Power supplies and cables - observations, considerations & commentary

FYI If you purchased a microRendu with an iFi iPower supply (9V @ 2AMPs) you do not need to purchase the energizing power supply for the Uptone Audio LPS-1 power supply. You can utlilze the iFi iPower supply to energize the Uptone Audio LPS-1 power supply. This reduces the price of the Uptone Audio LPS-1 upgrade to 380 USD.

Jesus, by chance do you have the specs on the stock SMPS that shipped with the microRendu?

I am trying to figure out if it can be used to power the LPS-1. My stock microRendu SMPS is in storage and not currently accessible so I am not easily able to look at it to verify.

Thanks

Jesus, by chance do you have the specs on the stock SMPS that shipped with the microRendu?

 

I am trying to figure out if it can be used to power the LPS-1. My stock microRendu SMPS is in storage and not currently accessible so I am not easily able to look at it to verify.

 

Thanks

Not sure what you mean by stock SMPS. The iFi iPower we offer as an option should be 9V/2A on the DC output. If you are not sure just look at the label on the power supply.

Jesus, by chance do you have the specs on the stock SMPS that shipped with the microRendu?

 

I am trying to figure out if it can be used to power the LPS-1. My stock microRendu SMPS is in storage and not currently accessible so I am not easily able to look at it to verify.

Hi Blake:

As long as you are bringing up the LPS-1, I just posted the below in the main microRendu thread, though I suppose it really belongs in this one.

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Wow, the microRendu is a real power miser! Check out pics of its low 160mA (0.16A) current draw (at 7V)--and of it in turn bus-powering an iFi iDSD DAC/headphone amp, with a total draw for the two of just 0.85A.

The isolated LPS-1 combined with the isolated microRendu and a bus-powered DAC really removes both the AC and computer stuff from the equation!

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Hope Jesus does not mind the shameless plug. But a lot of you microRendu owners have already signed up for our new toy, and I am pleased to report about how little Sonore's marvel sips.

--Alex C.

Not sure what you mean by stock SMPS. The iFi iPower we offer as an option should be 9V/2A on the DC output. If you are not sure just look at the label on the power supply.

Sorry, brain cramp on my part- I thought I recalled a smps coming with my microRendu in the box, which I then put in storage. It turns out I was thinking of one of my Regens. So please disregard my question.

Hi Blake:

As long as you are bringing up the LPS-1, I just posted the below in the main microRendu thread, though I suppose it really belongs in this one.

----------

Wow, the microRendu is a real power miser! Check out pics of its low 160mA (0.16A) current draw (at 7V)--and of it in turn bus-powering an iFi iDSD DAC/headphone amp, with a total draw for the two of just 0.85A.

 

The isolated LPS-1 combined with the isolated microRendu and a bus-powered DAC really removes both the AC and computer stuff from the equation!

----------

 

Hope Jesus does not mind the shameless plug. But a lot of you microRendu owners have already signed up for our new toy, and I am pleased to report about how little Sonore's marvel sips.

 

--Alex C.

Just the same the official spec for the unit remains as follows: Power input: 6-9 VDC at 1 Amp min continuous.

Sorry, brain cramp on my part- I thought I recalled a smps coming with my microRendu in the box, which I then put in storage. It turns out I was thinking of one of my Regens. So please disregard my question.

Okay.

Ok.....I have developed a problem. Whenever i plug in the ifi I get a horrendous "buzzing". I even have three separate dedicated circuits. I plug the ifi into a seperate circuit and i still get the buzzing. I've had the unit for several weeks. I've always had a tiny bit of noise but this is a deal breaker. Any ideas? Thanks.

Ok.....I have developed a problem. Whenever i plug in the ifi I get a horrendous "buzzing". I even have three separate dedicated circuits. I plug the ifi into a seperate circuit and i still get the buzzing. I've had the unit for several weeks. I've always had a tiny bit of noise but this is a deal breaker. Any ideas? Thanks.

Are you using an iFI wall wart as power supply? If so try changing it. I had buzzing issues with the iFi power supply before.

Ok.....I have developed a problem. Whenever i plug in the ifi I get a horrendous "buzzing". I even have three separate dedicated circuits. I plug the ifi into a seperate circuit and i still get the buzzing. I've had the unit for several weeks. I've always had a tiny bit of noise but this is a deal breaker. Any ideas? Thanks.

Is the noise coming from the power supply itself or the system? If it's coming from the system you need to provide a lot more information for us to help you trace it.

Just the same the official spec for the unit remains as follows: Power input: 6-9 VDC at 1 Amp min continuous.

To be clear on this point. If you have a microRendo connected to something like the Mutec MC3+USB, which draws approximately 350mA via USB, does the official spec for the microRendu PS remain at 1 Amp, or does it increase to 1.35 A? (mR 1 Amp + USB draw from DAC or Mutec)

When I disconnect the ifi psu the buzzing stops. I can either unplug it from the wall or disconnect it forum the microrendu and the buzzing stops. And yes I plan to get a different power supply. I do have the Meanwell that came with a regen. That won't work with the Microrendu will it?

When I disconnect the ifi psu the buzzing stops.

I too had this buzzing problem in my system and Jesus recommended me to change supplies which solved the problem too.

I regret buying the iFi 9V power supply with the microRendu (at 9V it makes the mR too hot anyway).

I suggest removing it from the recommended list of supplies as it's simply not a good supply.

I too had this buzzing problem in my system and Jesus recommended me to change supplies which solved the problem too.

 

I regret buying the iFi 9V power supply with the microRendu (at 9V it makes the mR too hot anyway).

 

I suggest removing it from the recommended list of supplies as it's simply not a good supply.

To be clear on this point. If you have a microRendo connected to something like the Mutec MC3+USB, which draws approximately 350mA via USB, does the official spec for the microRendu PS remain at 1 Amp, or does it increase to 1.35 A? (mR 1 Amp + USB draw from DAC or Mutec)

It would remain as follows: Power input: 6-9 VDC at 1 Amp min continuous.

I switched the ifi for the Meanwell and the Meanwell is dead quiet. I'll see if I can get ifi to check the psu this weekend at RMAF. And I'll be in the market for a LPSU.

I too had this buzzing problem in my system and Jesus recommended me to change supplies which solved the problem too.

 

I regret buying the iFi 9V power supply with the microRendu (at 9V it makes the mR too hot anyway).

 

I suggest removing it from the recommended list of supplies as it's simply not a good supply.

I appreciate your suggestion. However, the iFi iPower supply is serving a specific case for a universal power supply at a very reasonable price point. Not everyone needs or can afford to also spend 400 USD on a power supply upgrade. Anyway, feedback regarding the iFi on this forum and via email is overwhelmingly positive. I understand that you may have had an issue with the power supply, but these are system specific and not very common.

I switched the ifi for the Meanwell and the Meanwell is dead quiet. I'll see if I can get ifi to check the psu this weekend at RMAF. And I'll be in the market for a LPSU.

Thanks for checking back in. Enjoy the show...I'm stuck here tending to a Hurricane:)

Thanks for checking back in. Enjoy the show...I'm stuck here tending to a Hurricane:)

Best of luck with that! Hope it only brushes FLA.

Sent from my iPhone using Computer Audiophile

I was lucky enough to try an mRendu recently but didn't end up going down that path.

Since then I've learnt a lot and I've upgraded the weak links that were in my system chain previously (replaced noisy stock PSU's with low noise linear PSU's and disconnected a very noisy wifi router from my listening room and replaced with TP-link powerline adapter). These changes have really helped in a way I didn't expect so i'm ready to go the mRendu again and replace my NAS which is my current USB audio source with a high end USB audio source (the mRendu).

I don't want to spend the equivalent amount of money on USB audio conditioning/filtering (like a LANRover or iFi iUSB3.0 with Mercury and Gemini cables). I'd rather spend that similar amount of money on a better USB audio source in the first place - the mRendu.

Question: reading different threads, it seems like the only thing that might be required between the mRendu and DAC to cover the one thing that the mRendu doesn't take care of, is galvanic isolation, to isolate leakage current that an mRendu's PSU might introduce. Am I understanding that correctly?

Apologies for the silly question or if I'm not not making sense, but apart from going the battery power supply route to power the mRendu, then the other option is something like the Intona USB isolator?

So an Intona (or similar USB isolator) + mRendu covers:

1. galvanic isolation of the ethernet source connection

2. galvanic isolation of the mRendu power supply

3. regen, reclocking and jitter elimination

Am I correct in thinking that (in theory) I shouldn't need anything else?

Even with the mRendu I see some people are still using Jitter bugs and the Regn and iFI conditioners and LANRovers etc, which is why I am confused.

I thought the combination of Intona (or similar) + mRendu covered all bases (at least in theory)

It was John Swenson's post (here: http://www.computeraudiophile.com/f26-sonore-sponsored/why-does-my-microrendu-sound-so-much-better-my-regen-behind-it-29875/) that got me thinking that this combination of Intona (or similar product) + mRendu (or mRendu + UltraCap™ LPS-1) should be the bee's knees of USB audio but I definitely maybe didn't understand it correctly:

Because the microRendu is connected to the computer system with wired Ethernet which is already galvanically isolated, there are two different ways to break a leakage loop in the microRendu to DAC path, one is to galvanically isolate the USB connection, the other is to galvanically isolate the power supply to the microRendu. There are couple of devices that can isolate the USB connection, and a couple ways to do it in the power supply. You can run the microRendu off batteries, or use an LPS-1, an isolated supply I have designed that will be going on sale very soon now. Either of these approaches will work, you do not need both at the same time.

Thanks again and apologies in advance if I misunderstood. I definitely don't want to take John's words out of context or misinterpreted. I am by no means an expert but I am loving learning about this stuff around this forum :-)

I was lucky enough to try an mRendu recently but didn't end up going down that path.

 

Since then I've learnt a lot and I've upgraded the weak links that were in my system chain previously (replaced noisy stock PSU's with low noise linear PSU's and disconnected a very noisy wifi router from my listening room and replaced with TP-link powerline adapter). These changes have really helped in a way I didn't expect so i'm ready to go the mRendu again and replace my NAS which is my current USB audio source with a high end USB audio source (the mRendu).

 

I don't want to spend the equivalent amount of money on USB audio conditioning/filtering (like a LANRover or iFi iUSB3.0 with Mercury and Gemini cables). I'd rather spend that similar amount of money on a better USB audio source in the first place - the mRendu.

 

Question: reading different threads, it seems like the only thing that might be required between the mRendu and DAC to cover the one thing that the mRendu doesn't take care of, is galvanic isolation, to isolate leakage current that an mRendu's PSU might introduce. Am I understanding that correctly?

 

Apologies for the silly question or if I'm not not making sense, but apart from going the battery power supply route to power the mRendu, then the other option is something like the Intona USB isolator?

 

So an Intona (or similar USB isolator) + mRendu covers:

1. galvanic isolation of the ethernet source connection

2. galvanic isolation of the mRendu power supply

3. regen, reclocking and jitter elimination

 

Am I correct in thinking that (in theory) I shouldn't need anything else?

 

Even with the mRendu I see some people are still using Jitter bugs and the Regn and iFI conditioners and LANRovers etc, which is why I am confused.

 

I thought the combination of Intona (or similar) + Rendu covered all bases (at least in theory)

Providing clean power to a typical computer audio setup is a good idea. We have been doing this for years on our music servers. The issue (which I think you understand) is that a typical computer receives that clean power only to run it through a bunch of switching regulators through out the circuit. Some circuits are important and some are not and the microRendu addresses this and removes the bottleneck.

Anyway, if your concerned about leakage current with a SMPS then don't use one. I have no issue recommending an iFi iPower supply (which is a 50 USD SMPS), but I also recommend various linear power supplies to fit any budget. My advice is that you first buy the best power supply you can afford or need and start their. The microRendu has a regenerative circuit built in so I'll leave it up to you if think you need a second one inline;) You are also free to try other inline products, but again I'll leave that up to you.

I switched the ifi for the Meanwell and the Meanwell is dead quiet. I'll see if I can get ifi to check the psu this weekend at RMAF. And I'll be in the market for a LPSU.

Rust: please remember to come see us (Sonore) at RMAF, Tower Room 3021!

Providing clean power to a typical computer audio setup is a good idea. We have been doing this for years on our music servers. The issue (which I think you understand) is that a typical computer receives that clean power only to run it through a bunch of switching regulators through out the circuit. Some circuits are important and some are not and the microRendu addresses this and removes the bottleneck.

 

Anyway, if your concerned about leakage current with a SMPS then don't use one. I have no issue recommending an iFi iPower supply (which is a 50 USD SMPS), but I also recommend various linear power supplies to fit any budget. My advice is that you first buy the best power supply you can afford or need and start their. The microRendu has a regenerative circuit built in so I'll leave it up to you if think you need a second one inline;) You are also free to try other inline products, but again I'll leave that up to you.

Thanks Jesus. I know these things are complex and I don't want to turn this thread into Electrical Engineering 101, but generally speaking is leakage current less of an issue with linear PSU's than SMPS's?

Sent from my Blackberry DTEK50 using Tapatalk

 

Apologies for the silly question or if I'm not not making sense, but apart from going the battery power supply route to power the mRendu, then the other option is something like the Intona USB isolator?

 

So an Intona (or similar USB isolator) + mRendu covers:

1. galvanic isolation of the ethernet source connection

2. galvanic isolation of the mRendu power supply

3. regen, reclocking and jitter elimination

 

Am I correct in thinking that (in theory) I shouldn't need anything else?

 

Even with the mRendu I see some people are still using Jitter bugs and the Regn and iFI conditioners and LANRovers etc, which is why I am confused.

 

I thought the combination of Intona (or similar) + mRendu covered all bases (at least in theory)

Unfortunately it is not simple, there are several aspects that happen at the same time, different devices affect different aspects in different ways.

Major components of the USB connection that affect sound quality are signal integrity, and leakage loops. (there are others)

Signal integrity consists of the shape of the waveform, jitter and noise. The whole purpose of the microRendu is to get as good a signal integrity as possible.

Leakage current is current that flows in a loop from AC line, through power supply (NOT through AC safety ground), DC of power supply, powered device, interconnect between device (in USB case, power of computer, through shield and/or ground of USB cable, to DAC) DC of DAC, through AC supply of DAC back through AC line to AC supply of computer. It actually has nothing to do with the computer noise or USB noise, but is entirely a product of the DC output of the supplies connected together through the USB cable, it will still be there even if there is no computer or USB receiver at all!

These are two different issues that need to be dealt with separately. For example a REGEN gives very good signal integrity, but does nothing to block leakage current. An Intona blocks leakage current but does not have terribly good signal integrity. The "holy grail" is to do both at the same time.

So let's go over a few scenarios and see what does what.

Regular computer to USB DAC. Bad on both counts. Computer SMPS has a lot ogf leakage current, USB integrity is usually pretty bad.

Regular computer to REGEN powered by SMPS, to USB DAC. Signal integrity is much better, but nothing is done about leakage current from computer, but now we have an additional leakage current path through the REGEN power supply. Thus SQ is better from lower SI, but SQ from leakage current gets worse. Powering the REGEN from a low leakage current LPS cuts down on the additional leakage current.

Regular computer to Intona to REGEN to DAC. The Intona blocks the leakage current from SMPS of the computer, the REGEN has much better SI than either the computer or Intona, but you still get leakage current form the supply powering the REGEN. But cutting out the leakage current from the computer is a BIG improvement.

A word on "galvanic isolation", it means there is high impedance at DC. It doesn't matter whether a power supply is galvanically isolated or not, the power supply leakage current is AC, so it still happens even if the power supply is galvanically isolated. Now for a device powered by the DC output of a supply, galvanic isolation usually IS important. Most of the leakage current is low frequency (60/50HZ and harmonics) so if a device is galvanically isolated at DC and low frequencies it will cut down on the leakage current we are talking about here. BUT not all galvanic isolators have good isolation at the frequencies in question. For example a standard AC line power transformer has galvanic isolation, but 50/60Hz and harmonics go right through. On the other hand an Ethernet transformer is galvanically isolated and DOES block 50/60Hz and most harmonics.

Now on to the microRendu, its data connection to the outside world (connection to another computer) is through Ethernet which includes a galvanically isolated transformer which DOES block most leakage current. So the only way leakage current goes through it is the power supply connection, so ifyou use batteries or an LPS-1 you block leakage current going through the microRendu into the USB cable. Thus an Intona is unnecessary, leakage current is already blocked, and a REGEN is unnecessary because the microRendu is already producing extremely good signal integrity. The above is NOT true if you use any other power supply to power the microRendu , then leakage currents come into the system through the power supply.

So the upshot is that with a microRendu, an LPS-1 or batteries IS sufficient to block leakage currents and the SI is very good on its own, so the microRendu and LPS-1 feeding the microRendu should be all you need.

I hope that helps.

John S.

Hi John

Thanks for the clear explanation of leakage currents, definitely helps. Someone should tag your message as a reference on leakage currents.

A question:

Are leakage currents important after the DAC? Say in pre-amp or power-amp stage? When the signal leaves the DAC to pre-amp, can leakage currents back flow to the DAC via the interconnect from a pre-amp or power amp power supply?

I know you mention the following already - "..(leakage current) is entirely a product of the DC output of the supplies connected together through the USB cable.." but would like to clarify just in case since most pre and power amps have AC/DC convertors inside.

What about within pre-amps and power-amps in general, are leakage currents significant further along the audio signal path?

 

I hope that helps.

 

John S.

Thanks John, this absolutely helps. I completely understand the LPS-1 is the perfect power supply to complement the microRendu.

Just for my understanding, regarding "The above is NOT true if you use any other power supply to power the microRendu , then leakage currents come into the system through the power supply."

So a chain of mRendu-to-Intona-to-DAC won't break a low noice linear PSU's leakage currents as well as the LPS-1 supplying power to the microRendu?

Many thanks again for taking the time to explain this. It's greatly appreciated.