Hum from pedal board?

TJBass · #1 03-31-2008, 10:37 PM

No I haven't forgot to take my meds!

I have a powered pedal board, don't know the brand, I bought it used.

Anyway, there are six power leads and power jacks on it and I have currently a EHX Small Clone, Digitech BSW, Digitech Bad Monkey, Arion Stage Tuner, Behringer BDI21 and a Danelectro FAB Echo (powered by 9 volt battery). The lead that hooks to a battery clip is broken so I have to power one pedal with a battery.

But as I get four of the pedals on it I get a more significant hum out of it thru the amp. Five pedals and the hum is too loud to ignore.

So what can I do about the humming, I'm running hosa cables and theres no difference from the cheap cables I had before.

The reason I bought this was to not have to pay for batteries but it looks like I will have to go back to it or sell this thing and build my own. Just prefer not to change my setup yet again.

Heres a pic of the board, but the pedal lineup has changed since then.

bongomania · #2 04-01-2008, 12:05 AM

Process of elimination. Try each pedal individually- any hum? Is there more (or less) hum with any two specific pedals on there? Do any of them have center-positive power jacks?

niftydog · #3 04-01-2008, 03:47 PM

Hum is usually caused by one of two things: poor filtering in the power supply, or a phenomenon called a 'ground loop.' In this case, I'm almost willing to bet a kidney on the power supply filtering - there's just no substitute for a good quality power supply.

TJBass · #4 04-02-2008, 11:19 PM

I'll try that process of elimination. I don't think any of these pedals are center positive but now I am suspecting the small clone, it has the odd jack of them all and it could be the culprit.

I agree on the quality of a power suppl nifty, but its all I got at the moment so I have to live with it. I may have to unplug a few and run them on batteries but atleast I'm not having to buy stock in the energizer bunny!

JanusZarate · #5 04-02-2008, 11:39 PM

Hold on... I see a Sovtek Big Muff on your board photo.

I'm willing to bet THAT is your problem. You're using a battery clip adapter for it, I assume?

TJBass · #6 04-03-2008, 12:03 AM

Nope, that fuzz is long gone...just a small clone, bad monkey, bass synth wah and Behringer BDI21 now. I took the fab echo off too.

JanusZarate · #7 04-03-2008, 12:11 AM

Ah.

I don't think it'd be the Small Clone; I used to run one with seven other pedals on a daisy chain without any noise issues. I had a Small Stone on that same chain, too.

Technically, the jack is center-positive, but its ground is like most other pedals. There shouldn't be any negative interactions there. It's not like pedals wired with a positive ground... which are another story altogether (if that was the case, you'd have no power at all

).

TJBass · #8 04-03-2008, 12:16 AM

Pk, I'm thinking the poer supply, any more than any combination of three pedals in any power jack and its hum city. Any way to fix something like this or should I just build a pedal board and get a brick?

JanusZarate · #9 04-03-2008, 12:23 AM

A decent power supply like a 1 Spot should work much better, actually. Try that first - it'd be a lot cheaper. The packs with daisy chains are around $25 or so.

The Dunlop DC Brick is essentially the same thing as a wall wart with a daisy chain, but with somewhat better surge protection and 18VDC outs. Whether it's worth the $70 extra is a matter of whether you plan on getting an 18VDC-powered pedal.

And if you are, then you might as well consider the more expensive isolated-output power supply bricks.

TJBass · #10 04-03-2008, 01:04 AM

well I found a combo that allows me 4 pedals, the 4th being my tuner, without humming, but the small clone and the fab echo are off the board for now. Guess I will look into a 1 spot and see if that changes anything. I could essentially leave the setup I have and add the 1 spot to get the fab and ehx back on and with the extra outlets I could bu more pedals huh!

deesonic · #11 04-09-2008, 07:34 PM

That's funny... I searched the message boards today because I am having the same problem and I've been desperately trying to figure out where that hum is coming from. I found your post and see the pic of what appears to be the EXACT same board I have. I can tell you mine was a dirt cheap no-name from Ebay. It held up fine with just a few pedals (Sansamp DI, Boss TU-2, Boss Chorus), but once I got up to 5, then 6 pedals, the hum got ridiculous. So, I believe the power supply is the culprit since my pedals seem fine when plugged in individually. I'm learning s-l-o-w-l-y.