Active Pickups with Active Preamp? Will they work together okay?

[Mather]

I have a six string bass and I really wanted a nice 'punchy' single coil bass tone. EMG seemed like a good option, even though I am going to have to route the bass.

I called up Mike Lull who does this sort of thing in the PNW. He said that my Active EMG pickups would not work well with my IBANEZ SR506 Active preamp. Is this true? Should I pay to get the bass passive? Should I invest in a different pre amp?

 

[steamthief]

I can't comment on that particular combination, but active EMGs work pretty darn good with a Tonepump in my Spector Euro.

 

[line6man]

If a preamp is spec'd to work with passive pickups, then its input impedance is certainly going to be sufficient for active pickups, because their output impedance will be even lower than than of passive pickups. There are just three things that you have to watch out for. Firstly, there exist some preamps which are designed to interact with a high impedance magnetic pickup in some way. For instance, Audere preamps have a variable input impedance switch that is meant to cause varying loads on the pickup coils. With buffered (active) pickups, the preamp would still work just fine, but these extra features won't have any effect. (Note, however, that this is rather rare for preamps.) Secondly, as with any pickups, you must be sure that your signal is not too hot for the preamp, or else it will distort. If you choose a set of pickups that is too hot, you may have to pad them down with resistors, or see if you can run the preamp at a higher voltage to increase headroom. (This is also rarely an issue.) Lastly, if you have both active pickups and a preamp, there is a theoretical risk of raising the noisefloor and decreasing headroom, because you are chaining gain stages. This is normally not an issue, but I suppose it could be, under the right circumstances. Active pickups usually are not used with preamps, though.

Technical concerns aside, you may also want to address the tonality of the pairing. Some preamps are voiced to color the tone in a particular way, and not all pickups pair up harmoniously. You would have to let your ears be the judge, however. (I'm guessing that this was Mike Lull's concern.)

 

[mikezimmerman]

Correct me if I'm wrong, but one other consideration is that active pickups typically require different values for volume/blend pots (25k vs. 250/500k for passive pickups). While that is not technically part of the preamp, there are certainly some preamps with volume and blend pots as well as EQ pots attached directly to the circuit board. That would make swapping the volume/blend pots difficult, and it wouldn't surprise me if the Ibanez premp is one of those.

If a preamp is spec'd to work with passive pickups, then its input impedance is certainly going to be sufficient for active pickups, because their output impedance will be even lower than than of passive pickups. There are just three things that you have to watch out for. Firstly, there exist some preamps which are designed to interact with a high impedance magnetic pickup in some way. For instance, Audere preamps have a variable input impedance switch that is meant to cause varying loads on the pickup coils. With buffered (active) pickups, the preamp would still work just fine, but these extra features won't have any effect. (Note, however, that this is rather rare for preamps.) Secondly, as with any pickups, you must be sure that your signal is not too hot for the preamp, or else it will distort. If you choose a set of pickups that is too hot, you may have to pad them down with resistors, or see if you can run the preamp at a higher voltage to increase headroom. (This is also rarely an issue.) Lastly, if you have both active pickups and a preamp, there is a theoretical risk of raising the noisefloor and decreasing headroom, because you are chaining gain stages. This is normally not an issue, but I suppose it could be, under the right circumstances. Active pickups usually are not used with preamps, though.

Technical concerns aside, you may also want to address the tonality of the pairing. Some preamps are voiced to color the tone in a particular way, and not all pickups pair up harmoniously. You would have to let your ears be the judge, however. (I'm guessing that this was Mike Lull's concern.)

 

[line6man]

Correct me if I'm wrong, but one other consideration is that active pickups typically require different values for volume/blend pots (25k vs. 250/500k for passive pickups). While that is not technically part of the preamp, there are certainly some preamps with volume and blend pots as well as EQ pots attached directly to the circuit board. That would make swapping the volume/blend pots difficult, and it wouldn't surprise me if the Ibanez premp is one of those.

How would PCB mounting make it difficult to swap pots? You would just unsolder the pots from the PCB, and put different pots in their place. The only issue would be if you had oddball pots that were hard to source, but you can usually get PCB mount pots from electronics suppliers.

 

[JustForSport]

What year is your 506? Mine is '96 and has active pickups ( like split P inside). These pickups work well with an Aguilar OBP3PPK. Emg 40 series fit right in but are a hair smaller. The possible issue would be that the EMGs are pretty hot and you may need a trim pot to tame them some. AFAIK those Ibby preamps are designed for 9v only.
I have sevetal basses that have both active pickups and active preamps, different combos, no problems, just not EMGs connected to Ibby preamp.
I considered swapping the Ibby actives for EMGs but I like the Ibby actives enough to keep that config so far.
If you have a newer 506 the pickup shape/ size- Bart MkI is not the same size as any EMGs that I'm aware of.

 

[KevinPaulo]

What year is your 506? Mine is '96 and has active pickups ( like split P inside). These pickups work well with an Aguilar OBP3PPK. Emg 40 series fit right in but are a hair smaller. The possible issue would be that the EMGs are pretty hot and you may need a trim pot to tame them some. AFAIK those Ibby preamps are designed for 9v only.
I have sevetal basses that have both active pickups and active preamps, different combos, no problems, just not EMGs connected to Ibby preamp.
I considered swapping the Ibby actives for EMGs but I like the Ibby actives enough to keep that config so far.
If you have a newer 506 the pickup shape/ size- Bart MkI is not the same size as any EMGs that I'm aware of.

I’m sorry to bother you but From your explanation you might have a solution for my problem. I just swapped my current preamp for a OBP2. I own a warwick Rockbass ‘05 with active MEC pickups. But I’m getting a distorted output when I digg into the strings.

I replaced battery, check solder work, lower pickups heights but still getting the distorted signal when I play hard or thumb. Almost like a harsh compressor effect. any suggestions?

 

[northerngitbass]

Resurrecting an oldish thread, but...

Given that active pickups and active preamps both need a voltage source, is there any difference in wiring both into the same power supply or giving each a separate supply? I have room on the bass for two 9v batteries. Should I consider an 18v system feeding both or give the pickups and eq their own individual 9v supply..?

Ta

 

[ctmullins]

Generally you would run the pickups and the preamp from the same voltage source. So if you have room for two batteries, wire them up for 18V to feed everything. Most quality active systems will run at 18V, but please check with your particular manufacturer's documentation to make sure.

 

[dwizum]

The pickups and preamp will need a common ground anyways, so they'll never be fully isolated. The only potentially legitimate motivations for separating the batteries don't really apply here. Preamps and pickups are extremely low current, so there isn't any need to separate them as a way to avoid pulling too much current from one battery. They're also not able to operate independently, so there's no sense in separating them out of a hope of preserving function if one battery dies. And 9v batteries are pretty good filters, so there's no sense in separating them out of a desire of preventing noise from bleeding between the circuits via the power supply. On the flipside, by running two batteries in series as a single power supply, you get the benefit of much higher headroom, which can make a difference in some cases.

One other option, if you know you don't need the headroom. Wire in only one battery box, and use the second battery box as an onboard spare battery storage mechanism! No more hunting for a spare in the middle of a gig...

 

[iiipopes]

Yes. EMG is the best example of how they integrate everything: active pickups, preamps, accessories, etc.

 

[sunbeast]

I’m sorry to bother you but From your explanation you might have a solution for my problem. I just swapped my current preamp for a OBP2. I own a warwick Rockbass ‘05 with active MEC pickups. But I’m getting a distorted output when I digg into the strings.

I replaced battery, check solder work, lower pickups heights but still getting the distorted signal when I play hard or thumb. Almost like a harsh compressor effect. any suggestions?

Maybe you figured this out already in the last few years, but most likely with those active pickups you'll want to run the Aguilar at 18V power for maximum headroom. Most likely you are clipping the preamp

 

[northerngitbass]

Generally you would run the pickups and the preamp from the same voltage source. So if you have room for two batteries, wire them up for 18V to feed everything. Most quality active systems will run at 18V, but please check with your particular manufacturer's documentation to make sure.

Cheers man..!

 

[northerngitbass]

The pickups and preamp will need a common ground anyways, so they'll never be fully isolated. The only potentially legitimate motivations for separating the batteries don't really apply here. Preamps and pickups are extremely low current, so there isn't any need to separate them as a way to avoid pulling too much current from one battery. They're also not able to operate independently, so there's no sense in separating them out of a hope of preserving function if one battery dies. And 9v batteries are pretty good filters, so there's no sense in separating them out of a desire of preventing noise from bleeding between the circuits via the power supply. On the flipside, by running two batteries in series as a single power supply, you get the benefit of much higher headroom, which can make a difference in some cases.

One other option, if you know you don't need the headroom. Wire in only one battery box, and use the second battery box as an onboard spare battery storage mechanism! No more hunting for a spare in the middle of a gig...

Excellent, many thanks!