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New John Kenny Power Supply....


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16 minutes ago, jabbr said:

When using a cheap ADC to measure a DAC another variable is introduced into the system making it more difficult to know whether you are measuring reality vs artifact. 

 

You can isolate by looping the Behringers own DAC into it's AD loop though. The computer could be a laptop that isn't on mains therefore  the Behringer isn't on mains.

 

Not sure what you mean by 'cheap'. the Behringer is bus driven so you could even drive if from the computer driving the persons DAC and since the ground is referenced at pretty much the same potential....

 

Plus computer/ADC would simply be replacing other upstream component(s) and that may actually fix something and tell you more about the issue than if you hadn't. 

 

Basically there isn't a downside scenario that you can come up with that isn't easily dealt with what I'm offering. 

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2 minutes ago, jabbr said:

You are using it as a spectrum analyzer. Are HP/Agilent/Keysight just a huge waste   of $$$? Comparative  specs?

 

Is the Behringer / Arta incapable of reading voltages up to 20Khz? 

 

Last time I checked HP/Agilent/Keysight were scopes in the 100's of MHz range. 

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1 hour ago, plissken said:

 

Is the Behringer / Arta incapable of reading voltages up to 20Khz? 

 

Last time I checked HP/Agilent/Keysight were scopes in the 100's of MHz range. 

 

Ah ... consider the range as a window which can be adjusted with down mixing. So, for example, one spectrum analyzer might have a range from 0hz to 100khz in 64 usec increments. ... and say -160 dB/Hz noise floor. 

 

So 20 to 20 kHz in what increments and what is the real noise floor?

 

So at say 100 MHz, signal might be down mixed and then frequency intervals are 64 milliseconds 

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1 hour ago, plissken said:

 

Learn something new every day: Ni-Cads can be quieter than Cap-Resistor chains IN CERTAIN applications. 

 

Just wanted to make sure that was clearly stated. Interesting read, thanks. 

 

Yes! ... and it isn't always immediately obvious what the "best" soln is... batteries are like a huge cap with high ESR ... one can follow the batts with a supercap, followed by a faster and faster cap to reduce effective ESR but if not done the right way the chain can introduce more noise. There are active circuits that can smooth noise as well.

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4 hours ago, plissken said:

 

What do you call the 60/120/180 etc sprurie? Why is it 60 Hz? 

 

When is 60/120/180 fundamental and even/odd harmonics not AC leakage or capacitance of some kind? Does the LPS1 prevent AC loop?

What is your interpretation of this?

 

 

 

Low bandwidth lps1 with Meanwell Supply.png

Low bandwidth with Linear Supply.png

 

Hmm...

 

I would try:

 

1) use a battery alone (without meanwell)

2) use a battery and plug the meanwell into something else

3) xformer isolate the spectrum analyzer

etc...

a) not enough info to draw firm conclusions,

b) big point: that leakage current is not typically just at the fundamental AC frequency rather higher frequencies generated by the switching circuitry.

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5 minutes ago, jabbr said:

 

Hmm...

 

I would try:

 

1) use a battery alone (without meanwell)

2) use a battery and plug the meanwell into something else

3) xformer isolate the spectrum analyzer

etc...

a) not enough info to draw firm conclusions,

b) big point: that leakage current is not typically just at the fundamental AC frequency rather higher frequencies generated by the switching circuitry.

 

There are only a few possibilities for leakage.

 

1. Through ISO-R

2. Through the common, in-the-wall wiring and ground

3. Through the air, RF/EMI

4. Through the AP power supply: this was already disproved

 

I asked Amir to redo the test with AP and ISO-R on independent circuits (one on a battery/UPS) to eliminate #2. He didn't think this kind of leakage was possible. Still looks possible to me, although not likely.

 

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15 minutes ago, pkane2001 said:

 

There are only a few possibilities for leakage.

 

1. Through ISO-R

2. Through the common, in-the-wall wiring and ground

3. Through the air, RF/EMI

4. Through the AP power supply: this was already disproved

 

I asked Amir to redo the test with AP and ISO-R on independent circuits (one on a battery/UPS) to eliminate #2. He didn't think this kind of leakage was possible. Still looks possible to me, although not likely.

 

What is your definition of "leakage" and how are you measuring it? I've asked for a schematic. Simply measuring the output of a DAC is not measuring the leakage current.

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1 minute ago, jabbr said:

What is your definition of "leakage" and how are you measuring it? I've asked for a schematic. Simply measuring the output of a DAC is not measuring the leakage current.

 

I didn't measure this. Amir did. He measured ISO-R powered by LPS-1, powered by MeanWell SMPS into a USB-powered DAC. He posted AP-generated power spectrum showing AC fundamental and harmonics at the output of the DAC. The fundamental was about 20dB above noise floor. When MeanWell was replaced with a lab linear power supply, these frequencies disappeared from the DAC output. You'll find a lot more details on the ASR thread, no reason to duplicate it here.

 

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1 minute ago, pkane2001 said:

 

I didn't measure this. Amir did. He measured ISO-R powered by LPS-1, powered by MeanWell SMPS into a USB-powered DAC. He posted AP-generated power spectrum showing AC fundamental and harmonics at the output of the DAC. The fundamental was about 20dB above noise floor. When MeanWell was replaced with a lab linear power supply, these frequencies disappeared from the DAC output. You'll find a lot more details on the ASR thread, no reason to duplicate it here.

 

 

Well the graphs were posted here and you are talking about leakage here. If I wanted to participate in another discussion somewhere else I could and would. Some measurements were made but we have no reason beyond hand waving to determine that these are leakage currents. There are well known ways to analyze and measure leakage currents heck there are even standards that discuss this. It isn't good form to draw conclusions about things that aren't being measured, but who knows? Why would you draw conclusions about leakage currents when you are simply measuring DAC output? I mean thats more appropriately PSRR (I am assuming with the very little info I have). PSRR and leakage current are two different things.

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2 minutes ago, jabbr said:

 

Well the graphs were posted here and you are talking about leakage here. If I wanted to participate in another discussion somewhere else I could and would. Some measurements were made but we have no reason beyond hand waving to determine that these are leakage currents. There are well known ways to analyze and measure leakage currents heck there are even standards that discuss this. It isn't good form to draw conclusions about things that aren't being measured, but who knows? Why would you draw conclusions about leakage currents when you are simply measuring DAC output? I mean thats more appropriately PSRR (I am assuming with the very little info I have). PSRR and leakage current are two different things.

 

How about you read the ASR thread, and then come back here so we can discuss your questions. It makes no sense for me to duplicate everything that's been tested and reported there. It's multiple pages of posts and contains many tests and multiple measurements.

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1 minute ago, jabbr said:

I think the Meanwell issue is not that interesting actually and am wondering why this issue is still being discussed???

 

It's interesting because LPS-1 is sold with MeanWell SMPS. And because LPS-1 is claimed to eliminate all AC leakage currents and ground loops. Having AC frequency and harmonics introduced into the DAC output that didn't have them without these Uptone Audio products is, in my opinion, an important thing to know for someone considering their purchase (as I was).

 

Quote

*The LPS-1 completely blocks the path of AC leakage currents from entering into the portion of your audio system it is connected to. This is a complex and not broadly understood area, but our research—and likely some of your own component listening experiments—proves that reducing leakage currents and loops is one of the most important final steps to improving audio system performance.

 

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1 hour ago, jabbr said:

 

I'm not really that interested. It is well known that SMPS like the meanwell can induce leakage circuits in equipment plugged into the same AC circuit. I fully trust that @JohnSwenson designed a perfectly excellent floating supercap supply. I have many many times recommended that the analogue audio circuitry be isolated (I personally use both Topaz low leakage cap as well as the Equitech Q behind my best stuff). I also use Plitron transformers in the linear PSU's I've built. I go encourage folks to go out and get some NiCad batteries and use them when convenient.

 

I think the Meanwell issue is not that interesting actually and am wondering why this issue is still being discussed???

Agreed - very off topic already.. I have 2 LPS-1's and power both with separate 5A TeraDak 9V LPS.. easy.. no cheap switching PS in my stereo room..

 

My GUESS is that the JK battery PS unregulated version is using some type of "trickle-charging" method to hold the output voltage stable while the batteries discharge... not sure.. but he has offered this type of idea previously to improve the original Regen and was very well received from the folks I read who tried it.  Would multiple battery cells need to use some type of balanced charging system?

 

Another comment - I have had other (kind of DIY style) battery supplies that sounded great (perhaps preferred in my system to the LPS-1), but they proved unstable and twice I had problems with cells overheating (once when I inserted a cell reversed polarity).. so to me a safe, plug and play, usable battery PS that could be preferable sound-wise in some systems to a regulated supercaps PS would have some value.

 

 

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22 minutes ago, jabbr said:

Again what does this have to do with battery supplies? and the point has been made over and over in other threads ... why the perseveration?

 

Beats me. You were responding to a post regarding LPS-1 reported leakage with a set of questions. I obliged with a description you were seeking. If these questions were rhetorical, then I missed that memo, but I certainly wasn't the one that started down this path.

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3 minutes ago, motberg said:

My GUESS is that the JK battery PS unregulated version is using some type of "trickle-charging" method to hold the output voltage stable while the batteries discharge... not sure.. but he has offered this type of idea previously to improve the original Regen and was very well received from the folks I read who tried it.  Would multiple battery cells need to use some type of balanced charging system?

 

1) the trickle charger when left "connected" can transmit leakage current 

2) its recommended to use a balancing circuit with multiple cells -- can be tricky to charge and drain at the same time

 

3 minutes ago, motberg said:

 

Another comment - I have had other (kind of DIY style) battery supplies that sounded great (perhaps preferred in my system to the LPS-1), but they proved unstable and twice I had problems with cells overheating (once when I inserted a cell reversed polarity).. so to me a safe, plug and play, usable battery PS that could be preferable sound-wise in some systems to a regulated supercaps PS would have some value.

 

 

You can either use a switch to switch between charge and drain mode *or* dual bank battery supply -- see DIYAudio -- the LPS-1 is available and reasonably priced for what it does.

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Just now, Superdad said:

 

Gee, you are welcome. :)

 

Things (and people) are often more complicated than they seem.  I'd say my father taught me that, but the truth is, like most of us, I had to find out the hard way! :P  

 

I do a lot of product research because our business depends on the specs the servers, storage arrays, routing and switching fabric metrics, load balancing throughput, SSL / TLS encrypt/decrypt speeds.

 

You are providing a very technical product but you've provided very little to go on other than conjecture. Hopefully this will start changing. 

 

I'll await Amir's response. 

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