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Post by chinook9 on Jan 24, 2016 15:46:07 GMT
Chris, do you have reason to believe that the Rev 3 Soekris would sound significantly "better" to you than the Rev 2. I can wait for Rev 3 but I would prefer to get one ASAP. Did yours sound a much "better" after the mods?
Also, with the power supplies (DIYINHK, Salas) that may be set to output different DC voltages, do you know if it is necessary to change the ac input voltage (transformer) to match the selected output? I don't think it is but I'd like to confirm that.
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Post by chris1967 on Jan 24, 2016 19:52:14 GMT
The thing is that the revisions of the board have come together with revisions of firmware. The initial sound was a very rich analog like mid, but with grainy or sharpish treble albeit rolled, and a lower end that although had enough extension lacked in macrodynamics. The sound with the latest firmware and the caps/resistors is more balanced along the spectrum, better extended on both ends and improved macro and micro dynamics. Unfortunately the richness of the mids has subsided. Yet it still is much more lifelike compared to the sigma deltas. The Salas outputs a range of voltages depending on both the transformer used and a resistor (or trimpot). Usually you use the trim-pot/trafo to get to the desired voltage and then exchange the trim-pot for a good fixed resistor in the value that the desired voltage was reached. It is good to get a transformer that for DC gives you at least 5V extra from your target voltage. 7-10V is better against mains fluctuations, transformer regulation with high current etc in order to have voltage stability versus manageable heat dissipation on the transistors. diy.beyarn.com/bigdata/BIBguideRev2.pdf
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Post by chinook9 on Jan 24, 2016 20:00:28 GMT
Thank you for the explanations Chris. I appreciate it.
I have some thinking to do. I'll have to consider the trade-offs.
I just want to get some decisions made and order some parts/kits.
Thanks again.
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Post by chinook9 on Jan 26, 2016 21:25:42 GMT
After much thought I placed an order with DIYINHK. I ordered the AD1862 DAC kit with XMOS (non-isolated) USB to I2S adapter/receiver along with accessories and power supplies required for both the AD1862 and the Soekris. I also ordered an inexpensive enclosure from Par-Metal (20-16124N). Looks like a pretty good deal for a basic enclosure at $64 plus shipping. Just plain aluminum but I expect it will do nicely.
I'll probably order toroidal transformers from Antec in the next couple of days. They are well respected manufacturer of computer power supplies and happen to be quite inexpensive.
I plan to call Soekris in Denmark tomorrow and see what they can tell me about projected availability of the Rev 3.
Should very interesting to build and compare DACs.
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Post by chris1967 on Jan 29, 2016 20:50:27 GMT
Excellent, looking forward to hearing your opinion on the AD1862 kit!
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Post by chinook9 on Feb 15, 2016 14:46:48 GMT
Still waiting on the shipment from Hong Kong. Haven't seen anything on the tracking number since the package departed Hong Kong 16 days ago. Waiting, waiting, waiting,....
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Post by chinook9 on Feb 16, 2016 20:25:37 GMT
Received shipment from DIYINHK this morning. Everything looks pretty straight forward but no instructions.
Javier, you mentioned that they provide instructions. Have you seen them? I check their web site and didn't find anything I would call instructions. I can probably do without but I'd like them if they exist.
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Javier
Administrator
Digital bytes
Posts: 986
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Post by Javier on Feb 16, 2016 21:14:14 GMT
Havent seen them. I read some posts at DIYAudio where people mentioned they got pdf files with instructions for some of DIYINHK DACs but maybe it was for the most complex designs. From the pics un his website it looks like it shouldnt be difficult to build the 1862 without them but for peace of mind you could email him and see if he can help.
Sent from my GT-I9505 using proboards
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Post by chinook9 on Feb 16, 2016 21:21:35 GMT
I will send him an e-mail but I doubt it will do much good. I asked a couple of technical questions in the past but didn't get an answer that was helpful.
Thanks Javier!
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Javier
Administrator
Digital bytes
Posts: 986
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Post by Javier on Feb 16, 2016 22:28:23 GMT
If you get stuck or have any doubts post here and somehow we'll get it sorted.
Sent from my GT-I9505 using proboards
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Post by chinook9 on Feb 16, 2016 22:55:15 GMT
Thank you Javier. I just went through all the components and everything looks pretty straight forward. It was interesting, to an audio electronics noobie such as myself, that the +-9/12/15V and the 3.3/5/7V PS kits contain the same identical components. I didn't check the pre-installed SMDs. Do you know if the large inductors on the PS are likely to be bipolar? There are markings on the PCB but I couldn't see any on the inductors themselves. I expect I should just install them with the markings oriented as they are shown on the DIYINHK site. Another question: The AC input on the 3.3/5/7V power supply PCB indicates 6/8/10V AC input. Except for jumpers there are no adjustments on the PS. Will the PS output the jumper selected voltage as long as the AC input is reasonably close to that specified? I will need 3.3V for the AD1862 and I have not read anywhere if it can use more or less. I have a 7V transformer I can use with this PS. Assuming it has the required capacity, do you have any idea if this should work? Attachments:
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solderdude
Administrator
measureutternutter
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Post by solderdude on Feb 17, 2016 19:43:54 GMT
The inductors are actually common mode chokes. So basically 2 inductors on one core. Usually the 4 pins are positioned so they can only be mounted in 2 'ways' instead of 4. It doesn't matter which way around.
For a 3.3V regulator you will need a 6V trafo (the 7V will also work). When the input voltage is too high (say 10V) the regulators will become too hot. When the AC voltage is too low (say 4V AC)then you may get a ripple (hum) on your 3.3V.
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Post by chinook9 on Feb 17, 2016 20:02:56 GMT
Thank you Frans.
I will start a new thread for the building the DIYINHK AD1862 DAC and come back to this thread when I segue to the Soekris..
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ariel
valued member
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Post by ariel on Apr 23, 2017 12:12:03 GMT
It has been a while since I stopped reading about the Soekris DAC but a friend built one and wasnt happy with. He complained about design flaws, lack of support from Soekris and then wasnt convinced with SQ. If you are still not fully set on getting one you may consider one of DIYINHK R2R kits. He has some very interesting (and affordable) kits based on Analog Devices and BB chips which may not be as 'romantic' as a fully discreet resistor ladder but in the real world they perform much better. I'd suggest any of the 20bit ones like PCM1702 or AD1862. He also offers PS boards, isolated USB capable of outputting the data formats these chips require and lots of good quality stuff. Sent from my GT-I9505 using proboards I've read as much as I could about the Soekris DAC including what is written in this thread and eventually decided to purchase the Soekris DAM 1021 - 12. I've added a cheap LT3042 regulator to supply the DAC with clean +/- 12v and connected an amanero USB->I2S connected to RPi3. I've got only one advice for whoever is reading this : Do yourselves a favor and by this board!!! There's No way you'll be disappointed.
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Post by chinook9 on Apr 24, 2017 14:08:23 GMT
I still haven't lost interest in the Soekris but I've had other projects. I'd be interested to hear what you've compared it to and how they differ.
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