Afternoon all.

I’m stuck in the house making music and editing video on my stupid Lenovo laptop. Whenever I have to plug it in to charge I get so much noise coming through the speakers that it’s totally unusable. I just have to turn off the amp and wait for it to charge fully before commencing work. Or… use headphones which work just fine.

Now I know why this is happening – It’s a ground-loop.  When I was younger, more carefree and considerably stupider I had another (Dell) laptop with exactly the same issue which I resolved by disconnecting the earth wire in the charger’s plug. That completely cured the problem and I had at least seven years noise-free use out of it before it became obsolete.

Back then I didn’t know or even care what the danger was. But with age comes a bit more knowledge and respect for not getting electrocuted.

So what I’m basically asking is: am I just being a big girl’s blouse for not doing this anymore? I do understand the risk in theory – that if something breaks/goes wrong, the power can’t go to ground so goes through YOU etc. But what are the actual risks in the real world? Likelihood and probable severity of electricity-based pain/damage? And if it really is dicing with death, how could one break the ground loop on the safe side of the equation – the audio-cable running from the mini-jack out on the laptop into the amplifier?

There are a lot of people asking this question on the web. Usual advice is either “lift the ground” or buy moar expensive audio equipment that may or may-not work or even be safer than the ground lift…

Also, no replies of  “just get a Mac”. I’m well aware they don’t suffer with these issues but pennies are tight atm so I must piss with the cock I have.

Thoughts?

All I can tell you is that I have 2 laptops; one has a 2 pin charger, the other has a 3 pin. So my HP laptop charger isn’t earthed.

I must piss with the cock I have.

Do it on the charger.

It’ll be perfectly safe, it’s earthed after all.

I did it years ago when I was using a laptop as a sound module for live music performance for exactly the same reasons as you. I didn’t get electrocuted. Not sure if that helps or not…

Obviously cannot condone such reckless endangerment of human life. etc.

But.

You may note that loads of laptops run from two pin plugs in lots of countries. My 2p is that you’re at fairly low risk of getting electrocuted through the plastic casing of a laptop. Another 2p is that I expect (conjecture) there is no difference in the power adaptor for a 2 pin market to an adaptor for a 3 pin market, barring the actual connection of ground from the mains over to the low side of the DC plug.

Also, one would assume your house has RCD on the mains which are generally quite good at preventing large amounts of electric from finding their way through you.

However, do let us know if you get 240V-ed to death, so we can avoid the same mistake.

A lot of laptop chargers don’t have the earth pin connected to anything. I think the reason they are there is you cant insert the plug unless there is an earth pin. IANE

the US charger for your laptop will almost certainly be earthless, and connected to the mains via a figure-8 lead. maybe get one of those and run a uk figure 8 lead into it – they might have done more inside the brick to protect it from shorts without resorting to earth.

I have dell chargers with both the ‘clover’ style adapter (like figure 8 but with a wired earth as well) and with just figure 8 (mostly borrowed from colleagues in the US whilst on trips)

It could be ‘a dirty’ mains supply – have you tried it in different mains sockets elswhere in the house?

Or it could simply be interference inside the laptop (audio chip unshielded and too close to electronicaly noisy components) . I had a simmilar issue with an older PC, and a cheap dedicated sound card resolved the issue, but that’s not so easy/cheap on a laptop.

I didn’t get electrocuted. Not sure if that helps or not…

In my experience not getting electrocuted does help. (Unless you are Frankenstein’s monster)

What markings have you got on the charger? If there’s a square within a square on the label it’s double insulated and you should be able to dispense with the earth (check the laptop is similarly marked too).

At your own risk and IANAE

Back in the day the hifi nuts used to isolate their supply earth from the household by running an earth cable to a dedicated earth stake and removing the earth from the sockets twin and earth supply. Similarly at your own risk and IANAE.

If you die what bikes do I get first dibs on? 😎

It could be ‘a dirty’ mains supply – have you tried it in different mains sockets elswhere in the house?

Or it could simply be interference inside the laptop (audio chip unshielded and too close to electronicaly noisy components) . I had a simmilar issue with an older PC, and a cheap dedicated sound card resolved the issue, but that’s not so easy/cheap on a laptop.

Yeah, it’s the same everywhere. I think it’s a generic problem with non-mac laptops. It’s the cheap noisy power adapters, some are noisier than others. Desktops don’t suffer, and Macs don’t because they are double-insulated or something. I have a fancy Focusrite audio interface at my studio and the problem persists if I take this laptop. But I generally use the desktop there.

However, do let us know if you get 240V-ed to death, so we can avoid the same mistake.

🙂 I shall instruct the executers of my estate to update the thread should I become brown/fried-bread.

My 2p is that you’re at fairly low risk of getting electrocuted through the plastic casing of a laptop

What if the laptop casing is metal? Or, if one’s cheap stupid Lenovo is mostly plastic except the flat bit where you put your hands. Which is supposed to look like metal but is probably silver-painted plastic…

The laptop is only 20 volts, that’ll not do you much damage.

There are aftermarket power adaptors that don’t have an earth pin connected / are double insulated, fwiw.

The risk is the power supply becoming live but the casing is probably just plastic anyway. The cable to your laptop isn’t though!

Run it through an RCD? Unless your main house fuse box already protects against this?

What markings have you got on the charger? If there’s a square within a square on the label it’s double insulated and you should be able to dispense with the earth (check the laptop is similarly marked too).

Nope, no double-insulted markings on either unfortunately.

There are aftermarket power adaptors that don’t have an earth pin connected / are double insulated, fwiw.

Yeah, so I’ve heard. But I’ve never been able to find one. It’s either the original Lenovo (not double-insulated) or cheap aftermarket replacements (also not double insulated).

The laptop is only 20 volts, that’ll not do you much damage.

errm, pc are all 12v DC. the power supplies are essentially AC/DC converters.

The laptop is only 20 volts, that’ll not do you much damage.

I think the outside possibility is that it suddenly becomes a slightly less friendly 240V AC due to, I dunno, a small child accidentally slicing into the power adaptor with a garden spade*.

* your daily household routine may involve less hazardous children’s entertainment.

pc are all 12v DC. the power supplies are essentially AC/DC converters.

Mostly they’re 20V or thereabouts nowadays. You need a widdlier connector and thinner gauge wires for the 80W max power demand.

Dropped to 12V / 5V / 3V3 or whatevs, internal to the laptop, one presumes.

You can buy a ground loop isolator for a few quid on eBay. They plug between the device and the headphones/amp. Gets rid of the noise. No instant death

Also, just because the laptop is 20v doesn’t mean that you’ll only ever see a max of 20v. That voltage is with respect to its own 0v, not earth. It is theoretically still possible to see 240v

Yeah, so I’ve heard. But I’ve never been able to find one. It’s either the original Lenovo (not double-insulated) or cheap aftermarket replacements (also not double insulated).

Logik LPLENO17

I think the outside possibility is that it suddenly becomes a slightly less friendly 240V AC due to, I dunno, a small child accidentally slicing into the power adaptor with a garden spade*.

* your daily household routine may involve less hazardous children’s entertainment.

Yeah, no sprogs here. I live on my own so only have to account for my own lunacy.

Thanks everyone for the honest advice. I think what I’ll do is: leave this PS (molded plug anyway) as it is, but buy another plug and the cable that plugs into the PSU. Disconnect the earth on that one and clearly label it as such. Then just use the normal one 95% of the time but dig out the widowmaker for when I really need to get some work done noise-free.

All this discussion and nobody’s asked the obvious question – if it doesn’t work out can I have your bikes? (edit dammit missed that post from Sandwich!)

Fwiw I’ve cut through a live ring main by accident, the RCD did its job there so you’ll almost certainly probably most likely be fine. But just in case, see above.

You can buy a ground loop isolator for a few quid on eBay. They plug between the device and the headphones/amp. Gets rid of the noise. No instant death

Yes I’ve looked into these. Apparently they ruin sound quality though which is not acceptable. Have you tried them?

On all the laptops I’ve seen, the connector from the power supply has a concentric type plug – these have only two ‘pins’. They are DC, usually + on the inner pin and – on the outer. So your laptop is not connected to mains earth. Even the 220V Ac side of the power supply is usually a 2 pin ‘figure 8’ plug, and the power brick is double insulated. There probably isn’t an earth wire in the plug to disconnect, and the plugs are usually moulded on anyway.

Logik LPLENO17

Aidy to the rescue! That should do the trick. I always searched for my specific model which only brought up the dodgy ones.

It’s a laptop. Unplug it and use the battery while you’re recording.

Use an external DAC, which will avoid all the problems in the first place.

You may find that it’s impossible to remove the earth connector without breaking the charger open, and even if you do open it then it’s probably not connected as it’s double-insulated.

And just to rain on your parade even more, the speaker output of my laptop hums when it’s plugged in and the earth pin is plastic.

Flaperon,

The battery life is shite. I’d never get any work done.

I have an external DAC at my studio. Problem persists.

I’d remove the earth in the plug not the psu.

Yes I’ve looked into these. Apparently they ruin sound quality though which is not acceptable. Have you tried them?

They work fine. I can’t hear any sound degregation (but I am most definitely not an audio need)

In case it does turn “exciting”, maybe pop the 13 amp out of the plug and put in a 3 amp (if it indeed be 13 amps), so death is slow and agonising rather than swift, spectacular and smokin’.

Wrap some insulating tape around the earth pin for a quick test, then. I’m sceptical but would be interested to see if it makes a difference.

Edit: Don’t blame me if it gets stuck inside the socket…

That’s a great idea. Now, where’s the insulating tape…

you could use a DI box, they have a 1:1 transformer to isolate your kit, useful to have around

MTR do a stereo one, I use a BSS to DI guitars and Bass which sounds nice

…or thick rubber gloves..

FWIW,* I have been running UK Lenovo laptops on unearthed two-pin EU plugs for a decade. No problems yet.

The power-brick cable (mine is a figure-of-eight fitting) is very likely to be (IANAE) double-insulated even if the brick itself and the laptop aren’t.

I tend to buy UK-sourced laptops for the familiar keyboard. But the mains wall sockets here are 2-pin 230V (and always live; no off-switch on each socket). Depending on where I’m working, I swap the power cable out for one with a 2-pin EU or a 3-pin UK wall plug (on which the earth pin is plastic, so does nowt), and everything works fine.

* “FWIW” might be exactly zero. It “seems” like a non-issue to me… which suggests I’ve probably misunderstood the entire thing. Again, IANAE.
:))

Any good?

https://cpc.farnell.com/pulse/pls00548/ground-loop-isolator-3-5mm-p-s/dp/AV25542?mckv=sCENJr57l_dc|pcrid|224635168920|kword||match||plid||slid||product|AV25542|pgrid|46533246385|ptaid|pla-786534683025|&CMP=KNC-GUK-CPC-SHOPPING&gclid=EAIaIQobChMIv5nxz4yc7gIV2u3tCh0JEQtvEAQYASABEgLcK_D_BwE

Is the earth pin on the plug plastic or metallic?

So what bikes are we going to be fighting over?

@Flaperon

Just conducted your genius test. Albeit with parcel tape…

RESULTS

No tape: NOISE

With tape: Sweet, sweet silence.

Don’t try this at home kids. But if you do, wear a vest.

EDIT: Forgot to touch the laptop to test for presence of death.

So what bikes are we going to be fighting over?

You’d be sorely disappointed mate. An old Spesh hardtail and a racer from the 80’s. Neither of them are earthed.

Neither of them are earthed.

Another way of “making the trail come alive”.

IGMC

I had a jack lead with a cheap ground loop isolator to stop interference in my van. Worked a treat.

They may or may not affect sound quality, if you try it and don’t notice any degradation, happy days!

Rather than get a replacement power lead, you could rewire a 1 gang short extension lead with the ground wire disconnected. Plug the laptop in via that when necessary.