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Posted by: MickeM Dec 13 2007, 03:26 PM

I have two pedals that seem cooked. None of them give any sound when connected and both have the on-led lit constantly.
Both of these pedals just rescently stopped working and that's why I belive there's a common denominator and I'm leaning towards a faulty powersupply, one that's all of a sudden delivers more than 9V.

Anyone got any ideas on this?

Posted by: ZakkWylde Dec 13 2007, 03:31 PM

Did you use a high quality powersupply? It would help if we know brand of the plug and of the effects.

Posted by: MickeM Dec 13 2007, 03:34 PM

I've got one of the pockets in my gig bag full of different power supplies. I don't know which one is faulty (if anyone is). Different brands, different price ranges.

The two effects that are broken are
1) Behringer EQ7
2) Ibanez Weeping Demon

Posted by: Andrew Cockburn Dec 13 2007, 03:38 PM

Do you smell any burning? You often get a smell when you have cooked something electronic. Also, you could try putting a meter across the output to see if the voltage is too high.

Posted by: MickeM Dec 13 2007, 03:41 PM

I smell nothing burning and the led that incicated active/inactive is lit so there's some kind of life left in them.
I don't have a multimeter but it may be worth investing in one....

Posted by: mattacuk Dec 13 2007, 04:16 PM

Sorry to here your haveing issues with your pedals man I hope you find a solution soon !

Posted by: tonymiro Dec 13 2007, 04:32 PM

Sorry to hear it MickeM.

Have to say that I'm awash with mini transformers. One thing - whilst many deliver the same voltage they do not deliver the same current. I think it may be possible to fry an effects pedal by giving it too much current even if the voltage is correct. The other thing - lots of effects use the Roland reverse polarity pin set up - but I don't think all do. Don't know if that would fry a pedal or not though.

Posted by: Smells Dec 13 2007, 05:46 PM

I think that Tony is onto something with the current supplied by the transformer, I`ve been fumbling around the internet trying to come up with a firm solution for you (not with any great success I`ll add, sorry)

Have you tried a good/new 9v battery in the pedals just to make sure that they work instead ofusing the transformers?

I think if you`d of had a surge of current then the light wouldnt work either, I would guess that theres not enough current being drawn from the transformer to fully operate the pedals but enough to light up the LED

I`ll keep trying to look for you if I can, not getting very far with it tho atm, sorry

Posted by: Andrew Cockburn Dec 13 2007, 05:58 PM

Sorry to disagree Tony, but ohms law dictates that even though more current is available it won't be used - if the resistance of the circuit remains constant you would have to increase the voltage to push more current through it.

The reverse may however be true - if the transformer is not rated at the correct current, if it is straining to provide more current than it is capable of, its voltage would drop and that may do funny things to the pedals circuitry.

A cheap meter is all you need BTW, you could probably get one for around 20 - 30 Euro I would guess, and a meter may well be helpful when you get onto the electrics of your Guitar build

Posted by: tonymiro Dec 13 2007, 06:04 PM

Oopps - yes i=v/r. Looooooong time since I did physics .

Posted by: Muris Dec 13 2007, 06:17 PM

Sorry to hear MickeM

I'm really not strong in this field so only thing I would suggest is to try it on battery,
might be issue in adapter in/out or som.

Posted by: MickeM Dec 13 2007, 07:37 PM

This is a thing I've been wondering about. Isn't it that it's the perpiherar itself that decides the current load?

Say a transformer is set to 9V and the EQ I have is connected and use 5mA that would be doable with a transformer of 9V/300mA f.ex.
And things will run smoothly as I add pedal after pedal until it reaches the 300mA limit of the pedal.
So if adding six delays that consume 50mA each they would be testing the limit.

Like in a house where there's a 16A fuse in the kitchen, start all appliancies at the same time and things may work until you plug in the 2500W vacuum cleaner and all of a sudden all things together need 20A to run and the fuse blows.

So as I have understood things it's not the transformer that's delivering 300mA but it can handle that current at a max. An EQ only needs 5mA to run, a dist pedal like 7-8mA and a Delay takes 40-50mA so it's really small amounts of current needed to run a pedal.

But that's how I understood things... but then again I had to take the electronics exam twice in the university before I passed ;-)



Thanks Yeah I've tried a battery and it's the same, the led indicator is constantly lit, on both pedals and there's no sound.


Ok. Sorry I didn't see this at first. I pressed reply and then I was called away for dinner. I belive you're right.

And YES, I will get that meter. I've noticed it's handy when measuring pickups and while poles in a switch is used at what position, so it's a defianeiet buy. Could aswell do it now already

Posted by: kevin-riff-after-riff Dec 13 2007, 10:42 PM

nooo dont mix a 100 odd quid effects pedals next to a 5 quid behringer!

Posted by: MickeM Dec 13 2007, 10:45 PM

it's sinful perhaps they got into a fight and sent electric shocks at eachother. Would say the Behringer came out a winner since the Ibanez Wah was quite expensive and the Behringer was not

Posted by: USAMAN Dec 13 2007, 11:51 PM

The current rating of a transformer is how much the transformer can supply without damaging itself. The actual current flow in a dc circuit is determined by the resistance of the circuit. See Ohm's law. A transformer rated at proper voltage and a current rating higher than spec will not damage anything.
Proper polarity can have adverse effects in certain situations.

Posted by: Milenkovic Ivan Dec 14 2007, 12:00 AM

Ehm, maybe its a dumb idea, but did you actually put the cables into the inputs jacks? It happened a few times to me that I thought that my pedals dont work, and my mistake is that I didn`t plug them.

Posted by: MickeM Dec 14 2007, 12:06 AM

So is there a way theoreticaly a 9V transformer suddenly would start running higher, on say 18V for some reason?

I do recall I have one transformer that's switchable between 1.5 3 4.5 7,5 9 and 12V if I remember all the figures. *runs off* *returns* I checked it that it's set to 9V which is correct. It also has reverable polarity... I don't know really how that switch sits... if it's right or wrong.


Yes I did, proof of it is that the led indicator it lit. And I've did that too, connect all the effects into the loop and not getting sound assuming I switched the send/return cords and messing about for a while until I notice I forgot the power
But not this time.

Posted by: Andrew Cockburn Dec 14 2007, 12:12 AM

The polarity is kind of important

Probably a broken power unit could push out a higher voltage, not really sure.

Posted by: MickeM Dec 14 2007, 12:16 AM

Hehe but I'd want a polarity button to say "normal" or "reversed" polarity. Not just a filled dot at one end and a circle in the other.

I'm getting that meter tomorrow for sure!

Posted by: Milenkovic Ivan Dec 14 2007, 10:09 AM

If you have a changable voltage on the power adapter, than maybe you accidentaly change it to a higher value and damaged the pedals. Definately get that meter.

Posted by: MickeM Dec 18 2007, 03:48 PM

This is the result. I measured the switchable adapter and when set at 9V it dishes out 13 almost 14V
Set to 6V it runs at 9V

The second adapter was fine, the third was not working at all.

And a couple or three were gone...

Now when I connected a working adaptor I got the EQ to work properly, the Wah did too... sort of, now the foot pedal came loose but that's mechanical and should be less an issue to fix.

Posted by: Smells Dec 18 2007, 04:15 PM

phew, thats good so at least you dont need to replace your pedals now

Posted by: MickeM Dec 18 2007, 05:16 PM

Actually I have warranty left on the Wah but by the looks of it I have just been to violent on it myself so not much I can do about it.
It's like when I had a broken 500Gb LACIE harddrive, disk crash, I had the car running and was on my way to the store and the family was sitting in the car, I ran inside in a hurry and grabbed it and dropped in on the floor so it got dented real good in one corner. Man, the disk was honestly broken to start with but noone would belive that now. I had to take it apart not breaking any seals and then carfully repair the dent. Got it almost perfect and the store bought it.
But this Wah is my own fault so I will have to deal with it.


It's cool though I hade made a 14V mod on my 9V power adaptor. Yeah rock n roll!

Posted by: Muris Dec 18 2007, 05:21 PM

That's good to know MickeM,glad you manage it!!