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Author Topic: Positive power supply  (Read 2628 times)

MrBump

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Positive power supply
« on: March 23, 2011, 07:39:52 AM »
Possible dumb-ass question coming up...

I have a treble booster that I'm using on a board powered by a1 Spot. Would it be ok to use the 1 Spot 9v battery adapter to power the germanium treble booster without damage to either?

Mark.
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Frank

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Re: Positive power supply
« Reply #1 on: March 23, 2011, 09:35:41 AM »
Few things to consider here:

1) Does the adaptor supply AC or DC and does the pedal require AC or DC? Most pedals require DC, check the label on the bottom
2) Does the output voltage of the adapter match the voltage required by the pedal?
3) Can the adaptor supply enough current? If the pedal requires 300 mA and your adaptor is rated 150 mA then that's not enough current capability.
4) If you're powering several pedals from one adaptor then the adaptor must be rated to supply at least the combined current of all the pedals.
5) Most pedals have reverse polarity protection but don't rely on it, check if the adaptor plug is centre negative or centre positive to match the pedals.

jpfamps

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Re: Positive power supply
« Reply #2 on: March 28, 2011, 08:01:44 PM »
The main issue is that the vast majority of germanium booster have their "earths" tied to the positive power terminal.

Virtually all other pedals have their "earths" tied to the negative power rail.

If you connect a negative earth and a positive earth pedal to the same power source you will have a short circuit which may well destroy the power supply.

Your options are:

1) Use a battery for the booster. In fact many people prefer the sound of this type of pedal powered from a battery.

2) Use a separate power supply for the booster.

3) Use a power supply with isolated outputs, such as the (expensive!) Voodoo Labs Pedal Power

4) Use a Gig Rig virtual battery (and NO i don't work for Gig Rig!)

http://www.thegigrig.com/acatalog/CA_Virtual_Batteries.html

You also need to bear in mind that a lot of this type pedal are v-v-v-ery sensitive to noise on the power supply, so a poorly filtered power supply will inject a ton of noise into the pedal.

Frank

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Re: Positive power supply
« Reply #3 on: March 28, 2011, 08:07:18 PM »
Further proof that sand-based electronics cannot be trusted!