I found this short video about Ground Loops. After all these little ground loops can send most of us Loopy Loo fighting over which offending mains lead to disconnect to get rid of the offending noise.
The little box he the guy used hmm interesting.
I found this short video about Ground Loops. After all these little ground loops can send most of us Loopy Loo fighting over which offending mains lead to disconnect to get rid of the offending noise.
The little box he the guy used hmm interesting.
Another video of the same type of thing a little black box to eliminate those, Gremlin offending humming buzzes.
The isolation is achieved by the use of transformer with a 1:1 ratio.Originally Posted by JBL 4645
If you can remain calm in a crises, you don't understand the situation!
Okay I see I’ll look into it later on.
these things are generally used to "get out of a spot". It is better to find the reason for the ground loop and correct it.
Allan.
Al
You know with more and more electrical audio gear that we install sometimes its hard to trace it down to the intrusive noise offending audio gear, it might be one product or two working together?
I have 25 items attached just to play music or watch films. A few amps have extra grounding to nip that Gremlin humming bug, but I can’t tell when it will pop up again, maybe when I change my Alesis RA300 amps as I thinking of changing them for Behringer A500. Will it get humming and buzzing?
+1
Ashley...Al
You know with more and more electrical audio gear that we install sometimes its hard to trace it down to the intrusive noise offending audio gear, it might be one product or two working together?
I have 25 items attached just to play music or watch films. A few amps have extra grounding to nip that Gremlin humming bug, but I can’t tell when it will pop up again, maybe when I change my Alesis RA300 amps as I thinking of changing them for Behringer A500. Will it get humming and buzzing?
It is often not the amps that are the culprit - they merely amplify the symptom to be very audible.Typically in home (and SR) systems, it is something way upstream, most commonly before the pre-amp(s). In the home, too often there are mutitudes of AC grounding schemes used, AC/DC converters, and whatnot. It is a dog's (cat's...?
) breakfast as we all try and co-join all manner of source options. It is in those interconnects that signal gets loused with current...
Ashley, there is a situation looking for trouble from the start.
That is a lot of pieces. Maybe we could take a look together and streamline your rig a bit.
Clark
Information is not Knowledge; Knowledge is not Wisdom
Too many audiophiles listen with their eyes instead of their ears
I've posted a long summary a couple of times.
Bo is right.
My input, as it is every time: The EASIEST way to resolve all ground loop issues, especially in multiple amplifier systems (I've got 16); is to install a 15 kVA isolation transformer (or larger); in which all the audio equipment is powered by a isolated transformer which uses a secondary ground to the rest of the house. Everything else (in my opinion) is window dressing.
Its an easy thing to do, fleaBay an amp for 150 US, then use a 80 to 100 A relay on your main home bus, which shunts the power to the isolation transformer via 6 ga wire. The isolated transformers box is grounded to the primary ground (flex cable); then the secondary relay box comes off the transformer, and its grounded to a new 6' copper ground which is driven though the cement floor and epoxied shut. The new box In the case of a 15 kVA transformer, is capable of supporting 5 x 20A circuits; so if you're going to include any large amps you might need a larger transformer. These new circuits being grounded to the secondary ground are completely isolated from TV's clocks, refrigerators, and every mother loving fan or hum producing electrical item in the house.
A larger transformer will change the size of the wiring as well as increase the number of isolated circuits.
The other obvious thing is also to go balanced audio which helps eliminate ground loop as well, as RCA connections are notorious for hum.Certainly thats one reason theater's use balanced connections.
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Yes, the problem with that approach, as with many of the correct approaches to Ground Loop suppression, is it involves working over your home electrical system to be sure all circuits are direct, all connections are tight, all grounds are tied correctly, and all wiring is in phase, etc. Its a lot harder to do that sort of thing if you are in a rental/appartment type situation. Its not impossible, mind you, but it is tougher to resolve that way.I've posted a long summary a couple of times.
Bo is right.
My input, as it is every time: The EASIEST way to resolve all ground loop issues, especially in multiple amplifier systems (I've got 16); is to install a 15 kVA isolation transformer (or larger); in which all the audio equipment is powered by a isolated transformer which uses a secondary ground to the rest of the house. Everything else (in my opinion) is window dressing.
Its an easy thing to do, fleaBay an amp for 150 US, then use a 80 to 100 A relay on your main home bus, which shunts the power to the isolation transformer via 6 ga wire. The isolated transformers box is grounded to the primary ground (flex cable); then the secondary relay box comes off the transformer, and its grounded to a new 6' copper ground which is driven though the cement floor and epoxied shut. The new box In the case of a 15 kVA transformer, is capable of supporting 5 x 20A circuits; so if you're going to include any large amps you might need a larger transformer. These new circuits being grounded to the secondary ground are completely isolated from TV's clocks, refrigerators, and every mother loving fan or hum producing electrical item in the house.
A larger transformer will change the size of the wiring as well as increase the number of isolated circuits.
The other obvious thing is also to go balanced audio which helps eliminate ground loop as well, as RCA connections are notorious for hum.Certainly thats one reason theater's use balanced connections.
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True, and may be to arduous for some.
However, there are a number of threads on this and I think we have found the easiest method is to work from the amps (speakers) backward, or upstream, connecting one source at a time until that one connection produces a GL. That then, is the offending device (read: grounding scheme). That one device can be isolated via a transformer inter-connection, and most of the time you are fine.
You might notice, however, that there are few (consumer) devices that produce various levels of GL in your "rig" - each may be tolerable on it's own, but in the aggregate, it is not acceptible. Then, you need deploy a few of the transformers. Which, is exactly what I did for a number of years, blaming everything under the sun, but with the help of installing an Adcom preamp I determined the old Onkyo pre-amp I so dearly loved was THE culprit. Over the transom it went, and so did a half-dozen transformer interconnects. Result? Much improved S/N and audio quality. Then, in came the Bryston and all is dead quiet here. I'm not a home / consumer guy, so it took me a while...
In most home installations, hum is caused by current flowing on the shield of the RCA connection, from one device to another.
If two devices don't have the same potential on their chassis, those will try to equalize by travelling on the easiest path... the RCA shield.
In an unbalanced connection such as those, the shield carries audio information and the 60Hz AC current mixes itself with the audio.
Solution:
Like some have mentioned, use balanced interconnects where the shield does NOT carry audio, you can even disconnect the shield on one end if the hum is really tenacious, this is called "ground lift" and it's often provided by means of a switch on the back of the amp or processor (mostly amplifiers)
The other solution is to run a heavy guage wire as short as possible between the chassis of ALL devices in order to facilitate the equalization of the different potentials, providing an easier path than the RCA connector.
The secret here is to present a path of least resistance for the current.
This is a success in most installations, where one piece of equipment is connected to an external feed, like a cable TV drop (notorious) and another equipment is grounded to the house circuit like a PC or amplifier.
In this case, the ground loop is very large, going outside the house, and can carry relatively large amounts of current.
The difference of potential between the shield of the cable TV drop and the AC ground from the house will try to equalize through the shield of the RCA cables that connect one device to the other.
By running a good ground wire, or better, a ground strap between the two equipments (the one with the cable TV drop and the one with the 3 prong connector), the problem magically goes away 99% of the time.
I've done this many times, as I've become an expert in my community (Ham radio) to find noises and interferences
Remember that isolation transformers are placed in the audio path and are doing exactly the opposite of what I'm trying to explain (equalizing devices to the same potential) they can work when all else fails, but they are really a last resort IMHO.
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