Is it possible to use active pickup and passive pickup on one bass?

[grass903]

I'm thinking of installing passive pickup and active pickup on
my Fender P-bass.
Is it possible to use them on one bass?

[DavidRavenMoon]

Yes, but you have to make the passive pickup active so the impedances match. You can do this with a simple FET buffer amp. Active pickups are just passive pickups followed by a preamp.

[Nick Ioannucci]

not necesarily, what you mentioned would just be an active pre, hes asking about active pickups such as emgs. im honestly not sure if this is possitble, if sure it is in some way but i cant tell you exactly how.

[DavidRavenMoon]

Originally Posted by Nick Ioannucci

not necesarily, what you mentioned would just be an active pre, hes asking about active pickups such as emgs. im honestly not sure if this is possitble, if sure it is in some way but i cant tell you exactly how.

I'm talking about EMG's as well. They are high impedance windings followed by a buffer preamp with a low impedance output. What did you think an active pickup is? It's a passive pickup with a built in pre.

In EMG's case they also use a differential amp configuration to remove hum, and they do some tone shaping too. But that's basically it. Some active pickups use low impedance windings, and then need the preamp to also boost the level along with impedance matching. That's how Alembic does it. That's how I do it too... I use an external preamp... but they are still "active" pickups, since they need a pre.

I have installed EMG's along with passive pickups a number of times. The passive pickups will be over powered and loaded down by the EMG's low Z output. All that needs to be done is to buffer the passive pickup before it gets to the pickup switch/volume controls, and the two pickups will get along perfectly well.

There are some very simple and inexpensive FET buffer preamps you can build... so a search for "stratoblaster" for the Alembic pre schematic.

[hbarcat]

It may not be what you had in mind, but I use an EMG-P and a 60's Gibson EB0 pup together on my Ibanez bass; I have them wired to a switchable jack so that I can use either one or the other, but not both. I find it useful in my classic rock band to get the vintage tone from the Gibson for a particualar song and then switch to the EMG for a later style song.

EMG pups are not same as passives with a preamp. They have much lower magnetic strength and hence a lower intrinsic output which is then boosted to normal levels with a preamp.

[ScubaSteve]

You'd basically be putting an active preamp on the passive pickup to boost the level up to that of the active pickup.

If your amp has both active and passive input jacks, then you could theoretically run each pickup to its respective input, though you would need 2 output jacks installed on the bass.

Couldn't you also just lower the output of the active pickup ? Isn't that what the active input on a bass amp essentially does ?

[DavidRavenMoon]

Originally Posted by hbarcat

It may not be what you had in mind, but I use an EMG-P and a 60's Gibson EB0 pup together on my Ibanez bass; I have them wired to a switchable jack so that I can use either one or the other, but not both. I find it useful in my classic rock band to get the vintage tone from the Gibson for a particualar song and then switch to the EMG for a later style song.

Yeah, but if you buffer the EB-0 pickup, you can mix them together! I have a Ric bass with an EB-0 Sidewinder and a Hi-A treble pickup (Hi-A pickups was the original name for Bartolini). Even though the Hi-A is passive, it's a clear modern tone. I have them both buffered, and you can get some great tone combinations, from vintage boom to modern slap. The EB-0 pickup sounds great buffered too... same tone, but a bit tighter. You can hear it on a recording on my MySpace page on the song Buzz Worthy.

Originally Posted by hbarcat

EMG pups are not same as passives with a preamp. They have much lower magnetic strength and hence a lower intrinsic output which is then boosted to normal levels with a preamp.

What makes you think that? Don't believe all the hype you read. EMG pickups are passive pickups connected to a preamp. The preamp is based on an op amp. The coils are pretty normal, and they use a regular ceramic or alnico bar magnet, just like you find in many other pickups. Some of them are wound right on the magnet, and some use steel blades. The bass pickups, except the CS, are wound on the magnets. Steel blades will give you higher inductance for a warmer tone, and also increase the pull of the magnets somewhat.

While the magnetic pull is not all that strong, it's about the same as a Bartolini pickup, and many others. Ceramic magnets are pretty strong, but something like a Jazz Bass pickup has a lot more magnets on it, and if the pickup is very close to the strings, you can get that warbling commonly known as Stratitis.

There's nothing in an EMG that makes it any different from a regular pickup except the preamp, and that has nothing to do with the magnets. They just didn't use super strong magnets, and use the preamp to help boost the output level. Some people seem to think an active pickup means it has an electro-magnet, but that's not the case at all. Pickups are just wire and magnets... nothing magic in there. I'm not saying EMG's are not good pickups, I'm just saying they aren't all that radically different either. Some low impedance pickups wont get very much level without a preamp when plugged into a high impedance amp, although they would work fine plugged into a low impedance mixing board. They need to have their levels boosted with a preamp. My pickups are like this. But it has nothing to do with the magnets. EMG's would work fine with no preamp, since they aren't particularly low impedance coils. It's the preamp that makes them low impedance. And they use the preamp to do some other tricks, like noise reduction and tone shaping. But their magnets are just magnets. Try taking some EMG's and stick them on your refrigerator and pull them off. Now try some other pickups. This will give you an idea of how strong the magnets are in relationship to other pickups. Not all that different. On the weaker end of normal.

Don't believe me? Here's an EMG 81 guitar pickup. Two bobbins wound as high impedance coils. Potted in wax. Each coil has a steel blade polepiece, and they connect to a standard alnico magnet. The preamp is on the back plane of the pickup, which is a printed circuit board. (I didn't take these pictures, and the pickup was dead before it was taken apart...)

[DavidRavenMoon]

Originally Posted by ScubaSteve

You'd basically be putting an active preamp on the passive pickup to boost the level up to that of the active pickup.

If your amp has both active and passive input jacks, then you could theoretically run each pickup to its respective input, though you would need 2 output jacks installed on the bass.

Couldn't you also just lower the output of the active pickup ? Isn't that what the active input on a bass amp essentially does ?

It's more than just the level. There's an impedance mismatch going on. A passive bass pickup is anywhere from 8 to 12K, which is why you need 250K pots... while the output of the EMG is listed from 2K to 10K, and while that isn't much different from a passive pickup, the passive pickup will be loaded down by the active pickup (not to mention that the EMG's use 25K pots). Since the EMG's output impedance is lower, it sees a lower resistance to the input of the amp (output impedance is analogous to a resistor in series with the device), so it will have a higher output level.

By buffering the passive pickup, you will isolate the two pickups from each other, so they wont interact as far as impedance is concerned.

The active input on an amp just has a higher resistance, so as to pad down the signal level a bit. Some amps have a pad switch, like the GK 800RB, instead of two inputs. I usually use the passive input with my active basses... you get more level.

This is what EMG says on their website, notice they say the best alternative is to install their PA-2 booster preamplifier to buffer the passive pickups. I have used 500K pots to mix an EMG pickup with a passive pickup on a guitar, and it works well, except the volume control doesn't have much sweep on the EMG.

Can I mix EMG's with passive pickups?
It is possible to mix EMG's with passive pickups. There are three possible wiring configurations; one is better than the other two.

Use the high impedance (250K-500K) volume and tone controls. The problem is that the high impedance controls act more like a switch to the EMG's. The passive pickups, however, will work fine. If you have a guitar with two pickups and two volume pots, with a three-way switch, there is another alternative. Use the 25K pots for the EMG, and the 250K pots for the passive pickup. This way you can use one or the other with no adverse affects, but with the switch in the middle position the passive pickup will have reduced gain and response.

Use the low-impedance (25K) volume and tone controls provided with the EMG's. The problem here is that the passive pickups will suffer a reduction in gain and loss of high-frequency response.

This is the best alternative. Install an EMG-PA-2 on the passive pickups. There are two benefits to doing this. With the trimpot on the PA-2, you can adjust the gain of the passive pickups to match the EMG's. The PA-2 acts as an impedance matching device so you can use the low-impedance EMG controls (25K) without affecting the tone of the passive pickups. You will also be able to use other EMG accessory circuits such as the SPC, RPC, EXB, EXG, etc. For this application, we recommend ordering the PA-2 without the switch for easy installation on the inside of a guitar

[MuzikMan]

Emg has the buffer circuit you would need. It's called the PA-2.