not really, not cheap, but theres a fair bit packed in there and the case is all magnesium alloy and gorilla glass, so that wouldnt be cheap, these guys make a pretty decent portable headphone amp and this one will swing a fair bit of voltage like +/-15v from memory (dont quote me on that). its running a modified version of android with their own audio engine and custom player, not the standard audio player. this allows the 24/192 in flac or wav.
what does that mean? I have no idea what you mean there, my computer supports those too... doesnt make it unsuitable.
wifi can be turned on and off at will, most will use the SD slot or onboard memory, but still cool to be able to stream radio or from your computer and transfer/share files that way. many things about it I would do differently, but I wouldnt necessarily say its overpriced and its a few steps ahead of anything else like it. for instance given they control everything and its all in the one package, I would definitely be running with a synchronous clock, but they arent.
they have to sell into a niche market and customers expect a certain feature set, so there will for sure be some creeping featurism, but you just turn what you dont need off
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OK, I started to reply to RS's posts, but I realised that I'm just lapsing back into a confrontational paradigm. I've made my suggestions and I'm going to leave it at that.
Scott
What I'm thinking is a 4-momentary-pushbutton device with a small monochrome dot-matrix display. The buttons would function as follows:-
1) Toggle on/off. Playback to resume at the point where left off. There may be some complications arising when the card is replaced.
2) Toggle display/playback between directory (album) and directory contents (tracks).
3) Cycle forward through albums/tracks.
4) Restart album/track, or cycle backward if pressed twice quickly.
Display to blank after a delay.
One sample rate, 2496. Wav format.
SDHC supported, micro slot.
User to be responsible for maintaining directory structure under WinXP or greater using a standard card reader. Only one layer of directories. FAT32. It's probably easier if the contents are contiguous, so it may be preferable to blank and rewrite the whole disk.
USB port for power only.
What DAC do you want? Device dimensions? Audio connectors? To drive what impedance to what voltage? Endurance? Any particular clock you like?
Scott
What I'm thinking is a 4-momentary-pushbutton device with a small monochrome dot-matrix display. The buttons would function as follows:-
1) Toggle on/off. Playback to resume at the point where left off. There may be some complications arising when the card is replaced.
2) Toggle display/playback between directory (album) and directory contents (tracks).
3) Cycle forward through albums/tracks.
4) Restart album/track, or cycle backward if pressed twice quickly.
Display to blank after a delay.
One sample rate, 2496. Wav format.
SDHC supported, micro slot.
User to be responsible for maintaining directory structure under WinXP or greater using a standard card reader. Only one layer of directories. FAT32. It's probably easier if the contents are contiguous, so it may be preferable to blank and rewrite the whole disk.
USB port for power only.
What DAC do you want? Device dimensions? Audio connectors? To drive what impedance to what voltage? Endurance? Any particular clock you like?
Sounds good, I'm sure you know best on the particulars. I prefer simply using my HD-600 headphones, even an iPod shuffle drives them (quite a silly sight).
BTW quality pinot noir at about 1/6 the price of red burgundy Cooper Mountain Vineyard. They are fully into the mysticism of Biodynamics even to the point of using vortex energized water ala Victor Schauburger, but it seems to work.
You're confusing me, at best I would only count as one unit. I admit my enthusiasm wanes at the thought of paying for a one off custom job.
Scott, did you look at the ibasso DX100 that android based SD player with the ES9018 dac I linked? if running hd600 you'll need a bit more voltage swing than just about any portable out there has by itself without adding a portable amp. it does 24/192 and has more than enough swing for your purposes.
Little pricey, but looks good. I'm even considering a Tascam portable field recorder for this purpose. I have a Fostex but the disk needs to be formated by the recorder and you can't put your own files on it, you can but only the recordings will play.
Which is why you'd be required to show considerably more enthusiasm and make some input. It's not an offer to sell you something, it's an opportunity to participate in an open-source development.
I said, 'I can build it, but I haven't got a dScope.'
You said (paraphrased), 'You don't need one'
I'm taking you at face value. My gut instinct is that RS is wrong, that it's possible to build a transparent device without enormous expense in testgear. I'd welcome some help in demonstrating it. Without resorting to what I think is a glib and unrealistic suggestion to employ an audio consultant.
Otherwise, as qusp points out, many of the amateur developers here might as well pack up their bags and go home unless they're happy to be basing their efforts on listening tests alone, to say nothing of those budding entrepreneurs without whose contributions the audio scene would be a far less diverse and interesting place.
I'm not talking here about cable-wallahs and other lowlives, I'm talking about with people with skills and understanding who produce working devices, and who would produce better ones with some encouragement, but who are being dismissed as 'fantasists'. This is not to say that the possession of skills excuses every and anything, there are some with high levels of expertise and positively malignant attitudes; thankfully they are few and far between. These are worthy targets for all the disapprobation an objectivist can muster.
Take a look at some of the things amateur astronomers are doing, imaging faint objects by summing multiple images in software. They're doing interesting (and useful) things that were simply impossible a few years ago, until technology changed, became a lot cheaper, and somebody had a bright idea. I don't mean that the techniques are directly transferable to this application, I'm just pointing out that ingenuity in operating new technology is key.
This is why I'd prefer to see RS bending his efforts to making high quality measurement more accessible, or even attacking some of the more slippery, sinister and less well-intentioned denizens of the forums instead of beating up comparatively benign individuals like Ti Kan.
Where there is room for DIY is in coming up with inexpensive ways to use/build instrumentation. PC's provide such fantastic processing power, I have got to believe there is a lot of room for truly unique and innovative approaches to measurement that have not been capitalized by the traditional instrument makers. For sure, commodity stuff is so good it is hard to do better, but I contend there is a lot left to be done. As it has almost no commercial value, it is up to us.
Is anyone up for designing open source hardware for enabling null-testing to be done on DACs? I've never seen a commercial instrument supporting this but it would settle once and for all the claims of transparency in relation to S-D DACs.
I don't see it as that big a problem to just cobble up a test jig, depending on exactly what kind of null testing you're talking about.
If you just want to compare the output of 2 DACs, then you take a wav file and invert one channel into the other, then output it into an SPDIF splitter and thence to the DACs. Now you mix the left input from one with the right input from the other in a passive mixer and observe the output on a scope or audition it.
Is that what you mean? I can write you a program to process the file. If you mean something else, explain...
If you just want to compare the output of 2 DACs, then you take a wav file and invert one channel into the other, then output it into an SPDIF splitter and thence to the DACs. Now you mix the left input from one with the right input from the other in a passive mixer and observe the output on a scope or audition it.
Is that what you mean? I can write you a program to process the file. If you mean something else, explain...
The normal kind of null testing - where we attempt to get a deep a null as possible by subtracting the output of one DAC from another. But probably better to invert in the digital domain and sum though.
I can't follow you - we don't want to 'compare the output of 2 DACs' we want to null them. But there are several issues involved which make getting a null not totally straightforward. Firstly there's the need for a reference DAC - how to choose it? Myself I'd suggest a multibit DAC like TDA1541A because it has the best measured performance at 16bits.
The next issue is delay - S-D DACs have different delays so we need a parameter to be tweaked. Its not necessarily just an integer sample rate delay as its possible an S-D DAC has fractional delay. Thirdly there's frequency response - digital filters inside S-D chips aren't flat, they have ripples and this will affect the null. If the TDA1541A in NOS were used its ZOH droop would need correcting accurately. Ideally we'd like to be able to separate out the different error factors to characterize the null better.
I can't follow you - we don't want to 'compare the output of 2 DACs' we want to null them. But there are several issues involved which make getting a null not totally straightforward. Firstly there's the need for a reference DAC - how to choose it? Myself I'd suggest a multibit DAC like TDA1541A because it has the best measured performance at 16bits.
The next issue is delay - S-D DACs have different delays so we need a parameter to be tweaked. Its not necessarily just an integer sample rate delay as its possible an S-D DAC has fractional delay. Thirdly there's frequency response - digital filters inside S-D chips aren't flat, they have ripples and this will affect the null. If the TDA1541A in NOS were used its ZOH droop would need correcting accurately. Ideally we'd like to be able to separate out the different error factors to characterize the null better.
TDA1541 as "reference" in 2012?? - good for a laugh I guess
manufacturer's haven't been asleep the past 1/4 century - segmented ladder DAC with 20 bits, 1 uS settling 1-2 lsb INL, DNL are available today: http://www.analog.com/static/imported-files/data_sheets/AD5791.pdf
you don't have to just look at "Audio" converters - medical imaging has driven perfomance well beyond "Audio" today
manufacturer's haven't been asleep the past 1/4 century - segmented ladder DAC with 20 bits, 1 uS settling 1-2 lsb INL, DNL are available today: http://www.analog.com/static/imported-files/data_sheets/AD5791.pdf
you don't have to just look at "Audio" converters - medical imaging has driven perfomance well beyond "Audio" today
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