noise with 9V power supply

[johnny5]

i just got my RangeMaster clone (Tonepad) working and it's very cool. the only issue i am having now is that when i use it with a 9V power supply (one spot), it's really noisey. say if i have the volume on the guitar all the way down, turn the effect on when plugged into the onespot there is a pretty loud hum. unplug the power supply and let it run on the battery, and the hum drops significantly.

i wondered if my polarity was reversed on the jack but it looks correct to me. is there something i am missing? has this happened to any of you? how was it resolved?

thanks

[captntasty]

Probably just good ol' 60 cycle hum (the sound is AC power which alternates at 60hz, or 60 times every second) - the bain of every musician worried about the quality of their sound.  When you plug your power supply in it picks up this interference.  The RM will make it even more noticeable due to the high frequency boost.  Here's a link that will shed some light on it but the solutions for our applications aren't really feasible, they explain the phenomena pretty well though:

http://www.boblewisaudio.com/ts.htm

As for solving the problem there are myriad methods - you now have a place to start searching for solutions and advice on this site and others.

Wish I could give you a definitive answer, but it's driven me nuts for years.  The best solution I've come up with is to purchase a power supply - mine is an ART SP 4x4, not too expensive - Furman makes some great power supplies also.  This eliminates ground loops because all grounds are going to/coming from the same place.  Ebtech sells a hum eliminator and Boss has a noise suppressor which I have heard work well - never tried either though.  Fluorescent lights, AC units, computer monitors and refrigerators are a problem also.

Also, if you are using single coils by themselves rather than in positions 2 or 4 on a strat(2 SC's together middle PUP with reversed polarity) you will pretty much always get some hum and buzz - there are methods for shielding which help but it's hard to eliminate completely.

Well, I've rambled on enough... hope I haven't confused you even more - good luck.
Peace

[hairyandy]

I always put a 150-ohm resistor in series with +9v from the DC jack in all of my Rangemasters.  This will help filter some of that noise.  In fact, I usually use one in most pedals I make just in case.

[johnny5]

thats a great idea! thanks! i will try that.