Profex II hum

jolynyk · Post by **jolynyk** » 11 Sep 2011 11:02 pm

My Profex II has a hum in it, some sttings more than others, do I need a hum eliminator in my set up ?, other than trying to teach it the words..

Jack Stoner · Post by **Jack Stoner** » 12 Sep 2011 2:33 am

Most of the time, the hum is a "ground loop hum". Either caused by something else in the rack (if it's rack mounted) or just the "difference in ground potential" between the Profex II and the amp. If all you have is the Profex II and the amp, use a "ground lifter" to remove the ground from the amp and and if it's a ground loop problem that will fix it. You have to be careful with this as you are only getting ground in the guitar cable.

If this is the case, Ebtech makes a device you can put in line between the Profex II and the amp to fix the ground loop problem.

jolynyk · Post by **jolynyk** » 12 Sep 2011 4:20 am

Thanks Jack. I just ordered an Ebtech.. I'm sure it's a ground loop..
What do you mean that I must be careful?? Is there damage potential of some kind using the Ebtech..??

I tried bypassing the Profex II, and just put my Hilton pedal straight into my Evans SE200, & still get a tiny bit of hum. If I unplug the pedal, the amp is totally quiet, so I know it's not the amp..

Jack Stoner · Post by **Jack Stoner** » 12 Sep 2011 4:35 am

With the Ebtech it's OK. But, if you lift the ground on the amp, then it's "protective ground" is gone and you need to make sure you have a guitar cord connected to the Profex II (or whatever other device). It's just a potential safety issue, that many overlook.

If you are getting it with the Hilton, perhaps it's hum that is being picked up my the guitar's pickup, or a bad guitar cord. But, a ground loop hum does not mean anything is "bad", just that there is a ground "potential" (voltage) difference between two connected devices. This is very common with musical equipment, even if both devices are connected to the exact same AC power outlet.

Here is a discussion of a ground loop hum from Wikipedia:

http://en.wikipedia.org/wiki/Ground_loop_(electricity)

jolynyk · Post by **jolynyk** » 12 Sep 2011 7:37 am

Thanks Jack the info is appreciated.. getting a hum eliminator from a fellow forumite... Hope that solves the problem, very annoying when trying to record, or playing through the PA system..
I plugged the steel direct into the amp & I get a hum there too, so I'm getting a hum from everything.. My guitar is a GFI with a GFI II pickup on it.. It is a humbucker pickup???

Jack Stoner · Post by **Jack Stoner** » 12 Sep 2011 8:58 am

Yes, it's a humbucker. It's the same pickup that is on my Wife's GFI Expo S-10. As I've been told, it's basically a George L's E66 (humbucker) custom made for GFI.

jolynyk · Post by **jolynyk** » 12 Sep 2011 9:04 am

That's what I thought, so not sure why it would hum plugged directly into the amp, using a short George L chord...

Bob Cox · Post by **Bob Cox** » 12 Sep 2011 7:52 pm

You may try turning down your output volume on bottom of profex copletely down. Then Turn knob on top of profex with full pedal volume until it starts to turn yellow. Back it off slightly.Next set your amp to normal volume you will be useing then match that with the output volume on profex. This will take alot of the hum out.

jolynyk · Post by **jolynyk** » 12 Sep 2011 9:32 pm

Thanks Bob, I will give that a try tomorrow morning..

jolynyk · Post by **jolynyk** » 16 Sep 2011 1:34 pm

Bob I tried that, but still had a hum, I just recieved my Ebtech Hum Eliminator.I plugged the out of Profex into In on The Ebtech , out of there to In on my amp.. the hum is MUCH louder. obviously doing something wrong..

Kenneth Kotsay · Post by **Kenneth Kotsay** » 16 Sep 2011 4:32 pm

JACK - I had the same problem with my rack unit (Profexx & power amp) I purchased these plastic tabs called, "HUM FREES" from Mars Music years ago, they did the trick. They isolated the metal of the each unit from the frame of the rack. Try Guitar Center or Musicans Friends.

Ken Kotsay

Pete Burak · Post by **Pete Burak** » 16 Sep 2011 5:10 pm

Which Ebtech product did you buy?
The Hum Eliminater I have from them plugs onto the power cord.

jolynyk · Post by **jolynyk** » 16 Sep 2011 5:30 pm

This is the one I got... It only takes the 1/4" & XLR, but it creates more hum than it eliminates..

jolynyk · Post by **jolynyk** » 16 Sep 2011 5:33 pm

Kenneth I have my Profex mounted in a 2 space SKB rack all by itself. It's one of those cases where the top & bottom opens up..

Kenneth Kotsay · Post by **Kenneth Kotsay** » 17 Sep 2011 10:06 am

JOLYNKK - My rack unit is 8 space unit, I have a TransTubefex, Profex II, Power Amp, Korg Tuner & a Furman light & electric outlet connector box all inside the same rack. When I installed the HUM FREES plastic tabs on all the units, the hum went away. Like I said, I purchased these tabs at MARS years ago. Do search in Google for them.

KEN

Kenneth Kotsay · Post by **Kenneth Kotsay** » 17 Sep 2011 10:06 am

JOLYNKK - My rack unit is 8 space unit, I have a TransTubefex, Profex II, Power Amp, Korg Tuner & a Furman light & electric outlet connector box all inside the same rack. When I installed the HUM FREES plastic tabs on all the units, the hum went away. Like I said, I purchased these tabs at MARS years ago. Do search in Google for them.

KEN

Pete Burak · Post by **Pete Burak** » 17 Sep 2011 12:13 pm

Hum Frees:
http://www.musiciansfriend.com/accessor ... ation-tabs
Kill those ground loop hums by using Humfrees rack isolation pads to electrically isolate rack unit cabinets from each other and from the rack. Easily installed without removing units from the rack. Package includes 2 sets (8 tabs).

jolynyk · Post by **jolynyk** » 17 Sep 2011 1:55 pm

Ok,, But when I plug anything into the one I bought, why is the hum much louder.. Seems like it's a useless piece of junk.???

jolynyk · Post by **jolynyk** » 17 Sep 2011 2:10 pm

Well I was going to order them.. Item $4.99, Shipping to Canada $40.83..... I don't think so, I could ship my amp for less than that... OUCH.., I would think they could throw them in a mail pouch for a couple bucks..

Pete Burak · Post by **Pete Burak** » 17 Sep 2011 2:34 pm

Does it hum when it's not in the rack?

Jack Stoner · Post by **Jack Stoner** » 17 Sep 2011 2:37 pm

If you only have one device in the rack you don't need them. A couple of Nylon washers will basically do the same thing as the "humfrees".

I bought some cheap (I think 25 cents per package) at MARS Music in Tampa when they had their going out of business sale.

Back to the hum problems. First does amp, with nothing plugged in hum? If not, then connect the Profex II to the amp, but turn the input and output controls to Zero (off) and then see if it has a hum.

The Profex II is designed to drive a power amplifier directly, so if you are connecting it to the regular guitar input on a combo amp you have to cut the output level control way down or it will over drive/load the preamp in the amp.

jolynyk · Post by **jolynyk** » 17 Sep 2011 3:01 pm

Pete I haven't tried taking the Profex out of the case yet..but will soon..
Jack, I turned tthe input & output down & no hum, I am running it into the guitar input on the amp.. so then I turned the input up until almost yellow then turned the output up till I got decent volume, still a bit of hum, I pulled the cord from my Hilton pedal out of the input, no hum. So I disconnected the Hilton, & replaced it with my Goodrich H10K, & no hum.. So now have to figure out why the Hilton hums.. I tried differen plug in receptacles, even ran an extension cord to the Hilton from an outside plug, same results..
Thanks all, for your help..

Jack Stoner · Post by **Jack Stoner** » 18 Sep 2011 2:12 am

If you go from the Hilton directly to the amp (no Profex II) does it still hum?

jolynyk · Post by **jolynyk** » 18 Sep 2011 6:40 am

Hi Jack, just tried it...Yes it does going direct into the amp.. so with the Hilton plugged into the Profex, would the Profex then amplify the hum making it even louder?

Jack Stoner · Post by **Jack Stoner** » 18 Sep 2011 9:22 am

I hate to bug you and try more things. Did you have the guitar plugged into the Hilton when you checked for hum? If you did do not have anything plugged into the Hilton input, just the guitar cord from the Hilton direct to the amp and see if you get hum.

But, the Profex II will amplify whatever is input to it. You have to cut the input level way down and same way with the output level if you are plugging into the regular guitar input (preamp).