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UpTone LPS-1 Linear Power Supply Review and Measurements

amirm

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#1
Recently I measured the performance of UpTone ISO Regen, a device whose purpose is to clean up the USB power and signal. Alas, as shown in that review, http://www.audiosciencereview.com/f...ptone-iso-regen-review-and-measurements.1829/, the supplied MeanWell switchmode Power Supply managed to actually inject AC mains related noise which did not exist without ISO Regen.

The proprietor of UpTone, Alex Crespi while accepting the above issue, said that only 30% of their customers purchase the Iso Regen with the MeanWell Power supply. Many others apparently buy it with one of their other products, the Ultacap LPS-1.

Due to kindness of one of the owners of LPS-1, I have a unit on loan to evaluate.


The LPS-1 came without a power supply. Looking on their web site, they optionally sell the MeanWell with it. Fortunately that is the power supply I have that came with ISO Regen so I was all set.

upload_2017-8-16_11-49-58.png


Background:
The LPS-1 is a dual-bank supercapacitor unit. It charges one bank, then switches to charging the other while the first one powers the external device. In this case, it is powering the ISO Regen which in turn is powering my iFi iDAC2 DAC.

Super capacitors are like batteries but they comparably hold very little energy and hence the reason they have to be charged often. Powering the ISO Regen, the bank switching time was around 3 seconds. Power consumption of the MeanWell Power Supply powering the LPS-1 would range from high of 12.8 watts to a sudden low of 1.8 watts. And this oscillation would go back and forth.

The benefit that is sold here is that while the unit is powering your audio gear, you are isolated from mains power/power supply. Immediate visions of clean power translating into cleaner DAC output, lower noise, veils removed, etc. comes to minds of audiophiles. Question is, is that what is happening???

Wideband Measurements:
I started this test a bit differently, using the same J-test 12 Khz tone but this time, putting my Audio Precision Analyzer in its wideband mode that goes above 130 Khz of bandwidth. The noise floor of the analyzer goes up but it allows us to see if there are effects well above hearing range.

High Bandwidth.png


As you see, there are three graphs:
1. iFi iDAC2 by itself connected to my laptop with its ostensibly noisy USB link
2. ifi iDAC2 getting connected to Iso Regen, powered by MeanWell switchmode power supply
3. iFi iDAC2 getting connected to Iso Regen, powered by LPS-1 which in turn is powered by MeanWell Power supply.

The signal is 12 Khz J-test so the first spike is supposed to be there. The rest of the spikes are harmonic distortions from the iFi iDAC.

Sadly, there is no reduction of noise or distortions by addition of Iso Regen with or without LPS-1.

Narrowband Measurements
Here, I do a finer analysis using the high-performance ADC in the Audio Precision, limiting analysis to 1.1 Khz. This allows us to have much finer frequency resolution (well below 1 Hz).

Specifically, this lets us see if there is mains AC leakage. As I did with the test of Iso Regen, I powered the Meanwell power supply with my BK Precision 9801 AC generator. This is a lab grade AC generator which lets me specify the frequency. And of course it generates cleaner power than the AC wire in your home.

I programmed the 9801 to output 70 Hz while my Audio Precision analyzer, may laptop, etc. all ran on 60 Hz. This way we can see if mains leakage path is through the MeanWell supply+LPS-1 or elsewhere.

Low bandwidth with Meanwell Supply.png


Gosh this disappointing. :( As you see in red, when LPS-1 is powered by the MeanWell Power supply, the same pesky 70 Hz AC mains leakage remains. It travels through LPS-1, onto Iso Regen and eventually through the DAC! Engineering explains why but I won't go into that.

If anything, it seems that without LPS-1 we actually have slightly less mains leakage (in yellow)!

Measurements with Linear Power Supply:
Let's switch the power supply from MeanWell to my lab unit:

Low bandwidth with Linear Supply.png


We see that the mains related contributions disappear. This clearly indicates that LPS-1 does nothing to reduce or let alone eliminate AC mains leakage from the power supply.

And just in case you think the linear power supply plus ISO regen, plus LPS-1 is the answer, read the graph: I got the same performance not using any of that! Straight plug into my laptop USB bus produced the same thing!

Now, I asked Alex directly if AC leakage is eliminated by LPS-1 and this is the answer he gave me: http://www.audiosciencereview.com/f...view-and-measurements.1829/page-20#post-47181

upload_2017-8-16_12-14-46.png


Conclusions:
At this point, I love to see measurements from Alex that contradicts my data. Until then, I am afraid the combination of ISO Regen, LPS-1 with MeanWell Supply contributes noise to the system. And with a linear supply, only goes back to showing no benefit with the quality DACs I have tested.

As always, I am open to all feedback, comments, corrections, teasing, etc.
 

Jinjuku

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#3
But Amir tens of millions of reviews say otherwise. They all love Uptone products. How could your measurements be correct in the face of all that collective human will working against your AP?
 

amirm

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#4
In another thread, Thomas asked me for a recommendation on a good linear Power supply. As it happens, I have a linear power supply that is designed to actually better the performance of UpTone among others! It is from the Dutch company Sbooster and the specific product is "BOTW" https://www.sbooster.com/botw-pp-eco/

Here is a comparison of iFi iDAC2 DAC, being driven by ISO Regen and LPS-1 with power coming from my lab linear power supply and Sbooster BOTW:

Sbooster.png


As we see they are comparable and there is no extra mains contribution as there is with MeanWell power supply feeding the LPS-1.

I have met the company principals, Wiebren Draaijer, and Karin Hoks and they are delightful people. So happy to send them business (no affiliation) should you need a supply like this.
 

Blumlein 88

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#5
In another thread, Thomas asked me for a recommendation on a good linear Power supply. As it happens, I have a linear power supply that is designed to actually better the performance of UpTone among others! It is from the Dutch company Sbooster and the specific product is "BOTW" https://www.sbooster.com/botw-pp-eco/

Here is a comparison of iFi iDAC2 DAC, being driven by ISO Regen and LPS-1 with power coming from my lab linear power supply and Sbooster BOTW:

View attachment 8173

As we see they are comparable and there is no extra mains contribution as there is with MeanWell power supply feeding the LPS-1.

I have met the company principals, Wiebren Draaijer, and Karin Hoks and they are delightful people. So happy to send them business (no affiliation) should you need a supply like this.
Of course it appears there is no reason to get the BOTW instead of the Meanwell. At best it simply equals feeding the iFi iDac2 straight from the USB right?
 

BE718

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#6
Thanks Amir

Well that was all of no surprise. I bet that the 0V goes straight through LPS1 from the Meanwell to the DAC. Amir you could check this with a simple multimeter resistance check from the LPS1 input connector (outer contact) to its output connector.

In which case the leakage currents will go straight through. I bet a bunch of RF from the Meanwell does the same.

Again this is all marketing with no engineering substance - "use caps they are quieter........."

Do you think Uptone believe their own marketing hype?
 
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amirm

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#7
Amir you could check this with a simple multimeter resistance check from the LPS1 input connector (outer contact) to its output connector.
It shows open so it is floating from DC point of view.

I think the problem is capacitive coupling. The levels here are very low so it doesn't take much capacitance to pass that through -- in the order of what is used for the Y capacitor in switching supply.

This is why I keep saying small boxes are not good for high performance audio. We have plenty of space in our audio racks. No need to make pocket sized devices where you can't do a proper layout in a larger box to keep the input and outputs far from each other.
 

Don Hills

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#8
I would have thought that the LPS-1 would have been designed so that the capacitor bank feeding the output at any one time is completely isolated from the charging side, with no electrical connection. In other words, an electronic "double pole changeover" switch. Alex? Can you confirm? Or is there a hard connection via the ground rail, or the equivalent of a Y capacitor between output and input?

Edit - Thanks, Amir.
 

amirm

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#9
Do you think Uptone believe their own marketing hype?
I think Alex genuinely believes in the improvements here as confirmed by his sighted listening and testimonials from others. Heaven't knows I have been guilty of that at times but in my case, there were checks and balances that stopped me from screwing up our audio development path. :)
 

BE718

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#10
It shows open so it is floating from DC point of view.

I think the problem is capacitive coupling. The levels here are very low so it doesn't take much capacitance to pass that through -- in the order of what is used for the Y capacitor in switching supply.

This is why I keep saying small boxes are not good for high performance audio. We have plenty of space in our audio racks. No need to make pocket sized devices where you can't do a proper layout in a larger box to keep the input and outputs far from each other.

OK, thats at least one step in the right direction, but shows that no measurements have been performed to check for issues like this, or for product efficacy. As Don says, I would have thought a complete isolation would not have been too difficult to achieve.
 
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Jinjuku

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#11
Is it me or does his product sound better to his customers the worse they measure?
 

Blumlein 88

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#12
Is it me or does his product sound better to his customers the worse they measure?
No, it is a function of cost. The more it costs, the more complex the explanation of expected benefits, the more magic is promised, the happier the customer who hears all of it. I do believe Amir has generated income for Alex. Just in case Amir is right, more will go with the LPS1 to stop the bad noise of the Meanwell. Or even if they buy the BOTW instead of the Meanwell, they likely will put it with the LPS1 which brings in more revenue for the maker of course. They think of it as having the best of both worlds. Better measured results and the benefits of the handcrafted listening based design method of John Swenson.

Win-win for everyone........except for that mean minded Amir fellow who cost them this extra money by bringing it all up.
 

Thomas savage

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#15
There may yet still be a perfectly reasonable explanation for all this, @Superdad ?

I'm not sure alex will be coming back, tbh he's been a good sport but I think if I were him I'd stick my head in the sand on this one too.
 

Thomas savage

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#17
Does the LPS-1 have any real world benefits , leaving behind this particular leakage issue?

What's the argument for using it vs say just a good cheap linear supply?

Have we anything positive to say here?

I'm not brave enough to post this link in the uptone sponsored LPS-1 thread at CA but if someone else wants to...o_O

At this point I'm feeling bad for alex and really want to buy him a beer and say " everything's going to be ok" .
 

amirm

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#18
There may yet still be a perfectly reasonable explanation for all this, @Superdad ?
Certainly surprised me given his affirmation to me and what they say in the web page for LPS-1:
upload_2017-8-16_22-29-5.png



Unfortunately no measurements are provided so hard to say how they ascertained what they say. It is also strange that he says it is hard to measure or know how it propagates through the system.

They are certainly very strong on this point given this statement:

upload_2017-8-16_22-31-45.png


Well, I am not happy. Then again, I am never happy. :D
 

amirm

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#19
Let me make a related point: the most appropriate tool for measuring power supply leakage and noise is an audio analyzer! That is because a) frequencies are in audio band and b) audio analog to digital converters have best dynamic range (20+ bits).

Traditional electronic instruments are designed for much higher frequencies (even a cheap scope goes up to 20 Mhz or 1000 times higher than audio band). That means they compromise on dynamic range and ability to read very small voltages accurately.

Our use of FFT to look at things in frequency spectrum provides yet another powerful tool, letting us see very tiny contributions that if they were riding on top of the main output, would be hard to see in time domain.

Given all of this, one can easily be misled thinking they have designed a low-noise product without utilization of an audio analyzer.
 

BE718

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#20
Does the LPS-1 have any real world benefits , leaving behind this particular leakage issue?

What's the argument for using it vs say just a good cheap linear supply?

Have we anything positive to say here?

I'm not brave enough to post this link in the uptone sponsored LPS-1 thread at CA but if someone else wants to...o_O

At this point I'm feeling bad for alex and really want to buy him a beer and say " everything's going to be ok" .
Shipping weight and cost, need to meet product price point for maximum sales.

edit
Sorry misread thought you meant SMPS v linear supply :)

It will only add benefit if the device its powering has inadequate PSU regulation and filtering. However if thats a real problem for you you need to buy a different DAC. A very quiet PSU if required can be realised quite cheaply, you dont need to spend $400.

The logic of the product totally eludes me. Why would you spend $400 on a psu that (allegedly) improves your inadequate dac. Sell your inadequate DAC, add the $400 and buy a decent DAC!
 
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