Sealed Lead-Acid power for pedals...

Discussion in 'Effects [BG]' started by Trevorus, Nov 27, 2005.

  1. Trevorus


    Oct 18, 2002
    Urbana, IL
    I just had a though here. What if I used a sealed lead-acid battery for a main power for my pedal board. This would get rid of wall wart hum. But, my problem is a voltage limiting that would pass an amp without burning up. Anyone got any ideas?
  2. tplyons


    Apr 6, 2003
    Madison, NJ
    Like a car battery type?
  3. Trevorus


    Oct 18, 2002
    Urbana, IL
    Not really the car battery type, I mean the type for emergency lighting and stuff. It's a small battery that is sealed and uses lead/acid. I could charge it at home, and use it at gigs and such, and never have to worry about the buzz from plugging it in. I know how to figure the wattage used with the surrent and voltage used. I think you figure it after the dropping resistor.
  4. Well there are several ways to drop voltage.

    a) Instead of just a dropping resistor, use a voltage divider network--google it and there are calculators that do the math for you. These are independant of current.

    b) Use a Zener diode. Cheap and effective. Limited to 5 watts dissipation.

    c) Use a single voltage regulator (transistor) such as a 7809, these are capable of 1A.

    d) Make a sophisticated power supply using an output transistor such as a 3055....

    e) or...Forget the extra few volts, many devices can handle 13.6 volts DC just fine...

    However, it's really not that difficult to make a hum-free power supply that runs off of the wall AC.

    Do you REALLY want to lug a heavy battery around? :eyebrow: Especially a lead-acid type...which can leak and cause a real heartache. :eyebrow:
  5. Trevorus


    Oct 18, 2002
    Urbana, IL
    Well, enlighten me about quieting the wall warts. That is what I would really like to do!
  6. Personally, I'd make a single AC power supply to supply all the pedals from one source. I'll try to find you an article showing a simple power supply, but it just consists of:

    -a transformer
    -a rectifier
    -a filter capacitor
    -a voltage regulator chip, I'd try the 7812 for 12 volts
    -another filter capacitor
    -a metal enclosure to put everything in.
  7. build ye'self a Spyder power supply from the instructions at and be done with it. Make sure you use the largest filter caps you can and you'll never have another ground loop hum or power supply ripple hum in your life.


    No they're not. A voltage divider by itself (aside from the wattage rating of the resistors) is independent of current in as much as the fact that the voltage ratio stays consistent even though the supply voltage varies (hence varying current as well.)

    However, as soon as you hook up something to the junction of the resistors that sucks current out of the divider network then you run into problems. Especially given that the current demand is going to fluctuate a fair bit in this setup. ideal circumstances with significant heat sinking.
  8. I wrote my initial response rather hastily, so thanks for the clarifications...thanks for providing him a link to a power supply design.
  9. that's cool, no malice here! I've just seen heaps of people go down the path towards making their own supplies and they often come adrift on simple things like the 1A spec on a fixed voltage regulator - ending in brown smell and smoke!

    Oh, and while I'm at it, another plug for which has loads on useful info for anyone looking to roll their own effects, amps and power supplies.