MikeBettinger said:
At this point in time, I'm concentrating on what the externals do to the equipment. For example, if a ground loop exists from the pre to the amp, and ground currents are flowing, what is the path inside the pre?
Also, I worry about where the pseudo-dc currents will go, especially if there's more than one path available..
MikeBettinger said:
I don't believe so, I know so. Enjoying the discussion, I am..
Cheers, John
Actually the 2200 can be even more easily fixed. Just remove all the EXTRA caps off the power supply caps, etc. I now use a 2500, a 2200 on steroids, for my main power amp at this time.
Wow!!!
For the past 3 weeks or so, for about 12 hours a day, I followed this thread from page 1 to page 429 – collecting pearls. It was so much educating and it fascinated me so much that I gave up everything else, save sleep and eat.
Now I have 109 pages and counting of word document with citations from this thread, mostly of Sir John Curl, minority of some other contributors.
Thank you, John Curl, thank you all participants this thread. Even form John's attitude to the regular adversaries I learned.
For the past 3 weeks or so, for about 12 hours a day, I followed this thread from page 1 to page 429 – collecting pearls. It was so much educating and it fascinated me so much that I gave up everything else, save sleep and eat.
Now I have 109 pages and counting of word document with citations from this thread, mostly of Sir John Curl, minority of some other contributors.
Thank you, John Curl, thank you all participants this thread. Even form John's attitude to the regular adversaries I learned.
Thanks again John, I'll give it a listen first so I'll have something to "compare all my amplifiers to". Then I'll ask you which are the extra caps.
Matt
Matt
jneutron said:
I'm not so sure what pseudo-dc currents are and probably don't want to know
But I have learned a thing or two about the other... Actually what attracted me to this thread was the picture of the Blowtorch in the early pages; I was curious as to why the grounding was done as it was. I was eager to learn something based on the reviews I'd read that indicated the design was doing many things right. Unfortunately the person who created the layout wasn't participating so there are no explanations to be had.
That said, from my experience, when you think of currents between two separate components you have to determine why the current flows or what the attraction is. With that concept in mind one would use all of the concepts we've started to touch on here to design the layout.
I'm enjoying the discussion as well. If it's not pertinent to this thread we can take it offline.
Regards, Mike.
unanticipated benefit?
Running on a slower clock speed than most, I was thinking about this while driving over hill-and-dale returning from a paying gig in another field (every dog gets fed once in a while?).
Perhaps I am lost in space on this, but assuming equivalent noise from multiple supplies vs. a single supply (controlling ur currents, etc, as well...) might not the multiple supplies provide uncorrelated noise vs. correlated noise from the single supply?
_-_-bear
john curl said:
jneutron said:
Running on a slower clock speed than most, I was thinking about this while driving over hill-and-dale returning from a paying gig in another field (every dog gets fed once in a while?).
Perhaps I am lost in space on this, but assuming equivalent noise from multiple supplies vs. a single supply (controlling ur currents, etc, as well...) might not the multiple supplies provide uncorrelated noise vs. correlated noise from the single supply?
_-_-bear
A ground loop is formed when there is a current between 2 or more ground connections.jneutron said:
In well designed equipment, including Pre-Amps and Power-Amps, the mains power ground is separate from the signal ground.
Once there is a hum and therefore a suspected ground loop, first we need to make sure that this is actually so – that the mains ground and signal ground are separated.
If not – there is a little a user can do.
If yes – one should investigate into from where the ground loop come. May be from another device connected to the pre?
Anyhow, specific case would be easier to look into, rather than a general question.
Well said, Joshua_G. Interesting idea, Bear.
I have seen and worked with examples of bad layout and grounding, such as the SOTA headamp. That little guy would hum, even though it ran on a couple of D batteries, exclusively! I couldn't 'criticize' my business partner at the time (30 years ago) when that came together, as he felt that he knew everything and I was just a grouch.
I have seen and worked with examples of bad layout and grounding, such as the SOTA headamp. That little guy would hum, even though it ran on a couple of D batteries, exclusively! I couldn't 'criticize' my business partner at the time (30 years ago) when that came together, as he felt that he knew everything and I was just a grouch.
MikeBettinger said:I'm not so sure what pseudo-dc currents are and probably don't want to know
When I drew the ground loop and showed the paths the current will take with the wire resistance and inductance, I spoke of DC currents. Which of course, is not what audio is.
I wasn't sure how to mean "near dc", so used pseudo-dc to mean "almost dc so following the dc path". Clearly, it is very easy to figure the DC currents as well as the very hf, but how it distributes in between requires analysis. My first take is to use the DC analysis and figure out how to stop that as best as possible. Only later would I consider how to break the AC path.
NEC deems an inductive or resistive break to the safety grounds as illegal, so we have to get creative...
MikeBettinger said:
I think it's pertinent.. I started the ground thread in the "electronics and parts" forum to discuss how to force and measure ground loops and sensitivity..don't know if that's the best place of course...but I think offline does others here a disservice.
Cheers, John
Re: unanticipated benefit?
I am not speaking of noise per se, either correlated or uncorrelated..speak to JC for that stuff..that's his expertise, not mine.
In well designed equipment, the National Electric Code requires that all conductive surfaces which are exposed to any user must be bonded to safety ground. RCA shells, xlr shells, whatever.
Bonded to safety ground means that the resistance to ground is sufficiently low that a fault to line will be cleared (by the breaker) without hazardous voltage being available during the fault. NEC states (ambiguously of course) "facilitates the operation of the overcurrent protective device"... This ties our hands, and forces us at some point, to connect the signal ground of a piece of equipment to the safety ground. With two pieces of equipment, that forms the loop.
Double insulated does get around the 60 hz stuff basically, but doesn't eliminate the full audio bw, nor rf hash.
Bill Whitlock discusses this at some length as I recall, somewhere on the Jensen site..
I concur. If an artificial loop has been inadvertently created, find and fix. But if the loop is created by Code, then dressing the wires as I detailed in the electronics and parts forum thread is about the only thing left.
Ah, one point. Hum is not the only effect of the ground loop, just the most obvious as it occurs even with lack of signal. My work goes into coupling across the entire audio bandwidth, where the effects are not so obvious.
Cheers, John
If you two parallel independent signal paths, and anywhere along the chain they can affect each other, that is the def of crosstalk. This can be a result of voltage changes at the supply, or what I speak of, the result of the currents that the supply feeds the stages causing a signal in the other chain. Independent supplies stops the voltage possibility, and it can stop the current one as well.. As I said earlier, it is a solution to a problem. I speak of a solution only to current based crosstalk.bear said:
I am not speaking of noise per se, either correlated or uncorrelated..speak to JC for that stuff..that's his expertise, not mine.
Joshua_G said:
In well designed equipment, the National Electric Code requires that all conductive surfaces which are exposed to any user must be bonded to safety ground. RCA shells, xlr shells, whatever.
Bonded to safety ground means that the resistance to ground is sufficiently low that a fault to line will be cleared (by the breaker) without hazardous voltage being available during the fault. NEC states (ambiguously of course) "facilitates the operation of the overcurrent protective device"... This ties our hands, and forces us at some point, to connect the signal ground of a piece of equipment to the safety ground. With two pieces of equipment, that forms the loop.
Double insulated does get around the 60 hz stuff basically, but doesn't eliminate the full audio bw, nor rf hash.
Bill Whitlock discusses this at some length as I recall, somewhere on the Jensen site..
Joshua_G said:
I concur. If an artificial loop has been inadvertently created, find and fix. But if the loop is created by Code, then dressing the wires as I detailed in the electronics and parts forum thread is about the only thing left.
Ah, one point. Hum is not the only effect of the ground loop, just the most obvious as it occurs even with lack of signal. My work goes into coupling across the entire audio bandwidth, where the effects are not so obvious.
Cheers, John
Regarding the conversation asking for specific examples of ground loops, I have a Parasound HCA2200ii and after it warms up overnight, it has a buzzing coming from the chassis and the right channel is fuzzy. Any suggestions?
Thanks, I hope i'm not too far off subject.
Thanks, I hope i'm not too far off subject.
Re: Re: unanticipated benefit?
Audio signal and HF signal leaks are a different matter. They are caused generally by a design which is not very good.
I wonder, since so many A/V equipments are being sold commercially with only 2 wires mains cord, without mains ground at all. At least in my country it is so, where European models are used. For instance, Loewe Connect TV set and Harman Kardon A/V receiver AVR 255, as well as Satellite Set Box.jneutron said:
The ground loops discussed here pertain mainly to 50/60 Hz buzz, or hum.jneutron said:
Audio signal and HF signal leaks are a different matter. They are caused generally by a design which is not very good.
Buzzing from the chassis (but not via the loudspeakers) suggests faulty transformer, or loose mechanical part, like cover or inner metal partition, which get vibration from a transformer.ironhardware said:
>>In well designed equipment, the National Electric Code requires that all conductive surfaces which are exposed to any user must be bonded to safety ground. RCA shells, xlr shells, whatever. <<
I've had my share of strange hum problems with wall-wart powered XLR stuff.
Not to mention the time I brought a hot chassis TV into the lab and discovered that the electricians wire phases alternately from bench to bench (o'scope was plugged into neighbors bench on a 3 to 2 plug).
I've had my share of strange hum problems with wall-wart powered XLR stuff.
Not to mention the time I brought a hot chassis TV into the lab and discovered that the electricians wire phases alternately from bench to bench (o'scope was plugged into neighbors bench on a 3 to 2 plug).
Ironhardware, I don't know exactly what your problem is, but it may be due to DC on the powerline, a marginal power transformer, or something loose. It is an old design, at this point, it is best not to look at it as in the best of shape. My 2500 sometimes overheats, when I play loud recordings. I just live with it.
Re: Re: Re: unanticipated benefit?
Well now, that's the thing. We think we have a ground loop because we hear a hum. We think we have an RF problem because we have a dimmer (older models) causing buzz...we think we have a power supply problem because we hear a pop when the hot air blower clicks on.
All of these can be caused by an induction loop, and that is not necessarily a result of bad design.
What do we call it if the poweramp haversines are coupled to the input ground loop? No sound, no effect....no problem??? Maybe..maybe not.
Whoa. Well, you survived...
Cheers, John
Joshua_G said:
Well now, that's the thing. We think we have a ground loop because we hear a hum. We think we have an RF problem because we have a dimmer (older models) causing buzz...we think we have a power supply problem because we hear a pop when the hot air blower clicks on.
All of these can be caused by an induction loop, and that is not necessarily a result of bad design.
What do we call it if the poweramp haversines are coupled to the input ground loop? No sound, no effect....no problem??? Maybe..maybe not.
scott wurcer said:
Whoa. Well, you survived...
Cheers, John
Re: Re: Re: Re: unanticipated benefit?
Are you implying that some people get at wrong conclusions?
Sorry, who are those "we"?jneutron said:
Are you implying that some people get at wrong conclusions?
Induction loops has nothing to do with the design?jneutron said:
Re: Re: Re: Re: Re: unanticipated benefit?
We, as is all of us. A generic classification of, well, all humans.
We must consider the equipment design as a different entity from the externals. How the equipment reacts to induced currents on the ground is a major concern, but the equipment designer does not have control over the final useage. They can work to make the equipment ignore the currents, but they cannot control the currents from inside the box...short of disconnecting the chassis safety ground.
Cheer, John
This brings to mind the joke with the punchline "who are you calling "we"...... kemosabe?Joshua_G said:
We, as is all of us. A generic classification of, well, all humans.
No, I am not implying it..I am stating it. We all make mistakes at one time or another. Some can make educated causation guesses, some have much experience to bear on it, some are casual users who have no basis of understanding, and are forced to guess or......go to a forum such as this..Joshua_G said:
External induction loops have nothing to do with the design, they are a function of the wires and the environment, and how they are interconnected.Joshua_G said:
We must consider the equipment design as a different entity from the externals. How the equipment reacts to induced currents on the ground is a major concern, but the equipment designer does not have control over the final useage. They can work to make the equipment ignore the currents, but they cannot control the currents from inside the box...short of disconnecting the chassis safety ground.
Cheer, John
re re re
Why on earth does everyone think of earth as earth
regards
max
ps aren't our nuts cracked by electrons ?
Why on earth does everyone think of earth as earth
regards
max
ps aren't our nuts cracked by electrons ?
Re: Re: Re: Re: Re: Re: unanticipated benefit?
Such gross mistakes, as you mentioned, may happen, however, they are not regularly, or often, arrived at by competent engineers and technicians, such as I worked with for the past 47 years.
Anyhow, I fail to see what such mistakes and wrong conclusions have to do with the present thread. I'm under the impression that this thread is about better designing audio gear.
Again, I fail to see what it has to do with the present thread.
Anyhow, when an audio setup operates below the expected performance, obviously the user should first locate the source, or cause, of the bad performance. Most intelligent high end sound setups are quite apt to it. Those are not should hire a competent engineer or technician to do it.
I'm not sure where you are driving.jneutron said:
Such gross mistakes, as you mentioned, may happen, however, they are not regularly, or often, arrived at by competent engineers and technicians, such as I worked with for the past 47 years.
Anyhow, I fail to see what such mistakes and wrong conclusions have to do with the present thread. I'm under the impression that this thread is about better designing audio gear.
It is the first time you mention here "external" induction loops.jneutron said:
Again, I fail to see what it has to do with the present thread.
Anyhow, when an audio setup operates below the expected performance, obviously the user should first locate the source, or cause, of the bad performance. Most intelligent high end sound setups are quite apt to it. Those are not should hire a competent engineer or technician to do it.
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