Researching SD Card Transports

[Qhwoeprktiyns]

The SDTrans does not use a Linux operating system, but runs on a microcontroller which has been programmed to perform a limited set of functions. It only reads WAV files. A similar approach was implemented in ECDesigns UPL. I don't know of other "players" that have been build from the ground up like these two. 

 

On the other hand, stripping down a Linux system (or Windows or Mac) is not going to get you as far towards "minimalism". With Linux, you'll still be running Alsa for audio, and that's a big and complex  "black box". 

 

If you see SD card players advertised as playing other formats than WAV, such as Flac, chances are they are running Linux, and are probably using a standard card like a RaspberryPi. I doubt anyone has programmed from scratch a Flac decompression algorithm on a microprocessor but I could be wrong. 

[Qhwoeprktiyns]

12 minutes ago, Miska said:

 

Where is it "black box"? You have all the source code! I have done quite a lot of work on ALSA. Although using ALSA is not necessary, you can do it other ways too. And it is not particularly complex, it is pretty straightforward and streamlined. Actually very low overhead when used correctly.

 

 

Have you published any of this ? 

What have you used aside for ALSA? What are your recommendations for a "correct use"? Without any specifics I am a little skeptical about what you are referring to. 

 

 

 

[Qhwoeprktiyns]

7 hours ago, Miska said:

So far OSS, ALSA and my custom interface on Linux.

 

What I referred to as "published" was the source code. I assume your custom interface on Linux is not freely available. You are a vendor, selling a product.. 

 

There is little "transparency" about some of  these products (not necessarily referring to yours).

 

Having an SD card in itself is no guarantee that the solution will be in any way similar to the SDTrans. I seriously doubt a public OS based solution is going to be comparable. 

 

[Qhwoeprktiyns]

12 minutes ago, Miska said:

Haha, so making some "black box" solution is better than using "public OS"?

 

You are being a smart-ass, but we both know exactly what I meant. A lot of manufacturers of these so-called "SD card" players are not transparent about the solution they implement. If the OP is looking for something similar to an SDTrans384, he should be aware of this. 

 

Whether taking a raspberryPi and a linux distribution and using standard Linux programs to decode audio, and play it from an SD card is going to be better than having a microprocessor with a very small instruction set dedicated to audio - that's for everyone to decide. I am just highlighting the differences. Obviously, you are here to sell your own solution, and that's fine (send me the link to your "custom linux interface" source code, I'd be curious to see exactly what you are talking about, and we can continue this offline). I'm not in the market for any of this, so I really don't care either way, but once again, you cannot compare apples and oranges.

[Qhwoeprktiyns]

1 minute ago, Miska said:

 

Yes, that's why I said that if the device reads files from SDcard, it is invariably a software solution in first place. One way or the other.

 

Then if such device is supposed to improve over something else, next level of transparency I'd ask is measurement results that demonstrate it. So far I didn't find such yet...

 

 

No, it's not only a software solution, as the hardware is different as well.

 

Whether or not these solutions bring something to the table, is not the issue here. If you don't believe they do (based on measurements, or listening, or whatever), then you don't need to contribute in this thread.

[Qhwoeprktiyns]

23 minutes ago, Norton said:

Is there any reason to focus specifically on SD card transports as opposed to any minimalist device that offers file replay from locally  attached external storage, and which is navigable and operable without a network?

 

Is it because SD card is considered better then thumb drive for SQ?   Obviously SD cards were historically offered in larger capacities than USB sticks, but that advantage is offset by difficulty in navigating large capacity cards without some form of network interface. ( I find 256gb SD card just about navigable using the Mirus)

 

For example my Bryston BDP can be used precisely  as you suggest, as a file player in the manner of  a CD transport -  WAV, FLAC and DSD  from thumb drives, operated  without network via built in screen and front panel buttons or remote and outputs via AES and spdif.  But while it does sound good I’m not sure SQ would be considered SOTA these days and it is “just” a tailored Linux PC.

 

 

 

The starting point of this thread was to ask whether there are similar devices to the SDTrans384. There are a number of specificities to the SDTrans384, and the fact that it uses SD cards is not really that relevant - I assume it could work with a local USB drive. The main difference with a Bryston BDP, for example, is that it implements a very low power micro-processor, and minimal memory usage, which probably limits the size of the filesystem used. The processor/memory requirements probably also limit the ability to implement more sophisticated navigation solutions, and the ability to decode other file formats (such as FLAC, DSD...). There are obviously other hardware differences as well, but that is one of them.

 

Whether all this makes a difference can be debated (plenty of threads on the SDTrans384 or the UPL, for example) but I just wanted to point out the specificities.

[Qhwoeprktiyns]

1 minute ago, Miska said:

 

What is then?

 

 

I (once again ?) did not express myself clearly. It is not the issue in the discussion you and I were having. Obviously, the OP is concerned about SQ.

[Qhwoeprktiyns]

3 minutes ago, Miska said:

 

Is there an issue?

 

 

And you were talking about transparency, and related to sound quality are of course measurements. So just curious about demonstration about some assumed benefits of such device and differences between different implementation approaches (Linux vs some other software, etc).

 

Since you were talking about ALSA and such, I'm curious about substantiation of such assumptions.

 

 

No, I was talking about transparency of "vendors", not of sound !

I am not getting into an argument with you about:

a) what is more "minimalistic"

b) whether minimalism offers sonic benefits

c) measurements

I don't care ! Find someone else to pick a fight with today, thanks.

[Qhwoeprktiyns]

Agreed, @bodiebill, will stop replying here. 

[Qhwoeprktiyns]

If you are looking for something "low noise" I would stay away from devices with a screen like the JF DIGITAL. These screens are a source of EMI. If you have a small AM radio, turn it on and put the antenna next to the screen, you will be surprised...