Tony's Player

Tony's Player

Posted by John Swenson (A) on July 13, 2012 at 00:15:47

Below Tony was talking about an interesting concept in a player, I would like to explore this a little bit.

Basic concept: simple device that uses ethernet or some other remote mechanism to fill large amount of memory with data, remote interface gets disconnected and anything having to do with it gets physically powered down, simple system takes data from memory and clocks it into some form of DAC with as simple a path as possible using ultra low jitter clocks and ultra low noise power delivery. If possible the player would not have any form of DSP or digital filtering at all, this would be performed by the computer before sending the data to the player. Of course that means the amount of data can be very large. But memory is cheap and and ethernets are fast.

If I understand correctly the reason for doing this is to completely remove the computer from having anything to do with real time affects on sound quality.

I agree, I think this would be the best candidate I have heard of for doing this.

One interesting aspect of this post was that Tony proposed using DSD, while this can mean a very simple DAC part, I am surprised that Tony brought this up given some of his previous posts expressing some rather negative thoughts on DSD. Tony, have your thoughts on DSD changed? I personally am not a big fan of DSD, but I have never played with the 128 version so maybe that makes a big difference.

On detailed impelementation, I have actually already designed about 80% of this for another project. I am working on a high end squeezebox design with an FPGA, large memory, ethernet "chip" that talks to the FPGA, ultra low jitter clocks and a PCM1704 based DAC circuit (I REALLY like 1704s). The ethernet part is the same XMOS chip used for UAC2 implementations, but XMOS also has a nice network stack for it. I have most of this already done. Digital filters would be implemented in the FPGA.

Tony's concept could use most of this as is, I would have to add relays to the power for the XMOS chip and a relay on the cable connection. I would have to increase the memory significantly, but that is not too hard, DDR memory chips are designed to be used in large arrays. I already have the DDR interface in the FPGA so this is mainly a board layout challenge. I already have the digital side and DAC side completely isolated from each other with the low jitter clocks on the DAC side feeding the digital side to clock out the data. It will be two boards with LVDS interface between them with a each board in it's own shielded section of the box. Of course each secction gets it's own separate power supply. (actually 5 separate power supplies)

The concept of having the computer perform the reconstruction filter and sending the resulting data to the memory is an interesting one. I did some experimentation on that last night. I already have a DAC that has an FPGA driving the 1704 (with reclocking via the local clock of course) in which I can implement my own digital filter or send the data through direct. I tried applying a software filter on the file and sending it to the DAC at 192, this worked very well, vastly better sounding than hardware filters such as the DF1704. I was not able to tell for sure if the software filter sounded better than the filter in the FPGA, but I know for sure they were different filters, I was just trying a couple upsampling routines in some wave editors I had. So the concept sounds viable.

Of course the user interface on this box is going to be very primitive. I'm thinking of a play, pause, restart and connect buttons. You use the computer to choose a playlist, do any filtering etc, then download it into memory, then the box disconnects from the network and runs stand alone playing the playlist. You can start and stop but that is about it. If you want to change the playlist you have to do that on the computer, reconnect the box to the network and download the data. With a giga-bit ethernet connection the download won't take TOO long, but you do have to live with it.

Anybody interested in actually doing this? I don't have the cash to actually build this right now, but I can do all the design and prototype building if I can get some others to invest in it.

I'll let someone else figure out how the computer software side of this is going to work. Whether it's a new program or a plugin to something else we can discuss.

Any thoughts?

John S.

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Topic - Tony's Player - John Swenson 00:15:47 07/13/12 (49)

Is this dead? - GStew 13:01:38 09/2/12 (3)

RE: Is this dead? - jrling 12:08:43 09/27/12 (2)

Don't Hold Your Breath.... - Dynobot 14:03:41 09/27/12 (1)

Tony's Player - Any Progress? - jrling 10:59:56 11/23/12 (0)

Interesting - how about MEASUREMENTS? - Archimago 17:30:02 07/22/12 (0)

John, I think it's called an iPod :) - Gordon Rankin 07:09:00 07/16/12 (6)

RE: John, I think it's called an iPod :) - John Swenson 14:54:19 07/16/12 (4)

RE: John, I think it's called an iPod :) - Gordon Rankin 09:47:13 07/17/12 (3)

The Gods are talking - jrling 04:00:49 07/19/12 (2)

RE: The Gods are talking - SBGK 04:33:38 07/19/12 (1)

you just proved that the discussion is valid - bwb 06:51:45 07/19/12 (0)

John, I think it's called PlayGo - Roseval 12:55:01 07/16/12 (0)

Question about DSP and Filtering - Dynobot 09:42:38 07/14/12 (7)

RE: Question about DSP and Filtering - John Swenson 15:54:49 07/20/12 (6)

Theory vs. Practice - Tony Lauck 08:19:04 07/21/12 (1)

Nyquist Shannon - play-mate 22:36:52 09/2/12 (0)

RE: Question about DSP and Filtering - Bibo01 19:52:44 07/20/12 (2)

HQPlayer - Tony Lauck 08:26:37 07/21/12 (0)

RE: Question about DSP and Filtering - Ebit 01:04:56 07/21/12 (0)

RE: Question about DSP and Filtering - RioTubes 19:20:24 07/20/12 (0)

Disconnecting remote interface - Dynobot 07:13:24 07/14/12 (12)

RE: Disconnecting remote interface - AbeCollins 16:15:06 07/15/12 (2)

RE: Disconnecting remote interface - Dynobot 16:32:42 07/15/12 (1)

RE: Disconnecting remote interface - AbeCollins 19:04:32 07/15/12 (0)

RE: Disconnecting remote interface - SBGK 08:13:48 07/14/12 (8)

RE: Disconnecting remote interface - John Swenson 14:44:46 07/20/12 (2)

DRAM or SRAM? - Tony Lauck 07:39:54 07/21/12 (1)

RE: DRAM or SRAM? - John Swenson 16:18:49 07/22/12 (0)

RE: Disconnecting remote interface - John Swenson 15:04:01 07/14/12 (0)

RE: Disconnecting remote interface - Mercman 08:37:45 07/14/12 (3)

perhaps my memory is faulty but - bwb 09:10:06 07/14/12 (2)

RE: perhaps my memory is faulty but - Mercman 09:19:08 07/14/12 (1)

RE: perhaps my memory is faulty but - Dynobot 09:23:57 07/14/12 (0)

I'd Like to see this Topic Continue to the Point of a Parts List - Dynobot 05:33:25 07/14/12 (1)

Oh Well this thread is dead before it even started....Half baked Ideas go nowhere..nt - Dynobot 15:44:13 07/15/12 (0)

RE: Tony's Player - soundchekk 02:52:38 07/14/12 (4)

RE: Tony's Player - John Swenson 16:55:44 07/15/12 (0)

RE: Tony's Player - Dynobot 05:26:55 07/14/12 (0)

Rasberry PI at 35$ - fmak 03:33:31 07/14/12 (1)

RE: Rasberry PI at 35$ - soundchekk 04:07:51 07/14/12 (0)

RE: Tony's Player - audioengr 10:36:13 07/13/12 (5)

RE: Tony's Player - John Swenson 15:37:22 07/13/12 (2)

RE: Tony's Player - RioTubes 18:37:48 07/13/12 (0)

one possible implementation - bwb 17:24:53 07/13/12 (0)

RE: Tony's Player - Tony Lauck 13:42:54 07/13/12 (1)

Recurses! Foiled Again!!! (nt) - Skip Pack 08:16:32 07/14/12 (0)

PS Audio ? - AbeCollins 08:53:08 07/13/12 (0)

RE: Tony's Player - Tony Lauck 08:10:40 07/13/12 (0)

Are you suggesting a product that would be brought to market or just something for the hobbyist? - bwb 07:28:56 07/13/12 (0)

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