External power supplies for internal preamps

People here have made their own versions of this idea and it works fine. I guess I don't see the point of the EMG unit really. If I want to run off batteries the batteries in the bass are fine. An external supply should run off AC, IMO. And I do run my active basses off their internal batteries so I have no direct experience with either DIY or commercial versions.

Ken

 

It still seems silly to me that people want to overcomplicate things like this. Preamps usually require no more than a couple of milliAmps current, which makes a 9V battery the perfect power supply. Changing a battery once a year is hardly an inconvenience, but adding a power supply and using special instrument cable definitely is.

 

To wake up an old thread...

I worry that the 18v preamp in my NS Design CR Cello is a real vulnerability live, so today I made a series-linked double battery clip attached to a DC socket to get external power in, and that plus an Xotic voltage doubler means I can run the preamp at 18v from an external 9v supply. Just have to be sure to get the battery clips the right way round.

 

On EMG's website, they explain that the 9/18v external box is for guys and gals who have a bass where they want to add active EMG's but either a) don't have room in the exisiting routs to mount a battery or b) don't want the surgery to rout out and add a battery box. And with vintage prices, you could always put the original pickups back in and nobody's the wiser should you want to return it to original equipment. A good idea, but not sure how many takers they'll get as it requires a stereo cord between the axe and the box, and then a regular guitar cord out to the amp from there. And it can be powered from an optional 'wall wart' 110-9v.

Sure, there's lots of guys who could build one of these, but then again, there's a lot who can't. IF you ever see me with a soldering gun, run to your safe place and call 9-1-1 . . . . .

 

When I had my two Alembics ('84 Exploiter and '87 Persuader - Vector body) I added a TRS jack to each of them wired up so that the Tip was the audio signal and the Ring was for the 12V external power supply I built for them. The PS box had the TRS jack for a 3 conductor cable to go to the basses, and a TS jack for the audio to pass on to the amp.

I no longer have those basses but I still have the power supply if anyone would be interested in doing something similar with their bass.

 

I may be missing the obvious, but wouldn't a 1 Spot with the battery clip adapter work for 9v systems?

 

That's effectively what I've done for my 18v system with the Xotic voltage doubler... downside is a second cable running to the instrument (less hassle on my NS cello than a bass perhaps especially as it's mostly played on its stand).

 

You can do that, if you want. Just make sure your power supply is clean (no ripple, etc.) and that it has short protection.

 

There is no need for a second cable. Use a "stereo" cable, with the signal on the tip and the power on the ring.

 

In my case with the NS Design cello, that would involve a major rewire. As I don't need mobility I'm happy to put up with a separate power cable to avoid that.

 

Any chance you still have this box and wanna send it to California?!

 

I already sold it a couple years ago to someone near San Francisco! He is using it to power his Zon, otherwise I would have sold it on to you.

 

I do this on all my personal basses now. Either from the amp (modified) or a separate box. Just use a microphone cable (balanced type has two separate shielded conductors) and stereo jacks. I don't mix other instruments so there is no concern for me with swapping issues. I really didn't want battery boxes or extra routing for a clean look.

 

What power supply do you use? No extra noise?

 

At present I have power tapped from the amp and run via a stereo cable to my bass. I have to make a portable unit for when I don't take my amp with me.

 

Nice- I’m gonna build a box and see what my Cioks power supply gives me. I have almost everything I need already, not sure why I’ve never tried this before!

 

There is a french manufacturer who sales this kind of thing. He calls it the ZAM power.
You may try to buy from him:

Produits – Zampower

 

This is how I set it up on my amp (Vox V125 Bass). I added a power output jack and made up a cable using two conductor microphone cable. This way I can unplug the power and use a passive instrument using the same cable when I want. I built a simple regulated power supply and installed within the chassis and tapped voltage from the amps circuit. For a portable power supply I will build one into a Vox volume pedal I picked up.

 

Here's how I did mine on my Marco Bass:



That a 4 pin XLR and I still have options on how to use the extra conductor. We may add a piezo pickup next year, or maybe just a separate output for slide bass through a tube amp.