CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => DIY => Topic started by: Chris1967 on November 03, 2013, 09:17:43 AM
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I second comments about the performance of the 9023; or AK, or most modern 'budget' (read not 9018) dac chips; Dedicated, quality power can really get the most out of them. I just built a little slimline dac with the AK4396, and an XMOS USB receiver (>= 384 PCM/64/128 DSD). It isolates and reclocks the signal before feeding it to the DAC. I've powered both the USB and reclocker/DAC with dedicated Salas shunts. Then, I added a little filter/buffer well known over at diyaudio (JG Filter/Buffer), and just finished casing up a little DAC that costs less than $400, is small, handles PCM/DSD, and outperforms a stock Buffalo III (stock shunts/IV(s)/PS(s)).
Clean, correct power is I believe even more critical for digital circuits.
Great!! I would really apreciate it if you could make a small presentation of your DAC (if it is not too much trouble that is)
Thank you MisterRogers!
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Yes! The plebs crave for pictorials! Do post them!
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As you wish! Here are a coupe; one case/outside, the second all components, the final a close up of the USB receiver/DAC (I2SOverUSB/AK4396). The JB Filter/Buffer is located right behind the DAC. Excuse the unconventional way of building the shunts; wanted to mount them in this slimline case, which required the smoothing capacitors be mounted off board. Wiring isn't finalized yet. Anyway - here it is. I've built many more complex DAC's, but I find the sound of this little guy stellar.
(http://www.prettygoodsoftware.net/DIY/IMG_0984.jpg)
(http://www.prettygoodsoftware.net/DIY/IMG_0988.jpg)
(http://www.prettygoodsoftware.net/DIY/IMG_0989.jpg)
I second comments about the performance of the 9023; or AK, or most modern 'budget' (read not 9018) dac chips; Dedicated, quality power can really get the most out of them. I just built a little slimline dac with the AK4396, and an XMOS USB receiver (>= 384 PCM/64/128 DSD). It isolates and reclocks the signal before feeding it to the DAC. I've powered both the USB and reclocker/DAC with dedicated Salas shunts. Then, I added a little filter/buffer well known over at diyaudio (JG Filter/Buffer), and just finished casing up a little DAC that costs less than $400, is small, handles PCM/DSD, and outperforms a stock Buffalo III (stock shunts/IV(s)/PS(s)).
Clean, correct power is I believe even more critical for digital circuits.
Great!! I would really apreciate it if you could make a small presentation of your DAC (if it is not too much trouble that is)
Thank you MisterRogers!
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I need to talk to you about this. Expect me to get in touch with you soon.
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Thank you very much MisterRogers!! :)p1
I2S over USB and AK4396 board is from jlsounds right? i was looking to get the I2S over USB but i will go for the DAC too now!!
Is the buffer absolutely neccesary? i mean can you give a brief description how the DAC sounds with and without the buffer?
Thank you very very much!! :)p7
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Yep, that's the one. For cost/space reasons, the DAC only comes with a reconstruction filter. The components used are top quality, but I found it lacking a bit in slam and dynamics. I have to say though - while sonics are improved with the JG, it sounded pretty damn good with without. I would say built it with an emphasis on quality power and listen. I know a couple of builders/audiophiles that love the sound coming out of a reconstruction filter. To my ears, the JG just adds. Also - if any of you want to pick up a JG, gogowatch at diyaudio probably has some stock; just have to ask him. I ordered a couple more just to have them. You see, I have this problem - I'm nervous unless have have kit around to build something if I get a whim.
Not to forget your question:
RF: smooth, lower frequencies are a bit loose, otherwise good dynamics and range.
JG: more, more slam, better plankton.
Edit: Also - if any of you mates decide on a build that includes the JG and you can nab one, I'm happy to help build it if needed. It's a small board with 0603 surface mount. While I encourage every builder to gain their SMD chops, <= 0603 can be tough. Just putting that out there.
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Can you get an approximation on the final BOM cost for your project? This looks pretty darn interesting.
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Let me scratch it up more accurately RW; I build it from parts in the bin (as I mentioned, I have a nasty habit of collecting interesting kit) so I'll need to work it up. Seat of the pants, I'm pretty sure it can be built for ~$400 without the case. With that, you can spend as little or as much as you wanted. Btw, listening to it right now feeding a pimped Crack driving a pair of T90's. It's enough to make me park my ortho's - and I do love my ortho's.
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Not bad at all. I'm currently living with Sneis's DA100 Siggy and enjoying the crap out of it.
By the way - the power supplies you are using. I see one linear regulator for the buffer filter thingie, but the digital side of things has only shuntregs, correct? Most likely I would use Sjostrom super regulators in my build.
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Yep, correct. Two Salas shunts to drive XMOS-USB/Reclocker-DAC, and a linear to drive the JG. As much as I'm enjoying the hell out of it, I've heard the JG with better power.... and it's eating my brain. If there was any way to fit a Sjostrom super reg (great reg BTW, I have a couple of boards to be build) or two more Salas rails... Sigh. It never ends. In a real sense, most every build is a a series of trade-offs. Given the constraints of space, case, thermals - I think I made the right choice as to where to use the better power.
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Btw, did you match the fets on the JG? Are you getting any DC on the output?
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The JG is sold with the fets matched and soldered. The rest of the BOM is up to you. The Fastron Inductors/Chokes should be matched to 1%, but I've found they're pretty tight coming from Mouser (at least in my batch)
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Hmmm... This looks like an interesting project. Might hold off on buying a smaller case for my Sjostrom QRV-08 and stuff it into a 1A rack case together with four super regs and this DAC. Any idea on the current draw of these devices?
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The USB/XMOS side is ~400ma. The Reclocker/DAC side is about ~140ma.
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The USB/XMOS side is ~400ma. The Reclocker/DAC side is about ~140ma.
Excellent... i noticed the variation on the Salas shunts...
Is it asking too much too much to tell us what components and values you used on the two different Salas shunts?
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Not at all. It's fairly straight forward. For smoothing caps, I always use either ELNA LAO 10000uf >=63v or Nichicon fine gold similar capacity. I have a preference for hexa ultra fast diodes in my Salas shunts. Any good MKS4 or MKT for the *02/*04 caps will work. For digital, the *02 cap should be a good 220uf lytic. One of my favorite caps is the Elna Silmic II's. They work very well in this position, but a good Panasonic, or Muse is.. well good here too.
That's about it. Use the provided (in the build threads) calculator to dial in the rest of your component values. For those, I just use well rated, good components.
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Thank you very much! :)p7
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No worries mate!
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Thought I'd share what might be good news to some of you. I've been chatting with Lyuben - part of the team that designed and sells the XMOS/AK stack that I build this DAC around about designing an optimized JG filter that would stack cleanly on top of the other two boards. This just seemed really cool to me; a low profile, "just add power' stack that could handle PCM/DSD.
Drum roll... They've agreed to design/build such a board. So in the near future, anyone interesting in putting together a similar DAC will be able to do so without messing with the 0603 SMD's that the very small JG Filter requires. I'll keep this thread up o their progress, as I hope to be testing prototypes for them.
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If only they would add digital volume control...
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They've agreed to design/build such a board. ....... I'll keep this thread up o their progress, as I hope to be testing prototypes for them.
that is fantastic, was looking at these boards and am in no mood to try and solder tiny smd anymore.
..dB
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Yea, I get that - totally. I have to be in the right mood, but when I am I enjoy it. Of course at this point, I have a rather significant investment in gear (huge magnifying work light, Metcal & JBC soldering stations, tons of tips for every size/pad, etc.). Nothing like the joy of your very last 10k 0603 .5% thin film flying away to places unknown :-)
I'll keep you all up on their progress. I suspect that laying out a JG that will work with their stack is going to yield further sonic improvements as they'll be able to match the LR/Corner exactly to the reconstruction filter output.
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Nothing like the joy of your very last 10k 0603 .5% thin film flying away to places unknown :-)
I'm pretty sure that my carpet has more parts lurking in it than some Pass amps.
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Some day I'll share the story of my daughter's dog passing some small components :-) Well, I guess that's the story.
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:)p13 You are not alone... my dogs will eat anything and I know they've feasted on a few parts from under my bench.
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Here is mine... currently stock regulators (lm317) and shortly Salas Shunts...
(http://img41.imageshack.us/img41/9104/qjki.jpg) (http://imageshack.us/photo/my-images/41/qjki.jpg/)
Uploaded with ImageShack.us (http://imageshack.us)
Initial listening shows to be relaxed, large sound stage,very good stereo separation, lots of detail but without harshnes, but i feel the dynamics are a bit on the shy/slow side...
Salas shunts will improve things for sure...
Thank you MisterRogers for bringing this dac to our attention, and many thanks to Lyuben and all the jlsounds team.
Looking forward to new developments, and will keep you posted on my progress!!
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Nice! Yep, Salas Shunts will really step it up. Let me see if I can help dig up a JG buffer for you. The JG really picks up in the dynamics/slam where the onboard reconstruction filter leaves off.
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Nice stuff, congrats on the build! I'm working on a I/V buffer and filter too, first time seeing the JG buffer.
I might be missing something, but I think you'd get better phase response with a high order bessel? Here's a sim of the JG's filter section vs a 7th order bessel. The JG goes on Vout, while the bessel has to be used after a buffer on an Iout DAC. The filter's load impedance acts as the I/V resistor, so changing it would cause ringing - the impedance needs to be scaled to use it with a Vout DAC.
Filters: http://i.imgur.com/7kXKs0U.png
http://i.imgur.com/QjSLZXW.png
http://i.imgur.com/BMo48lX.png
Phase response is better on the JG, but group delay and stopband attenuation better on the bessel.
The JG seems to ring a lot more too, even with ideal components. It rings at 100KHz though, so maybe it doesn't matter?
http://i.imgur.com/qFxasIz.png
It's a few more components, and you need to unwind the inductors to get the exact values but even that's not really necesary (part tolerance isn't critical).
edit: better pics
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Good stuff; thanks for working up the sim. Phase response IS very good on the JG, and at 100KHz the ringing is audibly inconsequential. I'd be very interested in your efforts with your high order bessel filter. Please continue to share your efforts Peef!
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I think I'm set on the Bessel. Here's the latest iteration, exclusively for (buffered) current source DACs:
(http://i.imgur.com/9kA2y8Dl.png) (http://imgur.com/9kA2y8D)
This is a differential/balanced 7th order Bessel with an output impedance of 3k. All the values will need to be scaled for a different I/V value. This brings a pcm63 just about to line level. The caps are all standard Wima values, but L1/4 will need to be unwound from larger values, ideally within 2% tolerance. I've done it and it's not that bad with a decent L meter. No harm in rounding L2 and L3.
Here is the result: http://i.imgur.com/a026d8j.png
And against the JG buffer: http://i.imgur.com/QpCxYQP.png
The Bessel's biggest weakness is frequency response. It's at -0.1dB at 15kHz and -0.2dB at 20kHz. Not quite up to industry standard of -0.1 at 20kHz but it could be fixed by shifting the corner frequency up a bit- it's at 78kHz now. I picked it because it was possible to get the C values by combining just two standard caps with a filter impedance of 1.5K but it could stand to be optimized with. On the other hand, the maximum group delay is -6.6ns relative to the passband. Stopband attenuation is >50dB at 352kHz.
Since all filters necessarily introduce delay, it makes sense to optimize for constant delay rather than constant phase (i.e. minimize phase distortion). I've played with all-pass lattices as well, and they'd probably be great with a Butterworth but I haven't managed to optimize phase response. The Butterworth could easily reject 90dB of sampling noise but has bad delay characteristics.
It didn't pop up in simulations, but I'm also wondering if filter ringing couldn't be a source of IMD. High frequency AC heating of DHTs has been shown to increase IMD (through heterodyning) so it seems like risky business.
Will build and report back! :D
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Uhm, group delay is the corollary of phase distortion, specifically phase is the differential of group delay. What are you trying to say?
78k is almost unfiltered. Might as well skip it or reduce it to first order.
Filter ringing is not really a source of IMD per se, but it can make existing IMD louder and thus more active.
I recommend digital filtering instead.
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Sorry, bad wording on my part. I meant to say that it is not possible to design a low pass filter that will have both constant delay, and constant phase for all frequencies. Phase delay is phase divided by frequency, and group delay is that expression's first derivative. The only way for group delay to be constant, if there's already some delay in the system, is for the phase shift to be proportional to frequency.
I can think of tree ways of making sure group delay is constant within the passband: using all pass filters for phase correction, increasing the cutoff frequency to push delay far enough from the highest frequency of interest, and using constant delay filters. Because of its delay response and impedance requirements, I haven't been able to successfully optimize it using reasonable LC values. That's why I shifted the cutoff to 78k.
Even with the high cutoff frequency, there's plenty of filtering due to the high filter order. Here's a comparison of a 1st order with Fc of 30kHz and the 7th order Bessel:
http://i.imgur.com/wJyvTvg.png
In a NOS DAC, both filters are pretty useless (the 1st order having an extra 4dB or so of attenuation at 44.1k). At 8x oversampling, the Bessel is down 50dB while the 1st order is just down 22dB. Hardly unfiltered, but not quite a 16 bit system yet. :)
More attenuation wouldn't hurt. Jung designed an interesting 7th order linear phase reconstruction filter using a linear-phase FDNR filter. I forget why I didn't end up doing a passive implementation of that, but it has excellent characteristics, if not a bit of high frequency rolloff. It's somewhere in this 100 page pdf: http://www.analog.com/library/analogDialogue/archives/39-05/Web_Ch5_final_PtB_F.pdf
Very curious about the IMD stuff, any idea where I can read more about it?
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And (sorry for the double post) here's the lastest iteration. This one's a linear phase, based on the Jung FDNR reconstruction filter.
(http://i.imgur.com/zXFrMGR.png)
The simulation results are excellent. 80dB of attenuation with <1us of delay at 20 kHz. I think this is a more interesting compromise than the -1dB attenuation presented with the FDNR at 30 kHz. I think this is equivalent to 14 bits of dynamic range or so? Not enough for DSD or high res, but getting pretty close to the pcm63k's noise floor. Much better than the third order FDNR found in most older DACs.
Huge sim result, vs previous Bessel: http://i.imgur.com/i120ad4.png
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Thank you very much Peef. I'm not as knowledgeable in analog design as some others here, and I'm learning stuff from your posts :)p5.
Most of the Bessel's (and Bessel like) I've seen seem active (but involve mostly resistors and caps). Pretty cool you are doing it fully with passive components.
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Finished the Salas in the weekend...
(http://imagizer.imageshack.us/v2/1024x768q90/856/e7ap.jpg) (https://imageshack.com/i/nse7apj)
(http://imagizer.imageshack.us/v2/1024x768q90/829/3xo5.jpg) (https://imageshack.com/i/n13xo5j)
(http://imagizer.imageshack.us/v2/1024x768q90/27/ocf8.jpg) (https://imageshack.com/i/0rocf8j)
(http://imagizer.imageshack.us/v2/1024x768q90/838/r0to.jpg) (https://imageshack.com/i/nar0toj)
sounds nicer now... more detail and "air"...
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Looking good, I'd rather had tried to stuff everything in a more compact enclosure. So far how high would you rate the DAC?
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Thanks Hroðulf...
About the enclosure... it was very cheap (13 euro only), very sturdy sides, double bottom, and very easy to work with front and back (soft thin aluminium) which makes it easy to drill holes etc...
It has happened in the past that i couldn't cram everything into smaller enclosures, and had to buy again, plus the fact that i would prefer to have electronic components further apart, for isolation purposes.
I keep the noisy ones to the one side and gradually move to the audio out side to be the furthest apart.
I believe also in mains filtering... this takes up some space also, and it is noisy.
The regulators tend to heat up, so i also needed space for the heat sinks, plus enough space for convection...
In the future i will make an aluminium face-plate without handles, and i will try to incorporate the lock and sampling frequency leds on it... i think this will look pretty cool and it will be useful also.
Well how to i rate this dac...
I haven't had a lot of commercial product available to me so i cannot convey comparisons, but i must say that it has lots of detail, space and stero definition, is very natural sounding...and it causes no listening fatigue...
For me these are high priorities.
I will compare it soon, to two very hi spec, over engineered Buffalo III dacs, and will report back...
To me diy is a solution to get high value, out of spending relatively little, and i think this dac board, with the usb controller, is just that.
It is no giant killer (and i don't think it will kill the Buffalo's..), just a very very honest product.
I have made me three (relatively cheap) diy dac's in the last 4 years... i have gained a lot of listening experience, and bought some time allowing the technology to become maturer...
In the future i will most definitely go for a commercial product... but meantime, i am enjoying my diy projects... :)p1
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Very nice build Chris! By itself, the XMOS/AK stack with good value (as you have) is a very good performer for the price. You need to hear this with a JG Filter Buffer - it elevates this kit such that I prefer it to my more complex Sabre 9018 builds (PH regs, isolation/reclocking, NTD1 IV, etc.).
JG boards are hard to come by though. I mentioned awhile back that Joro/Lyuben (the designers of this kit) have been working on their version of a filter board. It's very flexible; allowing you to build it like a JG (2nd order harmonic filter), or apply filtering to other parts of the spectrum. I have a prototype board, parts on the way, and hope to build it this weekend.
When I have permission from Lyuben, I'll upload some photos/more information about this filter board.
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Do keep us posted!
In the meantime take a look at these http://www.diyinhk.com/shop/audio-kits/46-17uv-ultralow-noise-dac-power-supply-regulator-33v55v-1ax4.html
Might be a good fit for the digital side of things. I wouldn't bother with the bipolar version since it uses two positive regs which isn't too kosher.
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Very nice build Chris! By itself, the XMOS/AK stack with good value (as you have) is a very good performer for the price. You need to hear this with a JG Filter Buffer - it elevates this kit such that I prefer it to my more complex Sabre 9018 builds (PH regs, isolation/reclocking, NTD1 IV, etc.).
JG boards are hard to come by though. I mentioned awhile back that Joro/Lyuben (the designers of this kit) have been working on their version of a filter board. It's very flexible; allowing you to build it like a JG (2nd order harmonic filter), or apply filtering to other parts of the spectrum. I have a prototype board, parts on the way, and hope to build it this weekend.
When I have permission from Lyuben, I'll upload some photos/more information about this filter board.
This is good news MrRogers!! after a few hours of listening i think i will go for your advice and install a JG buffer...
I am waiting for you to post about the one Lyuben and Joro are planning.
Any other information on similar boards and a place to order them would also be helpful.
Thank you!!
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Here's a teaser. I'll be building my prototype this weekend.
(http://www.prettygoodsoftware.net/DIY/I2S_JG_1.JPG)
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Update: I've built JLSounds filter buffer in both a 3rd order and a 2nd order (JG Buffer approximation), and it works flawlessly. As an alternative to the scarce JG Buffer, it'll fit the bill quite nicely. The JLSounds team has been waiting for test feedback, and now they have some. I'll be strongly encouraging them to make this board available for sale. I'm not sure if they have a prebuilt component in mind, as it's designed to be configurable/tuned to the designed filter frequency, input impedance, etc. If anyone wants one but is timid re: the SMD components, let me know and I'm happy to do the SMD work.
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I was wondering, how do you calculate the values for a JG style filter? I haven't seen many RLC passive low pass filters, are the resistors to improve stability? Or some sort of neat impedance matching for the L?
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This filter is designed such that it could be used from first up to forth order. The value of R1 + R_source has to be 300 ohm. For the the AK board, this requires 270Ohm at R1. If the sum of the R1 and R_source is different from 300 ohm,then the amplitude frequency response would be different. L1, L2, R1, R2, R3,C3, C4 determine the characteristics of the filter (n-order). According to the desired approximation of the filter, some of the capacitors may be omitted, and if one of the coils is not needed it can be omitted too. With R5, R6 and R7 one can adjust the offset if is needed - alternatively, FET's can be matched.
While this filter can be used for 3rd & 4th order, it's optimized for 2nd order. 3rd/4th inject delay into the time domain and bring with it a treble roll-off that isn't to my liking.
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Hey All. JL can have boards produced in ~15 days. A couple of questions for all of you; would you like 1) bare boards, 2) boards with SMD assembled, or 3) boards full assembled and tuned for JL DACs & 2nd order?
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Just give me a board, a bom and some sorted transistors.
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Whoops, managed to miss a bunch of replies with that sticky on the top!
Looks like I was following the wrong schematic- R1 is either 470R or 18.9K here. I'd be very interested to see your schematic (especially the new approximation you're working on) if you can post it! :)
Very neat to see the source resistance and capacitance being used to form another filter pole. I hadn't accounted for this and that would explain why my sims were so ringy. You mention the FR changes depending on the filter order; is that a symptom of instability, or just a slower rolloff associated to the lower filter order? I've had issues with variable order filters going unstable when you'd just remove a pole in passive implementations.
No boards for me since I don't have any Vout DACs, but I'm with Hroð. Sorted transistors would be awesome, but nothing soldered in case we want to tweak. Since it's just a ladder filter and a JFET buffer you could easily make it into an awesome universal discrete DAC filter that way.
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Hi MisterRogers,
I will definitely be interested in a fully populated board optimized for the JLSounds DAC and 2nd order.
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Thanks mates; I'll pass that information on to the JLSound team. Here's a schematic of the a JLFilter build tuned for 3rd order. For second order, drop C3, change L1 to 18mH, and change C4 to 100p. This schematic is for 1 channel, so 2x for the build:
(http://www.prettygoodsoftware.net/DIY/JG_Buffer%20Sch.jpg)
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Btw, how does the buffer board interface with the DAC? Are they sandwich-able?
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Thanks for the schem! Are you sure about the values for the third order filter though? I calculated its transfer function and it's nothing like the second order implementation - the -3dB point is around 400Hz, and it's not unconditionally stable, assuming a source impedance of 30R + R1. The second order implementation seems much better, as you said.
Have you considered bypassing the R8/C1 (and equivalent on V-) power supply filter as well? Assuming you have a good power supply, all it would do really is increase the power supply's impedance. I think you might be better served by some carefully placed and derated np0 or c0g SMD ceramic decoupling caps to ensure the supply's stability. A big electrolytic won't be of much use past a few hundred kilohertz. If you want to do something really nuts, you could pick a cap that will have a self resonant frequency equal to the DAC's sampling frequency to improve its rejection and further reduce IMD.
There's an excellent paper on EEtimes on bypassing supplies that I can't find for the life of me. If you haven't seen it, this application report from TI (http://www.ti.com/lit/an/sloa069/sloa069.pdf) is also pretty great.
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C3 should be 2.2nF instead of 2.2uF ;)
2nd order = 124kHz (-3dB) = 72kHz @ -0.5dB
3rd order = 124kHz (-3dB) = 43kHz @ -0.5dB
with C3 at 2.2uF you would be getting a 1st order 237Hz (-3dB) = 61Hz -0.5dB filter
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Hah, good catch! Very nice time domain response, too.
With the inductor of the third order filter having such a small value I'm almost tempted to build one with a ridiculous air-core inductor...
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Ah! yes - apologies; I found that while I was building it for 3rd order, and forgot to pass it on along with the schematic. Great catch.
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All,
Finally got back some prices from Lyuben. Here's a snippet from his email to me:
I finally calculated the prices:
1. Non soldered board Euro 4.5
2. SMD soldered board Euro 18
3. Fully soldered board (and tuned if needed) Euro 27
The prices are with paypal fees and without shipping.
He'll eventually get it up on the store, but we can get an order in if there's enough interest. Also, he has a prototype clock daughter board I'll hopefully be building. He's also working on a max performance AK DAC to go with the receiver. I'll post what I know, when I know it. Chime in if you want a Filter board; I send him a count.
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Was there ever a BOM or more details for the build that started this thread?
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I think I'll wait for the max performance board.
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No, not really, but I'm happy to provide what's needed. Each of the components that make up this DAC have their own BOM (except for the USB Receiver/DAC), and the build's are fairly standard with the usual tweaks to match impedance, etc.
If anyone is serious about the build (I know one or two of you have already built DAC's with these components), I'm happy to share specifics of my component BOM's. I have a prototype oscillator board inbound, along with evaluation boards for the newer AK4490 & AK4495. I'll share what I learn.
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What I'd really like to see in the upcoming AK4490 board is the ability to drive an external output stage directly from the (balanced) chip output, bypassing the on-board output stage / BAL-SE converter (ideally it should be possible to order a board with all that stuff left unpopulated). Support for dual mono would also be nice.
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So since my last post, we've been through quite a few prototypes and completed the design work for a 4490/4495 DAC. With this one, you can tap balanced out, and it's designed to work stereo & dual mono. Hoping to see final boards this month.
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Don't keep us waiting more than we have to, MR!
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Ha! Will do mates. I should have final rev. schematics in a day or so; I'll post those so you all can start planning/designing.
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Awesome!
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Happy New Years Gents!
Thought I'd post a bit of an update. Still waiting for a final schematic, but I've been listening to a Rev 0 for a week now. As with most early articles, the back of the board is unsightly with trace cuts & jumper wires. How does it sound? Fantastic! We're working through firmware issues/bugs, but sonically it's natural, dynamic and organic. It's amazing how good it sounds without TOTL clocks (I have a couple I'll drop in once we've sorted all the firmware issues). Each channel has discrete power - the digital PS is dual stage. I'll break down a components list when the dust settles. The plan is to sell this board(s) assembled. I'll be able to get bare PCB's for us pirates if anyone's interested. Here's a basic breakdown:
- [/color][/size][/color][/font]Dual Mono AKM 4495S DAC’s [/color][/color][/color]Discrete PS for each channel. [/color][/color][/color]Discrete Pre-regulator / LDO for digital circuit. [/color][/color][/color]Galvanically isolated inputs. [/color][/color][/color]USB: PCM >= 384kHz, DSD64 / 128, 16 / 24 / 32 bits. [/color][/color][/color]Additional Inputs: S/PDIF, Optical, optional AES / EBU & S/PDIF. [/color][/color][/color]Outputs: RCA (SE) & XLR (Balanced). [/color][/color][/color]LCD Controller: filters, inputs, volume, etc. [/color][/color][/color]Premium Components: Silmic II, ADM7150, Nichicon FG, LME49724, LME49710, etc.
(http://www.prettygoodsoftware.net/DIY/Veritas.JPG)
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(http://i.imgur.com/DsIGDN0.jpg)
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Congrats. Not a fan of all-in-one boards though. Any chance of a just-the-DAC (IN: DC power, I2S; OUT: Vout+/- of the chip) board (for AK4490?) in the future?
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Certainly. I struggled with the choice for an all-in-one design myself, but decided in the end that if we were really going for the 'best we can do' approach, eliminating flying wires and controlling trace impedance would be worth it. Anyway - they'll be other builds I'm sure; we made a few decisions to get a proto ready for AKM to show at CES that we'll tweak.
I'll say this though - even without dropping in some high-end oscillators, it's pretty incredible that you can add transformers to this DAC and have it kick the ass of some of my uber DAC's with different chips and exotic power, etc.
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This is good news!! and just in time because i was looking for a full balanced dac.
Any estimates on specs and price?
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Any wild predictions on how much will the board kit cost?
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I'll actually have a ballpark number tomorrow I think.
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that board looks like a bitch to stuff.
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that board looks like a bitch to stuff.
More bitch than the QRV08 amp stage?
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Yea, the resister arrays will bring you to your knees if you're not experienced with them. This definitely isn't a 'starter' board.
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Any news on that ballpark price?
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Soon I hope; my partners at JLSounds (Joro & Lyuben) need to set this. Should be before EOD though.
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More bitch than the QRV08 amp stage?
maybe, maybe not. it appears to be a pretty complex BOM. other than the chip to the middle right, the pitches look easy. i'm not sure what resistor arrays MR is referring to.
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Yeah, that's the same thing I though. If or rather when I'm building this, I could use a local soldering shop to cook on the chips and leave the rest to me.
As for resistor arrays, they look like this, Fish -
(http://img.directindustry.com/images_di/photo-g/chip-resistor-array-34041-7076357.jpg)
Pretty sure that they also need some extra fine loving. That being said, they shouldn't mind extra heat.
Btw, MisterRogers - if I opt to get the board set sans parts and assembly, how would I go about getting the firmware?
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i've never soldered a SMD resistor array, but the pitches look easy enough. depending on the traces and ground plane, i would guess to dab some extra flux, turn up the solder temp a bit, and melt/sizzle :). if you can build a y2 or QRV08, this should be OK. personally, i would make sure you have some solderwick, flux, and an iron tip 1mm or less.
if i lived in Colorado, "EOD" = whenever i get off the slopes after a day of eating pow-pow and drinking a growler of Colorado's finest brews at established, legal joints.
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Yep, lots of flux and patience; not too tough. They can take the heat.
Re: firmware, we'll order the PIC's and I'll program them.
Listening to this DAC and working through firmware issues - I'm enjoying the new 32bit filters that AKM is using in the 4490/4495's. One particular one - I think it's Slow Delay Sharp, is quickly becoming a favorite. It works very well with the organic nature of this chip/dac.
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Hey All - so looks like the complete, built board with the control panel/LCD and the OEM USB receiver will go for about $550. To that you add case work and transformers and you're playing music. That price my change, but it's in the ballpark. That's pretty amazing really.
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Wow. Hmmmm.
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amazing!! 550$ is a very good price for that kind of hardware :)p6 :)p6 :)p6 :)p6
MisterRogers, I'm interested in a bare PCB :-) p:3
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Where do I sign up?
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Glad to hear that sort of response!
We should have everything firmed up by end of the month at the latest. The DAC will probably be on sale at both JLSounds & JoeAudiophile. Lucidita - bare boards will be available to interested pirates probably one time only. The plan is to sell it built, but JL has agreed to allow just PCB for me/friends.
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Hey Gang. I've attached the flyer that AKM will be making available at CES this week.
One small price change; seems the board house upped their cost for building the boards. The margins were so tight that the price had to be adjusted up to $600. Minor (IMO), and still one hell of a deal.
http://www.prettygoodsoftware.net/DIY/VeritasFlyer.pdf (http://www.prettygoodsoftware.net/DIY/VeritasFlyer.pdf)
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Looks great! At that price I'd be tempted to avoid messing with the surface mounts myself!
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Same here.
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wow Mister Rodgers! I'd love to hear this little gem, and may jump on purchase!
ahoy
to be clear: would buyers of the prebuilt at $600 still need to add their own case/transformer or ?
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Yes - this price includes the built board, USB board & LCD / Controller. The buyer/builder adds transformers and a case.
I've ordered a couple of transformers from SumR built for the needs of this board. They came to $88 per transformer. If we end up with a bunch that want to order we can run a small group buy for these; probably get the price down quite a bit. I've used SumR's transformers for quite a few years - top of the line build, and purpose built.
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What's the spec on them trafos? Something bonkers?
I am actually thinking of getting C-cores for this build.
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Nah, pretty pedestrian:
2 - 2 x 20V (discrete channel power)
1 - 1 x 15V (digital pre-reg, reg, LDO)
20V isn't super common, so 22V can be used if needed. A bit more heat, but within spec.
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Cool. And by c-cores I meant r-cores.
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heh. Figured :-)
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i like the Amveco TXs as well.
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Agreed - Amveco's are solid, quite and under-specc'd.
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Argh you guys, stop tempting me with shiny new toys... :P
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MisterRogers, any news? :-) :wheel:
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Sure!
We've completed another/final round of tweaking, and the order will go in soon for the release board. I'll be meeting tomorrow with AKM engineers to demo the DAC, and work out chip volumes / cost. The team of JLSounds should post a more detailed status on DIYAudio very soon now.
Hang in there, getting close!
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Great project seriously interested in a possible cobuy.
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I was wondering if any updates for this have been put up recently.
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Hey all. The It's taken awhile, but we've lined up the distributor / price for the main chips; that's been the hold up. Things should move quickly now.
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I can't wait.
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Any updates on this thing?
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Yep, apologies - been very busy with life lately. So my partners decided to design a version of the board with a much higher percentage of SMD components. Reason is, just the design articles we had to stuff each time convinced them that there was no way they'd be able to produce even a moderate number of boards on order. It's a very small team after all.
This past week was dedicated to final listening tests to insure that performance did not in any way suffer. are was taken to spec same or better SMD parts, and parts that were much more expensive in SMD were left unconverted. Anyway, short story - new board layout sounds great and measures very well.
Board / parts should be ordered very soon, and information for the Gb should be posted very very soon.