings of it, and be able to modify it. I found out about a switch that can switch between active and passive, so I thought "Bro, this is what should be on yours."

So now to my question. How exactly would I be able to wire a switch like this? Would I need to get active electronics? What precautions regarding wiring do i need to consider?

I have no problem using power tools such as dremel tools and soldering irons as well.

Also, I believe the wiring diagram would be the same as any precision bass, but if people tell me otherwise, I would be more than happy than to either find one, or take a picture of mine.

Regards,
Rick

Yes, you need active electronics. Otherwise, what are you switching to? Not that a mute toggle isn't useful... The exact wiring scheme depends on the active electronics being used. Most include a passive mode as a feature, in which case you just need to replace the existing electronics.

I am looking into getting either DiMarzio Will Power's or EMG's, if they don't seem to be too expensive. Do those have that feature?

DiMarzio makes passive pickups, and most EMGs are active pickups.
Active/passive switching actually means "preamp bypass." You need to have an onboard preamp, regardless of whether or not the pickups that feed into it require battery power. That being said, adding a preamp just so you can bypass it sounds rather silly.

Oh, so it is the preamp that requires the power... This goes to show how little I know. I do see the point in it being silly, come to think of it.

If you have passive pickups, you can install an active preamp. Then you will have an "active" system. If you install a switch, it will be an "active/passive" switch because when you are in "active" mode, you are able to use the preamp and shape your tone. Also, you will be running on batteries. In "passive" mode, you won't be using your batteries but you wouldn't be able to use the preamp because it is not on. Therefore, you would only be able to use your volume and blend knobs. All you would get is the sound of the passive pickups and not the sound of the preamp.

You can install EMG pickups with an EMG preamp. They are very easy to install and there is no soldering required. However, keep in mind that EMG pickups are active and therefore the batteries power not only the preamp but the pickups also. The pickups need the batteries in order to work. Therefore, the whole system is constantly "active". You can install a switch for this completely active system but it will function as a "preamp bypass" switch meaning that all you would get is the sound of the active pickups and not the sound of the preamp but the batteries would still be on.

I hope this provides some clarification.

It provides a lot of clarification, thanks. One final question though. Is it okay if I cut out holes in the body to snugly fit everything, or if there are any "no-go zones"? I have this feeling I'm going to mess up the guitar if I hack out a huge chunk and make it sound terrible.

This is not true. All active components draw current, as long as there is a connector in the output jack. It is possible to wire a power switch with the active/passive switch, however, this requires additional switch poles, and will generally cause popping noise when switching the preamp on.

I don't entirely agree. On some preamps, you are right. However, I installed an Aguilar OBP-3 in my Thumb that I paired with Delano soapbars. Out of curiosity, I toggled my active/passive switch over to passive mode and removed the batteries from my bass. I could still play just fine with full volume.

I followed one of the BestBassGear wiring diagrams and I get no popping whatsoever when toggling my active/passive switch. The only pop I had was with my push/pull mids. I easily corrected that by installing two 1 megohm resistors on this pot.

You can carve into the body to expand the cavity so long as you don't destroy the bridge ground wire. There really isn't a "no-go" zone. I've done it before.

So if I were to get the Dimarzio Will Power pickups, any recommendations for a good active preamp?

I would suggest any preamp that has 3 bands (bass, treble, mids).

The Aguilar OBP-3 is one of my favorites. It has everything you need: insanely powerful lows, very beefy mids, and excellent highs. It also does not take up much room.

Yes, that's because the switch only decides whether the signal goes through the preamp or not. Even if you bypass the preamp, it does not get shut off, it simply gets no signal at all - but it's still working. It's like a TV on standby, still using power, but not doing anything worthwhile.

I'm a repairman working on an active circuit in a jazz bass with an Aguilar OBP-3SK preamp. I'm getting a big popping noise when switching the preamp on, using the push/pull knob. I did not wire this circuit myself. I'm only installing it for a customer.

I'm also getting a pretty bad ground hum. I've re-soldered most of the grounds (some of the joints were terrible), but it's still there.

Any suggestions? Help is much appreciated!

Wire it like this:


This grounds the preamp's input when it's bypassed, so the preamp is amplifying literally nothing and there's no voltage spike once you switch it on.

Wiring courtesy of line6man.

What is your knob configuration? I can send you a link to a wiring diagram for your setup. Also, the switch wiring that Stealth posted is correct.

Just be careful not to route into the pickup cavities from the back.

Does this mean I would need to install a 3rd nob? I have what appears to be a precision bass guitar, so it only gives me 2...

If you only have two holes and don't mind drilling another hole AND you have the room in your control cavity for the extra pot, then you can do it. But, it all depends on whether you think it's worth physically modifying the body of the bass and if you really want a 3-band preamp.

bongostealth:

My knob configuration is: vol, vol, mid w/ active/passive switch, stacked bass/treble. A wiring diagram would be great! Thanks!