Rectifier tube put on a fireworks show...

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Steve

Re: Rectifier tube put on a fireworks show...
« Reply #40 on: 25 Aug 2011, 12:57 am »
Steve,  I respect your opinion but marketing hype would imply he advertises and pushes the extra capacitance as something special that makes it unique compared to other DACs.  Mine just came with it.  He didnt make anything special of this extra capacitance.  I didn't know about until I bought the unit.  Like I said, he's a low key guy.  He doesn't have any extensive white sheet on his technology.  I dont know why it works, but the extra capacitance in the digital section does make an audible difference so I know it not some baseless marketing hype.  Unless you've tried it yourself, why dismiss the idea?

Sorry I was not clear Drracule1. I see John gave the reason before I could reply. My comment about the 50 lb transformers was an analog equivalent. A good design just doesn't need that much huge  capacitance unless digital is crosstalking into the analog section, some other interaction between digital stages etc. I think it depends upon how the power supply is designed and the "stages"/sections the power supply drives.

I have a player where they use two 3 terminal regulators in series to derive a rail voltage. A different philosophy to be sure, and much less expensive. Maybe the capacitors do a better job? Maybe so, but it puts alot of strain on the rectifiers/transformers as well, especially during initial conditions.

The analogy of the 50lb transformer per channel works because one can design a better sounding preamplifier using a very small power transformer. The 50lb tranny, and super high capacitance filter section is an attempt to cover a, or multiple weaknesses in the preamplifier design. This can be accomplished because of class A operation and low current draw. If it was a typical amplifier, especially class AB or worst case B, then a high power transformer would be necessary.

A huge transformer and inferior design results in a much higher cost  than it needs to be, with no benefit. A superior design, with smaller power transformer, imo, is real value for superior sound.

Hope this helps.

Cheers.

ps. Sorry I had to edit my post a couple of times.

Dracule1

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Re: Rectifier tube put on a fireworks show...
« Reply #41 on: 25 Aug 2011, 02:00 am »
Steve thanks again for patiently explaining your points.  Makes sense to me although my knowledge in electronics is limited.  But can you explain why the extra capacitance in the digital section sounds better to me?  Your post suggests the capacitance is covering up some digital "nasties" (eg, cross talk) and "improving" the sound.  But why then does this DAC sound better than other DACs I've auditioned? Unless those other DACs have worse digital distortion.  By better I mean better macro/microdynamics, soundstaging/imaging, more accurate timbre of instruments, etc.

Steve

Re: Rectifier tube put on a fireworks show...
« Reply #42 on: 25 Aug 2011, 05:21 am »
Steve thanks again for patiently explaining your points.  Makes sense to me although my knowledge in electronics is limited.  But can you explain why the extra capacitance in the digital section sounds better to me?  Your post suggests the capacitance is covering up some digital "nasties" (eg, cross talk) and "improving" the sound.  But why then does this DAC sound better than other DACs I've auditioned? Unless those other DACs have worse digital distortion.  By better I mean better macro/microdynamics, soundstaging/imaging, more accurate timbre of instruments, etc.

Maybe some digital nasties were getting into the analog etc.

Or something is varying the Vcc voltage that drives the digital section. Maybe minimize hash, some extraneous garbage.

Cheers.

avahifi

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Re: Rectifier tube put on a fireworks show...
« Reply #43 on: 25 Aug 2011, 02:56 pm »
If you do some math, you can learn that a typical R/C power supply, even with loads of capacitors, has an output impedance at some frequencies of abut 800 ohms.  A shunt zener regulated power supply about 10 ohms, and a properly designed active regulated power supply about 1 ohm.  After you learn this, a rocket scientist can figure out that since drawing current from the power supply imparts a small clone of the audio signal in the wrong place in the circuit, and that since the size of the error signal will be proportional to the output impedance of the power supply, that the "lots and lots of capacitor approach only" supply design is rather futile.

If the circuit designer is not up to speed on power supply design, I would kinda wonder about just how innovative the whole thing is.

Regards,

Frank Van Alstine


Dracule1

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Re: Rectifier tube put on a fireworks show...
« Reply #44 on: 26 Aug 2011, 03:02 am »
Thank you Steve and Frank.  I will email the designer and ask what type of power supply (R/C, shunt zener regulated, or active regulated power supply) he has in the DAC. 

avahifi

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Re: Rectifier tube put on a fireworks show...
« Reply #45 on: 26 Aug 2011, 01:07 pm »
Remember that my thoughts above are just general guidelines.

A really well done R/C supply might outperform a ho hum active regulated supply.  Its as much in the details and the execution as it is in the actual basic design choice.

Remember too that the world's best power supply won't do all that much for a mundane audio circuit design.  It is necessary to get everything right at the same time, pretty difficult to do.

Regards,

Frank Van Alstine

Dracule1

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Re: Rectifier tube put on a fireworks show...
« Reply #46 on: 4 Sep 2011, 05:43 am »
Apparently there are multiple different power supplies in this DAC.   I mistakenly assumed there was only one for the digital section and one for the analogue section.  So I can't assume all those capacitance belongs to just one power supply.  He designed the digital power supplies to be fast and analogue to be low noise.  Hard to get more out of him due to language barrier and possibly proprietary design.
« Last Edit: 6 Sep 2011, 01:26 am by Dracule1 »