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Small electric shocks from strings and bridge


Harryburke14
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Hi all.

I have lately been noticing myself getting small electric shocks from the strings and bridge of 2 of my basses (Sire M3 and Harley Benton Jazz bass). They usually occur when I've been plugged into the amp for about 20 minutes and in both inputs on the amp. The amp itself is Ashdown Vintage 12 for those interested.

Does anyone know what would be causing this, and if so how to stop it?

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I would discontinue using that amp untill I was satisfied it was grounded correctly.

Actually - does it happen when you wear a certain item of clothing, shoes or are walking around on carpets? Small electric shocks sounds like it may be static electricity discharging to me!

EDIT: I should say - if your fingers are dry the 9v of most active electronic preamps in a bass isn't enough for you to feel it...
Not so sure about 18v though - you may very well feel that with dry fingers.

Edited by PlungerModerno
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Definitely check the ground on the amp is properly connected, sounds like an amp fault to me.

Having said that I also had this one in a particular rehearsal studio (but nowhere else) so it could be mains wiring related too (again some kind of fault with the earth)

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[quote name='6v6' timestamp='1471505194' post='3113448'] Having said that I also had this one in a particular rehearsal studio (but nowhere else) so it could be mains wiring related too (again some kind of fault with the earth) [/quote]

Yes, a mains wiring fault in the building might do it ? If the earth is floating, but there's other equipment connected to it. Try another building before calling an amp fault, that seems most likely. Otherwise, suspect the amp has a floating ground and perhaps another fault so get it checked pdq !

Played a gig recently where the PA was run from one building mains circuit and amps from another, and mic's would do just what what you describe if yer had hands on the strings and touched the mics. Engineer said something along the lines of 'wondered what that light on the desk 'earth fault' was........?!?

LD

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Okay cheers guys. I've tried all combinations of different basses, cables, pedals, etc. The only change I can find is when switching from the 75 watt practice amp to the dinky 10 watt one (getting shocks from the 75). I don't know whether it's because the 75 watter is at fault or if the 10 watt one is just so small I wouldn't feel the shocks?

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Just got in touch with PMT and the amp is luckily still under warranty but they've discontinued selling this model. They said to give them a ring tomorrow and explain the situation to their amp tech and see if he knows where the fault lies. If they can fix it, they said they will, and if it turns out cheaper to give me the in-store credit they said they'd do that instead. Happy days! In the meantime, I'll do my practicing through headphones methinks, even if that means the neighbors don't get to hear it :(

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Hi

Had the same issue a couple weeks ago and I was surprised that it didn't trip any RCds. After a wee bit of testing it was due to a grounding issue caused by a faulty "kettle" type power chord running into my amp. So it was an easy and inexpensive fix for me, hope you get yours sorted.

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Ah. So just noticed this is also the case on the 10w practice amp. A nice electric shock once again, this time enough for me to reel my hand away quickly and uncontrollably and into the shelf, and I now have a nice cut on my wrist. Fantastic.

So it's both amps and all basses - so likely a problem with the plugs. I will dig deeper when I get our mains socket tester back (brothers had it since he moved out). And since I inherited his room I want to know whether it is a problem located to this room, part of the extension that the previous homeowners had done, or whether it's housewide. I do however find it odd that I've only noticed this since a few weeks ago, despite having the amp for nearly half a year, and not having any troubles with the old one ever until now (had it for 8 years)...

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It sounds likely that a earth wire has come adrift somewhere, maybe inside a mains socket, possibly affecting all sockets on that circuit. If you're not confident with home electrics - please get someone qualified to take a look - after all it could save a life!

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[quote name='KiOgon' timestamp='1472047069' post='3117986']
It sounds likely that a earth wire has come adrift somewhere, maybe inside a mains socket, possibly affecting all sockets on that circuit. If you're not confident with home electrics - please get someone qualified to take a look - after all it could save a life!
[/quote]

And I haven't checked the earthing in the basses yet - waiting to get the new pickups before I put in that solderless loom

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Amp tech turned out to "not be in". I have it on good authority he'll be in over the weekend though for their alleged 25th anniversary weekend so I'm going to rock up and drop it at his feet or something. Just because y'know, drama.

And by good authority I mean all of his colleagues and the manager.

Edited by Harryburke14
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