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Topic: Ground loop buzz |
Gary Lynch
From:
Creston, California, USA
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Posted 20 Apr 2008 11:52 am |
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I need some advise concerning the easiest way to fix a ground loop issue.
I just bought the new improved Hilton Volume Pedal. I wanted to run two amps at once using the two 'out' jacks. When I plug in two amps, I get the ground loop buzz in each amp. When I unplug one of the amps, it goes away.
How can I fix this? I have heard of a 'ground lift' device but have no idea what they are, what choices there are, or where you buy them?
Also, is using a 'ground lift' dangerous?
I am hoping to solve this issue the easiest way.
Thanks in advance. |
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Lee Baucum
From:
McAllen, Texas (Extreme South) The Final Frontier
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Posted 20 Apr 2008 2:19 pm
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On one of the amps you can lift the ground, using one of those inexpensive 3-prong to 2-prong adapters.
The safe way to do it, though, is to use one of these devices from Ebtech:
CLICK HERE
_________________
Lee, from South Texas - Down On The Rio Grande
There are only two options as I see it.
Either I'm right, or there is a sinister conspiracy to conceal the fact that I'm right.
Williams Keyless S-10, BMI S-10, Evans FET-500LV, Fender Steel King, 2 Roland Cube 80XL's,
Sarno FreeLoader, Goodrich Passive Volume Pedals, Vintage ACE Pack-A-Seat |
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Gary Lynch
From:
Creston, California, USA
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Posted 20 Apr 2008 2:46 pm
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Lee thanks for the link.
I just tried one of those inexpensive adapters and it works great but probably not safe. But at least I now know that can be dealt with by using this method of ground lift. |
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Gary Lynch
From:
Creston, California, USA
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Posted 20 Apr 2008 4:58 pm
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| By the way, for those that do not want to sped $60 on the safe way to go and buy the $3 adapter, can that harm the amp at all? Who cares if I get shocked, but I do not want my amp harmed! |
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Jim Sliff
From:
Lawndale California, USA
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Posted 21 Apr 2008 5:10 am
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| Quote: |
| Who cares if I get shocked, but I do not want my amp harmed! |
Substitute "killed" for "shocked" and you may think differently.
Spend the $60 - or take your amps to a tech who can rewire the power section to eliminate the problem permanently.
IMO a lift is a seriously bad idea.
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
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Gary Lynch
From:
Creston, California, USA
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Posted 21 Apr 2008 5:59 am
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I ordered one of the Ebtech Hum X Voltage Hum Filters. I hope it does the job at that price.
In the 'old days' houses were wired with only two wires and black and a white. The black was the hot wire, the white is the return wire back to the main electrical panel. The white wire went to a ground bar then to the ground rod. In modern wiring, the white wire stills ends up going to a ground bar then ultimately to a ground rod. The ground wire that has been added ends up going to a ground bar and the same ground rod. So, both end up being ground wires.
I was wondering why very people got shocked from their amps when they only had two prongs? Does anyone know? I remember amps with two prongs (no ground). |
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Pete Burak
From:
Portland, OR USA
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Posted 21 Apr 2008 7:47 am
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The Ebtech worked perfectly for me.
I use it all the time when running two combo amps.
~pb |
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Blake Hawkins
From:
Florida
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Posted 21 Apr 2008 10:16 am
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Gary, The reason people got shocked by their amps is because the two prongs could be inserted either way.
(Modern two prongs are polarized)
In an amp, the shield of your guitar cord is connected to the amp chassis.
The "ground" side of the power line is also connected to the chassis.
If you get the plug inserted with the wrong orientation, you get the full power line voltage on the amp chassis, your guitar cord and your guitar.
In most quality amps of that era there was a current limiting network between the chassis and the power line to give some protection. In that case you would get anything from a "tingle" to a "nasty shock"
but it would rarely prove fatal.
Many more players have been killed in europe where the line voltage is 240 instead of the 120 we have here.
When you use the 3 prong ground lift device, the second amplifier (that is the one with the ground lifted) receives its ground through your cord connecting the two amps. If you hold the plug
in one hand and touch the amplifier with the other you may get a shock which could prove fatal under
some circumstances.
This is a simplification of what went on in the past
and what could happen now.
Much more detail could be added.
I agree with Jim. It's not a good idea to use
the power cord ground lift.
Blake |
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Gary Lynch
From:
Creston, California, USA
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Posted 23 Apr 2008 7:23 pm
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| It arrived. It works. I feel safe. I can run my Tweed 5E3 and a Twin or NV 112 at the same time without the buzz. |
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Lee Baucum
From:
McAllen, Texas (Extreme South) The Final Frontier
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Posted 24 Apr 2008 4:31 am
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More importantly, you can do so in a safe manner!
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Jim Sliff
From:
Lawndale California, USA
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Posted 25 Apr 2008 5:14 am
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| Quote: |
| I was wondering why very people got shocked from their amps when they only had two prongs? |
The short version of what Blake said - AC power has polarity, a fact most people do not know. Get it backwards, and you can be easily shocked. That's why extension cords can no longer be made with two holes the same size - and if you have any, throw them away - they're unsafe.
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
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