# Question about static discharge & amp



## Waterloo (Dec 25, 2012)

When I get up off the couch, guitar in-hand and I sometimes hear a static discharge coming through my amp. Could this static discharge cause any damage to the amp, to pedals? Just wonderin'. 

As for humidifier, yes I can crank that up but just wondering about static, tube amps, pedals etc.


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## Greg Ellis (Oct 1, 2007)

That's an interesting twist - you shocking your amp instead of your amp shocking you. 

I wouldn't worry too much about it. You'd have to deliver a pretty big shock to do any damage, I would think. Big enough that it would hurt you.


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## keto (May 23, 2006)

**Non-learned wild ass guess follows** maybe MAYBE on a solid-state amp, an op-amp or transistor might be in danger, though my real thought is that the circuit should be well enough grounded to ignore a little static. On any amp, if you have it cranked max, and your speaker is sorta borderline power handling, I could see a potential problem if the static causes a big volume spike. 

Are you talking about 'ZAP!' one snap, or 'zzx...zzx...zzxt' little trickles of static?


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## Sneaky (Feb 14, 2006)

I fried a transistor in a Z Vex SHO pedal once with static electricity. I emailed Zack about it, assuming I would have to send it to him to repair, but he told me he had taped a spare transistor inside the enclosure of his original SHO's since he knew they were prone to failure. Sure enough, mine had one inside and I had it back up and running in a few minutes. I think he uses something different in the SHO's now, but it is certainly possible to do damage to sensitive components with static discharge. I wouldn't worry about amps so much, unless it is the amp shocking you. Then you have a problem.


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## pauledc (Mar 4, 2013)

Maybee try a couple of those bounce laundry antistatic sheets in your pocket?


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## Waterloo (Dec 25, 2012)

thanks for the feedback, folks. It's not a loud popping, just a crackle that comes through the amp (tube amp) when I get up off the couch with my guitar in-hand. It's as if you were amplifying the sound of a hudson's bay blanket being unfolded in a dry room. When I first noticed it, I thought it was guitar cable or pedal connection-related but no, it's just static discharge from getting off the couch. I have an Xotic SP pedal that I had to have repaired (foot switch) and at the time I wondered if it was related to static so just wanted to learn more about it. The pedal issue was the footswitch which was replaced so don't think static was the culprit.

I'll try the bounce antistatic sheets as well, and crank the humidity.


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## dcole (Oct 8, 2008)

Sneaky said:


> I fried a transistor in a Z Vex SHO pedal once with static electricity. I emailed Zack about it, assuming I would have to send it to him to repair, but he told me he had taped a spare transistor inside the enclosure of his original SHO's since he knew they were prone to failure. Sure enough, mine had one inside and I had it back up and running in a few minutes. I think he uses something different in the SHO's now, but it is certainly possible to do damage to sensitive components with static discharge. I wouldn't worry about amps so much, unless it is the amp shocking you. Then you have a problem.


The problem there is that a MOSFET transistor is used in the SHO. They are inherently sensitive to static electricity. To minimize the risk of damage to these devices, they generally have a zener diode connected between the gate and source to shunt away any voltage that would otherwise destroy the device. From what I understand, the SHO now has this zener diode added.


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## Waterloo (Dec 25, 2012)

dcole said:


> The problem there is that a MOSFET transistor is used in the SHO. They are inherently sensitive to static electricity. To minimize the risk of damage to these devices, they generally have a zener diode connected between the gate and source to shunt away any voltage that would otherwise destroy the device. From what I understand, the SHO now has this zener diode added.


Is the zener diode a common design feature for today's pedals? Or is it something you need to be aware of & ask about when buying new equipment? At home won't be an issue as we increased the humidity but just wondering if i'm ever giggin or jammin in a dry environment.


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## keto (May 23, 2006)

Waterloo said:


> Is the zener diode a common design feature for today's pedals? Or is it something you need to be aware of & ask about when buying new equipment? At home won't be an issue as we increased the humidity but just wondering if i'm ever giggin or jammin in a dry environment.


I'm not sure about the big manufacturers, but I never used them when building my pedals. It's an easy enough option to implement, but adds cost and complexity.


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## dcole (Oct 8, 2008)

Waterloo said:


> Is the zener diode a common design feature for today's pedals? Or is it something you need to be aware of & ask about when buying new equipment? At home won't be an issue as we increased the humidity but just wondering if i'm ever giggin or jammin in a dry environment.


Depending on who your buying from I wouldn't expect many people to know what your talking about. Zener diodes are a common item on the terminals of a MOSFET for protection from ESD. I would normally expect them there and would not worry about it. I think Zvex's SHO is the only item I have heard this problem of.


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## jb welder (Sep 14, 2010)

Are you holding the strings as you get up from the couch? The strings should be keeping you grounded so I don't really understand how this would happen if you have 3 prong AC with chassis grounded and you are holding the strings. With you being grounded there should be no static build up.


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## bolero (Oct 11, 2006)

the IT guy at work drives me nuts because he carries parts with bare circuit boards around ( expensive graphics cards! ) in his hands, with no regard for static discharge. he doesn't even carru them by the edges, he wraps his fat hands around the whole damn circuitboard


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