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Do you have not-too-bulky suggestions on how to separate the backwash from SMPSs from other components? Would something like this be worth it? Other options? My headphone system has a Teddy Pardo PS for a microRendu, which sounds very good but has not much separation between the switching side (network switch) and the audio side (just different outlets in the same room) and I'm waiting for the LPS-1 to power a second microRendu for my speaker system, again not well-separated power for SMPSs (that would be the LPS-1, a small NAS, and a network switch) and the audio gear.

 

This is a complex question, there are two methods by which a power supply interacts with the AC mains and the difference is not well understood by most people (even many engineers). The solutions to deal with them are very different but get all jumbled up in most peoples minds.

 

I really need to write an article on this, but I don't have time right now so here is a quick and dirty run down on what is happening.

 

The two types are:

 

1) noise between the hot and neutral (and maybe ground wire)

2) leakage current between the AC line and the DC output of a PS

 

#1 is pretty straight forward and what most people think of when they talk about "noise injected into the mains". There are many types of filters, power conditioners etc that deal with this.

 

#2 seems to be much harder to understand. It is created by the power supply, some of the AC voltage on the mains sneaks through parasitic capacitances in the PS and winds up on the DC output. The strange thing here is that it is between the the AC line as a whole (hot, neutral, GND) and the DC output as a whole (+, -). It does NOT exist between hot and neutral or between the DC - and +. It is between the two groups.

 

Because of this any type of normal AC line filter or DC filter or regulator is completely useless at combating this. All these devices work by "filtering" the noise between hot and neutral or between + and -. But this type of noise does not exist that way.

 

So why is #2 important? Because most devices in your audio chain are connected through a power supply to the AC mains, so noise developed between the AC and DC of one power supply couple through the ground of your box to box connections (which might be the AC line ground, or it might be the shield of your interconnects, or the shield of your USB cable) thus adding this noise to the signal you have connecting between them.

 

This noise is not usually very high amplitude, so it is hard to measure, but by the time you start getting into really good systems it is usually the biggest source of noise left in your system. Remember that no amount of power supply filter, or super duper regulator is going to touch this.

 

Different power supplies produce very different amounts and frequencies of this leakage current. As a whole class SMPS usually have more than LPS, and the SMPS usually have way more high frequency components. Remember this is leakage of the AC line so it is either going to be based on 60Hz or 50Hz depending on where you live. The higher frequencies are harmonics of the line frequency. Note this has nothing to do with the high frequency "switching" of an SMPS, it is leakage of the AC line frequency and its harmonics, so this noise is right dab in the middle of the human hearing range.

 

The above does not mean that type 1 noise does not happen, but it is well understood and audiophile companies and users have worked hard to cut down on this type of noise.

 

But leakage current is entirely different, it is very rarely dealt with. (primarily because hardly anybody knows about it)

 

A lot of the audibility issues with USB are due to type 2 noise, the SMPS of all the computer equipment wind up coupling their leakage current to the audio system ground leakage current through the ground connection of the USB cable. Note this has nothing to do with the "noisy power" inside a computer, it is entirely caused by the power supply itself. You would get the same result if you took the computer PS, hooked up a resistor to give the same current draw and connected the ground from the PS to the audio system ground.

 

But there are ALSO other issues with USB such as signal integrity which the microRendu addresses, so you wind up with both of these at once with most systems. Using a microRendu gets rid of one class of problem which now leaves the other more exposed.

 

In some people's system the leakage current problem is not to large, in others it is.

 

That is the background to the question, the LPS-1 is designed to block this leakage current. Remember the leakage current is between the AC main and the DC output of a PS, the LPS-1 completely blocks that connection, the leakage current from the supply is completely blocked (OK not completely, but it is reduced by at least several thousand times). Yes there is always some type 1 noise injected back into the mains, but it looks like most of the audibility issues are mostly caused by type 2.

 

There are quite a few LPS that actually have more type 1 noise than most SMPS, but their type 2 noise is much less. Since the LPS-1 blocks the type 2 noise the difference in audibility of feeder supplies is going to be based on type 1 noise, which may wind up being different than you expect.

 

BTW this leakage current exists between ALL power supplies, so the supplies on the DAC, preamp, power amp etc ALL play a part in this. But the SMPS frequently used in the computer side of things seem to be the most damaging to SQ.

 

Sorry for the overly long response, but there was just no way to properly give an answer without some background.

 

John S.

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I really need to write an article on this, but I don't have time right now so here is a quick and dirty run down on what is happening.

<snip>

Thank you so much, that's a great summary of the article that we are all waiting for :) It will help me figure out next steps to upgrade my systems.

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This is not true at all. Whatever powers the Uptone would be plugged into the wall near your audio system, and will be sharing noise onto the AC line,a nd that noise will get back into your system via the AC line. It is best to keep all cheap power supplies as far away from the audio system as possible, and anything plugged into the same circuit as the audio system should be high quality/low noise.

 

You're relating to a different issue. Either John Swenson or Alex C already opined that using an iPower to power their PS is overkill. Part of the reason that they are supplying the PS with the Mean Well wall wart. Do you think the Mean Well puts no noise back into the AC?

As far as noise pollution getting back into the AC system, that's an indirect effect and not what the poster asked about. If that's your issue, the iFi is probably not a great solution, either. Probably better in either case (Mean Well or iPower) to deal with the issue of noise kicked back to the AC in a different way.

Main listening (small home office):

Main setup: Surge protector +>Isol-8 Mini sub Axis Power Strip/Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three (on their own electric circuit) >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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For me personally, I don't want any switching power supplies anywhere near my audio system. The sooner I can get rid of the iFi powering the microRendu the better. For both the noise transmitted into the microRendu and the junk it puts back out onto the circuit that my pre-amp and power amps are on. Ideally I would replace it with an LPS-1, but if I am adding another switching power supply to charge the LPS then I am still getting garbage out on that circuit and only solving half of the problem. (Even if LPS itself is impervious to grungy switched power) So it might be overkill for the output of the LPS, but for the rest of the system it isn't the optimal solution. So I'm looking for the lowest cost power supply that sounds better than iFi with the microRendu and can also be used to charge the LPS without dumping crap back onto the AC lines.

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For me personally, I don't want any switching power supplies anywhere near my audio system. The sooner I can get rid of the iFi powering the microRendu the better. For both the noise transmitted into the microRendu and the junk it puts back out onto the circuit that my pre-amp and power amps are on. Ideally I would replace it with an LPS-1, but if I am adding another switching power supply to charge the LPS then I am still getting garbage out on that circuit and only solving half of the problem. (Even if LPS itself is impervious to grungy switched power) So it might be overkill for the output of the LPS, but for the rest of the system it isn't the optimal solution. So I'm looking for the lowest cost power supply that sounds better than iFi with the microRendu and can also be used to charge the LPS without dumping crap back onto the AC lines.

 

I think this is the El Cheapo LPS that many have used as a cheap step up from the original Meanwell SMPS with the Regen units:

 

30W DC9V HiFi Linear Power Supply Regulated PSU for DAC Amp Digital Display | eBay

 

I'm not sure if this would be a step up from the iFi or not, but I'm hoping to borrow one from a friend soon to try it out. In the meantime, I have ordered one of these to reduce the backwash from the iFi (or the El Cheapo LPS) back into the mains.

 

AC-7A - AC line filter with 1 ft cord with 120 V AC NEMA standard plug and receptacle for Wall-Warts or other AC mains devices.

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In my experience the P.I. Audio UberBuss does an incredible job totally killing the SMPS noise that goes back into the AC mains.

 

Jason - interesting... I thought that was exactly what the PI Audio DigiBuss was intended to do. I've got both the Uber and Digi and do find the DigiBuss does a nice job with various SMPSs but never really considered to what extent the UberBuss was doing that as well.

Win 10 PC -> Roon -> Sonore µRendu -> Devialet 440 Pro -> Von Schweikert VR-35 speakers

Durham, NC

 

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Jason - interesting... I thought that was exactly what the PI Audio DigiBuss was intended to do. I've got both the Uber and Digi and do find the DigiBuss does a nice job with various SMPSs but never really considered to what extent the UberBuss was doing that as well.

 

IMO/IME the Uber does an even stellar job. The Uber really is the premier unit from what I've experienced.

W10 NUC i7 (Gen 10) > Roon (Audiolense FIR) > Motu UltraLite mk5 > (4) Hypex NCore NC502MP > JBL M2 Master Reference +4 subs

 

Watch my Podcast https://www.youtube.com/channel/UCXMw_bZWBMtRWNJQfTJ38kA/videos

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For me personally, I don't want any switching power supplies anywhere near my audio system. The sooner I can get rid of the iFi powering the microRendu the better. For both the noise transmitted into the microRendu and the junk it puts back out onto the circuit that my pre-amp and power amps are on. Ideally I would replace it with an LPS-1, but if I am adding another switching power supply to charge the LPS then I am still getting garbage out on that circuit and only solving half of the problem. (Even if LPS itself is impervious to grungy switched power) So it might be overkill for the output of the LPS, but for the rest of the system it isn't the optimal solution. So I'm looking for the lowest cost power supply that sounds better than iFi with the microRendu and can also be used to charge the LPS without dumping crap back onto the AC lines.

 

If your going to buy a linear supply why not just use it with the microRendu and call it a day.

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For the junk put back on the AC how about the AC-7 sold by Array Solutions ? I have one on order and others have found it is a good addition.

 

AC-7 - AC line filter with 6 ft line cord with 120 V AC NEMA standard plug and IEC receptacle for PC power supplies and other devices using IEC connectors

 

I use the AC-7A with the iPower and find it makes a noticeable improvement in my system for a modest outlay.

no-mqa-sm.jpg

Boycott HDtracks

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I tried the micro rendu in NAA mode as part of my HQPlayer trial. I was really happy to discover it worked on the first try. So easy.

 

Now I fervently hope it will continue to work after the 2.2 update. We have to install the update to find out what's in it. Sounds like the Affordable Care Act.

Pareto Audio AMD 7700 Server --> Berkeley Alpha USB --> Jeff Rowland Aeris --> Jeff Rowland 625 S2 --> Focal Utopia 3 Diablos with 2 x Focal Electra SW 1000 BE subs

 

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Another good Linear Supply option is the CIAudio 9V. I had one leftover from my SB Duet days and use it with the microRendu with excellent results. It is not cheap but it is very well built. Mine has years of continuous use and is still going strong. Alex at Uptone has a beautiful custom 5.5x2.5 ===> 5.5x2.1 cable that I use with this combo.

 

CIAUDIO : VDC•9 MKII - High Current Power Supply

Very nice looking and, I'd bet, sounding unit.

Will take a look at that Uptone cable.

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Very nice looking and, I'd bet, sounding unit.

Will take a look at that Uptone cable.

 

Pretty happy with my $140 TeraDak LPS and won't feel bad about buying the Uptone LPS-1 and using the Teradak as a "feeder" supply, not worrying about sending crap back into the AC line, and also not spending more than the microRendu on power supply(s).

 

Cheers,

l500.jpg

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This is a complex question, there are two methods by which a power supply interacts with the AC mains and the difference is not well understood by most people (even many engineers). The solutions to deal with them are very different but get all jumbled up in most peoples minds.

 

I really need to write an article on this, but I don't have time right now so here is a quick and dirty run down on what is happening.

 

The two types are:

 

1) noise between the hot and neutral (and maybe ground wire)

2) leakage current between the AC line and the DC output of a PS

 

#1 is pretty straight forward and what most people think of when they talk about "noise injected into the mains". There are many types of filters, power conditioners etc that deal with this.

 

#2 seems to be much harder to understand. It is created by the power supply, some of the AC voltage on the mains sneaks through parasitic capacitances in the PS and winds up on the DC output. The strange thing here is that it is between the the AC line as a whole (hot, neutral, GND) and the DC output as a whole (+, -). It does NOT exist between hot and neutral or between the DC - and +. It is between the two groups.

 

Because of this any type of normal AC line filter or DC filter or regulator is completely useless at combating this. All these devices work by "filtering" the noise between hot and neutral or between + and -. But this type of noise does not exist that way.

 

So why is #2 important? Because most devices in your audio chain are connected through a power supply to the AC mains, so noise developed between the AC and DC of one power supply couple through the ground of your box to box connections (which might be the AC line ground, or it might be the shield of your interconnects, or the shield of your USB cable) thus adding this noise to the signal you have connecting between them.

 

This noise is not usually very high amplitude, so it is hard to measure, but by the time you start getting into really good systems it is usually the biggest source of noise left in your system. Remember that no amount of power supply filter, or super duper regulator is going to touch this.

 

Different power supplies produce very different amounts and frequencies of this leakage current. As a whole class SMPS usually have more than LPS, and the SMPS usually have way more high frequency components. Remember this is leakage of the AC line so it is either going to be based on 60Hz or 50Hz depending on where you live. The higher frequencies are harmonics of the line frequency. Note this has nothing to do with the high frequency "switching" of an SMPS, it is leakage of the AC line frequency and its harmonics, so this noise is right dab in the middle of the human hearing range.

 

The above does not mean that type 1 noise does not happen, but it is well understood and audiophile companies and users have worked hard to cut down on this type of noise.

 

But leakage current is entirely different, it is very rarely dealt with. (primarily because hardly anybody knows about it)

 

A lot of the audibility issues with USB are due to type 2 noise, the SMPS of all the computer equipment wind up coupling their leakage current to the audio system ground leakage current through the ground connection of the USB cable. Note this has nothing to do with the "noisy power" inside a computer, it is entirely caused by the power supply itself. You would get the same result if you took the computer PS, hooked up a resistor to give the same current draw and connected the ground from the PS to the audio system ground.

 

But there are ALSO other issues with USB such as signal integrity which the microRendu addresses, so you wind up with both of these at once with most systems. Using a microRendu gets rid of one class of problem which now leaves the other more exposed.

 

In some people's system the leakage current problem is not to large, in others it is.

 

That is the background to the question, the LPS-1 is designed to block this leakage current. Remember the leakage current is between the AC main and the DC output of a PS, the LPS-1 completely blocks that connection, the leakage current from the supply is completely blocked (OK not completely, but it is reduced by at least several thousand times). Yes there is always some type 1 noise injected back into the mains, but it looks like most of the audibility issues are mostly caused by type 2.

 

There are quite a few LPS that actually have more type 1 noise than most SMPS, but their type 2 noise is much less. Since the LPS-1 blocks the type 2 noise the difference in audibility of feeder supplies is going to be based on type 1 noise, which may wind up being different than you expect.

 

BTW this leakage current exists between ALL power supplies, so the supplies on the DAC, preamp, power amp etc ALL play a part in this. But the SMPS frequently used in the computer side of things seem to be the most damaging to SQ.

 

Sorry for the overly long response, but there was just no way to properly give an answer without some background.

 

John S.

 

So how would one detect or measure #2? e.g. Spectrum Analyzer, Oscilloscope or something else?

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So how would one detect or measure #2? e.g. Spectrum Analyzer, Oscilloscope or something else?

 

I use a high voltage differential probe into either a scope or spectrum analyzer.

 

The problem with measuring leakage current is the test equipment will have it's ground connected to one of the grounds you are trying to test, which gets ITS leakage current all tied up in what you are trying to measure.

 

With a differential probe you can connect between say the AC line gnd pin and DC gnd and get reasonable measurements.

 

You have to take into account whether the DC gnd and AC gnd are connected or not. For example if you just look between the AC gnd and the DC gnd of the PS you will get a high voltage (very high impedance between), hence the high voltage probe. But if the chain the power supply is driving somehow connects the DC gnd back to the AC gnd (maybe in a DAC, or power amp etc), then the impedance between the two gnds will be quite low so the voltage due to the leakage current will be low.

 

John S.

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In my experience the P.I. Audio UberBuss does an incredible job totally killing the SMPS noise that goes back into the AC mains.

 

JT: How did you determine this? Without spectrum analysis, it is very difficult to be "sure". Personally, I do not allow any poor supplies to be on the same run of the AC line as my audio system. At least a dedicated clean circuit should be used in my opinion (and everyone should still understand, that even a dedicated line is connected to the other AC lines on that phase back at the junction box; the good news is that just the small amount of R/C of the wire run in the walls is often enough to attenuate very high frequency noise quite a bit).

But this discussion is a bit OT here...

SO/ROON/HQPe: DSD 512-Sonore opticalModuleDeluxe-Signature Rendu optical with Well Tempered Clock--DIY DSC-2 DAC with SC Pure Clock--DIY Purifi Amplifier-Focus Audio FS888 speakers-JL E 112 sub-Nordost Tyr USB, DIY EventHorizon AC cables, Iconoclast XLR & speaker cables, Synergistic Purple Fuses, Spacetime system clarifiers.  ISOAcoustics Oreas footers.                                                       

                                                                                           SONORE computer audio

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JT: How did you determine this? Without spectrum analysis, it is very difficult to be "sure". Personally, I do not allow any poor supplies to be on the same run of the AC line as my audio system. At least a dedicated clean circuit should be used in my opinion (and everyone should still understand, that even a dedicated line is connected to the other AC lines on that phase back at the junction box; the good news is that just the small amount of R/C of the wire run in the walls is often enough to attenuate very high frequency noise quite a bit).

But this discussion is a bit OT here...

 

It was objectively tested. Thanks.

 

Do you have the objective data for the µRendu and your power supply to show the gain?

W10 NUC i7 (Gen 10) > Roon (Audiolense FIR) > Motu UltraLite mk5 > (4) Hypex NCore NC502MP > JBL M2 Master Reference +4 subs

 

Watch my Podcast https://www.youtube.com/channel/UCXMw_bZWBMtRWNJQfTJ38kA/videos

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It was objectively tested. Thanks.

 

Do you have the objective data for the µRendu and your power supply to show the gain?

 

Which "gain"? I realize that the Sonore Signature Supply will not be the chosen for option for all, and I have no problem with that. Indeed, we do measure the SPS during development to make sure it is working as expected in terms of noise. In terms of dynamic response, the developer of the discrete regulator circuit does provide some pretty good measurements, which is one of the main reasons this specific regulator circuit was selected (blows away normal things like the LM317 and the SuperTeddy). The one measured spec I am happy to share is noise: < 8µV (that is microvolts, not millivolts).

 

My point was that removing the noisy power supplies from the situation is always a better solution than attempting to filter out the noise. If one must have a noisy supply, then filtering is of course a good idea if it is done well.

SO/ROON/HQPe: DSD 512-Sonore opticalModuleDeluxe-Signature Rendu optical with Well Tempered Clock--DIY DSC-2 DAC with SC Pure Clock--DIY Purifi Amplifier-Focus Audio FS888 speakers-JL E 112 sub-Nordost Tyr USB, DIY EventHorizon AC cables, Iconoclast XLR & speaker cables, Synergistic Purple Fuses, Spacetime system clarifiers.  ISOAcoustics Oreas footers.                                                       

                                                                                           SONORE computer audio

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