Looking for an Open Hardware DAC - Page 1
Forum section: electronics / general

author: Antipixel
author_rank: Newbie
timestamp: July 17, 2016, 11:44:34 am
content: TLDR;Looking for an open source hardware DAC plan or someone who built their own DAC and has mad ideasLong version:Was looking for a DAC, AMP, and a Speaker for a long time now. But none fit my needs... till it dawned upon me... I study physics, I can wield a soldering iron... build your own!So my current idea is to build my own easily fixable box with all of that jazz in + an audio jack for headphones. (All the details will trickle in with onsetting problems)But as much as I like reinventing warm water, I do need to also finish my degree. So I'd love it if someone has a template or tips how to deal with it so I'd only have to reinvent the parts I'd need specific for myself.Of course I'd post my progress and plans in the end.PS: Tips about components are welcomethe ones I had to deal so far were accademic, and perfect, and on paper

author: Kalvin
author_rank: Super Contributor
timestamp: July 17, 2016, 12:18:05 pm
content: The sound will get distorted as soon as it enters into the crossover filters and leaves the speakers.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: July 17, 2016, 12:19:58 pm
content: You mean something like this?https://hackaday.io/project/5996-drdac-usb-audio-dac

author: Antipixel
author_rank: Newbie
timestamp: July 17, 2016, 12:38:11 pm
content: @Blueskull Ya it sounds hard but if I want it to be tidy and not have 3 boxes on my desk or butcher the parts of 3 boxes and somehow squeeze them in one functioning box. Unless you have a better idea Im ears to everything at this point really.Quote from: Kalvin on July 17, 2016, 12:18:05 pmElaborate on this.Quote from: chickenHeadKnob on July 17, 2016, 12:19:58 pmSomething exactly like that.

author: Kalvin
author_rank: Super Contributor
timestamp: July 17, 2016, 01:02:27 pm
content: Quote from: Antipixel on July 17, 2016, 12:38:11 pmEven if the DAC and the amplifier are close to Perfect, the crossover filter will create phase/time error and the speaker elements with the enclosure will add their own artefacts [which are definitely audible by every person with golden ears, of course]. Most of the amplifier designs are driving the inductive speaker elements in voltage mode which may not produce ideal response either.Here is a nice article about the crossover filters, phase error and time error:http://sound.westhost.com/ptd.htmHere is a nice summary about the speakers and the current-drive mode by Tomi Engdahl:http://www.epanorama.net/newepa/2014/10/10/loudspeaker-operation-current-drive-better-than-voltage-drive/Disclaimer: I am not an expert by any means and I do not have golden ears.Edit: Added the link to Tomi Engdahl's article.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 28, 2016, 06:51:20 pm
content: If you're just looking for something to run some headphones, my best friend and I came up with this:https://github.com/NiHaoMike/OpenDAC-HDIf you also want to use speakers, things get a lot harder. I do not know of any DIY purely digital amplifiers and adding digital crossover makes things harder still.

author: ip2k
author_rank: Newbie
timestamp: October 20, 2016, 02:05:45 am
content: Check out the Henry Audio DAC. In general though, as others have said, implementing one from scratch or on something like an FPGA is going to be Difficult. If you'd like to try that route, check out FPGA4Fun 's One-Bit DAC.Sent from my iPhone using Tapatalk

author: Harrkev
author_rank: Contributor
timestamp: December 07, 2016, 06:42:23 pm
content: If you want to go COMPLETELY open-source, there is always the resister ladder. Getting 16 bits of resolution might be a bit of a pain, but certainly doable...https://en.wikipedia.org/wiki/Resistor_ladder

author: Lukas
author_rank: Frequent Contributor
timestamp: December 07, 2016, 11:53:41 pm
content: You may also want to take a look at this:http://nwavguy.blogspot.de/2012/04/odac-released.html

author: tszaboo
author_rank: Super Contributor
timestamp: December 16, 2016, 12:48:55 pm
content: Quote from: Lukas on December 07, 2016, 11:53:41 pmHe never released the design files. Also he disappeared some 2 years ago, such a shame.Quote from: NiHaoMike on August 28, 2016, 06:51:20 pmThat thing looks quite resonable, when I read the used ICs and the schematic. Then I looked at the implementationGood job

author: HSPalm
author_rank: Regular Contributor
timestamp: March 09, 2017, 09:49:42 am
content: Quote from: Antipixel on July 17, 2016, 12:38:11 pmSo you're looking for an IC implementation like Blueskull suggested.Quote from: Antipixel on July 17, 2016, 12:38:11 pmSo you're not looking for an IC implementation after all.Many who's in audio say DAC and mean the whole implementation, from input connectors (USB often), through the actual DAC (the ic), further on through an amp and then out to speakers or headphones via connectors again. Looks like this is the case here.Quote from: chickenHeadKnob on July 17, 2016, 12:19:58 pmAbout this, I admire the bodge-job on the DAC ic!

author: ECEdesign
author_rank: Regular Contributor
timestamp: April 08, 2017, 02:29:45 pm
content: You can read the literature on DACs. To make one you need a CAD tool like Cadence and the money to send your design to a foundry. Usually, only companies and well-funded universities have this kind of money since you can reach one million pretty quick. Better off just buying an off the shelf DAC and learning a bit about how DACs work.

author: tiger99
author_rank: Newbie
timestamp: August 07, 2017, 10:35:07 pm
content: A 16 bit DAC will cost you maybe a few pounds, dollars or Euros. A 16 bit R-2R DAC made at home will not be monotonic and so will cause horrible distortion. A string DAC made at home will be monotonic but not necessarily linear, unless you build it with Vishay S series resistors, of which you will need 65535, all of one value, at about 7 pounds/euros/dollars each, and at least 4096 16 bit analogue multiplexers plus decoding logic.You CAN make a PWM DAC at home, and it can be highly accurate and linear, but it will need time resolution of about 350 picoseconds to cover the audio band with 16 bit resolution. You would need a FPGA with a phenomenal clock speed and minimal jitter. It will also need a well-designed low pass filter, which is entirely feasible as it involves op amps and only moderately precise (say 1%) resistors and capacitors, and only a handful of each.A PWM DAC is supremely useful for low frequency instrumentation, where the superb linearity probably can't be beaten, and is a technique worth learning about, but is just not going to be useful for audio.So basically you can't beat, or come anywhere near to, a moderately priced chip from any of the major semiconductor manufacturers.

author: gagrdonik
author_rank: Newbie
timestamp: August 13, 2017, 10:36:46 am
content: Thanks for this link, it's really helpful for me