Measuring power line noise with the TriField EM100, and the impressive effect of Shyunyata products

[ArnoFenn]

IIRC from Engineering classes, within normal power supplies, the smoothing capacitors banks post-rectification have a current flow thats “pulsed” in nature due to their charge/discharge cycles (“ripple current”), and these get smoothed out with additional capacitors post power supply. However, I don’t believe that necessarily equates to the component as a whole drawing current from the mains in pulses.

So, is it really common knowledge? If so, do you have links pointing to such details? It sure seem like Shunyata are the only ones talking about this.

It is. Measuring power quality voltage/current signals in the main supply shows how current is being pulled by the many different "consuming" electronics which results in a very distorted total current (THD and often power factor affected drastically). Passive/active THD filtering on the mains (control board) can reconstruct the current again and take out much of the harmonics. Additionally power factor can be corrected, but all this is a rather "big game" for home-use so if a power conditioning unit just before the audio equipment can clean up (without reducing maximum current delivery) is preferable.

 

[AndrewChen]

Measuring power quality voltage/current signals in the main supply shows how current is being pulled by the many different "consuming" electronics which results in a very distorted total current (THD and often power factor affected drastically)

Agree with that. Those characteristics would show up on the AC line, which drives the need for noise and THD filtering by a power Conditioners, which is exactly what folks like PS Audio Power Plant, or a Torus Power unit does.

What I'm scratching my head about though is Shunyata's suggestions that audio components, like Power Amps, draw current in pulses. Is this really the case? If so, does anyone have actual measurements of that?

 

[ArnoFenn]

Agree with that. Those characteristics would show up on the AC line, which drives the need for noise and THD filtering by a power Conditioners, which is exactly what folks like PS Audio Power Plant, or a Torus Power unit does.

What I'm scratching my head about though is Shunyata's suggestions that audio components, like Power Amps, draw current in pulses. Is this really the case? If so, does anyone have actual measurements of that?

It is basic indeed when you're in to electronics, but simply said, the capacitors in an amplifier keep up with supplying the current most of the time of the sine-wave, but since the capacitors are not perfect nor endlessly large in capacity, at a certain point they might run out of current stored ("Empty battery idea") and that is the moment when the amplifier circuit with it's pull will "drink" on as it does but now directly from the mains supply since the parallel placed capacitors were empty (mind you this is via rectifier and transformer etc). This moment happens at the top of the sime wave and that is the moment when a smaller peaky current pulse is drawn from the mains.

Fig. 1: Supply voltage and current drawn by diode rectifier

Download scientific diagram | Supply voltage and current drawn by diode rectifier from publication: Harmonic currents generated by the voltage-source active rectifier | Share of current harmonics, which is taken from the power net, increases with the use of diode and thyristor rectifiers...

www.researchgate.net

How are bridge rectifiers rated?

So I'm getting ready to build a power supply, and it calls for a bridge rectifier. However, I can't find any information about HOW rectifiers are rated, except for a note that (and I don't have it in

electronics.stackexchange.com

In a half-wave rectifier, we used a 4.7uF capacitor. What would happen if we used a larger value than 4.7uF?

Answer (1 of 5): In a half-wave rectifier, we used a 4.7uF capacitor. What would happen if we used a larger value than 4.7uF? In general, since you gave no other details I will assume a simple 50 or 60Hz sine wave from a transformer. Ripple voltage will decrease, but peak current through the tr...

www.quora.com

 

[AndrewChen]

It is basic indeed when you're in to electronics, but simply said, the capacitors in an amplifier keep up with supplying the current most of the time of the sine-wave, but since the capacitors are not perfect nor endlessly large in capacity, at a certain point they might run out of current stored ("Empty battery idea") and that is the moment when the amplifier circuit with it's pull will "drink" on as it does but now directly from the mains supply since the parallel placed capacitors were empty (mind you this is via rectifier and transformer etc). This moment happens at the top of the sime wave and that is the moment when a smaller peaky current pulse is drawn from the mains.

Fig. 1: Supply voltage and current drawn by diode rectifier

Download scientific diagram | Supply voltage and current drawn by diode rectifier from publication: Harmonic currents generated by the voltage-source active rectifier | Share of current harmonics, which is taken from the power net, increases with the use of diode and thyristor rectifiers...

www.researchgate.net

How are bridge rectifiers rated?

So I'm getting ready to build a power supply, and it calls for a bridge rectifier. However, I can't find any information about HOW rectifiers are rated, except for a note that (and I don't have it in

electronics.stackexchange.com

In a half-wave rectifier, we used a 4.7uF capacitor. What would happen if we used a larger value than 4.7uF?

Answer (1 of 5): In a half-wave rectifier, we used a 4.7uF capacitor. What would happen if we used a larger value than 4.7uF? In general, since you gave no other details I will assume a simple 50 or 60Hz sine wave from a transformer. Ripple voltage will decrease, but peak current through the tr...

www.quora.com

Sure, I understand how rectifiers work, but looks like you had difficulty finding any real measurements and/or documentation of such current draw pulses on actual Audio components too just as I did. That in itself says something

 

[ArnoFenn]

Looks like you had difficulty finding any real measurements and/or documentation of such current draw pulses on actual Audio components too just as I did.

That's not the issue. I do measurements like that and any EE does (Developed and built all my (pre)amps over many years). The links are meant as introduction. Anyhow, looking forward to more shunyata data (RCL if possible) ;-)

 

[ack]

Maybe the following as highlighted will help and I don't really care to debate this further https://en.wikipedia.org/wiki/Rectifier

The advantage of this circuit is that the current waveform is smoother: current is drawn over the entire cycle, instead of being drawn in pulses at the peaks of AC voltage each half-cycle as in a capacitor input filter.

Capacitor input filter​

For a given load, sizing of a smoothing capacitor is a tradeoff between reducing ripple voltage and increasing ripple current. The peak current is set by the rate of rise of the supply voltage on the rising edge of the incoming sine-wave, reduced by the resistance of the transformer windings. High ripple currents increase I2R losses (in the form of heat) in the capacitor, rectifier and transformer windings, and may exceed the ampacity of the components or VA rating of the transformer. Vacuum tube rectifiers specify the maximum capacitance of the input capacitor, and SS diode rectifiers also have current limitations. Capacitors for this application need low ESR, or ripple current may overheat them. To limit ripple voltage to a specified value the required capacitor size is proportional to the load current and inversely proportional to the supply frequency and the number of output peaks of the rectifier per input cycle. Full-wave rectified output requires a smaller capacitor because it is double the frequency of half-wave rectified output. To reduce ripple to a satisfactory limit with just a single capacitor would often require a capacitor of impractical size. This is because the ripple current rating of a capacitor does not increase linearly with size and there may also be height limitations. For high current applications banks of capacitors are used instead.

Choke input filter​

It is also possible to put the rectified waveform into a choke-input filter. The advantage of this circuit is that the current waveform is smoother: current is drawn over the entire cycle, instead of being drawn in pulses at the peaks of AC voltage each half-cycle as in a capacitor input filter. The disadvantage is that the voltage output is much lower – the average of an AC half-cycle rather than the peak; this is about 90% of the RMS voltage versus 2 {\displaystyle {\sqrt {2}}}

times the RMS voltage (unloaded) for a capacitor input filter. Offsetting this is superior voltage regulation and higher available current, which reduce peak voltage and ripple current demands on power supply components. Inductors require cores of iron or other magnetic materials, and add weight and size. Their use in power supplies for electronic equipment has therefore dwindled in favour of semiconductor circuits such as voltage regulators.[10]

Capacitor-input filter - Wikipedia

en.wikipedia.org

A capacitor-input filter is a filter circuit in which the first element is a capacitor connected in parallel with the output of the rectifier in a linear power supply. The capacitor increases the DC voltage and decreases the ripple voltage components of the output.[1] The capacitor is often referred to as a smoothing capacitor or reservoir capacitor. The capacitor is often followed by other alternating series and parallel filter elements to further reduce ripple voltage, or adjust DC output voltage. It may also be followed by a voltage regulator which virtually eliminates any remaining ripple voltage, and adjusts the DC voltage output very precisely to match the DC voltage required by the circuit.

 

[VLS]

A ground does more than take lightning to ground. Done right it will drain RF. When you ground correctly a very tangible calm comes over the room.

I may be wrong, but it would seem the only way a ground can “drain RF” from the hot AC conductor is *through* the audio component’s transformer, where this RF will be induced into the circuitry. There is no direct path for the RF to go to ground. Unless there’s a grounded shield, which is not the case for typical AC wiring.

 

[Kingrex]

I was told by others in the know a preamp does have instantaneous peak current draw. It is amplifying a signal. Signal are varying in amplitude depending on the amount of information in them. Why would it be a linear current draw?

I still don't get what a Trifield actually measures, as compared to what actually matters. At this point I would like to hear more about the audible impacts of what is being turned on and off and what sonic impact that has. I know the MA600 and MA1000 dimmers audibly reduce the noise associsted with toroid transformer core saturation.

Ack is not using the dimmer I advocat. And the one he is using does not seem to decrease the measued noise much. But does it rid transformer saturation. If so, maybe the trifield is not measuring what actually matters. If the transformer saturation is not decreased, maybe the MACL 153MH is not very effective.

 

[ack]

I know the MA600 and MA1000 dimmers audibly reduce the noise associsted with toroid transformer core saturation.

Ack is not using the dimmer I advocat. And the one he is using does not seem to decrease the measued noise much.

Yeah, I looked up the MA1000 and it costs some $80-$90 with a few days delay to deliver. I am still considering it, but the easiest solution is to simply make sure these lights are turned off while listening. At the same time, the measured noise is so high, with all these lights that the MA1000 would need to be as effective as the Denali or similar, to be any worth. I think I will still give it a try. The audible impact of noise has been well described under my system thread, wall vs Denali + cords - staggering improvement, in fact, and it all started with a single V12 NR cord last summer, which as measured here in (well, I measured the V10 NR really), provided a sizeable but modest noise reduction. It was when all equipment was wired as it currently stands and plugged into the Denali that the system's performance was elevated a number of notches.

 

[ack]

Here's how alphalab describes the unit's operation:

The Line EMI Meter by AlphaLab, Inc. measures electromagnetic interference (EMI) in single-phase,110-240 VAC 50/60Hz power lines. It plugs into a wall outlet or mains socket and requires no battery or additional external power source.This meter measures the total line noise present onthe power outlet (differential noise between hot and neutral) into which the unit is plugged. This noise is displayed as a peak-to-peak value in millivolts(RMS x 2.82). A yellow signal-strength bar also displays the EMI noise and a speaker plays the sound of the noise.Hold the meter firmly in one hand and plug the smaller, female end (IEC-320-C7) of the supplied cord into the base of the meter. The range is 0.1 mV to 1999.9 mV peak-to-peak in frequencies from 10 kHz to 10 MHz. 50Hz and 60Hz power frequencies are ignored. Only noise frequencies above 10kHz and below 10 MHz are measured.

One would get a more accurate picture with a Fluke, but at $3000+ ??

What is more interesting to me is the relative readings as various devices are turned on and off, and as one goes from outlet to outlet

 

[K3RMIT]

Were any audio observations done , with music playing and readings taken ? just wondering how much of the noise is effecting the components via PSU or RFI/EMI proximity ?

 

[TrackingAngle]

Here's how alphalab describes the unit's operation:



One would get a more accurate picture with a Fluke, but at $3000+ ??

What is more interesting to me is the relative readings as various devices are turned on and off, and as one goes from outlet to outlet

Before anyone gets too excited about the measured results noted with the cheap AlphaLab (or rebadged TriField 100 meter), consider what my electrical consultant told me about it (as some of you know the installation of a transfer switch for an aux generator completely messed up my electricity due to grounding and other issues and I'm in the midst of a complete from the roof re-do of the power entering my home, which is the place to start, NOT at the wall sockets!) :

"this AC noise meter is a rebadged Alpha Labs. Cheap, inaccurate, covers less than 4 octaves of only one of three induced-noise modes. It’s ten-cent switching supply adds nearly as much noise as it often detects… Doing this for real starts at about $8000 for a portable meter, but this will be OK for the single purpose I described above. These can’t be used for judging AC power products, to poorly executed and not stable with varying AC impedance. The old Audio Prism Noise Sniffers were actually quite a bit better than these (and about 4 times the cost). Those are long gone though."

 

[TrackingAngle]

I was told by others in the know a preamp does have instantaneous peak current draw. It is amplifying a signal. Signal are varying in amplitude depending on the amount of information in them. Why would it be a linear current draw?

I still don't get what a Trifield actually measures, as compared to what actually matters. At this point I would like to hear more about the audible impacts of what is being turned on and off and what sonic impact that has. I know the MA600 and MA1000 dimmers audibly reduce the noise associsted with toroid transformer core saturation.

Ack is not using the dimmer I advocat. And the one he is using does not seem to decrease the measued noise much. But does it rid transformer saturation. If so, maybe the trifield is not measuring what actually matters. If the transformer saturation is not decreased, maybe the MACL 153MH is not very effective.

Before anyone gets too excited about the measured results noted with the cheap AlphaLab (or rebadged TriField 100 meter), consider what my electrical consultant told me about it (as some of you know the installation of a transfer switch for an aux generator completely messed up my electricity due to grounding and other issues and I'm in the midst of a complete from the roof re-do of the power entering my home, which is the place to start, NOT at the wall sockets!) :

"this AC noise meter is a rebadged Alpha Labs. Cheap, inaccurate, covers less than 4 octaves of only one of three induced-noise modes. It’s ten-cent switching supply adds nearly as much noise as it often detects… Doing this for real starts at about $8000 for a portable meter, but this will be OK for the single purpose I described above. These can’t be used for judging AC power products, to poorly executed and not stable with varying AC impedance. The old Audio Prism Noise Sniffers were actually quite a bit better than these (and about 4 times the cost). Those are long gone though."

 

[ACHiPo]

This is an interesting thread. It’s clear there are measured differences, and the Shunyata devices decrease (presumably) HF noise. What’s not clear to me is what impact this has on audible results? The measured noise varies quite a bit under the different circumstances. The p-p voltage varies much more than the noise, but no mention of that is made. Again, I think this is really interesting—just trying to piece together the impact.

 

[MarkK02474]

Here are more interesting experiments:

Two outlets on the same circuit, Lights OFF:

1) the one of the right, used by the audio equipment, going to an MIT distribution box with noise filtering using a Shunyata NR cord - VERY low noise. This is NOT the outlet where the Denali is plugged in, the Denali uses another outlet further out to the right and is not seen

2) the other one to the left - with an LED-lit cover - very HIGH noise, and I also removed that illuminated cover as well (third picture below)

My logical conclusion is that the NR cord + MIT box are actually working really well *at the source* as well, i.e. the wall outlet itself - in fact, Shunyata has a video where they show the exact same thing on their site


Right Audio Outlet, Feeds MIT with NR cord - Lights OFF - QUIET
View attachment 78508


Left Common Outlet - Lights OFF - NOISY
View attachment 78509

Left Common Outlet - Lights OFF, LED Cover REMOVED - NOISY
View attachment 78510

The MIT filter likely has MIT capacitors in it which are dampening the power line noise, even to another socket. Various makers have sold noise reducing wall warts which contain capacitors, at a lower cost.

Your 12v LED power supply is not just a transformer. LED lights run off DC power, and the LED chips themselves off a lower voltage, meaning there is a DC-DC voltage converter in the power supply. A transformer won't make noise, but the other components can.

Generally, significant noise is generated by switching transients, mostly off ones. For linear power supplies, that is the diodes in a bridge rectifier. They create a glitch when they switch off, much like crossover distortion in a class B amplifier. Soft recovery FRED diodes and ultra fast SiC rectifiers have much lower noise. https://www.microsemi.com/document-portal/doc_view/14617-rectifier-reverse-switching-performance

Light dimmers often control brightness with PWM, varying the length of on time the light is getting power. More light, longer pulses of power. On is continuous power, but there is still noise from the AC to DC conversion via noisy diodes, pwm pulses are on top of that.

Bad diodes in gear adds noise even when turned off. One leg of AC may be off, breaking a circuit, however the other leg is still seeing voltage go up and down. When it goes down (AC power cycle reverses) is when the diode sends out a noisy switch off transient. Some more testing could be done to show readings with and without various "off" components plugged in and out.

I've been telling people that every power supply in their audio system needs to be cleaned up. It takes just one bad one to pollute other components over the power or interconnect cabling.

Thank you for showing meter readings. Yes, noise is measurable and power conditioning is not snake oil. Luddites will still claim snake oil with paper theories, but a measuring device is irrefutable.

 

[Kingsrule]

Hi Kingrex
Can u recommend a speed controller similar to the MA 1000 for ceiling fans?
Right now I can hear the motor pulse at low speeds. Using a Lutron Homeworks light switch dimmer to control the fan speed

Thank u

 

[ack]

Were any audio observations done , with music playing and readings taken ? just wondering how much of the noise is effecting the components via PSU or RFI/EMI proximity ?

It was quite interesting to observe the following measurements at the various Denali, MIT outlets and wall outlets, and all components mentioned use the same V10 NR cords, and either have On/Off switches, or I just unplugged their cords:

At the Denali and MIT filter boxes:

1) The Yggy2 DAC (using my extensive internal shielding) raises a reading of 34mVp-p when turned off to 40 when turned on
2) The Spectral SDR-3000SL transport adds nothing back to the line
3) The Alpha DAC (using my extremely-low-noise Vishay diodes and custom power supply plus extensive internal shielding) adds so little that it's effectively a wash
4) The Spectral preamp adds nothing back to the line
5) The Magnum Dynalab tuner ((using my extremely-low-noise Vishay diodes and custom power supply) adds nothing back to the line
6) The Pass phono (using my my extremely-low-noise Vishay diodes) adds nothing back to the line
7) I have yet to measure the amps

At the wall, there are no fluctuations.

This exercise, so far, is confirming the following:

1) The incoming power line is extremely low in noise
2) All significant noise is generated inside the house
3) All significant noise is generated by 12V electronic transformers (feeding halogen bulbs) and 120V dimmable LED lights, plus my desktop computer. Replacing Lutron dimmers with rocker switches confirms that these dimmers are not really the culprit
4) The Denali v2 is an incredibly effective device, and their power cords are complementary. The CCI technology works and the unit operates well into the MHz
5) No major appliance whatsoever is adding any amount of significant noise, worth more than 5mVp-p, and the kitchen appliances are in very close proximity to the audio system, but not on the same circuit. The appliances are high quality (Bosch, Miele, SubZero, etc)
6) I do like the fact that the AlphaLabs device has a bandwidth up to 10MHz, but I am sure it's no Fluke or oscilloscope. Its specs do mention +- 8% accuracy
7) If one is inclined to do so, it's worth hiring someone to properly measure all configurations, but I already now know what the noisy devices are

Regarding the audible effects of the Shunyata gear, again, this has been documented under my system thread over the last 9 months as it was evolving, like the following posts:

ack's system - end of round 1

The question for micro is: what do you consider a "decent" power cord Officially mains has the ability to supply current at an well determine sinusoidal voltage - 50Hz in Europe or 60 Hz in US. A "decent" power cable will differentially show minimal voltage difference between its extremities...

www.whatsbestforum.com

ack's system - end of round 1

The question for micro is: what do you consider a "decent" power cord Officially mains has the ability to supply current at an well determine sinusoidal voltage - 50Hz in Europe or 60 Hz in US. A "decent" power cable will differentially show minimal voltage difference between its extremities...

www.whatsbestforum.com

onward.

The most important observation, as I said earlier, is that now, the system's performance is very steady all day long, with all noisy devices operating, and that alone is a major feat and the important end result. I am SO close to ordering the Everest... but the cost...

 

[ack]

I've been telling people that every power supply in their audio system needs to be cleaned up. It takes just one bad one to pollute other components over the power or interconnect cabling.

Thank you for showing meter readings. Yes, noise is measurable and power conditioning is not snake oil. Luddites will still claim snake oil with paper theories, but a measuring device is irrefutable.

Yes indeed! and you are welcome

 

[Mdp632]

It was quite interesting to observe the following measurements at the various Denali, MIT outlets and wall outlets, and all components mentioned use the same V10 NR cords, and either have On/Off switches, or I just unplugged their cords:

At the Denali and MIT filter boxes:

1) The Yggy2 DAC (using my extensive internal shielding) raises a reading of 34mVp-p when turned off to 40 when turned on
2) The Spectral SDR-3000SL transport adds nothing back to the line
3) The Alpha DAC (using my extremely-low-noise Vishay diodes and custom power supply plus extensive internal shielding) adds so little that it's effectively a wash
4) The Spectral preamp adds nothing back to the line
5) The Magnum Dynalab tuner ((using my extremely-low-noise Vishay diodes and custom power supply) adds nothing back to the line
6) The Pass phono (using my my extremely-low-noise Vishay diodes) adds nothing back to the line
7) I have yet to measure the amps

At the wall, there are no fluctuations.

This exercise, so far, is confirming the following:

1) The incoming power line is extremely low in noise
2) All significant noise is generated inside the house
3) All significant noise is generated by 12V electronic transformers (feeding halogen bulbs) and 120V dimmable LED lights, plus my desktop computer. Replacing Lutron dimmers with rocker switches confirms that these dimmers are not really the culprit
4) The Denali v2 is an incredibly effective device, and their power cords are complementary. The CCI technology works and the unit operates well into the MHz
5) No major appliance whatsoever is adding any amount of significant noise, worth more than 5mVp-p, and the kitchen appliances are in very close proximity to the audio system, but not on the same circuit. The appliances are high quality (Bosch, Miele, SubZero, etc)
6) I do like the fact that the AlphaLabs device has a bandwidth up to 10MHz, but I am sure it's no Fluke or oscilloscope. Its specs do mention +- 8% accuracy
7) If one is inclined to do so, it's worth hiring someone to properly measure all configurations, but I already now know what the noisy devices are

Regarding the audible effects of the Shunyata gear, again, this has been documented under my system thread over the last 9 months as it was evolving, like the following posts:

ack's system - end of round 1

The question for micro is: what do you consider a "decent" power cord Officially mains has the ability to supply current at an well determine sinusoidal voltage - 50Hz in Europe or 60 Hz in US. A "decent" power cable will differentially show minimal voltage difference between its extremities...

www.whatsbestforum.com

ack's system - end of round 1

The question for micro is: what do you consider a "decent" power cord Officially mains has the ability to supply current at an well determine sinusoidal voltage - 50Hz in Europe or 60 Hz in US. A "decent" power cable will differentially show minimal voltage difference between its extremities...

www.whatsbestforum.com

onward.

The most important observation, as I said earlier, is that now, the system's performance is very steady all day long, with all noisy devices operating, and that alone is a major feat and the important end result. I am SO close to ordering the Everest... but the cost...

There is on one audiogon ( as of this posting )

Shunyata Research EVEREST | AC Conditioners

Shunyata Research EVEREST for sale. Here’s a like new world best power conditioner, the EVEREST. It is less than 2 months old, with original box and packaging.

www.audiogon.com

Furthermore , one of the advantages of Shunyata products is their incredible residual value and low depreciation. Relative to other brands of power products.

I’ve always been able to sell my Shunyata stuff in a few days on Audigon. As I’ve upgraded over the years. Only further up the Shunyata chain.

I’ve wanted to try other products but , this is one of reasons (besides performance ) I’ve stuck with Shunyata.

 

[kennyb123]

Interesting findings @ack . Thanks for sharing.