I think that album art on the DAC is a neat gimmick, but of little value 12 feet away. I don’t have any great need for it, besides, I can see the art on my tablet MUCH better. If you are working from a computer then that display is even better. If you are spinning disce then hopefully you are using a PWT (or come October a DST) which will have an identically small display to look at at a distance. Besides, tue absence of a graphic display is part of a tiny little $2900 cost reduction. Seems to me like a fair trade.
Now for a big question… How does the sound of Junior compare to a PWD Mk. II & Bridge II?
wingsounds13 said
Now for a big question... How does the sound of Junior compare to a PWD Mk. II & Bridge II?
IMO the Jr sounds quite a bit like the DS, much closer to the DS than it does to the PWD Mk. II - I suspect that many when just walking into a room with a Jr or a DS playing wouldn't instantly know which was playing. When you hear them next to each other the Jr's treble isn't quite as clean/spacious, the soundstage positioning isn't quite as sharp, the background isn't quite as black. I'm perfectly happy listening to the Jr for background music and other casual listening, but when I want to let it loose in the evening I prefer the DS.
A bigger FPGA in the same family as the current Spartan-6 would have consumed a big chunk of the budget. Using an FPGA from another family could have gotten a little horsepower/buck, but as you mentioned it wasn’t really needed and then I’d need to maintain code on two different architectures. What’s worse is that they require two different tool sets - I’ve told Xilinx what I think of that
Ted, could we please get some detail on the Jr’s output stage?
If I have been following correctly, there are two sets of high speed +/- voltage switches, inverted, to generate balanced pulse trains from the 2xDSD output signal. And instead of going into a transformer these pulse trains are sent through a passive LPF. Is that correct?
Where does the op-amp come in to play, and why?
(Unrelated question – did PS Audio make any effort to source 25Mbaud optical input receivers for this product? 192kHZ PCM and 1xDSD over optical is so good.)
Yep for each channel the Jr uses the same balanced “digital switch” as the DS. Then there’s some passive filtering and then a balanced high speed high drive opamp that, like the DS’s transformer, will help isolate the Jr’s output from common mode noise (going out or coming in.) Then more passive filtering. The schematic is essentially the same as the DS but with an opamp where the transformer was. The opamp also allows us to have standard output levels with the same “digital switches”. I keep putting “digital switch” in quotes just because it’s just another of the same differential video opamp
Tho I looked at better optical receivers I couldn’t find compatible ones at a reasonable price (they aren’t that expensive, but I needed to meet a tight budget and another input that few customers could use was lower on the priority list.) Paul didn’t want to drop the 2nd I2S input either, but the cost and the panel space were both too much.
Feel free to move this but picking up on comments about reducing cost for the DS Jr:
This is somewhat off topic but would it make sense for the new PWT to forgo album display in order to drop the price ($5000) for the new PWT? Is there really any value about displaying album art across a room where it is difficult to read?
Thanks for the reply, Ted. I love that the same op-amps can be used for very different roles in that circuit. Very elegant!
Here’s an idea for the future. In the DARKO interview Paul says USB is the worst-sounding, hardest-to-implement input on the DACs. He also says optical should be the best because it’s galvanically isolated but suffers from bandwidth limitation.
So fix both with one go and give us the best sound from the most convenient/flexible transports! Stop putting USB receivers on your DACs. Build a simple USB-to-optical transceiver that gets connected to somebody’s PC or digital transport, and run high speed optical from that to your DAC. Your clocking strategy combined with the oversampling input decoder lets the DS sidestep the jitter problems which optical’s slow transitions cause in other DACs.
Use whichever optical transceivers suit you best, but please support 2xDSD if you can. I know that decoding that high a data rate from DoP in SPDIF might be a challenge in the DirectStream FPGA, but there are possible workarounds – like using a couple of cheap Toslink connectors run in parallel with I2S signalling for PCM and stereo bitstreams for DSD just like you do on the I2S input today. (So two cheap 16Mbaud Toslink connectors on a DAC could be used either as separate Toslink inputs or together as a pair to support high res audio from your USB transceiver.)
You could maybe even make this available as an expansion card for the existing DS. I would buy that in an instant.
PS Audio customers would be so happy to be able to use whatever USB transport they liked the best, with the worst of the USB-related audio problems totally eliminated.
(Not that I’m terribly unhappy today, having one of the best DACs in the world here in my room! But we can always imagine something better.)
I’ve looked at several similar possibilities - it wasn’t in the budget for the Jr but something like that is on my list. I’ve got a couple of Spice simulated low jitter optical connections for multichannel DSD, tho I want to get some more cost out of them. As you mention an advantage of the DS is that it doesn’t need to pass a clock upstream to get a low jitter connection so I2S (or clock, left and right DSD data) over three TOSLink cables is a pretty easy and low jitter double rate DSD capable connection. Only using two cables implies an encoded clock and the associated worries about some kind of modulation crop up but are essentially not different than having two parallel S/PDIF connections which as you mention is quite doable.
I wouldn’t be surprised if John Swenson/UpTone are working on such a box.
Still I have some ideas on how to make a device that will sound as good without an extra box that I’m more likely to prototype first.
FWIW I found a device that is a true optical USB cable (i.e. it encodes all of the metadata and transmits it over the glass connection along with the data and hence doesn’t have or need a ground connection or a 5V connection.) Tho it sounds better it’s not perfect and it costs a lot. (It’s still subject to the adaptive transceiver issues that the Regen addresses.)
Don’t get me wrong I totally agree that optical connections are the way to go for audio when compatibility issues aren’t present and I also agree that tossing USB out of the DAC would be great, as long as some USB solution were available.
Streets Still Works said
Easiest thing to do would be to photoshop a small black square on the apple orchard just under where the arrow would be so the arrow is more prominent. Just a thought.
wingsounds13 said
I think that album art on the DAC is a neat gimmick, but of little value 12 feet away. I don't have any great need for it, besides, I can see the art on my tablet MUCH better. If you are working from a computer then that display is even better. If you are spinning disce then hopefully you are using a PWT (or come October a DST) which will have an identically small display to look at at a distance. Besides, tue absence of a graphic display is part of a tiny little $2900 cost reduction. Seems to me like a fair trade.
Now for a big question… How does the sound of Junior compare to a PWD Mk. II & Bridge II?
J.P.
No comparison. Sorry. Jr. is much better than PWD II. Not as good as DS, but compared to PWD, just no contest.
brodricj said
Is there something proprietary about DST to stream pure DSD from SACD to DS/DSJ, or will it also work with other DAC's that have an i2s input?
No, it will be proprietary and other I2S inputs will not work. We had to restrict the use of it to keep in the good graces of Sony, the copyright holder on the music on SACD.
brodricj said
Is there something proprietary about DST to stream pure DSD from SACD to DS/DSJ, or will it also work with other DAC's that have an i2s input?
No, it will be proprietary and other I2S inputs will not work. We had to restrict the use of it to keep in the good graces of Sony, the copyright holder on the music on SACD.
So, I read this as if you stack 3 Junior, multi-channel SACD is possible when each Junior is connected to the upcoming PWT MKII?
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