Active pickups - 9v or 18v power?

[JimBobTTD]

Hello

What are the advantages of 18v over 9v? I'm going to put a pair of EMGs in a project bass, and EMG suggest using 18v. Not a problem - I'm going to cut a hole for one battery, so it's not much harder to do it for two, and I know how to wire them up to give 18v.

Some questions, though:

a) Why bother? "More headroom" is a little too abstract for me. What effect does this have on the sound? Does it sound "better"?
b) If both batteries are dead, and I only have one spare, will it still work on just one?
c) Anything else to add?

Ta much in advance!

Edited August 4, 2008 by JimBobTTD

[bnt]

a) I'm not entirely certain either. I did it for a while, but reverted to a single battery, because I heard no difference. A heavier player might notice squashed transients.
b) You definitely can not remove a battery and go, because the batteries are wired in series. (Unless you installed some kind of bypass shunt in place of the missing battery - NOT a switch, which would turn your bass in to an incendiary device!
But since a "dead" battery is still in the circuit and might still be supplying a little voltage, you might not even notice it's dead until the other battery goes. Best answer: carry a battery tester and multiple spares.
c) Not really. The EMGs in my bass are really thrifty with battery power, batteries last ages.

Edited August 4, 2008 by bnt

[alexclaber]

Try it with both one and two batteries - it's easy enough to bypass one clip with another clip. I went from 9V EMGs via MEC preamp to 18V EMGs and OBP-3 preamp (with bypass switch), which gave a huge change in tone but I can't say whether it was getting rid of the MEC, going to 18V or a bit of both.

Alex

[synaesthesia]

[quote name='JimBobTTD' post='254269' date='Aug 4 2008, 11:44 AM']Hello

What are the advantages of 18v over 9v? I'm going to put a pair of EMGs in a project bass, and EMG suggest using 18v. Not a problem - I'm going to cut a hole for one battery, so it's not much harder to do it for two, and I know how to wire them up to give 18v.

Some questions, though:

a) Why bother? "More headroom" is a little too abstract for me. What effect does this have on the sound? Does it sound "better"?
If both batteries are dead, and I only have one spare, will it still work on just one?
c) Anything else to add?

Ta much in advance![/quote]

This is one of those things that often devolves into mindless more is better thinking. There is a context to it all, it is not a generic thing. If you are using active EMGs, with an EMG circuit, yes there will be an audible benefit, particularly in a studio situation. I have had and still have EMGs in various basses with 18V, the results can be heard in the studio if you play clean and direct. If you run trough efx, or compress your signal, or distort your signal, there's no real benefit. Whatever headroom gained by 18V is subject to the consequential headroom of whatever you run it through.

The batteries are in series and that's how you get 18V. The circuit I guess will work on about 5- 6V cumulative supply, so if one battery dies, the circuit should operate. FYI, an EMG system will work with very low voltage supply, you can hear the circuit distort. What voltage that occurs I cannot tell you as I have never bothered to to measure it. My guess is it is around 5 V.

But if you are using other pickups and circuits, the answer really is, it depends. Some circuits are engineered to work with 18V, some not. Some will benefit, others will not.

Edited August 4, 2008 by synaesthesia

[JimBobTTD]

Interesting replies, thanks for the info.