What is the 18 Volt Mod?
tranztek said:
GH Welles - what is the 18v mod?? Is this something a tech has to do and what does it consist of?
This explanation is lifted from this website. The Website has picture diagrams:
http://mywebpages.comcast.net/mgollihur/emgmod.html
"The smart folks at EMG had the thoughtfulness to make their pickups able to handle voltages from 9v to 27v, reportedly to make them phantom-powerable (another intriguing thought, but the subject of another digression.) Some enterprising folks discovered that adding a second battery (thereby powering the pickups at 18 volts rather than the stock 9) makes an enormous difference in the voicing, sound quality, and headroom that EMGs can provide. That "choked" or "signature EMG" tone is no more. Clarity and "oomph" is yours for the taking. This mod improved all of my preset sounds, from the "rumble and click" setting to the "balls and chunk" preset. And it only takes 15 minutes and costs like a buck to try it; and for the faint at heart, it's totally reversible.
This is directly from the EMG Site:
"Can I use multiple batteries?
Yes. If you've got room for multiple batteries in your guitar, you can use two batteries wired in series to power your onboard circuitry at 18 volts. The output level will not appreciably increase, but you'll have increased headroom and crisper transients. This is especially useful for percussive/slap bass styles where you can generate enormous instantaneous power levels across the entire frequency spectrum. You can also wire two batteries in parallel to provide a regular 9 volt supply but with much longer lifespan between battery changes.
Although most of our products are rated for 27 volts, we recommend a maximum of 18 volts. The additional benefits of 27 vs. 18 volts are negligible."
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Materials required:
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* Soldering iron and solder
* 9V battery "clip"
* Something to snip and strip wiring (wire stripper, teeth, whatever you got)
* Electrical tape
* A couple of new batteries
* a 9V battery holder is preferable - it keeps the battery from bouncing around in the cavity. (Surrounding the batteries with foam is a decidedly low-tech but effective approach, as well.)
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The Instructions:
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Figure 1:What you've got now.
The clip for the 9Volt battery currently attaches directly to one of the prongs on the 1/4 stereo output jack; this way you're not draining the battery when nothing is plugged in.
1. Take out your current battery.
2. Figure out how you're going to jam 2 batteries into that little compartment (an important step - you may need an extra length of wire or some creative thinking, depending on your bass.)
3. Heat the iron and desolder the black wire from the existing 9v clip from the output jack.
4. Solder the red contact of the new 9v clip to the black contact of the existing one and completely insulate with the electrical tape.
5. Solder the black wire of the new clip to the output jack where the old one attached.
6. Do whatever else you need to do while you're there -- put in the battery holder, if applicable.
7. Put in two fresh batteries - mixing old and new will give less than stellar results.
8. Play and be stunned and amazed. If not stunned and amazed, reverse steps to negate, or use "Upgraded to 18v electronics" as a unique selling point when you get rid of this bass.
Figure 2: How it will look.
>Here's what it will (essentially) look like when you're done (but don't forget to insulate the wire-to-wire solder joint to prevent shorting.)
For those afraid of commitment:
Fellow TBL'er (The Bottom Line Bass Digest) Rick Blair suggests this alternate method which simply involves creating a harness with a three pack of battery clips:
"Wire 3 battery connectors in series and connect a battery to two of them and the third connector to the original battery connector in the bass. If you ever decide to go back to a single 9V battery, merely unplug the harness."
Important Note: this section has been recently updated due to some people having trouble with this method. Please completely Think the whole thing through as you're doing it to make sure polarity is correct - reversed voltage may damage your preamp or pickups.
Figure 3: The temporary harness
(Again, don't forget to insulate the solder joints to prevent shorting!)
For the real wackos:
You can, if slightly off-kilter in the noggin, even add a THIRD battery to increase to 27v. However, I'm told that the upgrade from 18 to 27 is not nearly as dramatic as that from 9 to 18; and it's probably not worth the extra battery costs or trouble to make room in an already crowded cavity.
Hey, this mod is also applicable to guitars as well. I have an old Peavey six-string that screams.
