Vintage/Current R2R DAC Owners Discussion, Insight, and Review Thread
Dec 29, 2017 at 12:07 PM Post #1,036 of 1,111
Hi Articnoise,

I appreciate your congratulations on our Mystique DACs, but you have a few things confused: it was our last gen tube DACs that won "Best Sound Value" and "Silver Sound."

Our new Mystique v3 direct-coupled DAC is the one that keeps winning "Best Sound" (cost no object) and "Best in Show."

So it is our direct-coupled not our tube DACs that are getting the highest praises as opposed to an honorable mention.

As for my "totally stupid" comment, that may have been a bit extreme and certainly taken out of context. Remember this whole topic started with a person asking about the PCM1704 K DAC chips. So my "totally stupid" comment was more directed toward the concept of obsessing over the K series DAC chip and simultaneously talking about putting the K chip in a tube DAC/pre amp. Fact is you couldn't hear the difference between the standard and the K series PCM1704 in most tube DACs due to the tube noise.

So let me retract my "totally stupid" comment and change it to "any tube DAC/pre amp is a compromise."

BTW, using the term "state-of-the-art" (SOTA) in regards to any R-2R tube DAC is sort of an oxymoron. Most of the R-2R DAC chips we're talking about are over 30 years old and the tube stages are more like 70-90 years old. SOTA in DACs would be 32-bit Delta Sigma DAC chips and these custom FPGA DACs. The R-2R tube DACs we're discussing would more accurately be labeled as "vintage."

And "less is more" sounds more like marketing mumbo-jumbo or Eastern philosophy than a technical fact. By that "less is more" theory the best sounding systems would be an all-in-one server/DAC/pre/amp, such as the entry level products by Naim and Linn. Fact is these multi-device in one chassis components are more "lifestyle" products then "high-end audiophile" products. And any DAC/pre amp is one step in that direction. If it were not true that all these "multi" products were a compromise, then the same companies that make all-in-one components would not be making more expensive higher performance separates. Once again I'm quite surprised that some of you are even debating this point.

Note that a volume control in a DAC is not "amplifying" (making louder) but rather "attenuating" (making quieter). That means you are sending a lower voltage signal down the interconnects. And that means that you now have a higher signal-to-noise ratio. That would mean the optimal place to attenuate the volume in a digital system would be the amplifier (last stage) as opposed to the DAC (first stage). This is why I'm a big fan of integrated amps. And this is why putting a pre amp and amp in one chassis makes sense where as putting a pre amp and DAC in one chassis does not make sense. Once again, it all comes down to the same dirty word: NOISE.

Please don't be offended by this Articnoise, but the fact you are asking the question "why would an analogue tube stage need to be bigger than an analogue SS stage" tells me you have little understanding of how these components actually work.

To begin with, any tube stage would require at least two additional power supplies: one for the tube's B+ and one for tube's filaments.

And since the B+ for tubes is usually a much higher voltage than required for SS, and since the current for the tube filaments is much higher than required for SS, these two additional power supplies for the tube stage in a DAC are usually larger than the SS power supplies. So you have to relatively double the size and complexity of the power supplies in a DAC if you are adding a tube output stage. And that's not even considering really good tube power supplies that would have Pi or double-Pi choke filtering, each choke often being larger than an entire SS power supply.

Then aside from the tubes themselves that are relatively quite large, tubes require an output coupling device, such as large capacitors or transformers that SS does not require. So all this theorizing earlier in this thread about how linear tubes are vs SS doesn't take into account the distortion from the caps or transformers required at the output of most tube stages. Even the best-of-the-best of caps and transformers measurably distort time, tune, tone, and timbre, and have a measurable sonic signature.

And lastly because of the significantly higher EMI from the tube power supply, a tube DAC would need to have more of a physical distance between noisy and sensitive component parts and/or additional shielding between noisy and sensitive component parts.

So in the end, a tube DAC of relatively the same digital circuitry as a SS DAC would have to be something like twice the size and would have to cost something like twice as much to account for all the additional circuitry and shielding.

And I haven't even mentioned the size and cost of volume controls or other pre amp related component parts.

Here's a perspective some of you may not have considered...

All DACs are SS devices. No way around this unless you wanted to custom build an all tube DAC that would need a room full of racked tube gear in a climate controlled room as was used in the early tube-based computers.

And all modern recording studios are 100% SS as well. OK...there are some digital versions of vintage recordings that were made on pre-Dolby tube reel-to-reels, but after the analog masters are digitized, all the editing, mixing, and mastering gear in studios is SS.

So if you look at playing recordings of music with a perspective from the musician in front of a microphone to music coming out of your speakers/headphones as one process, all I'm stating is that the most advantageous place to switch from SS to tube circuitry or to attenuate the volume would be after the DAC. And my reasoning for this has to do with significant amounts of tube and attenuation related noise that mask significant amounts of resolution as well as distort time, tune, tone, and timbre.
 
Dec 30, 2017 at 7:47 AM Post #1,037 of 1,111
Hi Articnoise,

I appreciate your congratulations on our Mystique DACs, but you have a few things confused: it was our last gen tube DACs that won "Best Sound Value" and "Silver Sound."

Our new Mystique v3 direct-coupled DAC is the one that keeps winning "Best Sound" (cost no object) and "Best in Show."

So it is our direct-coupled not our tube DACs that are getting the highest praises as opposed to an honorable mention.

As for my "totally stupid" comment, that may have been a bit extreme and certainly taken out of context. Remember this whole topic started with a person asking about the PCM1704 K DAC chips. So my "totally stupid" comment was more directed toward the concept of obsessing over the K series DAC chip and simultaneously talking about putting the K chip in a tube DAC/pre amp. Fact is you couldn't hear the difference between the standard and the K series PCM1704 in most tube DACs due to the tube noise.

So let me retract my "totally stupid" comment and change it to "any tube DAC/pre amp is a compromise."

BTW, using the term "state-of-the-art" (SOTA) in regards to any R-2R tube DAC is sort of an oxymoron. Most of the R-2R DAC chips we're talking about are over 30 years old and the tube stages are more like 70-90 years old. SOTA in DACs would be 32-bit Delta Sigma DAC chips and these custom FPGA DACs. The R-2R tube DACs we're discussing would more accurately be labeled as "vintage."

And "less is more" sounds more like marketing mumbo-jumbo or Eastern philosophy than a technical fact. By that "less is more" theory the best sounding systems would be an all-in-one server/DAC/pre/amp, such as the entry level products by Naim and Linn. Fact is these multi-device in one chassis components are more "lifestyle" products then "high-end audiophile" products. And any DAC/pre amp is one step in that direction. If it were not true that all these "multi" products were a compromise, then the same companies that make all-in-one components would not be making more expensive higher performance separates. Once again I'm quite surprised that some of you are even debating this point.

Note that a volume control in a DAC is not "amplifying" (making louder) but rather "attenuating" (making quieter). That means you are sending a lower voltage signal down the interconnects. And that means that you now have a higher signal-to-noise ratio. That would mean the optimal place to attenuate the volume in a digital system would be the amplifier (last stage) as opposed to the DAC (first stage). This is why I'm a big fan of integrated amps. And this is why putting a pre amp and amp in one chassis makes sense where as putting a pre amp and DAC in one chassis does not make sense. Once again, it all comes down to the same dirty word: NOISE.

Please don't be offended by this Articnoise, but the fact you are asking the question "why would an analogue tube stage need to be bigger than an analogue SS stage" tells me you have little understanding of how these components actually work.

To begin with, any tube stage would require at least two additional power supplies: one for the tube's B+ and one for tube's filaments.

And since the B+ for tubes is usually a much higher voltage than required for SS, and since the current for the tube filaments is much higher than required for SS, these two additional power supplies for the tube stage in a DAC are usually larger than the SS power supplies. So you have to relatively double the size and complexity of the power supplies in a DAC if you are adding a tube output stage. And that's not even considering really good tube power supplies that would have Pi or double-Pi choke filtering, each choke often being larger than an entire SS power supply.

Then aside from the tubes themselves that are relatively quite large, tubes require an output coupling device, such as large capacitors or transformers that SS does not require. So all this theorizing earlier in this thread about how linear tubes are vs SS doesn't take into account the distortion from the caps or transformers required at the output of most tube stages. Even the best-of-the-best of caps and transformers measurably distort time, tune, tone, and timbre, and have a measurable sonic signature.

And lastly because of the significantly higher EMI from the tube power supply, a tube DAC would need to have more of a physical distance between noisy and sensitive component parts and/or additional shielding between noisy and sensitive component parts.

So in the end, a tube DAC of relatively the same digital circuitry as a SS DAC would have to be something like twice the size and would have to cost something like twice as much to account for all the additional circuitry and shielding.

And I haven't even mentioned the size and cost of volume controls or other pre amp related component parts.

Here's a perspective some of you may not have considered...

All DACs are SS devices. No way around this unless you wanted to custom build an all tube DAC that would need a room full of racked tube gear in a climate controlled room as was used in the early tube-based computers.

And all modern recording studios are 100% SS as well. OK...there are some digital versions of vintage recordings that were made on pre-Dolby tube reel-to-reels, but after the analog masters are digitized, all the editing, mixing, and mastering gear in studios is SS.

So if you look at playing recordings of music with a perspective from the musician in front of a microphone to music coming out of your speakers/headphones as one process, all I'm stating is that the most advantageous place to switch from SS to tube circuitry or to attenuate the volume would be after the DAC. And my reasoning for this has to do with significant amounts of tube and attenuation related noise that mask significant amounts of resolution as well as distort time, tune, tone, and timbre.

Okay let see. A lot of hand-waving and straw man arguments in your last post.

1. Aries Cerat Kassandra Ref2, AQUA La Scala MKII Optologic, Lampizator GG, Aesthetix Pandora Eclipse, Ayon Stealth are state-of-the-art products and not vintage.

2. Aries Cerat Kassandra Ref2, AQUA La Scala MKII Optologic, Lampizator GG, Aesthetix Pandora Eclipse, Ayon Stealth has succeed in putting tube stage in a DAC, so it’s really possible in one chassis. To try to deny it is kind of foolish IMO.

3. None of the DACs above are considered "lifestyle" products.

4. Linn Klimax DSM is one of the best DAC I have ever heard and is an all-in-one product so it’s possible to make excellent all-in-one products.

5. Tube preamplifier are not much bigger or heavier than solid state preamplifier. Audio Research Reference 5 SE has long been one of the best pre amp and weight 30.4 lbs. including chassis. You can compare weight and measurement of SS to tube pre and see for yourself – no correlation to tube or SS design.

https://www.stereophile.com/content/mark-levinson-no526-preamplifier-specifications

https://www.stereophile.com/content/mark-levinson-no526-preamplifier-specifications

https://www.stereophile.com/content/audio-research-reference-6-line-preamplifier-specifications

https://www.stereophile.com/content/audio-research-reference-5-se-line-preamplifier-specifications

https://www.stereophile.com/content/ear-912-preamplifier-specifications

6. Yes, good coupling capacitors are very important. I have upgraded my Aesthetix Pandora to an Aesthetix Pandora Eclipse and one of the upgrade was to replace the stock capacitors with Peter Moncrief’s Stealthcap™ capacitors – Big SQ improvement.

http://www.trt-wonder.com/page20.html

7. like I said before, I’m not saying what it’s better to place a pre or headphone amp in the same chassis as the DAC. It depends on total budget, design and implementation. You said you can reduce price by 50 % by placing them in the same chassis. So with a “limited” budget a combined pre and DAC can be better than buying a separate DAC and pre. Room and shelf space is another consideration.

8. That, less is more is absolutely not mumbo-jumbo. The reason companies that make “all-in-one products” also make more expensive higher performance separates are because people have different budget. For xxx USD it can be better to put a pre in a DAC or to build an integrated amp instead of a separate pre and power amp.

9. Its correct that a volume control "attenuating" work by making the signal quieter. And that means that we get a higher signal-to-noise ratio. Not denying that. But if the attenuating occurs in a standalone pre amp or in a combined DAC/pre is the same.

10. If you mean that all digital to analogue converter are SS devices I agree. But you know that it’s not the digital to analogue converter there the tube stage are placed. The tube is used instead of transistors and they have one sole purpose and it’s to amplify the audio signal.

11. The line stage, no matter if it’s a SS or tube will amplify the audio signal to the same level no matter if a pre is used or not. With a modern good DAC the amplification in the DAC is often sufficient to drive a power amp directly, so double amplifying will be the result if also using a pre amp.
 
Dec 30, 2017 at 9:56 AM Post #1,038 of 1,111
Hi Articnoise,

If you're perceiving anything less than fully supportable arguments on my part, it is only for the sake of brevity.

Facts are facts:

1. Tube stages in DACs require at least two more power supplies than SS.
2. Tube power supplies add quite a bit of noise to the inside of the DAC chassis.
3. Tube power supplies, and other tube stage related parts, are relatively large and relatively costly.

There is no electronics engineer that will deny any of the above statements.

The question is not if any of the above statements are true or false, the question is that despite the facts stated above, can a tube DAC/preamp be made that is to equal or better than a SS DAC with a nearly identical digital circuit?

The answer is "YES."

But the conditions are:

1. The tube DAC has to be significantly larger than the SS DAC.
2. The tube DAC has to cost significantly more than the SS DAC.

Then that brings up the next question:

if you used the same larger size chassis and the same higher parts cost to build a SS DAC with improved digital circuitry would it sound better than the above tube DAC?

The only ones of us that are qualified to answer the above question are those of us that are DIYers and have done the "apples to apples" comparisons with prototype DACs using identical digital circuits.

As for the rest of you, sorry to say, but you've not been making fair "apples to apples" comparisons. You've been comparing two completely different DACs.

I'm one of those DIYers that have done those tests, and based on my prototyping, I believe that a direct-coupled DAC performs significantly better than a DAC with a tube-based output stage.

Is there anyone else on this thread that has compared identical DAC circuits with direct-coupled vs tube output stages?

Please chime in.

Even if there aren't any DIYers on this thread that have done similar tests, apparently I'm not the only engineer that's come to that conclusion when comparing tube vs SS DAC. There are significantly more high-end SS audiophile DACs than tube DACs, and 100% of the modern pro audio DACs used in recording studios are SS. I believe that says quite a bit on its own.

Let me respond to Articnoise's numbered points....

1. The term "SOTA" refers to the latest and greatest modern technology. So though those DACs you listed may incorporate some SOTA technology (like modern DAC chips or FPGAs), the tube stages and R-2R DAC chips in them are most certainly vintage technology.
2. You can almost built a tube DAC that would fit inside a pack of cigarettes (Nixon DAC). The question is not "size and weight" but "RELATIVE size and weight" in which the tube DAC will always be significantly larger than a nearly identical SS DAC.
3. Agreed. When I was referring to "Lifestyle" products I was referring to products like the Linn and Naim. But all of those tube DACs you mentioned are large, heavy, and expensive. Some are so large and heavy it is hard for many people to even pick them up.
4. Agreed. I'm a big fan of Linn and Naim. Fact is that you've proven my point since both Linn and Naim consider their all-in-one products to be "Lifestyle" and "entry level" and both companies make significantly larger and more expensive separates (that are SS).
5. Total BS. When comparing "apples to apples" there is no way to make a tube DAC/preamp that is close to the same size as a nearly identical SS DAC. As a matter of fact, several companies that make high-end pre amps sell tiny DAC modules that fit inside them.
6. And how big were these caps? And how much did these caps cost? So once again, you're supporting my points.
7. I'm am not stating "don't put things in the same chassis to save space and $$$" but rather that the place to do this for optimal performance, minimum size, and minimum cost, would be to have the source (DAC) separate and to combine the pre amp and amplifier in one chassis.
8. Agreed. But you are still supporting my points: tube DAC/pre amps and all-in-one "Lifestyle" products are a COMPROMISE as opposed to the ultimate solution in terms of performance.
9. I'm not advocating redundant amplification stages. I'm advocating separate SS DACs outputting full volume/voltage to travel down the cables. And I'm advocating combining pre amps and amplifiers with the attenuation to save space and $$$. And my reasoning for this is noise.
10. Agreed. But I am stating that the added noise from the tube stage inside the DAC chassis causes a reduction in performance that can not be reclaimed at any place later in the signal path. What is lost in the source is lost forever.
11. That would be somewhat correct if all things were equal, but they are not. And you are once again supporting my points: most DAC/pre amps can "adequately" drive amplifiers, but don't "ultimately" drive amplifiers. They are a compromise of space and/or $$$.

I hope the above clarifies some of what I've been trying to express.

But I don't want to spark a "holy war" on tube vs SS DACs.

And I don't want to keep debating and restating these same points over and over.

If you love your tube DAC or your DAC/pre amp GREAT. I'm happy that you have gear you love.

That doesn't mean there is no SS DAC or different amplification topology that you wouldn't love just as much or more. It only means you haven't heard those components yet.

Please don't be closed minded as I was for so many years thinking that only tube gear can sound musical (yes, I used to believe that).

So I invite any and all of you to hear our exhibit at an audiophile show and to hear first hand just what I'm talking about.

After you hear our SS DAC and DHT tube pre/headphone amp combo I would be interested in knowing if you still miss your tube DAC.

And I'll be loaning one of our direct-coupled Mystique v3 DACs to Wildcatsare1 (the guy that started this thread) next month, and you can all ask him how it sounds compared to his PCM63 tube DAC :ksc75smile:
 
Dec 30, 2017 at 10:35 AM Post #1,039 of 1,111
Hello,

Which one is the coupling capacitor on this circuit ? Also are these PSUs enough to seperate DGND and AGND? What happend to use higher values inductors instead of 4.7uH, like 1H?

limin_dac_4390sch.jpg
 

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Dec 30, 2017 at 11:39 AM Post #1,040 of 1,111
Hi Yildiray,

The catch up the rest of you, Yildiray and I have been discussing schematics via PM.

I'm kind of surprised this is not a PM, but since some of you may also want answers to those questions, here it goes.

1. There is no "coupling cap" in this schematic. This is a perfect example of a direct-coupled SS DAC circuit like the ones I've been comparing to tube DACs.
2. There are two independent power supplies in this circuit: one for digital and one for analog. That is as separate as you can get for your grounds.
3. Higher inductor values is not ever recommended on its own. PSU circuits are "tuned" with specific ratios between inductance and capacitance. You would need to change both inductor and capacitor values.

I'm also kind of surprised that Yildiray sent this schematic.

A very odd schematic indeed:

The CS4390 is an early 24-bit Delta Sigma DAC chip with built in variable digital filtering and voltage output. It also looks like it doesn't decode above 48KHz and it has special features for 32KHz (how odd).

And the S/PDIF receiver in this schematic is a CS8412, which also appears to be optimized for 32KHz, 44.1KHz, and 48KHz, just like the CS4390.

That all tells me that this is a very early Delta Sigma single-bit DAC design.

Another thing to note about this schematic is that though it uses chokes in the power supply (big plus), they are configured in what is called a "Pi" filter (CLC) with a capacitor input after the bridge rectifier.

The PSU circuit Yildiray last showed me through PM was a superior choke input circuit similar to what I use in my Mystique v3 DAC.

I hope some of you found this helpful.
 
Dec 30, 2017 at 12:40 PM Post #1,041 of 1,111
Hi Yildiray,

The catch up the rest of you, Yildiray and I have been discussing schematics via PM.

I'm kind of surprised this is not a PM, but since some of you may also want answers to those questions, here it goes.

1. There is no "coupling cap" in this schematic. This is a perfect example of a direct-coupled SS DAC circuit like the ones I've been comparing to tube DACs.
2. There are two independent power supplies in this circuit: one for digital and one for analog. That is as separate as you can get for your grounds.
3. Higher inductor values is not ever recommended on its own. PSU circuits are "tuned" with specific ratios between inductance and capacitance. You would need to change both inductor and capacitor values.

I'm also kind of surprised that Yildiray sent this schematic.

A very odd schematic indeed:

The CS4390 is an early 24-bit Delta Sigma DAC chip with built in variable digital filtering and voltage output. It also looks like it doesn't decode above 48KHz and it has special features for 32KHz (how odd).

And the S/PDIF receiver in this schematic is a CS8412, which also appears to be optimized for 32KHz, 44.1KHz, and 48KHz, just like the CS4390.

That all tells me that this is a very early Delta Sigma single-bit DAC design.

Another thing to note about this schematic is that though it uses chokes in the power supply (big plus), they are configured in what is called a "Pi" filter (CLC) with a capacitor input after the bridge rectifier.

The PSU circuit Yildiray last showed me through PM was a superior choke input circuit similar to what I use in my Mystique v3 DAC.

I hope some of you found this helpful.

Hi again ,

I want to say thank you Benjamin.You are very helpful and i learned many things from Benjamin also most of suggestions makes sense to me.When i saw the messages about coupling cap from you and Articnoise i wanted to write here.I want to understand which cap it is.I will decide to components for PCM63 and PCM1704 DACs according to the your answers.The circuit which i add just i want to show the power stages.I'm not interested with dac chip.I also try to understand of grounding and inductors roles in psu.Mystique v3 DAC has higher values chokes from 47uH and i still don't understand where is your hammonds in this circuit if they don't instead of 47uH?
 
Dec 30, 2017 at 2:13 PM Post #1,042 of 1,111
Good questions Yildiray.

The best performing linear power supply circuit is called a "choke input." In this type of circuit the choke is placed between the output from the bridge rectifier and the input to the first capacitor.

The reason choke input is the best performing power supply circuit is that the input choke literally cuts 50% off the peaks of the crests coming from the bridge rectifier. That means the choke literally did half the work of all the other components in the power supply. And that results in other components in the power supply, such as regulators, having to work half as hard, literally doubling their effectiveness. And a choke input power supply is more durable: it produces half the heat of a cap input power supply which significantly extends parts life.

But don't go running out to throw a choke in your DAC...

The DC voltage leaving a bridge rectifier in a cap input power supply is 1.414 times the input AC voltage.

The DC voltage leaving a bridge rectifier in a choke input power supply is .9 times the input AC voltage.

So you would need to change your power transformer(s) in order to convert a cap input power supply to a choke input power supply.

And that means the big area a choke input power supply loses in is efficiency.

Add size and cost of parts and now you know why few companies use choke input power supplies.

You'll find most choke input power supplies in high-end tube pre amps and amps.

The values of and relationships between the choke and capacitors of a choke input power supply are "tuned" to a specific non-critical resonance frequency and are directly dependent on the current and voltage the power supply is optimized for.

In other words, if you change the ICs in your signal path you may require a different choke for the input of your power supply.

To do the complex math on this type of stuff gives me a headache :triportsad:

Most of us need to use software to calculate the resonance frequency and optimal choke value for this type of power supply. Personally I use a Linux spreadsheet developed by my head tech Frank who is a @#$%ing math genius.

There are several free power supply calculators and circuit simulators you can find online. There are also a few power supply calculator programs that sell for a reasonable price (about $100) that you can purchase from some of the DIY audiophile websites.

I can't personally vouch for any of these power supply circuit simulators, but any one of them would be better than willy-nilly changing the values of the components in a tuned power supply, or keeping the same values in a power supply when you change your circuit.

Grounding is a very complex topic.

Digital and analog should each have isolated grounds from each other that only meet at one point.

In the case of a single rail power supplies, connect to the ground that comes off of each of their bridge rectifiers.

In the case of a dual rail single bridge, such as is used in the schematic Yildiray posted, you would connect to the first ground coming out of the two 47,000u capacitors that come directly after the bridge rectifier.

Then there are so many other grounds in a DAC it would take multiple pages of posts to discuss the relationships between digital ground, analog ground, chassis ground, and AC ground (not to mention shielding).

The important thing is that chassis and AC ground are connected and that all other grounds connect at one point close to their source.

AC grounds, DC grounds, chassis grounds, and signal grounds (digital and analog) can have any number of relationships. For example, in my Mystique v3 DAC we connect the grounds from the digital and analog power supplies as I mentioned above, but "float" the USB input power supply form the rest. This is to 100% galvanically isolate the USB input from the computer form the rest of the DAC. There is also a DC ground lift switch that allows audiophiles to "float" all the DC grounds from AC ground. Lifting DC ground from AC ground is very system dependent.
 
Dec 30, 2017 at 3:36 PM Post #1,043 of 1,111
...If you love your tube DAC or your DAC/pre amp GREAT. I'm happy that you have gear you love.

That doesn't mean there is no SS DAC or different amplification topology that you wouldn't love just as much or more. It only means you haven't heard those components yet.
...yes but...it's entirely possible that there isn't one they'd love as much/more given that 'sounds better' is a subjective construct.

What 'sounds better' to them is based on a variety of factors (both subjective and objective) which are different for each buyer.

That said, clearly some people will pay a lot of $$$$ for Dacs, Amps, even power cords ($1699????)
upload_2017-12-30_13-15-38.png
. FWIW, vendors that sell uber-expensive cords/cables/etc. are immediately suspect in my eyes.

For me, the higher value proposition, is to buy mid-level electronics and spend more $$$$ on a variety of headphones with different signatures and functionality...which allows me far greater enjoyment of my music library.

I take this approach after years of chasing the ghost of better equipment in the two channel world before realizing that it was a never-ending pursuit that detracted from the enjoyment of listening to great music.

Just one approach...that may/may not make sense for others.
 

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Dec 30, 2017 at 4:41 PM Post #1,044 of 1,111
Good questions Yildiray.

The best performing linear power supply circuit is called a "choke input." In this type of circuit the choke is placed between the output from the bridge rectifier and the input to the first capacitor.

The reason choke input is the best performing power supply circuit is that the input choke literally cuts 50% off the peaks of the crests coming from the bridge rectifier. That means the choke literally did half the work of all the other components in the power supply. And that results in other components in the power supply, such as regulators, having to work half as hard, literally doubling their effectiveness. And a choke input power supply is more durable: it produces half the heat of a cap input power supply which significantly extends parts life.

But don't go running out to throw a choke in your DAC...

The DC voltage leaving a bridge rectifier in a cap input power supply is 1.414 times the input AC voltage.

The DC voltage leaving a bridge rectifier in a choke input power supply is .9 times the input AC voltage.

So you would need to change your power transformer(s) in order to convert a cap input power supply to a choke input power supply.

And that means the big area a choke input power supply loses in is efficiency.

Add size and cost of parts and now you know why few companies use choke input power supplies.

You'll find most choke input power supplies in high-end tube pre amps and amps.

The values of and relationships between the choke and capacitors of a choke input power supply are "tuned" to a specific non-critical resonance frequency and are directly dependent on the current and voltage the power supply is optimized for.

In other words, if you change the ICs in your signal path you may require a different choke for the input of your power supply.

To do the complex math on this type of stuff gives me a headache :triportsad:

Most of us need to use software to calculate the resonance frequency and optimal choke value for this type of power supply. Personally I use a Linux spreadsheet developed by my head tech Frank who is a @#$%ing math genius.

There are several free power supply calculators and circuit simulators you can find online. There are also a few power supply calculator programs that sell for a reasonable price (about $100) that you can purchase from some of the DIY audiophile websites.

I can't personally vouch for any of these power supply circuit simulators, but any one of them would be better than willy-nilly changing the values of the components in a tuned power supply, or keeping the same values in a power supply when you change your circuit.

Grounding is a very complex topic.

Digital and analog should each have isolated grounds from each other that only meet at one point.

In the case of a single rail power supplies, connect to the ground that comes off of each of their bridge rectifiers.

In the case of a dual rail single bridge, such as is used in the schematic Yildiray posted, you would connect to the first ground coming out of the two 47,000u capacitors that come directly after the bridge rectifier.

Then there are so many other grounds in a DAC it would take multiple pages of posts to discuss the relationships between digital ground, analog ground, chassis ground, and AC ground (not to mention shielding).

The important thing is that chassis and AC ground are connected and that all other grounds connect at one point close to their source.

AC grounds, DC grounds, chassis grounds, and signal grounds (digital and analog) can have any number of relationships. For example, in my Mystique v3 DAC we connect the grounds from the digital and analog power supplies as I mentioned above, but "float" the USB input power supply form the rest. This is to 100% galvanically isolate the USB input from the computer form the rest of the DAC. There is also a DC ground lift switch that allows audiophiles to "float" all the DC grounds from AC ground. Lifting DC ground from AC ground is very system dependent.

I got it now Benjamin.People who curious can see more detailed information here as a continuation of what you explained : http://education.lenardaudio.com/en/14_valve_amps_6.html

I can make custom MRI coil and tune it to 123Mhz with network analyzer.Your method similar like that but it seems to me complex for how calculate power supply.I guess will make directly power supply which i put at Post #1039

I ordered jlsound usb board.It have i galvanically isolate already.So do you suggest extra one more isolator ?
 
Dec 30, 2017 at 8:57 PM Post #1,045 of 1,111
Yes, I both suggest and use an isolated 5th power supply with the JL Sounds (or any other) USB board.

In the case of the JL Sounds there is one +5V input and one +5V output power on the other side of the galvanic signal isolation.

Ideally you would want to put the 5th isolated power supply on the input side of the galvanic isolation on the JL Sounds (or any other) USB board.

And do not connect the ground from that 5th power supply to any other ground or it will bypass the galvanic isolation by polluting the ground plane of the entire DAC with the switch-mode power supply hash coming from the computer at the other end of the USB cable.
 
Dec 30, 2017 at 9:19 PM Post #1,046 of 1,111
GearMe, there is not one word you wrote that I disagree with.

All I'm trying to do is drop a bit of wisdom on this thread that will allow any of you that are receptive to wade through marketing jargon and audiophile myth and legend so each of you can make more informed decisions with future purchases.

It doesn't matter if your budget is $1,000 or $10,000 or $100,000 - all the same laws of physics apply.

And there is no way around the laws of physics in the scenario of a DAC/pre amp feeding a power amp vs. a fixed output DAC feeding an integrated amp.

All things being equal, if relatively identical circuits and identical quality parts were used (be they tube or SS), the fixed output DAC feeding an integrated amp will always sound better.

Anyone that understands the application of Ohm's Law will confirm that you will have lower noise by feeding the higher voltage/volume signal through the cable and attenuating once the signal is inside of the amplifier. Period. There is no way around this. There is no engineer working for any company that will dispute this. And the only reason companies do things differently is because uninformed consumers request something different.

The same type of baseless marketing happened to the auto market with soccer moms buying off-road optimized SUVs.

There are all-wheel-drive family utility vehicles, more like station wagons, with equal seating, nearly the same cargo capacity, and much higher performance.

These inner city optimized vehicles have better acceleration, better braking, better cornering, more extreme condition stability, better safety, and better fuel economy than an SUV.

But that never stopped soccer moms from buying lower performing, less safe, gas-guzzling, off-road optimized SUVs in droves.

The same thing is true with pre amps built into DACs: performance wise they are known to be inferior even by the engineers that designed them but since the market demands them companies manufacture and sell them. Purely a marketing phenomenon.

Anyone in the mood to debate the validity of Ohm's Law with me?
 
Dec 30, 2017 at 9:21 PM Post #1,047 of 1,111
And BTW, this is a headphone thread.

And every headphone amp I know of has a built in attenuator.

So any of you that buy a DAC/pre amp to use with a headphone amp paid extra for additional redundant features in your DAC that lower its performance.
 
Jan 1, 2018 at 11:21 AM Post #1,048 of 1,111
Not to derail the current discussion, but wanted to drop a line in about my experience with R2R/NOS DACs.

In the last 6 months or so, I've switched almost exclusively to R2R designs. The first time I laid ears on one, the natural presentation and 'ease' of the sound was something that I couldn't get enough of. If memory serves, the first ladder DAC I owned was the Denafrips Ares, an excellent new-production model in it's own right. Shortly thereafter, I auditioned and ended up purchasing @Luckbad's modified Atlantis from MHDT. It checked all the boxes, with the only pseudo-shortcoming being a somewhat collapsed soundstage. Shortly after that I scored a great deal on the 1704-equipped Pagoda from MHDT and while it seemed to solve the soundstage issue, I just didn't fall into the music as easily as I did with the AD-equipped Atlantis.

Here's where things get interesting (probably to the chagrin of some readers). On a whim, I picked up the new R2R-11 from Audio gd, a DAC/amp combo unit that uses an in-house designed R2R module. I've generally been a fan of AGD stuff as it always seems to be very well-built, versatile, and not massively overpriced. Here's what happened after I took delivery of that bad boy. After nights and nights of A/B testing between it and my Atlantis/MAD Ear desktop rig, I concluded that the R2R-11 got me at least 80% of the way to the big rig. Not to mention it had a better USB module, and a much heartier headamp.

In the 3-4 years of my being in this hobby, I can count on one hand the number of times I've purchased something brand new. Between my experience with the R2R-11, reading/researching, and curiosity, I ended up forking out for the bigger brother R2R-2 and C-2 amp from AGD about two weeks later. Here's where it's really going to get some people - after getting those two guys hooked up, I've sold almost all of my other source/amplification gear.

I can't speak about measurements, or design, or parts, but I can tell you that the presentation I get in my rig from this setup is the most natural and well-tuned I can think of. Granted I've never laid ears on some of the summit-fi stuff, but I have owned the Schiit Gumby/Mjo2 stack, the Auralic Taurus/Vega stack, and the Chord Hugo, and none of those have left me so NOT wanting to change my rig!

For anyone looking to dip there toes in the R2R pool on a budget, I can't recommend the new ladder stuff from Audio-gd enough. Doesn't cost an arm and a leg, is very overbuilt, and sounds great!



PS - Here's my chain: Tripplite Isobar8 -> Mac Mini running JRMC21 -> AGD R2R 2 -> AGD C-2 or MAD Ear+HD -> HD650, PS1000, or HD800S
 
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Jan 1, 2018 at 12:42 PM Post #1,049 of 1,111
GearMe, there is not one word you wrote that I disagree with.

All I'm trying to do is drop a bit of wisdom on this thread that will allow any of you that are receptive to wade through marketing jargon and audiophile myth and legend so each of you can make more informed decisions with future purchases.

It doesn't matter if your budget is $1,000 or $10,000 or $100,000 - all the same laws of physics apply.

And there is no way around the laws of physics in the scenario of a DAC/pre amp feeding a power amp vs. a fixed output DAC feeding an integrated amp.

All things being equal, if relatively identical circuits and identical quality parts were used (be they tube or SS), the fixed output DAC feeding an integrated amp will always sound better.

Anyone that understands the application of Ohm's Law will confirm that you will have lower noise by feeding the higher voltage/volume signal through the cable and attenuating once the signal is inside of the amplifier. Period. There is no way around this. There is no engineer working for any company that will dispute this. And the only reason companies do things differently is because uninformed consumers request something different.

The same type of baseless marketing happened to the auto market with soccer moms buying off-road optimized SUVs.

There are all-wheel-drive family utility vehicles, more like station wagons, with equal seating, nearly the same cargo capacity, and much higher performance.

These inner city optimized vehicles have better acceleration, better braking, better cornering, more extreme condition stability, better safety, and better fuel economy than an SUV.

But that never stopped soccer moms from buying lower performing, less safe, gas-guzzling, off-road optimized SUVs in droves.

The same thing is true with pre amps built into DACs: performance wise they are known to be inferior even by the engineers that designed them but since the market demands them companies manufacture and sell them. Purely a marketing phenomenon.

Anyone in the mood to debate the validity of Ohm's Law with me?


Thanks, MojoAudio. I believe in the value of separate components as well and have always paid a premium for this type of setup in my main systems. My home headphone system is composed of separate dacs and amps. That said, there is a place (as you pointed out) for form over function for a lot of consumers. Where I would differ with you is that it's purely a marketing phenomenon; although likely in some/many cases...not so much in others.

One example, my work desktop unit is a Sony UDA-1 which I got NIB from Woot for $200 as a lot of Head-Fiers did. Is it the absolute best solution from a sound perspective? Probably not, but it's more than adequate and fits the use case -- condensed form factor with decent dac/hp amp/speaker amp/remote. Would I listen to it over my Schiit gear at home? Unlikely.

My V30 phone combines a mid-level PDA with a solid phone...no separate Dac, no separate Amp, no cables! Does it sound as good as a bunch of separates or an expensive PDA? Again, maybe not, but this purchase was a big win as far as I'm concerned since it can even power high-impedance cans with ease...and I'm not carrying a bunch of gear. :ksc75smile:


All the above aside, I've owned 2 channel equipment in the price range that you sell yours at (Audio Research, Quad, Maggies, etc.). For me, I found that after a point, the electronics (GAS/Sumo vs Threshold vs ARC vs Krell) didn't contribute to any noticeable sound difference -- but the speakers sure did!...same in the headphone world as far as I'm concerned. The one exception to this is tube vs SS. Hence, I have an OTL amp and an SS amp running off a multibit dac.

Taken to extremes, the high-end electronics market seems to be adding very marginal (if any) value for the incremental investment -- $1700 power cords, $15000 headphone amps, $20000 monoblock amps, etc. My $.02

Capitalism is a great economic system!...one that allows you to chase a dream of providing your clients with a 'high-end' audio experience.

That said, my hope is that market disruptors continue to offer alternatives that make consumers think about where they spend their hard-earned money. In a nutshell, this idea that Jason Stoddard recently proposed in his thread sums up my view of uber-expensive audio electronics...would love to see it happen.
upload_2018-1-1_12-42-24.png


Now that we have our own CNC and 3D printer (Tormach 440 and Formlabs Form 2, in case you're interested), I'm tempted to make a one-off beautiful NC-milled-from-a-solid-block-of-aluminum style chassis, hang a couple of tubes out the top and light them up (just the heaters), and stick a Magni 3 inside. Then cart it around to shows to display our "new upscale design philosophy," listen intently as people proclaim it far superior to anything we've ever made...then flip it over and show them the Magni 3 guts.

Of course, this is an excellent metaphor for (some of) the ultra-high-end, so it may be a little too on-point. So I probably won't do it. Plus, I have other things to do on the CNC and 3D printer. We won't be using these machines for production, but they will allow us to accelerate development, produce accurate models to use for casting and injection-molding, and to put any final tweaks on prototype parts for the turntable in near-real-time.
 
Jan 9, 2018 at 10:37 PM Post #1,050 of 1,111
I got my hands on an old Monarchy Audio Model 22 (original version before A/B/C) that uses PCM63P-K chips.

It wasn't playing out of one channel when I received it, but I was able to fix that by soldering the left RCA output positive wire back into place.

It clips/distorts a bit if I feed it a full level signal, but sounds pretty good if I drop the dB by ~5-10. This only happens in the right channel and, when it distorts, it almost sounds like it's inverting phase briefly.

Anyone else have a Model 22 and experience a similar issue?

Or, any suggestions on how to fix the problem/troubleshooting tips?
 
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