olds1959special
Senior Member
I did this to solve a ground loop issue. Is it safe? Will it compromise quality?
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disconnecting ground (remove third prong) from DAC
- Thread starter olds1959special
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KSTR
Major Contributor
It is called "safety ground" for a reason.
Disabling it is forbidden, no insurance will pay in case of an incident and you will likely go to jail if someone gets hurt or killed.
Disabling it is forbidden, no insurance will pay in case of an incident and you will likely go to jail if someone gets hurt or killed.
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olds1959special
Senior Member
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- #3
thanks, what about using a hum x ground isolator ?
KSTR
Major Contributor
Web search doesn't find anything for this term.
If you mean some kind of audio isolation transformer inserted into the interconnection then yes, this is one way to deal with ground loops.
OP
olds1959special
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Find and Eliminate Ground Loops - Circuit Cellar
Everything had been fine with my home entertainment center—comprising a TV, surround-sound amplifier, an AM/FM tuner, a ROKU, and a CD/DVD/BlueRay player—until I connected my desktop PC, which stores many of my music and video files on one of its hard drives. With the PC connected, the speakers...
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KSTR
Major Contributor
Unlikely. And this device doesn't show any safety approval labels so I'd be cautious.
solderdude
Grand Contributor
When you have a ground loop you solve this by connecting all involved devices to the same wall outlet and if that does not help you must solve it in the connections between the devices.
as @KSTR stated.. safety ground is there for safety reasons do not disconnect.
When you do disconnect one of them there might still be 'safety' but that would only be present and by the grace of the interlinks between devices (which might be too high impedance to provide real safety).
Disconnecting a safety ground pin is not the same as 'ground lift'.
as @KSTR stated.. safety ground is there for safety reasons do not disconnect.
When you do disconnect one of them there might still be 'safety' but that would only be present and by the grace of the interlinks between devices (which might be too high impedance to provide real safety).
Disconnecting a safety ground pin is not the same as 'ground lift'.
MaxwellsEq
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This!
Only qualified engineers and electricians should ever temporarily disconnect a safety ground, and they should do so only while taking other precaution to prevent electrocution and/or fire and setting out warnings for others that this is what they are doing.
If you have a hum problem that can only be resolved by disconnecting the safety ground, you have bad gear or a bad setup.
Weren't SMSL DACs among those found to have "dummy" PE connections anyway? That may render the entire affair moot. Should be easy to check with a multimeter in continuity.
Not all devices need a protective earth a class 2 device may not have one for instance.
Ground loops through mains PE connections are indicative of badly designed equipment.
Also to reiterate what others have said you must never disconnect a protective earth if one is present.
I do not care if you electrocute yourself due to a fault causing the case of the piece of equipment to become live however I do care that you could kill someone else who happens to be visiting your home or who happens to obtain the equipment after you have disposed of it in the future.
Which is kind of the entire point of Class II (double insulated).
Side note, IEC Class II devices are commonly thought of as never having a PE connection, but actually they very well may. While you'll probably want to keep it insulated from secondary-side ground with a Y class cap (as an equipment designer), it can be useful for getting rid of pesky power filter leakage currents and the like. (Designers may shy away from this due to cost implications, plus there's a bunch of countries left where mains PE isn't much of a thing.)
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Find and Eliminate Ground Loops - Circuit Cellar
Everything had been fine with my home entertainment center—comprising a TV, surround-sound amplifier, an AM/FM tuner, a ROKU, and a CD/DVD/BlueRay player—until I connected my desktop PC, which stores many of my music and video files on one of its hard drives. With the PC connected, the speakers...
I am very suspicious of any device that interferes with a direct connection between safety ground on the mains cable and the ground connector on the mains socket. This looks much like a 'cheater' plug, which is a thoroughly dangerous device.
Without getting inside the equipment, The ONLY SAFE way of eliminating ground loops is to use an isolating transformer on the audio connections. Good transformers like Sowter in the UK or Lundhal in Sweden aren't cheap. but very effective.
One can avoid (or significantly reduce) ground loops by creating a ground-lift on the audio ground, RETAINING THE SAFETY GROUND, but not all equipment is suitable for conversion.
S.
Speedskater
Major Contributor
From the Bill Whitlock (Jensen Transformer - retired) seminar:
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olds1959special
Senior Member
- Thread Starter
- #16
good thing I no longer need to do this right now, but the info is helpful.
If a Class I device incorporates an adequately specified power transformer then the secondary circuits can be left floating. Every manufacturer of bench-top DC power supplies appears to be aware of this, but manufacturers of audio gear not so much.
I agree that no one should ever bypass or remove a safety ground. However, your comments about insurance and being jailed are not correct. I've been in the insurance business for some 48 years now and have never seen a policy with a stupidity or accidental carelessness exclusion. Many insurance claims are paid following stupid mistakes by an insured that result in a loss. To void coverage, one has to get into areas where the actions were intentional - like arson, or setting up a situation to intentionally injure someone.
Even illegal acts don't always void coverage -- think about a drunk driving accident -- drunk driving is illegal, but your auto insurance policy will still pay for the damage to your car and the injuries and damage you inflicted on other parties. (Then your insurance company will cancel your coverage going forward.)
Restrictive endorsements are usually limited to major issues such as requiring a sprinkler system or burglar alarms be kept turned on, or a restaurant's vent hood be cleaned on a regular basis. I've never seen an endorsement having anything to do with a ground plug.
Regarding jail, if another party was injured by the removed ground, a civil lawsuit may result but criminal charges are highly unlikely unless it can be proved that the removed ground was an intentional effort to harm someone else or cause damage. That's highly unlikely when the person's goal was to fix a ground loup noise. The injured or damaged party may sue you as a result, but civil lawsuits do not result in jail.
EDIT -- by the way, Amazon sold over 5,000 of these in the last month...
Generally yes. However, a lot of equipment has the audio ground tied to the chassis whether there's a safety ground or not. There may even be multiple connections of the audio ground to chassis, making it very difficult if not impossible to create a safe 'ground lift' facility.
That's why using transformers on the audio outputs is pretty much the only safe way of avoiding ground loops on badly designed equipment.
S.
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