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I think I fried my Milk Box ...

#22
Adamixoye said:
I think the DL4 supply is actually an AC supply. For reasons I don't fully understand, it will accept some DC supplies although Line6 recommends against it.
Click to expand...

It is indeed AC. Bad news for a pedal expecting DC. Line 6 and other makers who depart from the standard 9VCD sleeve positive supply but still use the same DC connectors are *ssh*les.
 
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#24
tpaul said:
If it is dead, you can have mine for $50. I just recently got it, it's in great condition but it's not my style. I was going to put it in the classifieds, but if you need one, you can have it for what I paid - $50 shipped.
Click to expand...
This. Unless you like tinkering with electronics I would take tpaul up on his offer and then sell your fried one to someone else who wants to play with it.
 
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#25
ficelles said:
It is indeed AC. Bad news for a pedal expecting DC. Line 6 and other makers who depart from the standard 9VCD sleeve positive supply but still use the same DC connectors are *ssh*les.
Click to expand...

Yeah, the only reason I expressed doubt is because the information you find on line is kind of confusing. I was quite sure that the supplied PSU is AC. But you get conflicting information on whether or not it can run off of a DC supply. My understanding (and I disavow any damage from bad information...) is that a center positive DC supply with enough current will work because of how the incoming voltage is rectified, and indeed there are "DL4" adapters made for this very purpose. On the Line6 message boards they sort of half-acknowledge this while also continuing to recommend the original PSU.
 
#26
Adamixoye said:
Yeah, the only reason I expressed doubt is because the information you find on line is kind of confusing. I was quite sure that the supplied PSU is AC. But you get conflicting information on whether or not it can run off of a DC supply. My understanding (and I disavow any damage from bad information...) is that a center positive DC supply with enough current will work because of how the incoming voltage is rectified, and indeed there are "DL4" adapters made for this very purpose. On the Line6 message boards they sort of half-acknowledge this while also continuing to recommend the original PSU.
Click to expand...

It's bizarre that you can run a DL4 off batteries ie DC...
 
#27
ficelles said:
It's bizarre that you can run a DL4 off batteries ie DC...
Click to expand...

The batteries would have to feed the circuit after the rectifier(s), and probably before the voltage regulator, where it would be expecting DC. The pedal more than likely runs on 5VDC internally. So it can run on 4 C batteries.

Why they set that pedal up to take an AC supply is the better question.
 
#28
mmon77 said:
Why they set that pedal up to take an AC supply is the better question.
Click to expand...
There's a couple of reasons a company might choose to power their gizmo with low-voltage AC. One reason why is that it eliminates having ground loops. With an AC power supply neither side is tied to the signal ground. Also, by having the current rectification and filtering built in the pedal, they can be assured of having clean, filtered and regulated DC for the internal circuits rather than relying on some random wall wart adapter for filtering and regulating the DC.

So, there are reasons for using an AC power supply. You may not agree with those reasons.

[over-explanation]
There's two basic methods of polarity protection, both use a DIODE because it acts as a "one way valve" for electricity. The simple method is to simply have a diode in series with the power supply. If a reverse-polarity power is connected, no current flows. Simple and effective, however, it takes voltage to "shove" the electricity through the diode, so this caused about 0.7 volts of loss. This can be reduced to close to 0.2 volts by using special 'Schottky' diodes (whatever those are). The other method uses a resistor from the power jack, usually about 10 -50 ohms, and then a diode to GROUND. If reverse polarity is connected to the pedal's power jack, the diode will send the current to ground, basically a short circuit except for the presence of the resistor. That resistor will then heat up, and depending on the resistor's value and the current available from the power supply, could 'melt', 'blow up' or otherwise fail. Ideally, just the 'sacrificial resistor' should be the only damaged component. [/over-explanation]
 
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#29
Crater said:
There's a couple of reasons a company might choose to power their gizmo with low-voltage AC. One reason why is that it eliminates having ground loops. With an AC power supply neither side is tied to the signal ground. Also, by having the current rectification and filtering built in the pedal, they can be assured of having clean, filtered and regulated DC for the internal circuits rather than relying on some random wall wart adapter for filtering and regulating the DC.

So, there are reasons for using an AC power supply. You may not agree with those reasons.

[over-explanation]
There's two basic methods of polarity protection, both use a DIODE because it acts as a "one way valve" for electricity. The simple method is to simply have a diode in series with the power supply. If a reverse-polarity power is connected, no current flows. Simple and effective, however, it takes voltage to "shove" the electricity through the diode, so this caused about 0.7 volts of loss. This can be reduced to close to 0.2 volts by using special 'Schottky' diodes (whatever those are). The other method uses a resistor from the power jack, usually about 10 -50 ohms, and then a diode to GROUND. If reverse polarity is connected to the pedal's power jack, the diode will send the current to ground, basically a short circuit except for the presence of the resistor. That resistor will then heat up, and depending on the resistor's value and the current available from the power supply, could 'melt', 'blow up' or otherwise fail. Ideally, just the 'sacrificial resistor' should be the only damaged component. [/over-explanation]
Click to expand...
Thanks, I kept trying to think of "diode" but could only think of resistor and capacitor as far as protection circuitry was concerned. Hopefully the Milkbox has one and it's all that was harmed. Would be simple enough to open the pedal and look for a burned out component with a glass shell somewhere close to where the power connects to the circuit board.
 
#31
J Posega said:
Would be simple enough to open the pedal and look for a burned out component with a glass shell somewhere close to where the power connects to the circuit board.
Click to expand...

If you're lucky. If it had burned up that spectacularly, you would have more than likely seen or smelled the "magic smoke" when you plugged it in.

You will probably need a multimeter to test the diode/resistor they used as a protection mechanism for an open circuit. It should be located in close proximity where the power jack connects to the circuit board.
 
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#32
For those of you hating on fried milk. . .

P1130669.jpg


If you think this doesn't look amazing come fight me.
 
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#33
I blew up my Idiotbox Blower Box (the main power filter cap, anyway) by accidentally using a center-positive adapter for a different pedal. I told AtariMatt and he fixed it for free even though it was my bad. :hyper:



I assume the OP won't have the fix-it-for-free option. Just posting here in case his misery would enjoy some company. :bag:
 
#34
Adamixoye said:
Yeah, the only reason I expressed doubt is because the information you find on line is kind of confusing. I was quite sure that the supplied PSU is AC. But you get conflicting information on whether or not it can run off of a DC supply. My understanding (and I disavow any damage from bad information...) is that a center positive DC supply with enough current will work because of how the incoming voltage is rectified, and indeed there are "DL4" adapters made for this very purpose. On the Line6 message boards they sort of half-acknowledge this while also continuing to recommend the original PSU.
Click to expand...

Those pedals that have universal power capabilities (DC positive tip, DC negative tip and AC) use a full-wave rectifier to put the DC in the proper polarity for the circuits. So, it makes sense that a DC supply would work on units that have a DC rectifier, but don't use an internal power transformer. Taking a DC voltage and rectifying, regulating and filtering it again is probably a less noisy supply for the circuits, since you are filtering DC twice.:thumbsup:

-Frank
 
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#40
mmon77 said:
The batteries would have to feed the circuit after the rectifier(s), and probably before the voltage regulator, where it would be expecting DC. The pedal more than likely runs on 5VDC internally. So it can run on 4 C batteries.

Why they set that pedal up to take an AC supply is the better question.
Click to expand...

That's what I mean, I get how it works but it's an odd thing to do that can easily give the impression that it's a DC supply. Line 6 should repair the Milk Box for free :)
 
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