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In Reply to: Do I need to worry about no ground wire in my Electraglide posted by budburma on February 1, 2007 at 11:17:04:
.....The Epiphany pic does indeed show an Earth GND pin on the male plug. Elecro Glide does not have a pic of the Epiphany X.R U saying there is no continuity between the Earth GND pin on the male plug and the Earth GND connection on the IEC connector?
Cheers,
Follow Ups:
although i haven't spoken directly to the designer, i have had that information confirmed by a dealer who offer to have a ground wire inserted for me by the designer.....at an undetermined price. i passed assuming the sonic characteristics would also likely change,
Have U taken a DVM and measured between the 2 Earth connections yourself?Keep in mind that if your preamp is tied to Earth GND via a 3 prong cord, your most likely OK using the Epiphany on your amps.
Also, read the owners manual of your amp(s) to ascertain their recommendations for suitable power cables. U could also call them to inquire about their thoughts on the Epiphany.
Cheers,
While the audio ground connection through the interconnect cables will keep the amp chassis close to ground potential during normal operation, it will not have the current handling capacity to keep the amp safe in the event of a power fault. This particular amp also has a ground-lift switch, which will disconnect the amp case from the audio ground if it is thrown.Safety-earth connections create a ground loop that always induces some level of noise into an audio system. Even if the system is silent to the ear when there is no input signal, I've found that there is a subtle degradation to the performance. This is a PITA, but there is no safe way to lift the ground on gear that is designed to be grounded. Contrary to what that idiot Burns thinks, I never, ever recommend lifting the safety-earth connection. I've seen imbecile wiring errors in expensive, highly-regarded audio amps, so I would not trust an amp to be safe if it is meant to be grounded and it is not.
"While the audio ground connection through the interconnect cables will keep the amp chassis close to ground potential during normal operation, it will not have the current handling capacity to keep the amp safe in the event of a power fault"Agreed but it does offer a margin of safety and the Preamps fuse/CB will most likely blow/trip in the event of an amp failure/fault.
"This particular amp also has a ground-lift switch, which will disconnect the amp case from the audio ground if it is thrown."I have seen dozens of amps that offer GND lift switches. It all depends on the design topology of the amp. Surely a company with the pedigree such as Plinius would not offer such a feature if it were to have the possibilty of electrocution from failure/fault?
I have converted all 3 of my systems to balanced power and no longer have any hum/noise issues although an audio transformer can be used in either unbalanced or balanced systems to safely address ground loops.
Cheers,
I agree that Plinius has a great reputation and would not provide a ground-lift switch if it were dangerous. However, any amp can be dangerous if not connected properly. An amp such as the Plinius is designed to have the case connected to the AC safety-earth through the third wire of the power cord. Breaking this connection makes the amp possibly lethal in the event of a power fault inside the amp. The connection pathway to safety-earth through audio ground and the interconnect cable to the source or preamp is uncertain at best, and very likely not sufficiently robust to carry the fault current in the event of a power fault inside the amp. If the preamp circuit breaker trips and the amp is on its own circuit, then this pathway provides no protection at all.Your balanced power installation may be safe, but many naive audiophiles try the dangerous trick of breaking the AC safety-earth connection to the power amp with an adapter plug and hear better sound. They are content to leave things in a dangerous condition because they do not understand the weakness of the connection pathway through the interconnect and source/preamp. I don't know why the OP's power cord lacks a safety-earth connection (or even if it in fact does). If the cord was made to serve the function of an adapter plug cheat, then shame on the cord maker!
For instance, the "ground lift" switch on a Bryston amp switches in a circuit that increases resistance. Earth ground stays connected.
A "ground lift" switch on an amplifier disconnects audio ground from chassis ground. Chassis ground remains connected to safety-earth to maintain protection.All audio equipment that uses the safety-earth to protect against internal power faults has some coupling of the audio ground to the chassis and safety-earth. In many cases, this coupling is deliberate: a single-point direct connection somewhere in the power supply, or some more elaborate scheme. A "ground lift" switch would break the direct connection and float the audio ground.
However, even if the direct connection is broken or deliberately avoided, there is still parasitic capacitive coupling throughout the equipment. Noise of sufficiently high frequency on the safety-earth can travel through these unplanned pathways. Managing these pathways is up to the skill of the person who performs the mechanical layout of the equipment. People who think of the safety-earth wire as a magical sink for noise of any frequency will not be motivated to think about the parasitic coupling pathways. This is one of the reasons for differences in perceived performance in equipment with otherwise similar topologies.
I can always rely on you providing well thought out info..Cheers
that increased resistance must be able to force the breaker to clear a fault.If a 10 ohm resistor were used, as an example, a hot to chassis short by any means, would cause 12 amperes to flow, the chassis would rise to 120 volts, and safety is violated.
If a 1 ohm were used, 120 amperes flow, and the breaker will clear the fault in a specified (by the breaker design criteria) time.
But 1 ohm may not remove the ground loop sufficiently. Hence, some use 25 ampere bridges instead of a linear element. No conduction for small voltages, but major clamping occurs during a fault, this clear the breaker in a reasonable time frame.
You confuse me with another idiot because I am on the side of never ever kifting the AC ground via busting the third pin. It is completely unsafe.Maybe you misread one of my posts so I will check myself. I am a pro audio touring engineer and we never lift gound EVER.
Stop trash talking and listen..both of ya..Al said:
""It is perfectly legal and safe to use double-insulation instead of the safety-earth grounding scheme for audio ""I believe Burns took this to mean "equipment designed three wire could be used two via double insulation". This is not what Al said.
I believe both of you are basically in agreement..just relax and re-read the posts and you'll agree.
Just my .02...
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