[DACLadder]

The 2021 models are not outdated. Kingwa may roll his designs faster than the break in cycle but all three of my older Audio GD DACs sound better today than they did when first purchased. Firmware upgrades, affordable HW options, and support from this forum keep then sounding fresh and relavant. I cannot say about other products. In comparison I have owned 8 DDCs since purchasing the Master 7 almost 10 yrs ago.

 

[sajunky]

#1 If it's a complete waste of resources, Kingwa wouldn't have implemented it in the first place. He did a few tests and decided to implement that despite the cost and risks because it's so god damn better with pure class A power supply regulation on whole digital circuit. But problem arises and solution must be made for them so it's understandable to keep only clock circuit with pure class a regulation for lower temperature. And goes by your logic, clock should be the most obvious place to switch to low noise servo to decrease spike yet it was kept there. That's how much he wanted to use pure class a design on digital implementation.

You must be aware that before 2021 version there was no isolation on USB (except R-7) nor I2S. It was OK to power both parts from the same power supply. In 2021 version isolator had been added to the USB port on all lower tier models, but isolator for I2S required major archtecture changes, including adding extra power supply. If not adding a new power supply, it would reduce benefits of isolation of both ports. So what you would chose? Keep the existing Class A PSU on both ports (which is more appropriate for analoue circuts than digital), or bringing two separate PSU's that can afford glitches of digital circuits at the battery level? For me it is obvious that the right decision was made. What is the best for analog, is not the best for digital and in reverse.

The last portion is beyond of my understanding what you wanted to say. It is said clearly that clock circuit is still on the Class A PSU.

#3 While I agree that separated isolation is good, you seem to miss the point that it's no longer "pure class A isolated power supply" that feeds USB and i2S. I would rather have pure class A isolated power supply design especially on Kingwa's DAC with sharp and precise sound signature.

If you read again my answer to the #1, there are now two independent PSU's for USB and I2S logic. My second answer give more explanation why.

#6 The point is parallel processing decreases integrity that serial processing has. You will have more linearity and transparency with serial processing. And I never have issue with internal clock and high precision clock I use with his DAC. He needs to adapt parallel processing to deal with lower precision clock and that implementation along with his new design to compromise with lower accuracy clock will worsen performance that requires high precision clock.

This is not true that parallel processing decreases clock integrity. Where did you find it? You must be more specific on this topic.

 

[DACLadder]

Kingwa found parallel data processing in the FPGA is simpler and more straight forward to implement for his designs. The FPGA inputs and the i2s output to the analog boards are still serial. But all the data crunching is parallel. It creates a more efficient FPGA code. The DSP filter taps are processed on the parallel boundary for instance.

Serial disadvantage is it creates more noise as you are constantly shifting bits at 64 times the sampling rate (32bit x 2ch). The noise is internal but also can be coupled onto the power rail. Parallel has the disadvantage of many 32-bit register arrays possibly changing state at the same instance, the sampling rate. Sometimes a data glitch if power is wimpy. The FPGA is just a data bucket in our case. The actual D/A conversion is handled by the V2 DAC boards on the R7/R8.

If parallel data processing sounded bad we would have complained long ago. Been around for 2 yrs.

 

[XavierP56]

In R7-HE21, there are USB Isolator and HMDI but they are powered by the same power supply is that right ?
I'm only using USB so it's probably not a big deal for me

 

[FredA]

In R7-HE21, there are USB Isolator and HMDI but they are powered by the same power supply is that right ?
I'm only using USB so it's probably not a big deal for me

I doubt so. Kingwa says

"USB and HDMI apply the separate isolators and isolate pure class A PSUs for avoid the interrupt from computer and HDMI sources."

I think he means isolated class a psus. So things are properly done.

 

[WindowsX]

You must be aware that before 2021 version there was no isolation on USB (except R-7) nor I2S. It was OK to power both parts from the same power supply. In 2021 version isolator had been added to the USB port on all lower tier models, but isolator for I2S required major archtecture changes, including adding extra power supply. If not adding a new power supply, it would reduce benefits of isolation of both ports. So what you would chose? Keep the existing Class A PSU on both ports (which is more appropriate for analoue circuts than digital), or bringing two separate PSU's that can afford glitches of digital circuits at the battery level? For me it is obvious that the right decision was made. What is the best for analog, is not the best for digital and in reverse.

The last portion is beyond of my understanding what you wanted to say. It is said clearly that clock circuit is still on the Class A PSU.


If you read again my answer to the #1, there are now two independent PSU's for USB and I2S logic. My second answer give more explanation why.


This is not true that parallel processing decreases clock integrity. Where did you find it? You must be more specific on this topic.

I'm aware that 2021 starts having isolation and mk2 give individual isolation to USB and i2S. However, 2021 has pure class A regulation on USB/i2S and mk2 only mention about linear power supply. I'd rather keep pure class A on 2021 design.

I'd rather have one good wholesome regulation to feed everything even if there'll be some noise shared than having some linear power supply regulated for each one which is not as good as pure class A. That's my preference from my experience.

I'll buy $40k Esoteric K1X Grandioso later so this DAC is just in between to play around with R2R from my usual $20-30k sources. I don't really hate it for performing price. Just feel disappointed to see newer version coming up right after 2021 in like 3 months.

Anyway, you don't have to agree with all my two cents here. Even if I own $100k system or heard all highend DACs in market, that doesn't mean you need to agree with my thoughts and just enjoy your hobby.

Regards,
Keetakawee

P.S. This is my own implementation of 10MHz Rubidium clock feeding R7HE right now based on Esoteric flagship Rubidium clock. I know my stuff about clock and you do yours OK?

 

[DACLadder]

Class A power regulation = linear power regulation. Just means the regulator DC pass transistors are conducting 100% of the time. If there is a difference please give circuit examples.

For audio purposes the Stanford Research PRS10 rubidium clock has worse phase noise at 1hz and 10hz versus many OCXOs like the Morion mv89. Rubidium clocks have better long term stability but that is not as important for audio. GPS yes, audio no.

I’m not trying to pick a fight but you say you prefer the 2021s class A regulators to the Mk2s linear regulators. So I really don’t fully understand your disappointment other than model change with no prior notice. The Mk2 is just an evolutionary model. Not really revolutionary in design when compared.

 

[sajunky]

Class A power regulation = linear power regulation. Just means the regulator DC pass transistors are conducting 100% of the time. If there is a difference please give circuit examples.

For audio purposes the Stanford Research PRS10 rubidium clock has worse phase noise at 1hz and 10hz versus many OCXOs like the Morion mv89. Rubidium clocks have better long term stability but that is not as important for audio. GPS yes, audio no.

I’m not trying to pick a fight but you say you prefer the 2021s class A regulators to the Mk2s linear regulators. So I really don’t fully understand your disappointment other than model change with no prior notice. The Mk2 is just an evolutionary model. Not really revolutionary in design when compared.

I agree to every word. It doesn't matter whether music stops 2 seconds earlier or later during one year period, but a clock needs to have one frequency peak and no sidebands, especially in the acoustic band. There are number of sources pointing out that rubidium clocks carry a lot of noise.

Some explanation regarding Class A power supply. It works as a power amplifier where an input voltage is constant. It has relatively high output impedance, but it can handle large load differences. A feedback loop serial regulator type give much lower output impedance, LDO designs are very energy efficient. It is a linear power supply (LPS), please do not mistake it with SMPS. LPS is the better suited than Class A for digital circuit that carry constant average load, but generate series of short peaks.

 

[Crow123]

I agree to every word. It doesn't matter whether music stops 2 seconds earlier or later during one year period, but a clock needs to have one frequency peak and no sidebands, especially in the acoustic band. There are number of sources pointing out that rubidium clocks carry a lot of noise.

Some explanation regarding Class A power supply. It works as a power amplifier where an input voltage is constant. It has relatively high output impedance, but it can handle large load differences. A feedback loop serial regulator type give much lower output impedance, LDO designs are very energy efficient. It is a linear power supply (LPS), please do not mistake it with SMPS. LPS is the better suited than Class A for digital circuit that carry constant average load, but generate series of short peaks.

 

[Crow123]

Well I read through this thread yes all 483 pages and it seems to be the best source of info on new audio gd DACs. I have just recieved tracking number for r8 Mk2. I hope you guys are right as this is a blind purchase . I strongly considered the denafrips pontus it was possibly a "safer" choice but the internal schematics of the r8 just seemed so focused on sq (ie transformers, noise isolation and output stage) that I just ordered and hoped.

 

[FredA]

Well I read through this thread yes all 483 pages and it seems to be the best source of info on new audio gd DACs. I have just recieved tracking number for r8 Mk2. I hope you guys are right as this is a blind purchase . I strongly considered the denafrips pontus it was possibly a "safer" choice but the internal schematics of the r8 just seemed so focused on sq (ie transformers, noise isolation and output stage) that I just ordered and hoped.

Excellent bang for the buck. I am pretty sure you will be pleased. Audio-gd gets the balance right and have a non fatiguing and natural sound. The soundstaging/imaging is first class.

 

[jimmychan]

Well I read through this thread yes all 483 pages and it seems to be the best source of info on new audio gd DACs. I have just recieved tracking number for r8 Mk2. I hope you guys are right as this is a blind purchase . I strongly considered the denafrips pontus it was possibly a "safer" choice but the internal schematics of the r8 just seemed so focused on sq (ie transformers, noise isolation and output stage) that I just ordered and hoped.

Congratulations to join the Audio-GD family.

 

[PLGA]

Well I read through this thread yes all 483 pages and it seems to be the best source of info on new audio gd DACs. I have just recieved tracking number for r8 Mk2. I hope you guys are right as this is a blind purchase . I strongly considered the denafrips pontus it was possibly a "safer" choice but the internal schematics of the r8 just seemed so focused on sq (ie transformers, noise isolation and output stage) that I just ordered and hoped.

I think you won't be dissapointed. Give it at least 600 hs of burning time. You can ask Kingwa if it burns just leaving it powered on. I believe the internal clocks do.

By the way, wich DAC will R8 replace?

 

[Crow123]

I think you won't be dissapointed. Give it at least 600 hs of burning time. You can ask Kingwa if it burns just leaving it powered on. I believe the internal clocks do.

By the way, wich DAC will R8 replace?

It will replace an SMSL M500 I thought this dac was pretty good and I still do but I also think it's quiet forward with vocals and although it is good at detail retrieval it just doesn't create the sense of atmosphere or presence I am after - hence my search for a r2r dac.

 

[Crow123]

I also have question or two.

I currently use a pi4 as a roon bridge which then goes into a ifi defender (USB) into dac.

Q longer term I want to consider a d2d like the di 20 but with the r8mk2 re-clocking is this necessary. I think SAjunky said there would be no benifit until di20he so should I not consider any d2d until that level?

Q once again because of superior usb implementaion should I still use ifi silencer on USB from pi in above set up or just go directly from pi to r8?

Q I was considering upgrading pi output with something like usbridge Signiture as well would this be better or worse than a d2d?

Q should I consider a power supply upgrade for pi I was thinking of getting an ifi 5v plug for this I am just looking for cost effective solution in the interim?

Thanks in advance