Hum in EMG HZ Bass pickups?

exalted

Senior member
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723
My wife has a Schecter bass, totally stock. It's worked well for her, but last night it started to buzz, and if the cable isn't situated just right, the sound cuts out.

I opened it up to see if I could fix it, but there are a TON of wires in there all zip-tied together, and it looks like I have to cut them loose to get access to the pots. I want to take my time and do it right (we were at band practice).

Anyone have any ideas? Is this just a loose wire? I've never messed with EMGs before...
 

exalted

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723
Based on what I could see, it looked like it was a stereo output jack, and no wires seemed to be flailing about, but I couldn't get a good view. I'll cut those zip ties tonight and see what I can find.
 

exalted

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723
I took a long lunch and decided to open it up this afternoon.

The jack *looks* okay, but it's kind of weird. It is sort of like a stereo jack, but has two grounds, and a single hot lead, and is all encased in a weird little box. A cheap Korean thing, I guess. I have a spare stereo jack I'll install and see if that helps. If it works, I imagine she'll only be able to use mono cables, but that's no biggie.

 

SkuttleFunk

Senior member
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1,156
the stereo juack is used to turn on/off the battery by using a mono cable

tip = hot lead
ring = battery neg lead
sleeve = ground lead

when you plug-in a mono cord it completes the battery circuit and powers your pre-amp and/or pickups. this is a very common wiring configuration

all the best,

R
 
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8,318
My EMG radar went off as I'm used to the stereo jack closing the battery circuit.  However, aren't the EMG-HZs passive?  Is the stereo jack there for an active preamp maybe, or is it just an extra soldering point for the ground?  One to the components, the second to the bridge.
 

blue313

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I'm not sure what model you have, but this diagram covers a bunch of Schecter's current basses.

http://www.schecterguitars.com/schematic/schecter_Basses,Ultra,SCustoms,SElites,C-4-5.pdf
 

exalted

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723
It's a Damien 4-string bass. Looking in to it, it looks like the HZ's are indeed passive.

Blue - That schematic is the way her bass is wired up, so is the battery and second ground wire for the preamp? If it has a preamp isn't it then an active? Or...I mean...how do these things work?

If it is indeed a passive setup...I just tried the bass with the amp set to "passive", and it eliminated 80+% of the noise.  She just replaced her 15" cab with a 4/10" a few weeks ago. This was our first practice with it. :doh:

I guess the 4/10's articulates even the noise.  :icon_jokercolor:
 
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The active/passive switch is just a pad, usually +/- 10db.  Basically, an active pickup has more output, but most people don't like to turn their amp down.  The active/passive switch allows you to keep your levels the same regardless of instrument output.  Translated, an active bass can turn up to 6 with the pad on and be at the same level of the passive bass with it off.  That of course is an oversimplification but it in a nutshell.
 

exalted

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So do you think that's what was the source of the buzzing?

We're having practice tonight, so I guess we'll find out.
 

blue313

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exalted said:
It's a Damien 4-string bass. Looking in to it, it looks like the HZ's are indeed passive.

Blue - That schematic is the way her bass is wired up, so is the battery and second ground wire for the preamp? If it has a preamp isn't it then an active? Or...I mean...how do these things work?
"Active" pickups just have a preamp built into the pickup housing.  The preamps need the power regardless of where you locate them in the guitar.  The stereo ring on the jack is primarily to extend battery life by cutting the circuit when unplugged.
 
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