#1
Hi UG

I’m borrowing a Mesa Boogie Dual Rectifier from a friend, but I’m having some issues with it. I’m constantly getting electric shocks when I play guitar and touch people or microphones.

I live in Denmark, and the amplifier is from USA, so there is a step-up converter connected between the amp and the outlet. Stepping it up from 110v to 230v (I assume).
Right now the converter is connected to a power outlet via a non-ground-stick. The problem is, when I connect it via a grounded-stick, it takes out all the electricity in the building. I don’t now if the settings on the converter are the right ones, and hope some of you know what’s wrong.

Here are some pictures. https://www.dropbox.com/sh/2xrxi7kybjnhetm/AACE60gBNFtvBYst_uNp_kmwa?dl=0
#2
Okay so first thing is first, I probably wouldnt use it until you sort this out.

Are you sure the shock is from the amp? Does the amp work in other buildings and is just messing up in your own house?
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Last edited by H4T3BR33D3R at Nov 30, 2016,
#3
Quote by frederik-jensen
Hi UG

I’m borrowing a Mesa Boogie Dual Rectifier from a friend, but I’m having some issues with it. I’m constantly getting electric shocks when I play guitar and touch people or microphones.

I live in Denmark, and the amplifier is from USA, so there is a step-up converter connected between the amp and the outlet. Stepping it up from 110v to 230v (I assume).
Right now the converter is connected to a power outlet via a non-ground-stick. The problem is, when I connect it via a grounded-stick, it takes out all the electricity in the building. I don’t now if the settings on the converter are the right ones, and hope some of you know what’s wrong.

Here are some pictures. https://www.dropbox.com/sh/2xrxi7kybjnhetm/AACE60gBNFtvBYst_uNp_kmwa?dl=0
I think the "its shocking me" is obviously because of the lack of ground. The normal voltage input for a USA amp should be 120v, not 110v. Not sure why the transformer is at 110v. Voltage in Denmark apparently is between 220v and 240v, so 230v is a good estimate I guess. As to why using a grounded power plug shorts out the rest of the house, I dunno. My suggestion is to be safe and have an electrician check out the house wiring. You might could end up with a fatal shock if you are not careful.

If my thinking is correct, the transformer should be a "step down" transformer. It should take the ~230v and drop it down, outputting at ~120v. Not the other way around.
Last edited by Will Lane at Nov 30, 2016,
#5
Thanks for the replies
It's not just in my building all the power goes out. I've tried several places, and the same thing happens.
I'm not shure about the 230v/120v thing. It's my bass players amp, so I don't want to risk blowing it up.
#6
Are you sure you have the correct power adapter? This doesn't sound like an amp specific problem.
Guitars:
Jackson Kelly KE3 - MIJ (Distortion/Jazz)
Jackson DKMGT Dinky (EMG 81/85)
ESP E-II Eclipse Custom (JB/'59)
ESP LTD EC-1001FR (EMG 81/60)

Amps:
Mesa Dual Rec Roadster 212
Peavey 5150 212 with V30s
Peavey Vypyr 30
Peavey ReValver
#7
if you plug your guitar to a different amp, do you still get electric shock?
If answer is 'YES', the grounding of your guitar is not right.. you need to check it (if you know how), if you are not confident or knowledgeable in checking for shorted or loose grounding wire, you have two options, watch youtube videos to learn how to and buy the needed tools to do it yourself (better in the long run) or you can pay someone to do it for you..

If answer is 'NO', there is something wrong with the converter... USA made is 110v so if your converter is producing something more than that, you can overload the transformer of the amp or maybe damage it in the long run... suggest try different power converter if it has same effect.

Don't keep getting shock, it ain't worth it.
I have Washburn guitars 'Maverick Series' and bass 'Bantam Series' and a few pedals and amps, but man I wish to have more patience and drive practicing my playing, if it's equal to the modding itch, then I'm golden.
#8
Sounds to me like the convertor is messed up. If the main fuses are blown unless you disconnect the ground it means that the hot lead is shorted to the chassis in the convertor. Or it means that the hot and neutral is swapped between the convertor and the main. You should not use this setup until you figure it out. Check the impedance between hot and ground on the convertor (unplugged). It might be shorted.

Since you have tried it in different places I would suspect the main wiring. But check the voltage between the hot and ground and check between neutral and ground. Neutral to ground should be zero. Hot to ground should be over 200V. If that's not the case them I'd be concerned about the house wiring.
Last edited by fly135 at Dec 2, 2016,
#9
Also worth mentioning that if you are isolated from ground you can touch the hot lead all you want. So what might be just a tingle can turn into a legal shock if you happen to also touch something that has a path to ground.