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schematic for a hum eliminator?

Started by freakazoidalnumbskull, May 03, 2005, 01:07:36 AM

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freakazoidalnumbskull

May 03, 2005, 01:07:36 AM
Hi everyone!
I'm looking for a schematic for an easy to build hum eliminator.  Ebtech makes one and i've noticed ART has come out with one.  Whats the technology?

smccusker

#1
May 03, 2005, 01:09:18 AM
Perhaps a transformer of some kind?
Guitar -> Amp

niftydog

#2
May 03, 2005, 01:31:49 AM
isolation transformers.

should be some good info if you search around here a bit.
niftydog
Shrimp down the pants!!!
“It also sounded something like the movement of furniture, which He
hadn't even created yet, and He was not so pleased.” God (aka Tony Levin)

niftydog

#3
May 03, 2005, 01:42:49 AM
niftydog
Shrimp down the pants!!!
“It also sounded something like the movement of furniture, which He
hadn't even created yet, and He was not so pleased.” God (aka Tony Levin)

barret77

#4
May 03, 2005, 02:45:39 AM
hey, looking there I found this link

http://www.jensen-transformers.com/as/as032.pdf

Is this a good testing for stompboxes and homebrew amps?

Mark Hammer

#5
May 03, 2005, 11:16:51 AM
Hum can come from a lot of places, and transformers are only the solution to some of those sources.  Sometimes, hum is addressed by ridiculously steep 60hz notch filters.

R.G.

#6
May 03, 2005, 11:21:36 AM
The isolator trick shown in the "Hum Free Splitter" at GEO works nicely with one output as well. It uses an opamp to drive a cheap transformer to get accurate frequency response across the range of 62Hz to 20kHz out of a $2.75 Mouser transformer.

It's a a way to not use $50 Jensen transformers, although Jensen makes great transformers if you have the $.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

freakazoidalnumbskull

#7
May 03, 2005, 07:48:28 PM
WOW!  Thanks guys!
I did a search here and only found the hum canceler/splitter.  I may investigate that.  I had a quiet effects rack until I added one last unit.  Now I have I buzz.  Seems to be in the higher freq's.  It goes away when I unplug one of the vintage tube amps from the last stereo processor.  I will experiment with isolating the last unit from the rack.  Haven't tried that yet.  Thought I might try the Ebtech "hum eliminator" or better yet,build one.I was looking for schematics,if anyone can help.
Could it be the power supply?

freakazoidalnumbskull

#8
May 03, 2005, 07:51:33 PM
The jensen link doesn't seem to work. :(

freakazoidalnumbskull

#9
May 03, 2005, 07:55:35 PM
The jensen link doesn't seem to work. :(

niftydog

#10
May 03, 2005, 08:45:15 PM
yes, power supply ripple may cause hum in audio circuits.
niftydog
Shrimp down the pants!!!
“It also sounded something like the movement of furniture, which He
hadn't even created yet, and He was not so pleased.” God (aka Tony Levin)

freakazoidalnumbskull

#11
May 04, 2005, 10:03:53 AM
I've traced the noise to a ground loop from the rack rails.  I will isolate the offending unit.  Thanks for your help!

Satch12879

#12
May 04, 2005, 10:35:02 AM
QuoteI've traced the noise to a ground loop from the rack rails. I will isolate the offending unit. Thanks for your help!

Lonnie would be proud ;)...

Sorry, wrong forum :mrgreen:!
Passive sucks.

Progressive Sound, Ltd.
progressivesoundltd@yahoo.com

pantufla

#13
April 21, 2012, 10:30:20 AM
 ???

6 years after any of you guys know how to build one of this?  schem, pictures, anything :icon_question:

cheers.

pantufla

#15
April 21, 2012, 05:38:02 PM
Quote from: Craiz on April 21, 2012, 01:58:02 PM
http://www.beavisaudio.com/Projects/Huminator/


Shabam.

I already know that proyect, but if you notice the hum eliminator is not another filter phase for a power sypply it worck with 1/4" plugs, so you can connect it to your chain of pedal or maybe in the conection between cabinet and head.

FiveseveN

#16
April 22, 2012, 12:10:34 AM
Like Mark Hammer said, hum has many causes and there are many devices that address them. The Ebtech Hum Exterminator plugs into the mains socket (I guess it filters and/or isolates power). Others filter the audio signal or isolate devices through transformers, and as such need to be in the signal chain.
Quote from: R.G. on July 31, 2018, 10:34:30 PMDoes the circuit sound better when oriented to magnetic north under a pyramid?

teemuk

#17
April 22, 2012, 01:02:37 AM Last Edit: April 22, 2012, 01:07:58 AM by teemuk
QuoteWhats the technology?
- Ground loop breakers (including isolation transformers)
- Extra filtering for power supplies
- high Q notch filter @ hum frequency

Pick your poison. Only the last one can be fitted to the signal path with conventional methods and instead of cause of the hum will remove hum that is already in the signal.

QuoteI already know that proyect, but if you notice the hum eliminator is not another filter phase for a power sypply it worck with 1/4" plugs, so you can connect it to your chain of pedal or maybe in the conection between cabinet and head.

You are wrong. Check again.

Mark Hammer

#18
April 22, 2012, 11:11:05 AM
I think we are focussing a bit too much on hum from the wall.  I do most of my pedal testing using a battery-powered amp, and use batteries for the pedals.  So there shouldn't be any hum, right?

Wrong.  My office/workshop has fluorescent fixtures, and most of my guitars use non humbucking pickups.

I can assure you that even if I use the very best power supply designed by RG and his hotsy-totsy EE buddies, my guitar WILL hum when I'm sitting under those lights.

A true hum eliminator is one that is designed to take out 60hz (orwhatever the wall AC is where you live) signal and its byproducts, no matter where they come from or where they show up in the signal chain.
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