Static Discharge on Amplifier?

[Deus Gladiorum]

Hey guys, so with it being Winter and all I've been getting a lot of static discharge. I'm pretty familiar with static discharge being an electronics killer but this is a problem limited to my amplifier rather than my desktop tower.

About 5 or 6 times now probably, I've touched my Lepai Amplifier and felt and/or heard (in the form of a crackle or zap) a static shock, which would subsequently cause my amplifier to stop working though the power LED would still remain active, prompting me to just switch the I/O switch off and back on again and everything would be fine, no perceived problems with sound or anything. But I'm wondering, have I just been lucking out? Is it basically a ticking time bomb at this point and the next static shock could actually cause some really noticeable or permanent damage? In addition, what would be the best way to prevent this discharge?

 

[InvalidError]

How much damage you might be able to cause depends on how the device is actually built. If static discharge cause your amplifier's CPU/micro-controller to crash, then the discharge is obviously going somewhere it should not be able to. Whether or not this might cause a lifespan issue depends on the exact cause. If the inputs have proper protection and the crash is caused by the noise the discharge puts on the power or ground traces static gets shunted to, then there probably is no problem. If the crashes are caused by static jumping between traces on the PCB or possibly within the CPU, then it might be a matter of time until the affected inputs fail.

One simple way to reduce the likelihood and magnitude of static discharges is to use a humidifier. Removing synthetic fiber rugs and clothes also helps. Another possibility would be to ground your amplifier's case if it is metallic and has no ground through its power cord so you can simply discharge static by touching the case before pressing buttons.

 

[buzznut]

Curious about what kind of AMP. But I would say it sounds like a grounding issue.
I remember having a bathroom mirror that kept shocking me. Some idiot had grounded a light socket to the mirror. Removed said ground wire and no more problems.
Anyway, if it is a static discharge issue you could just grab metal such as a car or comuter chassis and discharge yourself.

 

[Skylyne]

The probability of you damaging your equipment really depends on where you're touching the amp, the strength of the discharge, and how your amp is designed to handle static discharge when it encounters it. Since you don't really give any real details about where you touch it, whether you wear a lot of synthetic fibres, etc., it's difficult to really say too much.

Since your amp is obviously shorting out, and shutting itself down, I'd say it's built okay.... to an extent. While you might be fine with this happening all of the time, it's better to avoid static discharge, just in case your amp stops protecting itself (since electronics do fail). The best way to prevent this problem would be to decrease the amount of synthetic fibres you wear, and have in your computer room, and maybe even ground your amp.

 

[Deus Gladiorum]

The amp is a Lepai LP-2020A+ and the discharge has happened both when I've just touched the top of the amp and when I've touched the volume dial. I have the amp on top of my right Micca MB42 bookshelf speaker, so it's not touching anything metallic. I do have a humidifier in my room, but I'd consider that to be more of a temporary solution or a workaround since I often don't pay attention to when its water tank runs out if the room feels comfortable. I guess I'd like to ground it, but I'm not really sure how to.

If that's a silly question, I apologize, but what would be the most effective way to ground it? It's a carpeted room and I can't do much about that at the moment.

 

[InvalidError]

what would be the most effective way to ground it?

If it has a metal case, the easiest way to ground it would usually be to run a #14-16 gauge wire with eyelet terminal at both ends from one of the case screws to the outlet's face plate screw. If the case is plastic, you would need to find some way to attach the ground wire to the input terminal ground.

 

[Skylyne]

The amp is a Lepai LP-2020A+ and the discharge has happened both when I've just touched the top of the amp and when I've touched the volume dial. I have the amp on top of my right Micca MB42 bookshelf speaker, so it's not touching anything metallic.

I'm assuming the volume dial is metallic, or there is a metal surface near it. I'm curious if the amp does its internal shut down when you arc the chassis (aka body/case/etc.)... If so, then you definitely should ground the body to an outlet, as IE explained (haha, same initials as Internet Explorer). Once the chassis is grounded, I'd make it a habit to touch the top of the amp before touching any other part, to prevent arcing directly to the components. The downside is that if you arcing the chassis, and that causes it to shut down as a safety, then your chassis isn't grounded properly; and that would make me very uneasy.

I do have a humidifier in my room, but I'd consider that to be more of a temporary solution or a workaround since I often don't pay attention to when its water tank runs out if the room feels comfortable.

I wouldn't use a humidifier for temperature control, as it actually can cause more problems when used too much around electronics. Electronics can function a bit better with some humidity, but not when the room's temperature is controlled by the humidity (even for a short period of time). High humidity in a room can cause condensation to build up in places that are vulnerable to shorting, and cause more problems than what you have now. Best to keep the humidity limited, unless your health needs it.

If that's a silly question, I apologize, but what would be the most effective way to ground it? It's a carpeted room and I can't do much about that at the moment. [/quotemsg]
Not a silly question. In fact, it's quite common, since the majority of devices have an internal grounding system, and most people don't even know what grounding equipment means. In fact, it's a good question... I've seen some experienced people "ground" devices in a way that made me wonder if they understood what grounding their equipment meant. I've seen plastic being "grounded" to metal that could potentially be hot... it isn't always very clear to some, obviously.

what would be the most effective way to ground it?

If it has a metal case, the easiest way to ground it would usually be to run a #14-16 gauge wire with eyelet terminal at both ends from one of the case screws to the outlet's face plate screw. If the case is plastic, you would need to find some way to attach the ground wire to the input terminal ground.

Forgive me for being blonde, but I can't help it... this won't sound very intelligent, so blame my hair (get it?).

Personally, I would also advise to run a ground from some of the other internal areas of the amp. The input is one, but there are others. If I had it in front of me, I would be able to at least point to places... but I just can't think of anything descriptive enough. Massive brain fart going on here. It's one of those days.

 

[InvalidError]

Personally, I would also advise to run a ground from some of the other internal areas of the amp. The input is one, but there are others.

On amplifiers with grounded metal chassis, the input connectors' shields are often bonded to chassis by screws or nuts and the PCB by the connector's leads, same goes for most outputs. If ground happens to be bonded to secondary-side neutral, there will usually be at least one screw or jumper on the PCB to connect the two.

One may argue this creates ground loops but you are probably already creating much bigger and nastier ground loops by hooking up different pieces of grounded equipments with multiple cables anyway: your PC (grounded) connects to your AV receiver (usually not grounded) which then connects to your TV (often grounded) and building ground from the TV/monitor to the PC completes the loop.

So, the amplifier is most likely already grounded, albeit indirectly by the other devices it is connected to. This is not ideal since all those devices in-between also get exposed to the discharge and those connections are usually not intended for passing static either.

 

[Deus Gladiorum]

I'm really not quite sure if my desktop tower is grounded, as it sits on top of a plastic box and doesn't touch anything surrounding it aside from maybe the wall and a curtain. In addition, I'm not sure if my monitor, which is just sitting on top of a wooden desk alongside my speakers and amp, is grounded either.

I also have a 2nd, quick problem. I just hooked up my Wii U and my amp to my monitor (the amp is usually connected to the pc). As I was playing, I got to this one instance where the game would (try to) play a very heavy booming sound but I think the bass was so powerful it caused my amplifier to lose power or turn off for a second and then come back on. I was able to repeat this one more time on the exact same section before I decided to adjust the bass and the volume to lower levels. I feel pretty concerned about this, but it's not something that's unheard of according to a Google search I just did. Any advice or is there not a reason to worry? This has never happened to me before.

 

[InvalidError]

I'm really not quite sure if my desktop tower is grounded, as it sits on top of a plastic box and doesn't touch anything surrounding it aside from maybe the wall and a curtain. In addition, I'm not sure if my monitor, which is just sitting on top of a wooden desk alongside my speakers and amp, is grounded either.

If your PC and monitor use a standard IEC C14 (or C20) three pin connector with the region-appropriate cable like most large computer equipment does, they should be grounded at the power outlet by their power cord assuming your electrical wiring is up to modern electrical codes.

As for your issue with the amplifier shutting down when there is excessive bass, that could simply be its power supply shutting down due to an overload condition. Not much you can do about it apart from reducing your bass setting.

 

[Skylyne]

On amplifiers with grounded metal chassis, the input connectors' shields are often bonded to chassis by screws or nuts and the PCB by the connector's leads, same goes for most outputs. If ground happens to be bonded to secondary-side neutral, there will usually be at least one screw or jumper on the PCB to connect the two.

One may argue this creates ground loops but you are probably already creating much bigger and nastier ground loops by hooking up different pieces of grounded equipments with multiple cables anyway: your PC (grounded) connects to your AV receiver (usually not grounded) which then connects to your TV (often grounded) and building ground from the TV/monitor to the PC completes the loop.

So, the amplifier is most likely already grounded, albeit indirectly by the other devices it is connected to. This is not ideal since all those devices in-between also get exposed to the discharge and those connections are usually not intended for passing static either.

I was really getting at grounding certain internal areas if the case was plastic... Probably could have made that more clear, but I still blame my hair colour for that. I was also referring to a few different sets of circumstances, since I have no real clue how the setup is wired/etc..

As for your issue with the amplifier shutting down when there is excessive bass, that could simply be its power supply shutting down due to an overload condition. Not much you can do about it apart from reducing your bass setting.

It sucks, but yeah... not much you can do about it.

 

[Deus Gladiorum]

Hey guys, so I've been away at school for most of the past few months up until now, and now that I just got back home I'm getting really tired and really worried about the amplifier not being grounded or whatever, so I want to take InvalidError's and Skylyne's advice and ground it using some 16 gauge speaker wire I got with the amp and speakers. However, I know really, really little about electronics outside computing, and this makes me very worried. I'm not very familiar with a good amount of some of the terminology that's been used in the posts above, but the prospect of securing a wire from a screw on the back of my amp to a screw on an outlet's face plate seems dangerous since I have absolutely zero experience with this and have never studied it before. Sorry for not responding or choosing a best answer. I was a bit intimidated by this, so I just sort of ignored it for a few days until I had to leave to go back to school and it was no longer something I had to deal with, but now that I'm back I really want to solve this problem in the safest manner possible.

I also don't think my outlet's faceplate has a visible or easily accessible screw, nor do I have access to any eyelet terminals. So, I guess would there be other devices to connect the wiring to from the amplifier? Such as one of the screws on the back of my PC case? Sorry if that's a terrible idea, I really have so little experience with this and no real idea of what I'm doing :\

 

[InvalidError]

If the amplifier connects to your PC, you could ground your amplifier to your PC's case and it should get the job done.

 

[Deus Gladiorum]

Alright great, that sounds pretty feasible and my amlifier is connected to my PC via a standard 3.5mm auxiliary cable. What would be the best way to do that, do you think? I can pick up the eyelet terminals if necessary, and I assume they work by placing them in between a screw and the chassis sort of like a nut, but I'd like to see if there's a way to do this without spending anything first. Just so long as the copper ends are touching both my PC case and my amplifier chassis, it'll have done the job, right?

 

[Skylyne]

That should do the trick, given that both chassis are metal, and the amp is grounded to the chassis. I would definitely suggest using eyelet terminals for the grounding, since they are going to be the most reliable, and easiest method of attaching the two together.

If you still have problems, let us know. Hopefully we can get this fixed for ya

 

[Deus Gladiorum]

I really am appreciating the help, guys, and holy crap, it seems to work! I just tried a temporary "ghetto" fix until I can get eyelet terminals, and it seems to work from a first run trial, but I'll have to test a bit more and under safer circumstances. My amp's whole chassis is metal, I'm sure, so I took some 16 gauge copper speaker wire and placed it underneath the amp. I made sure that the wire was secure and that the copper ends were making contact with the amp's chassis too, and then I took the other end of the wire and just held it to the PC case while touching the amplifier as I sat down (touching the amplifier while or after sitting down is usually the easiest way to get the popping to start and the amplifier to stop working). To my surprise, it didn't seem to create any noise and it worked just fine!

Of course, I still need to test this more and I guess use some electrical tape to hold the wire in place. I'm still worried though, perhaps irrationally so. Isn't it possible that electricity could arc across my case and over-volt one of my components?

 

[InvalidError]

Of course, I still need to test this more and I guess use some electrical tape to hold the wire in place. I'm still worried though, perhaps irrationally so. Isn't it possible that electricity could arc across my case and over-volt one of my components?

What is the voltage across a dead short? Unless you are passing very high current, it will be close to 0V.

What is the normal current on line-level audio cables? Milli amperes at most, so the voltage drop across a #16 wire should be negligible.

Also keep in mind that your amplifier already has a weak signal ground connection to your PC through the 3.5mm jack on your PC and the RCA connectors on the amplifier. In case of a major electrical fault between your amplifier and ground, the fault current through ground, the RCA jack and 3.5mm jack would go through your flimsy audio cable. With the #16 wire binding amplifier ground to PC chassis ground, most of the fault current would go through the #16 wire and then the PSU's IEC connector out to building ground, hopefully without creating any harmful voltages along the way.

 

[Deus Gladiorum]

Thanks a lot for the help guys. It seems to have done the trick, though building up enough static still results in the amplifier cutting out, but it's still far better than it was before. Had to give the Best Answer to InvalidError, but both of you guys were a huge help. Thanks again!

 

[Skylyne]

Glad we could help. And yeah, grounding the amp to your case shouldn't cause anything negative to happen. Worst case scenario (pun intended), you can probably find something else to ground it to.