Wiring up a Active Pick Up.

[jbassist]

Greatings!!,

first post up here.. i ask around other forums and no one could realy help me so here go's:

I bought a EMG 81 from a friend and it came without the Tone and Volume Pots..
i can go without the tone since i will be using this guitar for high gain stuff only anyway..
and i was told i realy didn't need a 25 k Ohm Volume pot, and i could go with a 500 K ohm aswell... only thing would be that it would only work as a On/Off switch..

anyway... so i did... like this: http://img195.imageshack.us/my.php?image=emgaansluiting2pc.png

forget about the tone control and the comment about the wire..there's just a wire going from the pot to the stereo jack.

Anyway: it worked... kind of:gurmpy: only if i plugged in my jack half way did it give "full tone" (missing alot of treble..) and if i plugged it in the whole way it gave a scratchy/crunchy tone... even with full distortion on:smack:

i re checked it:
EMG quick connecter was in correctly...
Ground going to the bridge (not the element...) was disconnected.. (common fault i was told..)

Still didn't work...

so took it out again.... put it on a 250 K ohm Pot i had lying around to hopefully solve the lack off treble problem.... and re wired it again.... (Emg quick cable/baterry suplied cable, and the rest with 15qmm wire.. is this correct at all?)

still had the same damn problem!!!

so if anyone can tell me what i'm doing wrong.. please do so!!!

Btw, i useally allways take these kinda things to the guitarshop but i thought it was time i learned to do it myself incase it happens off a live gig (i got my own band and i do live mixing.. so it should come in handy...) and save me some money!!

thanks, JB.

 

[Artie]

Re: Wiring up a Active Pick Up.

Hi JB; Welcome to the forum. If you get any sound at all with the plug pushed in part way, it means you've wired the output jack wrong. (Easy to do.) Look over those connections carefully. It sounds like you have the "hot" wire going to the ring terminal instead of the tip terminal. Look at this diagram:

You want ground to go to the red arrow, "Hot" out from the volume control to go to the blue arrow, and the negative battery clip wire to go to the green arrow.

Let us know if you still have problems. We'll get it.

Artie

 

[jbassist]

Re: Wiring up a Active Pick Up.

hey, thanks man.
yeah, since the quick connector is in correctly it can't be anything else:smack: DOH!!

so i got my negative battery clip wire going correctly.

"Hot" is the one going through the ghost tonepot and Ground the other?
and maybe a dumb question but which one is in and which one is out? :smack:

and is the 0,15qmm wire i'm using okay bytheway?

well cool, i'll try it.. that should solve one problem anyway!!:beerchug:

now for the loss of treble.. is that the 250 K ohm pot?

thanks alot in advance... i'm still a noob in this right know.. but i bet once i've made all the ultra dumb mistakes i'll see the logic!!

Jb.

 

[Artie]

Re: Wiring up a Active Pick Up.

The pickup "hot" wire should go to one end of the volume control. Ground should go to the opposite end. The middle terminal should go to the blue terminal.

Using a 250k pot should make the sound much brighter than the suggested 25k. There may be something else wrong also. What did you mean by "ghost" tone control?

 

[jbassist]

Re: Wiring up a Active Pick Up.

Ghost in that there is no tone pot at all... just the wire going from the volume to the Jack.
its the sleeve that activates the battery bytheway?

and i changed the ring and tip wires around yesterday and it still had the same problem!! :eek13: so i'm gonna turn around my quick connector for fun now to see what that will do!! who knows...

i'll let you know.

and what could cause the loss of treble? wrong wire? like i said i use 0,15qmm wire for the ring/tip connections between the volumepot/jack maybe thats it.
i'm kind of confused on the 250/500 k Ohm pot thing, this is what they said on another forum:

forum User 1:

If you use 1 meg pots with regular passive pickups you lose a little bit of treble, but using a 500k pot instead of a 25k pot is gonna kill a LOT of treble....

user 2:

Now.... you have to use a 25k pot with your active emg. The active signal is extremely weak and the low resistance 25k pot allows the high freqeuncies to pass through. If you use a 500k pot your tone will be extremely muddy, it will have NO treble at all.

A guitartech i see from time to time told me it didn't matter and you said it'll even give me brighter tones..

its easier to believe experienced guys like you but its still pretty strange...

 

[octavedoctor]

Re: Wiring up a Active Pick Up.

The pickup "hot" wire should go to one end of the volume control. Ground should go to the opposite end. The middle terminal should go to the blue terminal.

Using a 250k pot should make the sound much brighter than the suggested 25k. There may be something else wrong also. What did you mean by "ghost" tone control?

No Artie, you must use the correct value pots with EMGs as they are designed to work with 25k. Using too high a value causes problems with the taper and impedance matching issues. Any value up to about 50k is OK but 250k is an order of magnitude too far.

(ex-EMG support tech talking here :wink
EMG sell pots separately and aren't expensive.

 

[octavedoctor]

Re: Wiring up a Active Pick Up.

Ghost in that there is no tone pot at all... just the wire going from the volume to the Jack.
its the sleeve that activates the battery bytheway?

The negative (black) leg of the battery clip goes to the ring (second) terminal of the stereo o/p jack, the ground lead goes to the sleeve terminal; it then functions as an off switch by switching the power using the negative side rather than the more usual positive side of the supply. At low voltages it makes no difference...

When you insert a mono plug into this set up the shank makes a connection between the ring and sleeve terminals, completing the power circuit.

 

[Artie]

Re: Wiring up a Active Pick Up.

No Artie, you must use the correct value pots with EMGs as they are designed to work with 25k. Using too high a value causes problems with the taper and impedance matching issues. Any value up to about 50k is OK but 250k is an order of magnitude too far.

(ex-EMG support tech talking here :wink
EMG sell pots separately and aren't expensive.

I've always wondered about that. I've never messed with active's myself, and wondered how sensitive the preamps were to output loading issues. One of these days I need to get one, just to play with.

Artie

 

[octavedoctor]

Re: Wiring up a Active Pick Up.

I've fitted quite few EMGs in my time; they are nice pickups but a bit of an acquired taste. The most common criticism is that they sound a bit clinical and I can identify with that. They are certainly very noise free but with close attention to screening protocols you can get a Texas Special installation almost as quiet and I think they have more immediacy, punch and dynamic range.

They don't seem to be in as much demand as they used to be but the current UK distributor, Selectron, tells me that EMG cannot keep pace with demand and they ae always on back order! Must be selling somewhere...