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My amp has a ground loop.
I used a cheater plug and the annoying hum went away.Is it safe to use the amp like this (cheater plug --> surge protector)?
Follow Ups:
The mere fact that there is a ground loop means the amp has two different ground potentials.One is via the power cord and the other via the interconnect.
So if you eliminate the ground via the power cord the amp is still grounded as long as it is connected via the interconnect to the preamp which is in 99% of cases grounded too, if it were not there wouldn´t be a ground loop in the first place. If the ground at the input were not connected to chassis ground there wouldn't be a ground loop either.
Sooooo as long as the amp is connected to another grounded preamp (via the IC) it IS grounded. Now I'm not saying this is the preferred method of grounding the unit but in the case of a fault condition that would case the breaker to trip it will.
Sooooo as long as the amp is connected to another grounded preamp (via the IC) it IS grounded. Now I'm not saying this is the preferred method of grounding the unit but in the case of a fault condition that would case the breaker to trip it will.Not necessarily, no. It would only trip the breaker if the resistance of the fault loop were sufficiently low enough to cause enough current to flow to trip the breaker. That wouldn't necessarily be the case for every fault condition and the current that does flow could be more than sufficient to cause a fire hazard or in the case of interconnect wires melting a shock hazard. If the interconnects blow, then there's no path to ground leaving you with a hot chassis.
se
The typical powercord delivered with hifi gear has a ground wire of about 18awg.So why can't an IC carry that current? Even if the IC were less than 18awg the 18awg ground wire is no doubt 200-400% the actual current carrying capacity. Or do they design on the absolute limit?
My amp has a ground loop.
I used a cheater plug and the annoying hum went away.Actually there's no such thing as a cheater plug. The so-called cheater plugs were never designed or intended to be used to defeat the safety ground. Rather they were designed and intended to be used to preserve the safety ground.
Many older homes while not having three prong outlets, have a safety ground which is tied to the metal box that the outlet is mounted in. The spade or pigtail on the "cheater plug" is intended to be connected to the metal frame of the outlet (via the cover screw) which is connected to the metal box which is connected to the safety ground.
Is it safe to use the amp like this (cheater plug --> surge protector)?
Whenever you defeat the safety ground of a component that does not meet Class II insulation standards, it is less safe than if the safety ground is preserved. However there are probably many components on the market which do meet Class II safety standards and don't require the use of a safety ground but due to market demands, use three wire IEC connectors anyway so users can used aftermarket power cords.
The problem is you'll never likely know which components those are. And I dare say that many high end manufacturers aren't even familiar with the various safety standards in the first place and wouldn't be able to tell you if asked.
se
My amp also has a ground loop problem. Amp made by a very well known name brand high end manufacturer. I called them and they told me to use a cheater plug. They said not to worry about causing harm to the amp as they have found that even when grounded a surge that will do harm to the amp is not helped by grounding. In a hi-rez system, the cheater plug can change for the worse the sound of your power cord/amp. If you have the ability, disconnect the ground wire at the outlet or fuse box.Bob
You should have the company in question prepare an affidavit for you. Make sure they include statments from a qualified electrical engineer outlining how this recommended procedure will not pose additional risk to person in event of an insulation failure shorting a hot lead to the case. Though they don't hold an insurable interest in your home or family it may provide you with legal recourse should you wish to recover damages at a later date.I trust in your post you've left out the part of the discussion that touched on the safety hazards and potential liability if you defeat this ground. If the discussion only touched on affects to amp I can think of nothing that better epitomizes reckless hedonsitic behavior on both a corporate and consumer level.
Unbelievable.
By the way, who is it?
First off, I continue to use the amp properly grounded and live with the ground loop hum. Which by the way disappears when i run it in balanced mode. IMO you only need 1 wall outlet ground in the system as the interconnects will ground the other components. I once had a lightning strike that took out this amp even though it was correctly grounded. So what appears to be the argument hear is not what happens to the amp/equiptment, but what happens to you injury wise should you be touching the equiptment during a fault condition. I asked the manufacturer about this and they told me that the ground does not insure saftey to you even when connected. As I look around the house I take note of many electrical devices that use only a two prong polarized plug with no ground. Should I not ever go near, use or touch those? No ground on my vaccuum cleaner or toaster oven- guess there not safe.
Further to what Zorpman has replied, the polarized plug is also used in conjuction with the appliance on/off switch to help reduce shock hazards. I believe it is standard to have the hot lead switched at the appliance, this ensures that the appliance itself is not energized when turned off. If the nuetral wire was switched the appliance would always be energized, even when off, just waiting for a ground connection to cross it path.The double insulation practice with polarized plugs ultimately means two appliance failures is required instead of just one for a shock hazard to exist (under intended usage)
I now have to go and pry that damn bagel out of the toaster.
Further to what Zorpman has replied, the polarized plug is also used in conjuction with the appliance on/off switch to help reduce shock hazards. I believe it is standard to have the hot lead switched at the appliance, this ensures that the appliance itself is not energized when turned off. If the nuetral wire was switched the appliance would always be energized, even when off, just waiting for a ground connection to cross it path.Yes. And polarization also assures that the fuse remains inline with the hot lead rather than neutral.
se
The reason you have some appliances that do not have a gound prong is that they are double insulated, i.e. they have certified to UL standards that the case will not be energized if there is an internal ground fault.The reason you do not defeat a ground wire is that in a short situation, electricity will seek the path to ground with the least resistance. A 14ga copper wire (your ground circuit)has minimal resistance, hence, the jolt will be diverted to the low resistance gound wire rather than your nerve infested body. However, if you are standing bare footed on a salt-water wet concrete pad floor you may be the unfortunate winner of the low resistance award and have the dubious honor of setting your body hair on fire.
BTW, a ground is not designed to protect your equipment from a lightning strike, thats why you have surge protectors (which may fail if the strike is to close).
My amp also has a ground loop problem. Amp made by a very well known name brand high end manufacturer. I called them and they told me to use a cheater plug. They said not to worry about causing harm to the amp as they have found that even when grounded a surge that will do harm to the amp is not helped by grounding.They said to defeat the safety ground and not worry about causing harm to the AMP!?!?
May I ask which very well known name brand high end manufacturer this was?
se
If you appeared to be a regular laid back inmate type we find around here i'd tell you. But your style is a bit too authorative for me.
good day.
I'm not certain that the Electrical Code would have any exception allowing the removal of the grounding pin.A thought would be to install a GFI circuit breaker to feed that outlet. That would preserve a high degree of shock prevention.
Do any inmates have any experience listening to GFI protected circuits?
Kind regards,
Ray
Ray, i don't have any personal experience with GFI's but i do remember reading more than a few comments that were not very positive about them. Sean
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Here in Germany the electrical code requires that the whole house/apartment whatever be protected by a master ground fault breaker. So who knows what it sounds like without? I can only say it shuts down the whole house in the blink of an eye.I did substitute traditional screw-in ceramic fuses for the SS breakers on the dedicated lines to my listening room. Seems to make a difference but I could be fooling myself.
Cheers!
It is best if all your your components are grounded using the third pin. But... if you lift the ground on just one of the components to get rid of a ground loop, you are still OK because the chassis for each of your components are grounded through your interconnects. But do not use a cheater on the power strip.
Ground loop problems are a pain, and sometimes a cheater plug is the easiest solution. I assume you have tried plugging all of your components into the same outlet to get rid of the hum. Use a power strip if needed for extra sockets are needed. Also, it is preferrable to use a cheater on your preamp, or other other component, rather than the amp. Lots of times a cheater on the preamp will solve the ground loop.Best wishes,
Mike
But... if you lift the ground on just one of the components to get rid of a ground loop, you are still OK because the chassis for each of your components are grounded through your interconnects.That can be as much or more of a safety hazard than if you just went ahead and lifted the safey ground on all the components.
Many interconnects do not use wire gauges sufficiently large to handle the amount of current that would be required in the event of a failure and not all failures would result in sufficient current to actually trip the breakers and with some users reversing the polarity of the AC cords, the equipment fuses may no longer be in line with the AC's hot lead.
In such a case the wire can heat up, burn off the insulation and possibly cause a fire. Or the wire may simply blow like a fuse leaving the failed component with a live chassis.
se
Yes, but you MUST use an audiophile approved cheater plug, like a FIM, or Synergistic, or TG, or Harmonic Tech, or Electraglide, of Elrod, or Magnan, or......Just kidding, but I CAN see a whole new line 'must-have' power related components ;-)
I've been building this sort of thing for 18 years.....All are built to order BTW.....
I have no less than 4 of your cords and one power strip - love them all!! I bought 3 of them with the ground lift[ed] option.Didn't know you made cheater plugs as separate items?
The folks that buy them are normally reviewers as they cannot go inside the gear and swap wires if the unit is delivered with AC in reversed phase for instance.....My company is a job shop so we can build whatever is needed....
btw.. if you're able to build something custom for Metralla, I'll take one. Er, make that two. (One for me and one for the wife) ;-)
fifty into two twenty-fives :-)
OK, Bob. Here ya' go mate.Build Me a Woman
================
Give me a witness, darling.
I need a witness, babe.
I got the poontang blues. I got the poontang blues.
From the top of my head to the bottom of my cowboy shoes.
Build me a woman,
Make her ten feet tall.
You got to build me a woman,
Make her ten feet tall.
Don't make her worthless,
Don't make her small.
Build me a woman,
Make her ten feet tall.
You got to build me a woman,
Make her ten feet tall.
Don't make her worthless,
Don't make her small.
Build me someone I can ball
All night long.The Doors
Regards,
Metralla
KP
Seems to me another perfect item for Mothra.
Ain't that the truth!
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