EMG PJ pickups working fine without batteries...

CoolCat

Well-known member
I was trying to fix up a bass for the sons band. It has a set of EMG PJ bass pickups.

There was some dual batterie thing in there a couple pots missing and pretty dead.

So Ive fought it a few hours yesterday and got some life and noise from it using a schematic from online and just removing all pots except one for volume /off.

Tonight, the second try, cleaning up the soldering and mess of wires and kept having issues (rarely do this stuff).

I finally had it together working and as I played it the batteries died.

So I removed the batteries and turned up the amp and the bass seems to play fine without the batteries?

Is this normal? Im glad because everyone hates the batteries because no one pays attention and they die at the wrong time.

Looking up the pickups they look like $179 PJ Set. But I dont read anything about them working as Active or Passive?

Not complaining!
 
ok, so I got my passive Jbass out and the preamp before clipping is like on 2-3 volume on the amp while the EMG active/passive mode needs to be at 7-8 before the clipping light goes yellow......the amp out put master will have to do?
maybe tossing a old pedal in front might help. Its great though, at least it works and they dont have to buy a guitar.

slapped a sticker over the empty potentiometer holes lol...its ska punk nobody has clean and shiny.
 
Well typicaly its not the pickups themselves that need power, its the preamp, so looks like you've probably bypassed that.
 
Thats good to hear.

There were three wires coming from the pickups...

a red one to the battery
a white/signal and the outer ground wire.
the guitar jack plug had three points, the signal and then two appears ground, 1 to the battery (-) and one to the shield ground.

it works ok. the preamp level on the Fender bass amp is 8!.....they leave the output of the amp on 10/max.

my Jazz bass passive had tons more volume and had to turn the preamp/level to 2 or else it started hitting "red" clip lights.
theres a button pad for active/passive too.

its kind of funny put in actives to get more gain and then hit a pad to reduce gain.
 
Hey,
+1 the pickup itself is just a pickup so it should work straight to jack,
however, if they were made to be part of an active set they may have a reduce number of windings and lower output than you'd expect.
If the active board is depended upon for tone shaping you might find the pickups don't sound right.

On the other hand, everything might be a fine, but I'd give them a good run in to make sure. :)
 
cool and makes sense, reduced windings. somehow it gets through the preamp section.

sound wise its probably not ideal , its not a classic guitar or anything, homemade body and had 4 knobs and now has one knob after surgery! lol

but it works and in the live gigs the house can run it through the board too.

the fact the battery fear is over is great.
 
To confuse things a bit further, EMG makes both active and passive pickups. Many basses on the market (including 6 of my own) have a configuration of passive pickups with an active preamp that essentially gives you 2 or 3 bands of EQ that you can boost or cut from onboard the bass.

As an example, if you had a passive jazz bass or something, you could purchase a John East preamp or whatever and use that with the existing pickups. Some of them have a switch for passive mode which would allow you to bypass the preamp and run the bass without batteries. Some of them also have a trim pot inside the control plate to match levels between active and passive mode so you're not 15 dB louder in active mode.

EMG active pickups are available with or without active EQ circuitry, but are usually supplied with at least a volume and passive tone control, battery clip and input jack with the extra leg for the battery disconnect. I'm pretty sure they still have a magnet and coil assembly, similar to a passive pickup, so that might expalin how you're able to pass signal without powering the preamp inside the pickup.

The levels you're getting sound really low. How's the tone?
 
its not as full as the passives, but its not total thin, it has the sound of a bass guitar but its on the treble-ish side compared to the JazzSquiers...but even with the battery in it was a little more treble in the tone.

theres a huge volume difference side by side I might try it with batterys, but damn the batteries failed in less than 45 minutes?
I'll try some known batteries too maybe they will last longer....or run a 9VDC on a TRS cable! lol...

actually I wish they'd trade off some stuff and just grab a new Passive Bass and be done. Get a Squier PBass or Jbass and call it a day. but its not $$$$ time at the moment.
 
Sounds like there is something wrong. The batteries should last month's, not minutes. (Unless you leave it plugged in 24 hours a day)
 
thats a good idea, that jack is kind of messed up and might be touching the battery ground to the guitar ground...hmm?
I can check that easily, great input. thanks.


the battery was supposedly new. it wasnt on the guitar for more than 4hrs...and while I was playing it to check the soldering it went out....like someone turning the volume off slowly.

Its got some wierd ass "dual 9v" battery wiring. Im pretty happy with it in Passive mode. It works, not a big deal to turn the PreAmp Volume to 8 from 2.
 
People put two 9 volt batteries in emg systems to run them on 18 volts. It's for higher output, but normally it's guitarists that do that, not bass players.

You should probably just pick up some used passive pickups and wire it like a standard bass. The active systems are cool, but once you start hacking them, it's time to start over. Especially if you have no idea what sort of system was in the bass to begin with.
 
The battery lifespan sounds weird. One of my basses uses an 18 volt system - the Sire V7 with the switch for passive mode. The preamp is touchy and powerful on that one. I think the 18 volt thing is for more headroom.

Thing is, with my Stingrays I can put a battery in and do the occasional weekend gig maybe once a month or two, forget to unplug it overnight occasionally and do rehearsals and practice with it for a couple of years and the battery is fine. 45 minutes seems faster than you can drain a battery with a delay pedal. There shouldn't be a huge draw.

Do you know the resistance of the volume pot? Just from doing a quick google search I noticed a value of 25k for one of their systems. Seems low compared to passive stuff. 250k and 500k are more common values for passive stuff.

If it isn't something simple like that I'd be inclined to look at craigslist or whatever for a passive pickup. Or a bass for that matter. I have no idea how much merit the instrument has.

At the end of the day I guess Ska Punk doesn't wait for the most ideal gear.
 
There are passive sets of pickups cheap $30 new and even American Fender P-bass for $65 ish used....
I ohmed the plug connector and the tip and the ground is right.
Made sure they arent touching when the cable is unplugged.

I took out one of the batterys and went single 9v, and compared that to the "passive" and it works fine.
I dont see a difference other than volume, the active can clip the input at 3, and the passive needs 8 to clip the input.....so no huge tone difference.

and the tone difference can be adjusted with the three EQ sections and this amp has Enhancer and Compressor built in. (Bassman 400)

the actives with battery installed are so loud the preamp has to be turned waaaay down and theres an active button that can pad it down too. this still doesnt make a lot of sense to me? why have louder pickups and then overload the preamp? better for tube amps?

either way, I unplugged the Jbass pickup so its running on only P-bass pups and works fine. I might have a switchcraft guitar jack laying around to swap out and get something that grabs better.

Im not sure what the ohm is of the volume pot...but it was one of the last ones of five that worked.
the necks soundgear by ibanez, the bodys homemade and the pickups are a EMG PJ set.

thanks for the inputs
 
The less windings a pickup has, the less distortion there is. So they make a clean pickup and use a preamp to boost the output.

There is also nothing sadder than an SVT that you can't get to distort.
 
The less windings a pickup has, the less distortion there is.
???

It's basic gain staging. Get as much gain as you can as early in the chain as possible so your not amplifying so much inter-stage noise.

Most of the point of an active system is to keep cable length and load impedance (the In-Z of the amp) from affecting the tone coming out of the guitar.

I personally can't imagine how the things pass anything at all without power, but I don't know much about those pickups...
 
I guess I should have said "the clearer the pickup will sound" The more windings, the more output and the muddier the sound.

If you want high output and clear bright sound, you want less windings and an preamp.

Yes, the ultimate in "phat" is the super high output humbucker which has high inductance (LOT of thin wires) and high inter-winding capacitance. The pup is of high internal impedance and therefore needs high value pots and this all adds up to the cable shunting the highs.

There was a Gibson guitar that had low impedance pups (EMGs?) and a lift transformer. The same could be done today with very wideband low Z pups and preamp technology which borrows from moving coil phono cartridges but I guess there is not the market?

I cannot explain how the circuit can work both actively and passively but a good set of photos would help.

Dave.
 
That's one of the reasons why a lot of super high gain guys use emgs. Having all that extra high end gives you better pick attack with super high gain. It counteracts some of the moosh.
 
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