AC power distribution is really lossy above 30 MHz. power line communications devices need to pump amps of current at MHz frequencies to be detectable at the other end of a typical residence. However it can certainly act as a long wire antenna (common mode) and bring lots of ambient RF into whatever. That should be blocked at the entrace of the audio device with common mode inductors. I am uncomfortable with shunt caps to ground since they will dump current into the ground and that can get picked up elsewhere as a voltage difference across the ground. Even without shunt caps and a low leakage transformer there still could be distributed noise on the line from a little leakage. A milliAmp of broadband noise across 1 Ohm of impedance in the grounds (10' of power cord in a loop?) would be 1 mV of noise that could get mixed with audio.
Agreed. I know you know how effective good power conditioning can be for a system.
Page 7 of the first article does not show a ground at the power pole distribution transformer. I have never seen a residential power transformer without a ground running down the power pole in the USA. This may be different in other countries.
When it comes to radio frequency interference, I would be much more concerned about cable shields, the shield's attachments to the chassis and poorly designed input stages.
Well designed AC power input stages have lots of loss at high frequencies.
and the DC supply has even more rejection. PSRR.
Well designed AC power input stages have lots of loss at high frequencies.
and the DC supply has even more rejection. PSRR.
Here is something interesting, and Audiophile power line filter being used in medical. It has pictures showing the noise reduction. What I don't understand is I feel the medical equipment is well designed and has good power supplies, yet adding this plug in unit to the AC power shows an improvement. There must be something on the mains that passes thru the medical equipment's power supply and makes the image not as clear. This is the company that as a patent on using the salt talked about in this thread.
https://shunyata.com/medical/
https://shunyata.com/medical/
Yes. Like for perhaps shielded power cords according to their website:
"COMPARISON AFTER: Screen 2
Depicts the same conditions, but with monitoring equipment and recording amplifiers plugged into Clear Image Scientific® power distribution and shielded power cords."
"COMPARISON AFTER: Screen 2
Depicts the same conditions, but with monitoring equipment and recording amplifiers plugged into Clear Image Scientific® power distribution and shielded power cords."
Medical equipment for ecg, eeg, is extremely sensitive to 50, 60, 100, and 120 hz line noise. Often wires to the patient are long and are susceptible to magnetic induction, ground loops and even capacitive coupling. I have been involved with data recording in clinical studies where it’s a pain to get clean signals. Results varied amongst study rooms. Isolation transformers insure safety, but winding capacitance defeats noise elimination. Very subtle changes in wire draping and equipment configuration affects noise that is observed.
Quote from Shunyata's site:
"Conclusion: The CIS® Model 6 reduced baseline noise by 144% on the surface and 37% on the EGM."
Rather impressive, I would think.
"Conclusion: The CIS® Model 6 reduced baseline noise by 144% on the surface and 37% on the EGM."
Rather impressive, I would think.
Looks like many different medical locations are all getting better images. I would think that if it was just shielded power cords doing this the companies that build and sell the medical equipment would know that a shielded cord is required and include one with the equipment.
Much of it has to do with standards and newer equipment that play well together. Much emphasis has been placed on emi emissions and sensitivity.
About normal EMG measurements: https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/electromyography-emg
"When an electrode is inserted, a brief period of activity can be seen on the oscilloscope, but after that, no signal should be present."
Doesn't look to me like any noise is normal. So what exactly was the noise problem caused by as claimed by Shunyata?
"When an electrode is inserted, a brief period of activity can be seen on the oscilloscope, but after that, no signal should be present."
Doesn't look to me like any noise is normal. So what exactly was the noise problem caused by as claimed by Shunyata?
No reason to believe some form of mains conditioning, regen, couldn't have an effect in some cases. Plenty of errant smps in a hospital.
It is true that electrodes themselves produce noise. Contact potentials and motion artifacts. No mains filter helps with that.
I would not have thought this thread would last this long but then, as all too often here, there is far more speculation and argument than trying things out. To each his own and from each a comment.
All the audio DIYer can do is report what they have heard. This is only possible if one bothers to try the idea.
All of us are looking for ideas that will make music in the home (the phrase coined by Voight) more suspending of disbelief. No one thinks perfection is possible but that is no reason to not see how close one can become. As Salvador Dali said - do not fear perfection - you will never achieve it. I think those are wise words.
One thing that attracted me to cdacosta's work is that he hears the problems associated with shielding. If that is one's only choice for noise reduction then you have no other choice but to use it but for most shielding creates ugly sonic problems.
To repeat - when I first saw the advertisements for the ground boxes and the prices quoted I had a good laugh, too. No way I would buy the things but when someone came up with a DIY recipe that made sense to me I thought I would give it a try. One could throw more money away eating dinner at a restaurant.
I assembled some boxes following cdacosta's recipe but not exactly - as Herb Rechert said in the SOUND PRACTICES article about his 300B amplifier: if you change anything it is your amplifier not his - I have not followed the recipe exactly since I wanted to use materials I had on hand before buying the recommended wires and connectors. When the mood struck to give it a try I did not want to wait for the recommended items - I could always change them out in time and if I heard nothing I could consider the venture as nothing tried, nothing gained. On to the next thing ... But to repeat - these boxes are mine and do not represent cdacosta's advice.
With the first two connected to DACs for left and right channel - my system is digital all of the way - to play LPs I must use an RME ADC - my speakers - Chris Askew's Klipsch K402 MEHs require DSP to work properly unless one is a passive crossover wizard and then are willing to use much higher power amplifiers to push past those crossovers. I am using the xilica SOLARO box for DSP with a Focusrite Rednet box connected with dante for the input and outputs. I use three DACs - nothing exotic - TOPPING D90 with the ESS chips. I would like to hear what a DCS device would do but $40,000 for DACs is well beyond my ability to pay. And that would be for thier least expensive ones.
Music from a dedicated music computer enters a MUTEC MC3+usb governed by the lamented and banned audiophile extraordinaire Andreas Mori's 10 mHz clock he made for me with the best of ten oscillators he recieved. This clock also governs the REDNET device. The Mutec is powered by a SALAS shunt regulator fed by a 12 volts 200 Ah battery I used to use with the inverters. This same battery also powers the RME though using its internal regulators whatever they may be.
I go into this only since I think it might have something to do with my results. Whether this would help a pure analog system is something I do not know. I hesitate to give this inventory but I figure you should know my baseline.
I had read someone intellegently speculate that devices with very litte ground plane area, such as the DACs I use, would probably benefit more from the ground box approach than far more lavish gear.
Using cdacosta's basic idea - I am not using the wires he recommended or the screw down jacks - I am using mil spec wire from APEX JR - two lengths of 10 gauge unstranded for the wires in the box and the 12 gauge for connection from the box to the gear. I am soldering the RC and XLR jacks which is something cdacosta says is problematic - I do not doubt he is correct with this but since all of my other connectors are soldered I figured why not? Maybe one of these days I will convert to all of the jacks being screw down. I am not tuning with the various materials in the box since I have not found the motivation to try that yet.
My speakers throw a massive sound into the room - there was already great depth of field - the image has always extended as far into the room as behind the speakers with the obligatory sound seeming to come from well beyond the side of the boxes but with these ground boxes the most interesting aspect is the defintion gained in the nether regions of this sound field. There is far more information in all aspects but the most striking is the aforementioned effect.
I am mystified by the comment about hiss reduction - if anything I find the hiss, too, is more defined and is not diminished at all - while easier to ignore. I mean real tape machine hiss.
At this point I have the boxes connected to all three of the DACs and to the Rednet box which I figure is the busiest component in the chain. I figure I will add boxes for the phono stage and the line stages after the DACs. Line stage is Rahul Althaye's design and my amplifiers are power buffers using the Tokin THF51 in a circuit by Rahul.
If I could figure out how to add one to the xilica I would but there is only ethernet in and out and not an easy ground spot. Not that i am afraid of going inside but I would prefer to connect to a signal ground and I suspoect the only ground i would find is the output from the power regulator.
Another thing that might have bearing is none of the gear is using the ground connection at the wall - all components are connected to the same outlet through two "power strips" that I made. The line stages and power buffers are on wooden boards - there is no casing so no place to connect a ground to the AC outlet. My bias is that metal boxes, unless required for noise reasons, bring a sonic penalty plus I am really cheap and do not want to buy boxes I may end up discarding when a new idea comes along. Ther is no noise audible from the speakers when one's head is insde the horn. Amps and line stages have the FO-FELIX AC filter at their power inputs. I am not sure that switching supplies benefit from AC filters so those devices are on their own.
The noises quelled by the ground boxes are noises generated in the reproduction of music - I do not know what else to call it - whatever it is that is masking the sound that is in the music file.
So in this case I find there is something happening and it is not insignificant.
I am sure there are systems that will not benefit from this.
All the audio DIYer can do is report what they have heard. This is only possible if one bothers to try the idea.
All of us are looking for ideas that will make music in the home (the phrase coined by Voight) more suspending of disbelief. No one thinks perfection is possible but that is no reason to not see how close one can become. As Salvador Dali said - do not fear perfection - you will never achieve it. I think those are wise words.
One thing that attracted me to cdacosta's work is that he hears the problems associated with shielding. If that is one's only choice for noise reduction then you have no other choice but to use it but for most shielding creates ugly sonic problems.
To repeat - when I first saw the advertisements for the ground boxes and the prices quoted I had a good laugh, too. No way I would buy the things but when someone came up with a DIY recipe that made sense to me I thought I would give it a try. One could throw more money away eating dinner at a restaurant.
I assembled some boxes following cdacosta's recipe but not exactly - as Herb Rechert said in the SOUND PRACTICES article about his 300B amplifier: if you change anything it is your amplifier not his - I have not followed the recipe exactly since I wanted to use materials I had on hand before buying the recommended wires and connectors. When the mood struck to give it a try I did not want to wait for the recommended items - I could always change them out in time and if I heard nothing I could consider the venture as nothing tried, nothing gained. On to the next thing ... But to repeat - these boxes are mine and do not represent cdacosta's advice.
With the first two connected to DACs for left and right channel - my system is digital all of the way - to play LPs I must use an RME ADC - my speakers - Chris Askew's Klipsch K402 MEHs require DSP to work properly unless one is a passive crossover wizard and then are willing to use much higher power amplifiers to push past those crossovers. I am using the xilica SOLARO box for DSP with a Focusrite Rednet box connected with dante for the input and outputs. I use three DACs - nothing exotic - TOPPING D90 with the ESS chips. I would like to hear what a DCS device would do but $40,000 for DACs is well beyond my ability to pay. And that would be for thier least expensive ones.
Music from a dedicated music computer enters a MUTEC MC3+usb governed by the lamented and banned audiophile extraordinaire Andreas Mori's 10 mHz clock he made for me with the best of ten oscillators he recieved. This clock also governs the REDNET device. The Mutec is powered by a SALAS shunt regulator fed by a 12 volts 200 Ah battery I used to use with the inverters. This same battery also powers the RME though using its internal regulators whatever they may be.
I go into this only since I think it might have something to do with my results. Whether this would help a pure analog system is something I do not know. I hesitate to give this inventory but I figure you should know my baseline.
I had read someone intellegently speculate that devices with very litte ground plane area, such as the DACs I use, would probably benefit more from the ground box approach than far more lavish gear.
Using cdacosta's basic idea - I am not using the wires he recommended or the screw down jacks - I am using mil spec wire from APEX JR - two lengths of 10 gauge unstranded for the wires in the box and the 12 gauge for connection from the box to the gear. I am soldering the RC and XLR jacks which is something cdacosta says is problematic - I do not doubt he is correct with this but since all of my other connectors are soldered I figured why not? Maybe one of these days I will convert to all of the jacks being screw down. I am not tuning with the various materials in the box since I have not found the motivation to try that yet.
My speakers throw a massive sound into the room - there was already great depth of field - the image has always extended as far into the room as behind the speakers with the obligatory sound seeming to come from well beyond the side of the boxes but with these ground boxes the most interesting aspect is the defintion gained in the nether regions of this sound field. There is far more information in all aspects but the most striking is the aforementioned effect.
I am mystified by the comment about hiss reduction - if anything I find the hiss, too, is more defined and is not diminished at all - while easier to ignore. I mean real tape machine hiss.
At this point I have the boxes connected to all three of the DACs and to the Rednet box which I figure is the busiest component in the chain. I figure I will add boxes for the phono stage and the line stages after the DACs. Line stage is Rahul Althaye's design and my amplifiers are power buffers using the Tokin THF51 in a circuit by Rahul.
If I could figure out how to add one to the xilica I would but there is only ethernet in and out and not an easy ground spot. Not that i am afraid of going inside but I would prefer to connect to a signal ground and I suspoect the only ground i would find is the output from the power regulator.
Another thing that might have bearing is none of the gear is using the ground connection at the wall - all components are connected to the same outlet through two "power strips" that I made. The line stages and power buffers are on wooden boards - there is no casing so no place to connect a ground to the AC outlet. My bias is that metal boxes, unless required for noise reasons, bring a sonic penalty plus I am really cheap and do not want to buy boxes I may end up discarding when a new idea comes along. Ther is no noise audible from the speakers when one's head is insde the horn. Amps and line stages have the FO-FELIX AC filter at their power inputs. I am not sure that switching supplies benefit from AC filters so those devices are on their own.
The noises quelled by the ground boxes are noises generated in the reproduction of music - I do not know what else to call it - whatever it is that is masking the sound that is in the music file.
So in this case I find there is something happening and it is not insignificant.
I am sure there are systems that will not benefit from this.
While it's rare, an AC power cord can act as an interference antenna (either receiving or transmitting).
But it takes almost Perfect Storm conditions! Difficult to repeat or replicate.
So it's possible for a shielded power cord to reduce that interference. But don't count on it.
Rick it's not a gnd box, if it has one connection to a piece of gear it's an aerial, if it has two connections it's a ground loop. All they have been shown to do is add measured noise.
The problem is that these reports cannot be treated as anything more than Confirmation Bias.
Without a well-controlled independently administer blind test there is no reason to believe that there is any validity at all in the reports being posted here.
While it's rare, a 2 conductor cable like an AC power cord or a loudspeaker cable can act as an interference antenna.
A 'ground loop' is when a signal interconnect common has two different paths.
Or power line related noise uses an interconnect to get back to it's source.
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