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2 hours ago, barrows said:

An internal power supply is better than an external supply, given that the supplies in question are of the same quality.  DC does not like to travel distances, and the added L, C, & R of sending DC power over a cable between boxes reduces performance.

This is especially true for digital or high speed circuits of any kind, a clock source running at 10 MHz is certainly a high speed circuit.  The problem is that power supply impedance increases over distance, and digital circuits perform best with the lowest possible power supply impedance.  

Less boxes is often better.

 

Not necessarily. Big PSUs near sensitive clocks and other devices can have a negative effect and is why MSB, Naim, DCS and Esoteric either have a separate PSU box or a separate clock-box in their SOTA DACs.

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23 hours ago, barrows said:

Well sure, if you do a poor internal layout and put the supply too near to critical components it can be a problem, but this is a part of good engineering and layout practices.  A poor design is a poor design, and using an external supply to overcome a poor design is not the best approach. 

For line level components the power requirements of the supply are low, and such that radiating interference fields are very small, and can be accommodated inside a standard size chassis with appropriate layout, and perhaps a bit of shielding in some cases.

Separate power supply boxes offered by some manufacturers for line level components are usually an unnecessary added expense (and allow for much additional revenue to the manufacturer).

 

And it is ALWAYS (necessarily) true that distributing DC power over a cable is a poor compromise.

 

Seriously you are saying that MSB, Naim, Audio Research, VAC and others that are using an external supply has poor design, that’s laughable.

 

Why is distributing DC power over a cable a poor compromise?

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14 hours ago, barrows said:

Because the distance over the cable increases impedance.  Low power supply impedance is critical for most circuits in audio, but for digital anything it is especially important, as digital circuitry grabs current in chunks at very high speeds.

It is important to get the power to the circuits with the least impedance possible, hence the use of very good regulators in some power supplies, and large amounts of capacitance, and big transformers, etc, etc...  But a lot of that power supply optimization goes to waste if one raises the impedance of the power supply by asking it to travel through additional connections (DC barrel connectors are especially poor) and wiring distance.

 

Yes a longer cable have a higher impedance than a short cable, if everything else is held the same. But it’s not only the length that determines impedance/electrical resistance. The gauge (thickness) of the wire and the wire material and the material’s purity is of equal importance. A wire is a conductor with electrical resistivity that cannot lower and only increase the electrical resistance so it’s paramount to have as low impedance as possible at the output of the power supply, no matter if the PSU is internal or external.

 

I think company’s like Pass labs, MSB, Naim, Audio Research, VAC and many more that use an external box for their power supplies know very well how things like the length, gauge, wire material and the material’s purity effect performance and SQ. That those, by many considered the best of the best high end manufacturer, would use external power supplies in their top gear if it result in poorer sound is highly unlikely. Have you never heard a MSB Analogue with or without an external PSU? The difference is profound. The same is IMO evident with many other audio gear and not only the very expansive ones.  

 

Let’s be real, the length of the DC cable matters and should be kept as short as possible. The length of the DC cable that most High End companies use is not very long and is normally not longer than 1,5 meter. Their cables are thick and are made of good material to not increase impedance more than absolutely necessary. They of course know Ohm's law and have tested with or without placing the PSUs in the same box as their DAC or preamp and have come to the conclusion that the gain of having the PSUs in a separate box is higher than the small loss of a bit longer DC cable. The electrical resistance is only one factor that a High End manufacturer has to take in to account than it’s comes to design their PSUs. To have separate PSUs for different circuits is often considered very important if seeking to get best sound. To have a separate PSU for digital and another for analogue is common as is to have one PSU for left and right canal. BUT with more PSUs that radiate EMC/EMI and cause vibration etc etc, and the better and more delicate clocks and other circuits one use, the more important it is to keep the PSUs away.

 

Am I saying that DACs that that has internal PSUs are sounding bad? Absolutely not, am not talking in absolute and my DAC for example has 3 internal PSUs (while not in a separate enclosure are kept separated to the digital and analogue circuits by internal walls).    

 

BTW look up Rob Watts explanation to why he don't want to put a M-scaler in DAVE.

 

http://www.daycounter.com/Calculators/AWG.phtml

https://www.cirris.com/learning-center/calculators/133-wire-resistance-calculator-table 

 

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18 minutes ago, barrows said:

You might be interested in taking a look at the Stereophile review of the Analog DAC, and pay particular attention to JA's findings that when stacked on the power supply box (as it is designed to do), the transformers in the power supply coupled into the DAC box and produced power supply artifacts in the analog output.

Of course these companies know what they are dong, for the most part, but the fact that they know what they are doing does not mean they produce external supplies for improved performance rather than improved revenue.

 

For every high end component which one might use an example of a high performance component with an external supply, I can reference another component of equal or better performance which uses an internal supply.  It is clear that external supplies are certainly not necessary to achieve SOTA performance in line level components (with the possible exception of high gain phono stages, but that is a separate concern). 

 

Ultimately, my position is that external power supplies are an unnecessary additional expense, and do not improve performance (and may actually hurt performance RE impedance) vs. a well engineered component with an internal supply (again, possibly excepting phono stages as they are a very special case).

 

If stacking (the aluminum milled) power supply box on top of the DAC result in artifacts in the analog output. Just imagine the result if the same power supplies had been inside the DAC box O.o

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2 hours ago, barrows said:

Wrong: It is all about the layout.  The way MSB laid it out, the transformers were very close to the critical circuitry when the boxes were stacked, actually closer than they could be if they were in the same box!  Remember, relatively thin aluminum (under an inch thick) has virtually no magnetic shielding ability, so the box itself does very little.  This is pretty simple engineering here.  When dealing with transformer based noise issues, one must understand the radiation fields for the flux lines, and then lay things out accordingly.  

 

It’s not wrong, the only thing that’s wrong is your understanding of what a separate power supply is and how it should be placed for best performance. Only because it’s POSSIBLE to stacking a power supply box on top of the DAC doesn’t mean that’s the BEST WAY of doing it. It similar to a matching preamp and power amp. They can be stacked on top of each other, but that’s not the way to get the best out of them. Or an ultraRendu which can be placed near a computer but it’s not as good as placing it in another room on a different AC line. Sure you get most of the improvements of the uR, but are not using the designs full potential and the same is true of the use of a separate power supply very close to a DAC or amp.

 

JA didn’t say that the MSB power supply was poor he said “the DAC sat atop the Power Base for the measurements—this lay at –120dB (0.0001%) and will be irrelevant to sound quality. No spuriae were present at the full-wave–rectified power-supply frequency of 120Hz, indicating superb internal grounding and optimal circuit layout.” And finished by saying “It was a pleasure to measure such a good-performing product as MSB's Analog DAC. And I loved the top-mounted volume control, the display, and the ergonomics. It is rare to encounter an audio component so well thought out and so well engineered.—John Atkinson

 

You are IMO giving many conflicting statements all depending on what you have and your bias; things like a LAN input is no good in a DAC because it will need a transformer which radiate a lot of noise, but are not accepting that power supply can be placed in a separate box and its pros. You totally dismiss the benefit of a preamp. I would have expect that someone that design power supplies to understand the pro and cons of using a separate power supply and to know why many manufacturer of High End gear chose to put their PSU in a separate box, but I was obviously mistaking.  

 

https://www.stereophile.com/content/msb-technology-analog-dac-da-converter-and-analog-power-base-power-supply-measurements#L8OuDJYb4wKkOaCo.99 

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1 hour ago, Ralf11 said:

 

so... we want the P/S close to reduce impedance in the cable

 

but... we want the P/S far away to minimize noise...

 

A short well done DC cable of 1-2 meter is not as sensitive like a clock cable for example and a good DC cable are not increasing impedance or electrical resistance in any meaningful ways.

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15 minutes ago, barrows said:

@Summit, i suspect that you need to up your reading comprehension my friend, I never said:

 

"LAN input is no good in a DAC"

 

Yes, you are "obviously mistaking" ,

 

Given that it appears that english may be your second language I will give you a pass here.

 

To be clear:

 

Yes, a preamp is redundant in a digital only system and can only add noise and distortion.

 

LAN input in a DAC can be good, but only if it is implemented very well, and in most current implementations this is not the case.

 

MSB designed the Analog DAC and its power supply to stack, and in this they made an error as is clearly shown in JA's measurements, otherwise there is nothing wrong with design which I am aware of and I did not say that there was.

 

Additionally, I have no bias, I have direct experience.

 

My reading comprehension is okay. JA didn’t say that the MSB power supply was poor he said the opposite and this with the DAC  on top of the PSU.

 

 “the DAC sat atop the Power Base for the measurements—this lay at –120dB (0.0001%) and will be irrelevant to sound quality. No spuriae were present at the full-wave–rectified power-supply frequency of 120Hz, indicating superb internal grounding and optimal circuit layout.”

 

“It was a pleasure to measure such a good-performing product as MSB's Analog DAC. And I loved the top-mounted volume control, the display, and the ergonomics. It is rare to encounter an audio component so well thought out and so well engineered.—John Atkinson”

 

If someone is always promoting what he/she have or make, in my book its bias.

 

https://www.stereophile.com/content/msb-technology-analog-dac-da-converter-and-analog-power-base-power-supply-measurements#L8OuDJYb4wKkOaCo.99

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