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Discussion Starter #1
So I lucked into picking one of these up at Jack's Attic Sale (Long & McQuade). It's a large effects board with many different voltage offerings and input/output options to accommodate various effects boxes, and comes with a nifty heavy-duty hardshell case. Here's the issue: I'm cabling it together, and everything works so far except my Zoom Multi stomp box. I notice that the standard 9 v dc feed on the board is 100 ma, and the Zoom box needs 500 ma. There are some other 9v options, but the board doesn't specify the amperage from them... and of course I'm afraid to blow it up. Do I keep using batteries on the Zoom or does anyone know the answer to this riddle?
 

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Discussion Starter #3
Apparently the manufacturer's not making them any more, so no info on the website. That was my first thought too.
 

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edited after google search
 

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  • Hardcover professional pedalboard designed to accommodate nearly any possible configuration of pedals
  • (2) 1.3 amp 9VAC jacks for powering pedals from Digitech and Line 6, etc. (2) variable DC jacks to allow any voltage from 4-12 volts (simulate an almost dead battery). (4) standard 9 VDC jacks for Boss, Electro-Harmonix, etc.
  • (1) 18 VDC jack for MXR EVH Flanger, etc. (1) 24 VDC jack for boutique and vintage pedals and (2) 9/12 VDC jacks to accommodate additional boutique and vintage pedals
  • All DC jacks have polarity switches so center negative or center positive is not a problem with the SKB-PS-55 Stagefive Professional Pedalboard
  • All DC outputs have a current rating of 100mA each
According to the Amazon Description.

so 2 of your outputs have 1.3 amps... just have to figure out which 2. Pretty sure its the red rectangle.....

 

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sorry, didn't see that without my glasses

Zoom needs a wall wart. If they were 250Ma outputs you could buy a current doubling cable, it joins 2 outputs to 1 input but 200Ma still won't cut it.

I have the same problem with the Digitech trio. Needs 500Ma as well IIRC so it's on a wall wart.

I was going to suggest an AC/DC to DC buck converter placed in a Hammond 1590LB but with only 9V out there will be a voltage drop so the pedal would only be running 6.8 volts plus or minus depending on the chip used in the converter.
 

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Discussion Starter #8
Thanks for helping, everyone. I guess I need to do some more research. The board has a couple of variable dc voltage outlets (you can dial in anything from about 4 v up to 12) but doesn't specify the amperage.
 

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The board has a couple of variable dc voltage outlets (you can dial in anything from about 4 v up to 12) but doesn't specify the amperage.
That's the one to try then. It doesn't matter if it puts out 30 amps at 9VDC, the pedal will only take what it needs, 250mA (sorry 500mA, corrected). Just don't exceed the voltage by too much.
 

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All the DC outputs are 100Ma. the + switch changes polarity to center positive for certain pedals that require it and the white phillips trim is for adjusting voltage. There is nothing to adjust the current.
 

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or just build a cable with a 3 amp 50v diode in it
or put in a 10 amp 50v diode bridge and a couple of caps inside the box before the 9V output jack.
 

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100ma is a sign that the unit uses 3-pin regulator chips to down-regulate a higher voltage for each output. Traditional 3-pin regulators come in 100ma and 1A flavours. Anything else is using a different approach or even a proprietary device.
Because wallwarts tend to come in round numbers like 200, 300, 500, or 1000ma, manufacturers specify the next likely rating one up from what the pedal actually requires, to provide a margin of error. If the pedal truly needed 490ma, the manufacturer wouldn't take the risk of recommending a 500ma unit but would have said 750ma or something like that. Nothing would "blow up" in the pedal, but pushing any electrical device to its limits results in heat being generated and compromises the lifespan of the heated device. So the odds are quite good that the Zoom units needs much less than 500ma, but more than 200ma, such that a 500ma recommendation meets all the safety margin needed.
 

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Nothing would "blow up" in the pedal, but pushing any electrical device to its limits results in heat being generated and compromises the lifespan of the heated device.
Maybe clarify how each 'device' in question can be pushed to it's limits.
There are misconceptions re this and here's a chance to clear em up.

If the device is a power SUPPLY, it can be pushed to its limits when ___.
If the device REQUIRES power, it can be pushed to its limits when ___.
 

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My bad for not being clear enough.
Think about fuses, the little glass kind. They work by passing current until such time as the heat generated by the current being pulled through exceeds the capacity of the wire/filament. The tiny conductor inside the fuse is selected for its ability to handle the heat produced by passing X amperes through it. As that amount of current is approached and exceeded, the fuse overheats and succumbs to the heat, burning out and creating an open circuit; a useful one, thankfully.
A well-regulated power supply will include semiconductors that have their own fuse-like properties, and limits to current-handling capacity. Thankfully, many commercial pedals will include circuit adjustments to limit the amount of current they draw, such that the pedal will rarely be pulling more current than it can handle internally. So the risk tends to be more to the power supply.
The upshot is that if a pedal (or combination thereof) draws more than 100ma on its own, and is being fed by a 3-pin regulator spec'd for handling up to 100ma, the regulator is likely going to get warm, possibly hot, and possibly too hot for its own good.

I should add that what modulates/mediates the risk of heat damage is heat-dissipation opportunity.

To illustrate, forum member zdogma has two Diamond Memory Lane pedals. One works fine, and the other worked but had an annoying whine, that he was hoping I could cure. After several exchanges with the good and responsive folks at Diamond, I was able to jog the memory of the tech support fellow, who said that in early runs of the pedal, a shipment of voltage-regulators they received for the Memory Lane had been found to have abnormally thin heat fins. The Memory Lane uses a trio of 1A-rated 3-pin regulators to derive several different voltages from a common wall supply. None of them is in physical contact with any other surface to conduct heat, and rely entirely on the metal fin to dissipate heat from the guts under the epoxy. The Diamond tech sent a pic of what the "bad" regulator might look like, and sure enough, one of the three looked exactly like the pic. What tipped him was that the whining would take about 5-10 minutes to start occurring. The unit fired up fine, but because the regulator could not dump enough heat fast enough (especially in a small closed space), after a short period of use the regulator would overheat and drift off-spec, leading to the "wrong" voltage and the whining. I replaced the existing one with another of the same part number, but having a heat fin with the normal thickness, and the problem disappeared.

That's not a recipe for curing whining. Rather, it illustrates that overheating of portions of a power supply by taxing it don't necessarily result ONLY in damage, but can also result in a number of other sorts of issues, stemming from components not observing their best-case operating conditions.
 

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I just meant...

If the device is a power SUPPLY, it can be pushed to its limits when it is asked to supply more current (mA) than it can produce.

If the device REQUIRES power (e.g., a pedal) , it can be pushed to its limits when..
-the supplied voltage (V) is too far above or below what's required.
-the supplied current (mA) falls below the required current.
 

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I just meant...

If the device is a power SUPPLY, it can be pushed to its limits when it is asked to supply more current (mA) than it can produce.
Yes.
If the device REQUIRES power (e.g., a pedal) , it can be pushed to its limits when..
-the supplied voltage (V) is too far above or below what's required.
-the supplied current (mA) falls below the required current.
Shorts in a variety of locations can result in a pedal drawing too much current. Depending on the design, if it's a thoughtful and cautious one, that may simply result in one or more components along the power path fry like fuses. I think we've seen many instances over the years of a resistor along the power path fried beyond readability. Because the resistor behaved like a fuse, that saves the life of everything else. Some designs, however, are a bit less anticipating of such catastrophic errors. Remember that there was a lengthy period when the majority of pedals either came with an on-board transformer and AC cord, or else were run off a battery. Many battery-operated pedals lacked a power jack for use with an adapter. The very idea that people would power a pedal with an outboard source that might be able to do damage to the pedal was still a long way off. So I'll forgive pedals from the '60s and '70s that did not include protection against power catastrophes.

Most semiconductors (transistors, diodes, chips) used in contemporary pedals are either very tolerant of higher voltages (within reason), or else are accompanied by regulator circuits intended to step down whatever voltage is being fed to the pedal. So, whether you feed your chorus or flanger pedal 9, 12, 15 or 18V (though I'm not recommending this), the delay chip is unlikely to be receiving more than 5V because of an onboard 5V regulator. Of course, while the delay chip is protected in that manner, and the op-amps can likely "take it", that doesn't mean that any electrolytic caps included in the circuit are spec'd to handle higher voltages. There's a very good chance they are, but one needs to confirm it first, before proceeding. Powering a pedal that uses 16v-rated caps with a 15v supply is risking those caps being off-spec, and the pedal sounding bad for a variety of reasons. And while it is not a result of "stressing" anything, many pedals have biasing that is predicated on a particular supply voltage, and use of a different voltage is akin to mis-setting the bias.

Providing insufficient current is unlikely to damage anything, but IS likely to result in poorer sound. I suppose the exception would be fuzz pedals where "starving" the circuit of current results in desirable glitchy sounds. I did this to a Jordan Bosstone clone, and a Fuzz-Face-like circuit, and feeding less current to the circuit yields some interesting results.
 

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100ma is a sign that the unit uses 3-pin regulator chips to down-regulate a higher voltage for each output. Traditional 3-pin regulators come in 100ma and 1A flavours. Anything else is using a different approach or even a proprietary device.
Because wallwarts tend to come in round numbers like 200, 300, 500, or 1000ma, manufacturers specify the next likely rating one up from what the pedal actually requires, to provide a margin of error. If the pedal truly needed 490ma, the manufacturer wouldn't take the risk of recommending a 500ma unit but would have said 750ma or something like that. Nothing would "blow up" in the pedal, but pushing any electrical device to its limits results in heat being generated and compromises the lifespan of the heated device. So the odds are quite good that the Zoom units needs much less than 500ma, but more than 200ma, such that a 500ma recommendation meets all the safety margin needed.
Can you change your username to Wikipedia ;P
 
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