# Electro Harmonix Distortion Pedal Problems???



## BlueCheese (Jun 29, 2011)

Hey guys, I'm new on this forum, and I'm not a very experienced guitar player either. Recently I've been having some problems with my Big Muff Pi distortion pedal. When I plugged it into my amp, a loud humming came from it when I turned on the distortion. I haven't used it in a while as I've been busy with exams and summatives, but when I plugged it in the other day, the distortion didn't even turn on. I thought that the battery might have been slowly running out, but I'm pretty sure I didn't leave it plugged into the amp. Help please???kkjq


----------



## hardasmum (Apr 23, 2008)

Was it still dead after you swapped in a fresh battery?


----------



## jimihendrix (Jun 27, 2009)

My pedals start to sound strange and the switch won't turn the pedal off...when the battery gets low...

Try the guitar-cable-amp (no pedal at all in the chain) first to make sure a signal gets to the amp...

Try an 9V power adapter (if you have one) to see if your pedal acts normally...then proceed to try the pedal with a new fresh battery...lastly...make sure your patch cord ends haven't loosened up...a quick twist re-tightens them...

One more thing...check that the nut on the guitar input jack hasn't loosened up...that could cause no signal getting through to the pedal...


----------



## GuitarsCanada (Dec 30, 2005)

I believe those will draw power if they have anything plugged into them, so if you did happen to leave the guitar plugged in check the battery for sure.


----------



## blam (Feb 18, 2011)

yup. lots of EHX pedals require you to unplug the guitar cable otherwise it draws power.... I run my pedals into a pedal power into a surge protector and turn that off when I am done playing.


----------



## mhammer (Nov 30, 2007)

blam said:


> yup. lots of EHX pedals require you to unplug the guitar cable otherwise it draws power.... I run my pedals into a pedal power into a surge protector and turn that off when I am done playing.


Actually, it is an industry standard that pedals using a 9v battery have a stereo input jack. Plug your cable in and it joins two contacts which then turn the battery on. If there is a plug inserted into the external power jack the battery will remain out of circuit, but if you are using battery power and there is a plug inserted into the input jack, that battery is powering the entire circuit, whether you think its on or not. In fact, it is powering the entire circuit even when bypassed.

For folks who try and make or repair their own pedals, it is a regularly occurring source of difficulty when they mistakenly solder wires to the wrong lugs on the input jack and inadvertently leave the battery in-circuit even when nothing is plugged in. They go to use the pedal the next day, and wonder "It worked last nght. Why isn't it working now?". It's not working now because you left it on all last night and today and the battery is now dead. I hate when that happens.


----------



## sulphur (Jun 2, 2011)

Yes, if you're running battery, you must unplug jacks from the pedal, not the amp.
Get an adapter to avoid this issue. 
Good luck.


----------



## blam (Feb 18, 2011)

interesting. good to know!


----------



## mhammer (Nov 30, 2007)

Though it doesn't apply in nearly as many cases, when a pedal is able to use a battery, the external power source has to be able to disable that battery when you plug it in. This is why Boss-type pedals that use the 2.1mm barrel-style plug/jack are always outside-hot, even though safety might dictate that you want the part people have the greatest likelihood of touching to be ground. The reason is that the outside of the plug has to physically nudge a contact in the jack out of the way in order to switch over from battery to wallwart. The inside contact that touches the pin in the jack cannot do that, so the outside has to be V+ ("hot").

*IF* you have a pedal that can never use batteries, because it consumes too much power (nobody wants a stompbox with a bunch of D-cells inside) or requires a supply voltage that is simply hard to achieve with batteries, then nothing has to be "switched over" and it then becomes the manufacturer's perogative to use an outside-positive/hot adaptor, or let safety-consciousness rule and make outside ground so you don't hurt yourself by inadvertently touching the faucet and the outside of the plug at once.

This is why Boss and others make such a big deal about how you "must use" their adaptors. Some commercially available adaptors can easily provide clean power with more than acceptable regulation at the right voltage with enough current, but the plug is flipped around, since it wasn't built for a device that needed you to switch the battery off when plugging the wallwart in. They _*could*_ explain all the theory to you, but I suspect their legal team said "You know what? We don't need the aggravation of people suing us, or people demanding we repair a pedal that they fried through their own negligence. We'll just say they have to use our adaptors so we can be sure they aren't screwing things up, and can simply blow them off if they didn't follow our stated requirements and ran into trouble."

EHX and others have traditionally used a mini pĥone plug/jack for their wallwarts. In this arrangement, it is always the tip of the plug that has to be "hot" since it is the portion of the plug that moves one contact out of the way and switches over from battery to external power. Those jacks are both cheaper and smaller, making them easier to install in a wider variety of locations in the pedal. Some feel they make a more secure contact, as well, which is what you want with live power. As more and more players have shifted to higher current-capacity supplies and "daisy-chain" plugs, though, companies that used to use mini phone jacks have switched over to the barrel style. It is also fair to note that, for all their other advantages, mini phone plugs short out against the jack and cause sparks and potential wallwart failure if you forget to insert them *before* you plug in the wallwart.


----------



## keto (May 23, 2006)

I'm gonna guess and throw out what I have done many times - check you have the cables right way round, ie, input comes from guitar and output goes to amp. Can't tell you how many times I've got that backwards, sometimes it even takes me a while to track down the 'issue'.


----------



## mhammer (Nov 30, 2007)

Been there, done that, bought the t-shirt, worn it out, waxed the car with it.


----------



## BlueCheese (Jun 29, 2011)

Thanks heaps for all the feedback, guys, I really appreciate it. I will check the batteries and make sure everything is set up the way it's supposed to... if I left a cable plugged into the pedal but it wasn't connected to anything else, would it have still drawn power??


----------



## Jeff B. (Feb 20, 2010)

BlueCheese said:


> Thanks heaps for all the feedback, guys, I really appreciate it. I will check the batteries and make sure everything is set up the way it's supposed to... if I left a cable plugged into the pedal but it wasn't connected to anything else, would it have still drawn power??


Yes, it would still be drawing power. As long as there is a plug in the input jack irregardless of whether the other end is connected to anything or not it still draws power.


----------



## mhammer (Nov 30, 2007)

BlueCheese said:


> if I left a cable plugged into the pedal but it wasn't connected to anything else, would it have still drawn power??


Yes, and here is why. Take a look at these two phone plugs, a mono and stereo.








When the left (stereo one is inserted into a stereo jack, one part of the jack makes contact with th tip, another with the "ring" in the middle, and another with the shaft. When the righthand mono plug is inserted into the same jack, the jack contact that would have made contact with the ring portion will now also be in contact with the shaft. Doesn't matter what's on the other end of the cable, the ring and shaft portion will be connected to gether.

And that's what turns on the battery. If the ground/black lead from the battery is connected to ground, current will flow, but if it isn't connected, no current will flow. The battery's black lead goes to the ring contact on the jack, and when you insert a mono plug it becomes connected to ground and turns the battery on.


----------

