ASK: Amp Problem

[slim_blues_boy]

hello newcomer here .
I have problem with amp.
I got Marshall Valvestate VS15R.
when I use that amp, I always get electrical shock every time I touch the guitar strings when my foot/any parts of my body touch the floor/wall.
the electrical shock was low (it wont kill you or make you blackout :loco), but it's still hurts and very-very annoying  :grr.
anybody know what's the problems and how to fix it?

thanks

[joecool85]

hello newcomer here .
I have problem with amp.
I got Marshall Valvestate VS15R.
when I use that amp, I always get electrical shock every time I touch the guitar strings when my foot/any parts of my body touch the floor/wall.
the electrical shock was low (it wont kill you or make you blackout :loco), but it's still hurts and very-very annoying  :grr.
anybody know what's the problems and how to fix it?

thanks

That is NOT GOOD!  It could be very dangerous to use the amp as-is.  Sounds like there is a short inside the amplifier.  Do you have any experience working with electronics?

[phatt]

I second joecool,,
adding if no experience with electronic gear don't go near it until it has been checked by a certified electrician or just take it to a repair shop. This is no joke, you could be flirting with something very dangerous.
Phil.

[slim_blues_boy]

I have experience working electronics and know a little bit about electronics, I got basic-electronics lesson when I was in junior high.
I made my own stompboxes pedal (Tonebender and it's derivatives, Rangemaster, Fuzz Face, Tubescreamer 808, etc) and also some small battery-amp (Ruby, Little Gem, Noisy Cricket).
but never have any experience with bigger wattage amp, that's why I'm looking for more information.

[gbono]

You have a fault to ground somewhere in your amplifier. Does your power cord have a three prong connector? Does the amp have a polarity/ground switch? You risk a potential fatal shock with your amp in it's present condition - it needs to be trouble shot and the problem corrected.

[J M Fahey]

Hi Slim.
It hasn´t killed you *yet* only because you are young and your heart is good and fresh.
Valvestates have no ground switches, so it looks that either it´s faulty or *your power line installation sucks* and I'm not kidding.
Very probably your outlet ground connection is poor or even not connected. (Or the Valvestate power cable is bad).
Buy a neon indicator screwdriver and use it everywhere, everyday.
Good luck.

[slim_blues_boy]

ok, so grounding is the first suspect  :trouble.
I will open the amp and check it.
will report in here if there are something that I don't understand or if I need further guidance.

[va3ux]

Grounding definitely is the first suspect. And not just inside the amp, but also at the electrical outlet (or the whole house).

One thing to bear in mind folks is that signal ground and chassis ground are not always the same. If the signal ground is floating above chassis ground, then so is the guitar when it's plugged into the amp, and so are you when you're touching the strings. Hence, shock hazard. 

Phil

[joecool85]

Grounding definitely is the first suspect. And not just inside the amp, but also at the electrical outlet (or the whole house).

One thing to bear in mind folks is that signal ground and chassis ground are not always the same. If the signal ground is floating above chassis ground, then so is the guitar when it's plugged into the amp, and so are you when you're touching the strings. Hence, shock hazard. 

Phil

I always tie chassis and signal grounds.  It's good practice to do so, much safer.