#1
Hi,

I bought a Yamaha OD-100 pedal from my friend for 15 dollars aprox. I had to buy an adaptar that has a switch with options like 4.5v , 6v , 9v, and 12v. I use the pedal with the 9v option and it works but it also hums. I bought a battery and it worked, but I dont want to buy batteries everytime to play at home. I dont know why I cant use the adapter? Any ideas? It also has a switch with these signs : + -
#2
Quote by WhenStarsDie
Hi,

I bought a Yamaha OD-100 pedal from my friend for 15 dollars aprox. I had to buy an adaptar that has a switch with options like 4.5v , 6v , 9v, and 12v. I use the pedal with the 9v option and it works but it also hums. I bought a battery and it worked, but I dont want to buy batteries everytime to play at home. I dont know why I cant use the adapter? Any ideas? It also has a switch with these signs : + -


You bought a crappy adapter, it's bleeding 60hz (or 50, depending on location) into the DC side.

Buy a better adapter.
“Ignorance more frequently begets confidence than does knowledge.”
Charles Darwin
#3
Quote by Arby911
You bought a crappy adapter, it's bleeding 60hz (or 50, depending on location) into the DC side.

Buy a better adapter.



I dont understand the part of 60 hz?
#4
hz = hertz

hertz is used to measure frequency (pitch)

60hz is the frequency of the humming you are hearing, from most likely a bad adapter as mentioned above.

#5
Try plugging it into different outlets, could be bad ground where its plugged in, and yes sometimes cheap adapters can do it to.
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#6
Quote by WhenStarsDie
I dont understand the part of 60 hz?


The wall socket where you plug in your adapter is AC, and will be either 50 or 60hz depending on where you live. (50 in much of the world, 60 where that ass-clown Westinghouse got his way...)

Cheap adapters don't filter it out, so it bleeds over in the pedal and you hear it in your amp.
“Ignorance more frequently begets confidence than does knowledge.”
Charles Darwin
#7
Arby made a slight error. Unless it's only a halfwave rectifier (and some cheap supplies are) it would be 120 Hz (or 100 over here).
A quick lesson (assuming a full wave rectifier and a 60Hx supply):
The rectifier takes the 60Hz signal and flips the negative half of the signal 180 degrees so it is all positive. It still goes up and down between zero and full but now it's 120 Hz.

So we have to smooth that out or else that 120 Hz will be heard. To do that we add a capacitor which we call a filter capacitor. A capacitor stores charge and takes a finite time to discharge. Pick a big enough one and it will result in smooth DC because it never gets time to discharge.

We can also add a regulator which will clean it up even more. Cheap plug packs rarely have a regulator.
Your supply's filter capacitors are too small so the ripple is large enough to pollute the pedal's audio.

Got it?
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#8
Quote by Cathbard
Arby made a slight error.


Yeah, yeah, yeah... You're right, I was lazy in my response.

Nice explanation though...I'll be stealing that for future use...
“Ignorance more frequently begets confidence than does knowledge.”
Charles Darwin
#10
What gets me is how these cheap plugpacks can't even add a simple zener regulator. One zener and a resistor and everything would be peachy. And it wouldn't cost more because you could just raise the secondary voltage and skimp on the filter cap a bit.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band