Building Pedals

Pickups, pedals, amps, cabs, combos

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timhulio
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Post by timhulio »

I wonder what sort of voltage you'd need to burn-out the thin copper wire in guitar pickups. Would 9v on the input jack of a pedal do that?
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Post by aen »

I dont think so. Some of my first pedals blasted squarewaves of nine voltage in all directions, never killed a pickup. Which is not to say it couldnt happen, but it just didnt happen to me.
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Post by aen »

ekwatts wrote:
One question: Why does my soldering iron look like it's on its last legs? The tip has gone all knobbly, and now that it's cooled down, I've noticed it's all wobbly too. It looks like the nib has etched grooves into itself from being stood in my ghetto-ass homemade stand I made this morning (triangle of wood with a coiled metal coathanger) for some bizarre reason. This is the only time I've used it. Looks like I'm going to have to do a bit more practice. And maybe not use that stand. And probably buy a new soldering iron.
Any iron under $40 is going to shit the bed, and fast. The shitter of it is, ost of these irons are designed for "emergency DIY" like, chicks and dudes who have to fix a lamp cord or something. If you have any intention on soldering again, step up to a weller or something. We use 2 weller stations ($60 a piece?) and the tips are replaceable, but they usually last at least a couple months of constant use. I also just bought some super fancy temperature controlled thing from xytronic which has held up well these last few weeks.
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ekwatts
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Post by ekwatts »

Here's the power socket as viewed from the inside of my Molie:

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You can't really make it out, but there's a tag above the centre metal bit, not connected to the centre. One of the tags is tall, the other one short.
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Post by Bill Oakley »

Before you hook it up, just plug a power supply into it and check it with a multimeter. If you have the probes backwards, you should get a negative reading (as in -9.46). If they are the right way, you will get a positive reading. When you get a positive reading, where the red probe is, that is your 9v and the other is ground.
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ekwatts
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Post by ekwatts »

Bill Oakley wrote:Before you hook it up, just plug a power supply into it and check it with a multimeter. If you have the probes backwards, you should get a negative reading (as in -9.46). If they are the right way, you will get a positive reading. When you get a positive reading, where the red probe is, that is your 9v and the other is ground.

Brilliant! I'll have to dig out my multimeter now.
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Post by Mike »

If you use the tag of the input jack to switch the power on and off, the pedal casing and the jack grounds are now positive. This means it can't be on a daisy chain with regularly wired case-jack-ground pedals.

Surely?
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Post by NickS »

timhulio wrote:I wonder what sort of voltage you'd need to burn-out the thin copper wire in guitar pickups. Would 9v on the input jack of a pedal do that?
Checking StewMac, the pickup winding wire they sell is either 42 AWG or 43 AWG copper.
This site lists the fusing current of 43 AWG copper wire as 1.06 amps. So, if the DC resistance of your pickup is 6k ohms, you'd need around 6000 volts DC to make it glow and pop. I extrapolate the rated current carrying capacity of 43 AWG to be around 70mA; do not exceed 42V. 9V or 12V should not damage the wire.
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Post by ekwatts »

Mike wrote:If you use the tag of the input jack to switch the power on and off, the pedal casing and the jack grounds are now positive. This means it can't be on a daisy chain with regularly wired case-jack-ground pedals.

Surely?
Shit, really? How do I get past that, then? I already have all the wires in place on the bypass box. That's a proper shitter, I rely on my daisy chains.
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Post by Mike »

Yeah, you're going to want to wire it with the negative connections/ground on the DC jack going to the input/output jack grounds, and not the positive/9V connection, or you won't be able to daisy chain this pedal and others from the same power supply as they'll short it out.
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Post by ekwatts »

Like this?

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Post by Mike »

No that still has the 9V lug of the DC jack connected to the jack grounds, which is not what you want.

DC jack ground connection goes to all your grounds including the jack grounds and the 3PDT.
DC 9V lug goes to your LED anodes only.
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Post by ekwatts »

I'm confused.

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Now the point where the red wire was going from the input jack to the DC socket on the other diagrams is the input jack ground? So the black wire going from the middle input jack lug should actually be connected to that lug?
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Post by Bill Oakley »

That is where you would hook the battery snap negative or black wire so it disconnects the battery when you unplug the guitar cable so your battery doesn't drain. If you aren't using a battery snap, nothing goes there and you could actually use a mono jack instead of the stereo jack.
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Post by ekwatts »

Ah good, so this circuit will work, and work in a daisychain then?
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Post by Bill Oakley »

Looks good to me. I'm assuming you're attaching the loose wires on the right to the input jack though.
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Post by Earth »

ekwatts wrote:Here's the power socket as viewed from the inside of my Molie:

Image

You can't really make it out, but there's a tag above the centre metal bit, not connected to the centre. One of the tags is tall, the other one short.
Turn the Blue 3PDT around 90 degrees and its right. Unless of course you specifically want it the way you have it. 8)
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Post by Bill Oakley »

Good point. The way you have the switch in the illustration, the holes run up and down. In the picture of the inside of your pedal the holes run left to right if the bottom of the pedal was towards you. The switch won't work if you wire it up sideways. 180 degree flips are ok but 90 degree flips are bad.
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Post by ekwatts »

Bill Oakley wrote:Looks good to me. I'm assuming you're attaching the loose wires on the right to the input jack though.
No, I meant for the stereo jack featured to be the input. Why?
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Post by Bill Oakley »

Sorry. I meant to write output jack not input jack.