TEAC NT 503 or UD-503: Opinions?

[Miska]

I got my NT-503 on Friday...

 

- be seen and used by HQPlayer as a target device on the LAN input?

 

No, it is pretty much UPnP + Spotify Connect. So far I've only tested Spotify Connect which worked fine.

 

- assuming the question the the above is yes, can the LAN input accept DSD256?

 

No, based on specs, up to DSD128.

 

- assuming yes to both of the above, can HQPlayer running on OS X send DSD256 over the LAN or is it limited to Core Audio's DSD128 over DoP?

 

I believe USB output from Mac is limited to DSD128.

 

I have successfully tested DSD256 using ASIO driver from HQPlayer on Windows.

 

I really want a DAC that can accept DSD256 via LAN which can also have it's own filters defeated.

 

Choices for such are so far pretty limited...

[Miska]

for COMPARISON, HEGEL hd30(4000$ ) received 88 points!!!

 

I guess it depends how you use the DAC...

 

To me, HEGEL HD30 is uninteresting since it is stuck to max 192/24 inputs.

[Miska]

I tend to believe the same thing as the filters looks like the same to the ones proposed on the AK4490 (with one missing : the super slow roll-off). But how can you be sure ? Also I thought upsampling and digital filter go together ..? I thought the upsampling and DG filter was maybe performed by the FPGA chip and the DAC is runing in EXTERNAL DF mode ..?

 

The "upsampling" option is external to the DAC chip. At the beginning I suspected it is an AK4137 chip, but not sure anymore as I would have expected better performance from that chip. So maybe it is TEAC's FPGA or DSP stuff afterall.

 

The digital filter selections change the DAC chip filters, at least when the upsampling is off.

 

Agree with that, but is there a difference between : a)passing through the interpolator of the AK4490 but with no processing when sending in x8 PCM and in standard mode. Or b) having the chip in External DF Mode and going directly to the DS modulator, bypassing the interpolator ... ?

 

Since the AK4490 interpolator is 8x PCM, sending 8x PCM means running it in External DF Mode.

 

It is more for curiousity than for pure SQ. Also how can you be sure that the DAC run in real bypass mode (volume and DS modulator) and not in Normal Path ??

 

With DSD inputs, the DAC chip doesn't have 150 kHz filter option available in "normal mode". However, since the TEAC has it available, it must be running in Direct/Bypass DSD mode. I can also clearly see the difference between 50 kHz and 150 kHz modes in wide band (5 MHz) measurements when sending DSD256 there.

 

And generally they don't need the digital volume control of the DAC chip at all, because they have a separate analog volume control.

 

There is so much uncertainty on how everything is handle by TEAC inside that I might go for a DIY or boutique solution based on AK4490 (as Mirand Audio DAC or KLEIN DAC II) as I can be sure of the mode the DAC is really running with those ... Too bad because the TEAC seemed to be a really versatile device.

 

I've been just verifying the functionality with measurements to the extent possible. And seems to work pretty much the same way as UD-501 did, but of course with different chip.