#1
Hello guys =o)

I've just built my first pedal board, which, aside from a Deluxe BMP and Morley Vol/Wah, is covered with budget clones (Biyang, Nux, Joyo etc.) while I'm finding my feet (no pun intended) before shelling out for the high end stuff. As a temporary measure to save on batteries, I bought one of those Caline/Joyo power bricks, which came with a US 18v/1A wall wart and a small US->AU adapter, which fits rather loosely, even when I tweak the prongs to tighten the fit, so it powers off very easily with any slight movement. So I had a look through my bag of spare wall warts from over the years and found a 15v/1A with a suitable barrel.

My understanding is that less voltage and correct current shouldn't cause any damage, especially in this scenario where the required voltage isn't actually required because all pedals are 9v, so the 12v and 18v ports are not used. So if I only use 9v and 12v pedals, is there any reason this 15v/1A wart couldn't replace the original 18v/1A? Theoretically, even an 18v pedal should work, it'll just have a weaker output because of the lesser voltage strength...?

One possible theory is that the ~17% drop in voltage supplied may drop the output by a similar % (making the 9v output 7.5v)? Sorry if that sounds dumb, I'm not much of an electronics wiz.

Any help appreciated =o)
#2
Depends on the pedal. Some might work just fine. Others present an inductive load to the power supply and will draw more amperage at low voltage. This may toast the pedal, power supply or both. Feeling lucky? If not, run this by the pedal mfg first. Typical tolerances for a pedal are DCV+/- 10%. You are well outside that so BBQ is very possible.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
#3
Man that is a confusing post. I'm guessing that a US 18V supply would actually be 36V if run on Aussie (that is what US->AU means right?) wall sockets (you guys are 220V) right? So it sounds like you are really messed up. Get a multimeter and check your voltages. If the supply is a regulated supply, which is what you should be using then feeding it 220V may burn up the regulator. Need Cathbard in here to sort this out. He's an Aussie.
Last edited by fly135 at Nov 28, 2014,
#4
Quote by Jaisun-UG
Hello guys =o)
....
One possible theory is that the ~17% drop in voltage supplied may drop the output by a similar % (making the 9v output 7.5v)? Sorry if that sounds dumb, I'm not much of an electronics wiz.

Any help appreciated =o)



Running a 15v adapter into something that was made to use 18v should not cause problems with the adapter (like fry it).
But its performance may not be adequate. Voltage output may not be enough (read below) .
Or it may not even work at all.

As for the part I bolded, will the 9v drop to 7.5v?
It all depends on what they use internally for a voltage regulator.
Some regulators output an absolute voltage regardless of the voltage input, some just drop down the voltage by a percentage of the input voltage depending on the supporting components (resistors) it uses.
Last edited by CodeMonk at Nov 28, 2014,
#5
Quote by Cajundaddy
Depends on the pedal. Some might work just fine. Others present an inductive load to the power supply and will draw more amperage at low voltage. This may toast the pedal, power supply or both. Feeling lucky? If not, run this by the pedal mfg first. Typical tolerances for a pedal are DCV+/- 10%. You are well outside that so BBQ is very possible.


With my luck? Nope =oP I think I get what you mean by inductive load... Some pedals might draw a higher amperage because it's not getting a full supply of voltage? If that is the case, would it still be safe for, say an overdrive that pulls around 5mA, would the the higher draw matter when there's 100mA on tap?

Quote by fly135
Man that is a confusing post. I'm guessing that a US 18V supply would actually be 36V if run on Aussie (that is what US->AU means right?) wall sockets (you guys are 220V) right? So it sounds like you are really messed up. Get a multimeter and check your voltages. If the supply is a regulated supply, which is what you should be using then feeding it 220V may burn up the regulator. Need Cathbard in here to sort this out. He's an Aussie.


It's a wall wart with an 18v output, which is there to counter the voltage difference, not factor it. 100-240v in, 18v out. By US I mean the plug type of two vertically parallel prongs, unlike AU plugs with two opposing 45 degree angled prongs. I didn't specify that, sorry for the confusion. A multimeter is a good idea, except I don't have one. I may buy one soon if I'm going to start tweaking this stuff, but for now I may need to just buy an 18v/1A AU wart to be safe.

Quote by CodeMonk
Running a 15v adapter into something that was made to use 18v should not cause problems with the adapter (like fry it).
But its performance may not be adequate. Voltage output may not be enough (read below) .
Or it may not even work at all.

As for the part I bolded, will the 9v drop to 7.5v?
It all depends on what they use internally for a voltage regulator.
Some regulators output an absolute voltage regardless of the voltage input, some just drop down the voltage by a percentage of the input voltage depending on the supporting components (resistors) it uses.


Is 'they' the pedals, the brick, the wart, or all of those? If you mean the wart, does that mean I could connect the 15v to the brick with no pedals attached and use a multimeter (if I had one) to test the output of the ports to determine if it is absolute or not?

I appreciate the replies guys =o) I am suspecting though that it'll come down to "stop being a tight ass and just buy a 18v/1A AU wart". Oooorrr glue the AU adapter onto the original US wart, lol =oP
#6
Quote by Jaisun-UG
....

Is 'they' the pedals, the brick, the wart, or all of those? If you mean the wart, does that mean I could connect the 15v to the brick with no pedals attached and use a multimeter (if I had one) to test the output of the ports to determine if it is absolute or not?

I appreciate the replies guys =o) I am suspecting though that it'll come down to "stop being a tight ass and just buy a 18v/1A AU wart". Oooorrr glue the AU adapter onto the original US wart, lol =oP


Well, your (The one that I guess was included with the Joyo Brick) "standard" wall wart puts out 18 volts.
It will likely have a regulator and/or transformer in it as well to change the voltage from the wall (120 or 220 AC) to 18 DC volts , but thats to drop it down to its 18 volt output.
In this case, thats not relevant.


As for this part:

As for the part I bolded, will the 9v drop to 7.5v?
It all depends on what they use internally for a voltage regulator.
Some regulators output an absolute voltage regardless of the voltage input, some just drop down the voltage by a percentage of the input voltage depending on the supporting components (resistors) it uses.


The "They" in this part refers to the power brick.
It takes in 18 volts and reduces it as needed to 9 volts.
Measuring the pedal power connection outputs may or may not tell you anything.
Many 9v pedal power supplies can put out up to 12 volts if nothing is hooked up to it.
This is common behaviour. Without a load some power supplies can give a power reading higher than its rated value.

You can however get an accurate reading by making an adapter.
Any standard pedal power connector should work. but make sure you have access to the bare connections on the pedal power plug.
MAKE SURE THAT THE GROUND AND THE POWER CONNECTIONS DO NOT TOUCH. THAT WOULD BE BAD
Set a multimeter to DC voltage.
Hook things up.
Power things up.
With the multimeter, touch one probe to the ground connection, and the other probe to the power connection. This will give the an accurate reading of what the power supply is actually sending to a pedal.

Have a read here. It can tell you many things about pedal power, including how much current a pedal actually draws (VERY VERY useful when running multiple pedals fro ma single power supply):
http://www.beavisaudio.com/techpages/PoweringPedals/index.htm
Last edited by CodeMonk at Nov 28, 2014,
#7
I just did a google image search so I could see what the insides of your power brick has inside.
It appears that the voltage regulation is done by the wall wart.
But that doesn't mean the power brick doesn't have some sort of power regulation itself.
Its all SMD (Surface Mount Device, REALLY SMALL parts) so its hard to tell what's in there.

If the wall wart puts out 18 volts, and the power brick puts out 9 volts, then some sort of power regulation is in there the power brick.
It could be a power regulator or it could just be a diode doing that.
Last edited by CodeMonk at Nov 28, 2014,
#8
Quote by Jaisun-UG
It's a wall wart with an 18v output, which is there to counter the voltage difference, not factor it. 100-240v in, 18v out.
I should have looked it up. I didn't realize that it was designed for 100-240V. If it was me I'd plug it in and give it a try. I don't see much potential for hurting anything.
Last edited by fly135 at Nov 28, 2014,
#9
I'm no electrician, but, as a rule, I just use the correct power supplies for all my pedals. No reason to risk breaking things when correct power supplies aren't hard to come by.
#10
Just spend a little time reading the mice type (specs) for each of your pedals. All of it is online. Make sure voltage, polarity, and AC/DC are correct or within tolerances. Then add up the sum miliamp draw for all the pedals and make sure it is no more than 80% of the rating on your power supply. If you need a second power supply for one odd voltage pedal they are usually only about $20. Now you will have a pro quality pedal board that is hum free and dead nuts reliable.

Here is the cya language from Morley:

"AC ADAPTER (ALL PEDALS)
All Morley pedals use Morley's 9VDC 300 milliamp regulated adapter. Center pin polarity
is negative. Using a non-regulated adapter could cause a low frequency hum in your amplifier.
Using an adapter with the wrong polarity may damage the pedal."
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
#11
Just measure the voltage with a multimeter. If the voltage isn't too high it will be fine.
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