Wiring Passive And Active Pickups Together

[IbanezFreak666]

how can i wire an active pickup and a passive pickup together on the same guitar?

iv heard it can be done but you have to do something weird and it costs loads :/

[GregP]

Depends on your definition of "loads". ;-)

A passive signal is a "high-impedance" signal. One from active pickups are already pre-amped, which puts their signal at a "low impedance" level.

The solution? Make the passive signal active as well. You will need to feed your passive pickup signal into a preamp of some sort. Ideally it will be a preamp with a similar amount of output and headroom as your existing active pickup.

I've no doubt that Googling or forum searching will yield more thorough answers than I could ever provide, but this is the starting point. A preamp can cost very little to make or buy (as little as $10 if you make it, or as much as $110 if you buy, and everything in-between) and then new pots (assuming you're adding actives to a passive setup rather than the other way around) will cost a few bucks... the whole thing can probably be done for in the neighborhood of $50, not including the cost of the pickups themselves. It depends on how DIY you want to go.

When I was researching a "piezo + magnetics" blend knob, I came across products that will do the job for you right out of the box, blending actives and passives. If memory serves, those were around $100.

Greg

[IbanezFreak666]

thankyou..its for a friend so i dont know exactly what hes doing but that should be extreamly useful to him

[GodBlessTexas]

Lovekraft (RIP) had a simple circuit for turning passives into a low impedence load so you could use them with actives. I have the diagram at home if it's not in the archives here.

[GodBlessTexas]

Here's the link to Lovekraft's buffer:

http://projectguitar.ibforums.com/index.ph...mp;#entry257121

I just realized that his webpage is gone. I'll post the images to that thread tonight.

Edited May 25, 2007 by GodBlessTexas

[GodBlessTexas]

Here's the link to Lovekraft's buffer:

http://projectguitar.ibforums.com/index.ph...mp;#entry257121

I just realized that his webpage is gone. I'll post the images to that thread tonight.

OK, a week late, but here are the pics. Here's the tutorial, in Lovekraft's own words.

NOTE: This tutorial assumes a familiarity with basic soldering practice, component identification and orientation, and electronics construction technique - furthermore, no warranty, explicit or implied, is given regarding the suitability of this project for any given purpose, nor does the poster accept any responsibility for any damages pursuant to the assembly or use of this circuit. Proceed at your own risk.

OK, having gotten that out of the way, here's a relatively simple, inexpensive buffer circuit suitable for using to mix passive pickups with EMG active pickups, or buffering piezo pickups to mix with magnetics. Frequency response is pretty much flat, and noise is fairly comparable to passive pickups if built correctly. The circuit will easily drive a load of 10K or lower, so even long cable runs shouldn't be an issue. Here is the schematic:

The following are also available for download:

1. A Vero board layout

2. A Bill of Materials (including Mouser part numbers)

Part  QTY  Mouser #

C1	1	581-BF014D0224J

C2	1	581-BF074D0684J

R1,R2 2	660-MF1/4DC1004F

R3,R4 2	660-MF1/4DC1002F

Q1	1	512-2N5457

Q2	1	512-2N5087TA

misc		vero board, solder, hookup wire, etc.

3. A construction diagram

Finally, here's a photo of an earlier build of this circuit, thrown together hastily with "found" components a while back for "proof-of-concept" - the newer layout posted above is both smaller and cleaner, but at least this will give you a rough idea of the size (that's a US nickle in the pic, for scale).

Edited June 1, 2007 by GodBlessTexas

[Roggie]

I've got a strat with SA's in the neck and middle position - I plan to build the buffer circuit so I can add a 'Hot Rails' pickup in the bridge position to give me a bit more of a 'humbucking' sound without doing any body or pickguard modifications to the guitar.

Q1 - will I now need to ground the strings? When installing the SA system, I was advised to NOT ground the strings (cut the ground wire from the jack to the tremolo 'claw'.

Q2 - is the volume balance between the SA's and the passive pickup going to require the use of any trim pots for balance or are they close enough to get away with only the buffer/impedance matching circuit?

I know this is an old thread, I'm hoping someone who's already done this might be able to offer advice before I put it back together.

[demonx]

Electronics is definitely not my strong point, but I tried to "wing" a circuit I thought would work where I combined passive and active together.

End result was when j connected the battery the wires caught on fire in a bright white fuse like burning fashion. I pulled the battery and conceded that I'm an electronics dunce and left it as active only!

[ansil]

why not add the emg 81 circuit to the hot rail and make the whole thing active. i did that in my super wiring diagram for my jem

[psw]

Lovecraft is sadly missed...thanks a lot for bringing back these images.

I recently had to go active and the guitar now has 4-5 pre-amps in it!!! I'm sure that this will not be such a complex build. As said, got to match the impedances and a buffer on the passive to make it active too, perhaps the pot/s will also need to be adjusted (I used 100K's on the volume for instance..or what the EMG wants).

GN2 is a good forum for such things as well, here is a thread on some of some other buffer options and projects...

http://guitarnuts2.proboards.com/index.cgi?board=schem&action=display&thread=3150

[bob123]

Uh why dont you just wire up 2 different circuits and use an ON/ON switch for the output jack?