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Fatpants 17v mod

Started by bigmufffuzzwizz, June 08, 2011, 01:46:56 AM

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bigmufffuzzwizz

Im wondering if I can take the 17v output tap and wire it to a second dc jack? If so then i could use a male to male dc plug to power another pedal at 17v externally.
Im thinking 17v tap to outside + lug of dc jack. Would this work?
Owner and operator of Magic Pedals

stecykmi

For sure. You'll need to tap it from the positive side of C7 to get the +17v which may be a bit awkward, but definitely possible.

just make sure you get the polarity on the +17v output jack right. I wouldn't power anything digital with it (which includes anything that uses the mn3xxx series), and then only 1 or 2 analog things with it. it's only rated for about 300uA. 

bigmufffuzzwizz

The main thing I would run off it is my BYOC digital reverb. I was hoping it would clean up at 17v. I don't really understand the whole current draw in pedals.  :-[
Owner and operator of Magic Pedals

stecykmi

Actually, looking at the datasheet again, I realize misunderstood it. it should be fine as long as it's not crazy (like 200mA). The datasheet doesn't actually give a rating for max load current (which I think is strange), only for supply current (to power the chip itself, not the rest of the circuit).

I realized this morning 300uA doesn't make sense, since most pedals are on the order of 1 to 20mA. If 300uA were true, we couldn't even power the single circuit in the boxes were building the 1044's in.

bigmufffuzzwizz

The current draw on the reverb is 20uA so I should be fine to what your saying. But now I have three terms boggling me; current draw, max load current and supply current. This will help me understand better.
From the little research I'm doing to learn, the max load will be how much current the pedal must draw in order for the output to function. Current Draw would be how much it acutally draws? Then supply current is the amount needed to maintian opertaion so that would be very similiar to max load? woaahh
Owner and operator of Magic Pedals

k.rock!

From what I understand, I see if as three level stages ascending like this:

Minimum current draw: supply current (the minimum needed to operate)

Current draw: your average current draw on the circuit

Max load: the highest it can go without failure to operate

stecykmi can correct me if I'm wrong :)


-Kaleb
God bless!
www.kalebromero.com

stecykmi

pretty much. With most analog circuits, I don't think the minimum current draw is much different from current draw since no parts of the circuit are ever really shut off, just switched in and out of the signal path.

Supply current kind of suggests how much current the voltage source (in this case the 1044) is able to supply (or sink) before failure. So a power supply can supply ANY current UP TO the supply current (0 <= I <= Ismax).

Current draw suggest the current "demand" of the circuit. So it operates at some voltage (or voltage range) and draws X amount of current.