Active pickup mod.

H

henryj

Blues Newbie
A while back I was playing my ESP with EMG active pick ups.  The battery was getting weak and just before it quit completely I was getting an interesting heavy metal, crunchy, distorted, sound. This lasted for just a few minutes, before it went to complete garbage, as the battery gave up the ghost.

I was wondering if I could wire in a pot to my battery so I could adjust the power simulate the low battery and get that crunch sound intentionally.

Could it work?
I know could easily wire a temporary pot into the battery connection to test my theory, so I guess my real concern is could I cause permanent damage?
 
Cliff_Rogers

Cliff_Rogers

Blues Newbie
Problem with using a pot is to find one low enough in resistance to have a usable range.

I'd try wiring in diodes in series.
Each one will drop 0.7 of a volt.
You may only need 4 or 5 in series & then just put a switch across them in parallel to bypass them.
 
tommytubetone

tommytubetone

Great Lakes
The same thing happened to me yesterday, except I was not happy with the sound. I spent 10 minutes checking connections and amp settings, and then realized ...it's the battery stupid. I did find this explanation for active vs. passive pickups. So if I ever wanted to change out the pickups in my Budd Guy strat, would they have to be designed to work in an active system? I guess the broader question is if pickup manufacturers make 2 styles. One for active and one for passive. That's kind of what I got out of the article.   :(


http://proguitarshop.com/andyscorner/pickups-explained-active-vs-passive
 
Rancid Rumpboogie

Rancid Rumpboogie

Blues Mangler
The same thing happened to me yesterday, except I was not happy with the sound. I spent 10 minutes checking connections and amp settings, and then realized ...it's the battery stupid. I did find this explanation for active vs. passive pickups. So if I ever wanted to change out the pickups in my Budd Guy strat, would they have to be designed to work in an active system? I guess the broader question is if pickup manufacturers make 2 styles. One for active and one for passive. That's kind of what I got out of the article.   :(


http://proguitarshop.com/andyscorner/pickups-explained-active-vs-passive
Click to expand...
Well, I didn't get much out of that article other than that active pickups require batteries, which is reason enough for me to steer clear of them.

Their two biggest touted advantages are no change in tone when you roll your volume control back, and low impedance which negates the negative aspects of long cable runs.  Both of these same advantages can very easily be had with regular pickups ... a very simple treble bleed network on your volume control solves the volume tone change issue, and using only one pedal in your chain with a buffered bypass switch solves the impedance problem because it converts your entire chain to low impedance. 

That leaves only one more advantage to be considered, which is the lower magnetic field and less pull on your strings meaning more sustain.  But that difference is only discernible if you have your standard pickups so close to the strings that the tone is ice-picky, which 99% of players don't.
 
CapnDenny1

CapnDenny1

Student Of The Blues
What you want is an adjustable voltage regulator.  It would cost you a couple bucks.  The pot would control the regulator output and you could vary it anywhere from 0 to 9V.

Just a pot would work also, but you would have to know the power draw of your circuit to size it.  Something around 500 ohms would probably work.

That's basically how the amps which allow you to crank down the power level work.  They reduce the clean headroom, and force the amp to work in a distorted region of operation.  Likewise with distortion pedals or high gain amps.

You could try powering it from some AAA batteries.  Each one is 1.5V, so 6 in series would give you 9V.  You could determine what the voltage is that sounds good and build a switch that switches between that and the full 9V.

Or just get a distortion pedal? :D
 
allen

allen

Blues Newbie
it can be done,you need a female 9volt plug and a 6volt regulator and light power cable.this is called voltage sag control,cut plug from guitar solder female plug on, plug power pack into female you now have sag control.you will have clean low voltage,also the voodoolab2 i have a 9volt power sag control as well it's worth a look, i put my ts 808 on 4volts and it can sound like a pig nose  :)
 
tommytubetone

tommytubetone

Great Lakes
A lot of good info here on pickup wiring. It's required reading if you want to understand the Rancid mods, and a whole lot more.  If you click on "misc. switching mods" at the bottom of the page, you will see the treble bleed circuits that Rancid is always talking about.  :D

http://www.1728.org/guitar.htm
 
Rancid Rumpboogie

Rancid Rumpboogie

Blues Mangler
A lot of good info here on pickup wiring. It's required reading if you want to understand the Rancid mods, and a whole lot more.  If you click on "misc. switching mods" at the bottom of the page, you will see the treble bleed circuits that Rancid is always talking about.  :D

http://www.1728.org/guitar.htm
Click to expand...
There are all kinds of treble bleed networks.  There are three in the link suggested, but none of those is what I use.  The one I use is shown in this video ... everything you need to know is here ... and I can vouch for it because it is in every guitar I own regardless of pickups and it works quite well in all of them. 
http://www.stewmac.com/tsarchive/ts0182.html?utm_source=newsletter&utm_medium=email&utm_campaign=ts0182
The type that I use is in tommytubetone's link (the parallel option) but it uses a different value resistor and different value capacitor than I use.  His link says use a 100K resistor, mine says 150K.  His link says use a .002 cap, mine says use a .001 cap.  I can vouch for the one I use, but not for anything else.

The series option in tommy's link put forth by Chris Kinman most probably works very well too, but I haven't tried it.  I have had a lot of pickup conversations with Chris Kinman over the years and I have learned to trust whatever he says because the man is very sincere and he doesn't B.S.
 
Rancid Rumpboogie

Rancid Rumpboogie

Blues Mangler
Thanks RR. Stewart McDonald is right down the road from me. I may have to pay them a visit.  ::)
Click to expand...
I don't know that active pickups even have the same problem with the volume control in the first place. :-/  I don't think they do.  I think that's one of the "selling points" for active pickups.

Stewmac has the capacitor you need, but not the resistor.
I got mine from Jameco
http://www.jameco.com/webapp/wcs/stores/servlet/StoreCatalogDisplay?storeId=10001&catalogId=10001&langId=-1&gclid=CPSikPixm7gCFUFyQgod-hYAxg
Once on the site, you will see a Product Search box, and right underneath it in small print is a link for "Advanced Search".  Click on "Advanced Search".  There, you can search by actual item part number.  Here's the two items you need:
Item 15190 @CAP,CERM,DISC,.001uF,50V,20%
Item 2159120 @RES,CF,150K OHM,1/4 WATT,5%
 
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