#1
I accidentally broke the ground pin off the plug on my blues jr and I was wondering if running it anyway could be a safety hazard, as ive heard tubes can build up a significant charge... anyone know a bit more about electronics who can shed some light? I want to keep playing with it, as I won't be able to replace the plug for a while...
#2
as far as I know it'll be fine as long as you don't play it at full blast. keep it down and it won't suck as much energy. therefore, keeping it from building up such a drastic charge.

I'm not 100% sure though so wait for more responses.
#3
since nobody seems to know i thought id update, i've been using it so far with no problems
#5
Get it fixed as soon as you can. It's a cheap thing to do, any tech or electrician can do it.

You can use it, and most likely nothing will happen, but if something goes wrong, or you're playing live and touch a poorly wired mic, you will die. That's not meant to scare you, it's just the reality of the situation. So I guess it kind of should scare you.
Get your amp fixed.
#6
A three prong plug has a neutral, hot, and a ground. Anything made in the US (at least in the past 20 years, probally longer) with a metal case has this three prong design. If a "hot" wire inside the object would come lose, and touch the metal case (without the third prong connected), you would get shocked if you touched it. The neutral and the ground are actually connected to the same spot in your houses fuse box, the 3rd prong is just an extra saftey measure.

Most likely a "hot" wire on a modern PCB amp is not going to come lose. I have several old school tube amps that don't have polarized plugs, so you get a little current through you if you have it in the socket upside down. Nothing bad, you can just feel it through the guitar.

However there is a greater potential for a fatal shock without the 3rd prong. It's there for a reason.

The "charge" built up in an amp comes from when AC is being converted to DC, and it is filtered through capacitors to "smooth" the flow. These capacitors can hold a charge even after the amp is turned off. So don't be poking around there if you don't know what you are doing. Just take your amp into any compentent amp tech/electrician, a power cord is a pretty easy thing to replace. In fact I'm surprised yours doesn't have a detachable power cord, most newer amps have them.
#7
Quote by Roc8995
Get it fixed as soon as you can. It's a cheap thing to do, any tech or electrician can do it.

You can use it, and most likely nothing will happen, but if something goes wrong, or you're playing live and touch a poorly wired mic, you will die. That's not meant to scare you, it's just the reality of the situation. So I guess it kind of should scare you.
Get your amp fixed.

+1. It's there to act, no matter the situation, as the path of least resistance. Depending on an impossible number of variables, YOU could be the path of least resistance to ground, which is the path it will take. I would go as far as to say to NOT use it at all. Get it fixed.
#8
while it is common in the realms of live and studio sound engineering to pull the ground pin out to eliminate hum, the removal of a ground pin (accidental or on purpose) is very dangerous, and should not be done.

Roc8995 is correct. This is a fault that has the potential to kill you outright. all it would take is for you to touch the wrong thing at the wrong time, and thats it. faulty mics, cables, and issues within the amp can be fatal.

And its something thats so easily fixed, so why risk it. hell, you could even do it yourself, but seeing as you asked about the dangers of not getting it fixed, I assume you have little or no electrical knowledge and this shouldn't be attempted if that is the case.
Quote by Dave_Mc
how do those marshall handles compare tonewise to, say, mesa handles?

Owns a Blackheart Little Giant...
#9
Quote by Roc8995
Get it fixed as soon as you can. It's a cheap thing to do, any tech or electrician can do it.

Or risk death, your call.
I wondered why the frisbee was getting bigger, then it hit me.
#10
Quote by blocky
I accidentally broke the ground pin off the plug on my blues jr and I was wondering if running it anyway could be a safety hazard, as ive heard tubes can build up a significant charge... anyone know a bit more about electronics who can shed some light? I want to keep playing with it, as I won't be able to replace the plug for a while...

You can buy a new 3-prong plug end at any hardware store for under $5, & install it yourself, or have someone who's more knowledgeable help you. Cost isn't a factor when personal safety is involved, but this is a ridiculously cheap repair.

Colin-the example you cited re touching a poorly wired mic---would that necessarily apply to older amps w/ 2-prong plugs also? I used to get the occasional minor jolt here & there, never anything close to lethal. Maybe the mics we had really weren't bad, & there was a polarity issue or something? I always wondered how we'd get those little shocks on our lips if we bumped the mics!
Quote by 311ZOSOVHJH
Riffhog for President


Quote by Cathbard
There's no point apologising for your feet smelling when there's a 300lb gorilla in the room taking a crap on the couch.


Recognised by the Official EG/GG&A Who To Listen To List 2011
#11
The deal with the mics in most cases has to do with a ground loop in the power supply or something to that effect IIRC, not necessarily with the amp discharging into you. Older 2 prong amps would be the same way in that respect as three prong, as I believe they ground exclusively to the chassis as their path of least resistance. For obvious reasons though, this is not as safe as the three prong method. the reason having a broken three prong is more dangerous is the chassis ground on newer amps is secondary, and I would imagine in part for noise canceling. Because of that, it is not routed to be the path of least resistance at all times like a ground plug is, hence why it is dangerous to run an amp with a damaged ground plug on those that have it.
#12
^Thx, CJ. I had a feeling the newer amps would have a different grounding circuit that relies on the 3rd pin. That stuff with the mics sure was eerie, though. Like when you test 9v batteries w/ your tongue.
Quote by 311ZOSOVHJH
Riffhog for President


Quote by Cathbard
There's no point apologising for your feet smelling when there's a 300lb gorilla in the room taking a crap on the couch.


Recognised by the Official EG/GG&A Who To Listen To List 2011
#13
The shock you get with mics is bad grounding, and it can be an issue.
The biggest danger, especially with a vintage 2-prong amp, would be if you had your amp plugged in one way and the mic was wired the other, in which case everything between those outlets turns into a big open circuit with you in the middle.
#14
Quote by Roc8995
The shock you get with mics is bad grounding, and it can be an issue.
The biggest danger, especially with a vintage 2-prong amp, would be if you had your amp plugged in one way and the mic was wired the other, in which case everything between those outlets turns into a big open circuit with you in the middle.


Whoa . I suddenly feel very lucky. God knows what crap mics we used.
Good to know.
Thanks!
Quote by 311ZOSOVHJH
Riffhog for President


Quote by Cathbard
There's no point apologising for your feet smelling when there's a 300lb gorilla in the room taking a crap on the couch.


Recognised by the Official EG/GG&A Who To Listen To List 2011