The Phison PD2 DAC/Preamp

[Mivera]

It will be interesting to try, but I have never had any issue with PCM.
Keith.

You won't have an issue with PCM with this DAC either, you will just get better sound when it's up sampled to DSD. But the beauty is you're free to choose. Whatever sounds better to you is the method you can use.

The Mola Mola DAC also up-samples PCM to a DSD like format as well. Same with the dCS vivaldi when the upsampler is used. The Rossini does it internally. The PS Audio direct stream up-samples all PCM to DSD with an internal FPGA, and then uses low pass DSD filters in the FPGA for the DSD. All of the EMM labs/Meitner stuff does the same.

So if you have ever listened to the above DAC's, you have heard PCM up-sampled to DSD.

 

[Mivera]

Maybe once I get my server up and running, if Amir is up for it, maybe we could get together and do an scientific evaluation (with measurements) of PCM handled in the AK4490 vs PCM up-sampled to quad DSD in my server engine. I know Amir is a skeptic as well of using this approach. So it would be an extremely interesting experiment that would likely draw lots of interest to the forum. The PD2 is the perfect unit for the testing.

I've yet to see a proper test of this besides what Jussi did with the IFI in the link I posted earlier. But one could argue his measurement gear was sub-par, and the tests were too limited to come to any firm conclusions.

 

[bibo01]

What you mean to say is use discrete low pass filters for the DSD. Yes Lampi is one of them. The AAVIK C-300 is another one. There's not too many out there because it's very difficult to get right, and much more expensive to implement than simply using the DAC chip to do it. But when done right it's the best sound you will ever hear from DSD.

Even the Lampi GG which is pretty much a $60 Amanero USB interface with a DSD lowpass filter and tube output stage gets rave reviews.

Good luck Mike for this new endeavor. The Phison PD2 DAC/Preamp looks definitely interesting.

On the matter of DSD DAC, there is also T&A DAC 8 DSD (Specifications). It seems to have a DSD implementation similar to Miska's DSC1.

 

[Mivera]

Good luck Mike for this new endeavor. The Phison PD2 DAC/Preamp looks definitely interesting.

On the matter of DSD DAC, there is also T&A DAC 8 DSD (Specifications). It seems to have a DSD implementation similar to Miska's DSC1.

Hi Bibo. Thanks! Yes it's a very nice unit. I was checking out that T&A unit already and looks to me like it's a very similar implementation as PS audio's new Directstream junior, only it uses a DAC chip for the PCM, where the direct stream up-samples PCM to DSD . The FPGA for the DSD decoding pretty much a simple low pass filter in the T&A. It's a very similar thing to what Acko has in the works with his Directdrive DSD DAC. And they call it a DAC/Preamp, but it has no analog inputs. So it's just a DAC with volume control that they decided to call a DAC/Preamp.

But looks like it would be a great unit to try with HQplayer though. The direct stream is quite poor with Hqplayer based on feedback I've heard.

 

[bibo01]

Hi Bibo. Thanks! Yes it's a very nice unit. I was checking out that T&A unit already and looks to me like it's a very similar implementation as PS audio's new Directstream junior, only it uses a DAC chip for the PCM, where the direct stream up-samples PCM to DSD . The FPGA for the DSD decoding pretty much a simple low pass filter in the T&A. It's a very similar thing to what Acko has in the works with his Directdrive DSD DAC. And they call it a DAC/Preamp, but it has no analog inputs. So it's just a DAC with volume control that they decided to call a DAC/Preamp.

But looks like it would be a great unit to try with HQplayer though. The direct stream is quite poor with Hqplayer based on feedback I've heard.

View attachment 344 View attachment 345

Are you sure it has a simple 1st order low pass like Acko's Directdrive ?! Miska said it was similar to his DSC1!

 

[Mivera]

Are you sure it has a simple 1st order low pass like Acko's Directdrive ?! Miska said it was similar to his DSC1!

Maybe it's not a 1st order, but I meant it uses an FPGA with low pass filter like Acko's DAC, rather than discrete components. Where the PS audio up samples PCM with the FPGA as well. Is Jussi going to buy one to test it out?

They are pretty much doing the same thing as the PD2 does by sending the DSD down it's own signal path. Only difference is they use an FPGA so they can apply the filtering in the FPGA rather than with discrete components.

 

[Mivera]

I just noticed that the T&A uses 7v version of the same Talema encapsulated toroidal transformer as the Melodious MX-U8 USB bridge I sent Amir to test. Although I wish waited and bought the new version 1.7

 

[Mivera]

Wait it looks like I was wrong. That was the wrong picture. It was the old DAC 8. It looks like they use 6 little 1 bit DAC chip similar to what the Mola Mola uses in-between the 4 PCM DAC chips

 

[bibo01]

By the way, the pictures you posted represent the old T&A DAC model; indeed, no DSD in those pics.
A real T&A DAC 8 DSD can be found here with further explanation on its discreet output stage.
This a review of it on German Stereoplay with some measurements.

EDIT: we cross posted

 

[Mivera]

By the way, the pictures you posted represent the old T&A DAC model; indeed, no DSD in those pics.
A real T&A DAC 8 DSD can be found here with further explanation on its discreet output stage.
This a review of it on German Stereoplay with some measurements.

Read my last post. I discovered that. The German's keep their reviews short and sweet I see

 

[bibo01]

The stray capacitance's in the JFETs can be a problem with high impedance, also leakage current that rises with temperature. Valves will have less stray capacitance. The stray capacitance is also very nonlinear. I think that is one of the advantages of valves.

@Sonny
Could you please tell us the difference - apart from case, touch screen, phono, remote and DAC inputs - between the PD2 DAC/Pre and the DAC you are selling for 1351€ on DIY?
http://www.diyaudio.com/forums/vendors-bazaar/274456-ak4490-usb-dac-dsd-support-90.html#post4641178
(I am trying to stir up... I am truly interested)
Thank you

 

[Mivera]

@Sonny
Could you please tell us the difference - apart from case, touch screen, phono, remote and DAC inputs - between the PD2 DAC/Pre and the DAC you are selling for 1351€ on DIY?
http://www.diyaudio.com/forums/vendors-bazaar/274456-ak4490-usb-dac-dsd-support-90.html#post4641178
(I am trying to stir up... I am truly interested)
Thank you

I can answer this because I know the answer already. I can answer most questions on Sonny's behalf regarding this unit because I already know the answers.

Here's the difference with the DAC:

"What is identical:

1) the 3 references around the AK4490 DAC, they are the best we can get and placement is perfect in terms of PCB layout
2) XMOS USB receiver is also close to perfect and there is no reason to change it. The placement of the XMOS receiver is also identical to the AAVIK Acoustic U-300 DAC which i did design also.
3) Analog filter which is discrete is the same until i have a filter that outperforms it. (* - keep reading)

The differences:

1) SPDIF Receiver with build in ASRC with two optical and two RCA inputs.
2) It uses two Crystek CCHD-957 crystals that outperforms Xpresso crystal in terms of jitter level
3) USB receiver is galvanic isolated using the best isolators available.
4) DSD and PCM is reclocked after galvanic isolation
5) 6 extra ultra low noise ultra high PSRR regulators.
6) PCB layout with 2 GND layers instead of only 1 which is stitched together to bond a stiff GND plane like on the Preamp mainboard.

Regarding the analog filter output board:

I am working on a new analog filter board which is in the design fase. But i need to listen to it to see if it actually is better. The analog filter board present is not marked with any description or name of design . The new filterboard will have the same outer mechanical properties. But I will make sure that anyone who purchases a PD2 before it's ready get's a new board when it is ready for free.

From cost point of view, I have put more than 6 month development time in this DAC main board alone.

No part of the circuits are identical to the DIY stuff I have made, which have financed some of the development in the Phison Series. I may choose to copy some parts of the PCB layout when it is not possible to do better as it is laid out as it should be."

It only takes 30min to install.

As far as the preamp board, why don't we compare pictures and you can tell me if they look the same:

And obviously the displays are much different. The power supply is much better. And the cases are not even close to the same league of build quality fit/finish.

But the Mirand stuff is still a phenomenal deal for the money.

 

[Phison Audio - Sonny]

@Sonny
Could you please tell us the difference - apart from case, touch screen, phono, remote and DAC inputs - between the PD2 DAC/Pre and the DAC you are selling for 1351€ on DIY?
http://www.diyaudio.com/forums/vendors-bazaar/274456-ak4490-usb-dac-dsd-support-90.html#post4641178
(I am trying to stir up... I am truly interested)
Thank you

Hi Bibo.

There are several points besides of what Mivera (Michael) already have told above.

1. The mirand Preamp is not pure balanced as the Phison PD2. The signal path through the preamp is Singleended only.
2. The gainstage in the Phison PD2 is superior to the Mirand Preamp. The Phison PD2 uses Single gain stage amplifier modules where the mirand is much simpler.
3. The Phison Audio PD2 uses two DAC8812 for the volume control giving better signal seperation.
4. The Differential signal path in the Phison PD2 means better channel separation as the influence is less.
5. The differential input impedance has tighter tolerance in the PD2.
6. The chassis of the PD2 is at thinnest 5mm thick. The chassis of the Mirand is folded 1.5mm aluminium.

 

[Mivera]

Hi Bibo.

There are several points besides of what Mivera (Michael) already have told above.

1. The mirand Preamp is not pure balanced as the Phison PD2. The signal path through the preamp is Singleended only.
2. The gainstage in the Phison PD2 is superior to the Mirand Preamp. The Phison PD2 uses Single gain stage amplifier modules where the mirand is much simpler.
3. The Phison Audio PD2 uses two DAC8812 for the volume control giving better signal seperation.
4. The Differential signal path in the Phison PD2 means better channel separation as the influence is less.
5. The chassis of the PD2 is at thinnest 5mm thick. The chassis of the Mirand is folded 1.5mm aluminium.

Let's not forget that the gain stages are on modular boards as well. So if you come up with a better gain stage circuit one day they can easily be upgraded.

And a bit better description of the case is it's CNC milled Aluminum plate on every panel. The top and bottom panels have a very nice brushed finish that's hard to see in photo's. The front and back has more of a bead blasted textured finish just like the apple macbook pro's/macmini/Iphone.

The Mirand case is folded laser cut aluminum sheet metal with a painted finish.

I wish I took better pictures of the case, but these pictures show the view from the top, the brushed finish, and finish of the front panel quite well.

 

[Mivera]

Okay finally got an initial impression from the 1st owner of the PD2 on the planet. And this guy has had some top level gear in his system. He's not ready to give a full evaluation because he wants to spend more time with it first. But he did say he would be willing to correspond with people via email about the PD2 after further evaluation.

"I've been super impressed with the PD2. I'm having trouble describing it and that's the highest compliment I can give it. Last night listened to the PD2 in my system and my mind just shut off and stopped dissecting the music and it was just sounding so pure. Great stuff.”

 

[bibo01]

Mike,

I don't know if you mentioned it or if it was asked before, how does PD2 work in Linux?
Does it support DSD non-DoP?

 

[Mivera]

Mike,

I don't know if you mentioned it or if it was asked before, how does PD2 work in Linux?
Does it support DSD non-DoP?

It works awesome. That's the only way I use it, and it's how my client has it setup. He built the Superstream from my WBF thread and up samples everything to quad DSD using the Poly-sinc-short-mp filter, and DSD7 256+ modulator. And yes it does native in quad DSD. He's going to be trying the new Sonore Microrendu with it soon as well. I already confirmed native quad DSD compatibility with Jesus at Sonore with it. I told him the galvanic isolation/reclocker is so good that it might not be any different, but he's confident it will be. He says they tried it with their fancy USB interface and it helped. But it's missing some tricks the the PD2 interface uses.

 

[Phison Audio - Sonny]

In Linux it support Native up to DSD 256 (non-DoP) playback.

In windows and OS/X it supports up to DoP 128.

BR

Sonny

 

[Mivera]

In Linux it support Native up to DSD 256 (non-DoP) playback.

In windows and OS/X it supports up to DoP 128.

BR

Sonny

What's your take on the above USB interface design Sonny? The FPGA does some upsampling algorithms, but besides that what do you think?

 

[bibo01]

In Linux it support Native up to DSD 256 (non-DoP) playback.

In windows and OS/X it supports up to DoP 128.

BR

Sonny

Doesn't it have ASIO DSD native support in Windows?!!!