DIY sound card building resources [links]

[smidi]

Dear all,

I am trying to compile a list of resources on the Net, that deal with, simply speaking, a do-it-yourself implementation of a sound card.

I am especially interested in entry level tutorials, as well as open source (open hardware) projects, which ideally supply schematics that can be reproduced in a student lab - since I am interested in learning a bit more about the implementation of sound cards in principle and in practise. Hence, under the category of "DIY sound card" I'd consider any project/resource that deals with implementation of PC hardware, that performs single or multi channel ADC (data acquisition) and/or DAC (full or half duplex); and/or corresponding driver software (Linux/XP) - ideally @ at least 8 bit, 22 KHz per channel.

I would like to ask the forum to contribute with other online resources that would fall within this category. I hope this is the right forum to ask this - if not, please point me in the right direction (since I can see that most projects discussed here deal with increasing audio quality, rather than entry level tutorials).

Here are some resources I could find until now, in no particular order:

1. DESKTOP 386SX PC AS DAQ - http://www.geocities.com/the_beijing_dragon/daqmac.htm
* A Desktop PC with custom made ISA card performs ADC and sends via serial to a Mac laptop. "ISA-BUS interface using a ADC0804, 74LS138, and a 74LS24", "The desktop 386SX PC has ... MS-DOS 5.0 is installed , a simple AUTOEXEC.BAT and a program that reads address 220h to access the ADC0804 and then send the value thru COM1: 9600,1 stop bit, No parity, 8 data bits. Using Turbo C BIOS services on INT14h to communitcate." - so apparently will be able to do max 8 bit, 1200 Hz sampling. Old resource, not all schematics are on the webpage, C code provided.

2. ADC interfacing with PC - http://www.control.com/1026204402/index_html
* Forum thread, some useful comments, references also the the_beijing_dragon link.

3. APPLICATION NOTE 633, Bench Characterization of ADCs Using a Low-Cost PC-Based Data-Acquisition Board, Maxim/Dallas, http://pdfserv.maxim-ic.com/en/an/AN633.pdf
* Schematic of a "a high-speed digital I/O card from National Instruments (PCI-DIO-32HS)" given, no code; 6 channel ADC card, 16 bit, up to 20 MHz?

4. PC ISA Bus Analog-to-Digital, Digital-to-Analog Card, http://www.boondog.com/tutorials/max158/max158.htm, [part of Boondog Automation tutorials]
* "The net result is an ADC/DAC card that has:
* Maxim's MAX158 8-bit eight analog-to-digital channel chip
* Sampling frequency (with interrupts) apx. 1 kHz
* National's DAC0832 one channel digital-to-analog chip
* Hardware interrupt handling option
* DOS Turbo C code sample and description"

5. ePanorama PC hardware projects page, http://www.epanorama.net/links/project_pc.html
* References a DAC schematics for PC (ISA) slot, AD/DA conversion for parallel port

6. ePanorama PC soundcard page, http://www.epanorama.net/links/pc_sound.html#projects
* References the ELRAD magazine articles (Take Five and PCI Recorder), under a "Build a soundcard" section, under "Soundcard hardware projects"

7. Take five optical digital interface card, http://www.xs4all.nl/~fjkraan/digaud/elrad/9408048/takefive.html
* "Take five is a digital audio interface card for the pc. The card supports 32, 44.1 and 48 kHz datarates. There are two optical inputs and an optical output available." so no ADC. German magazine "Elrad published this card as a D.I.Y. project, ", but the scanned pages on the site are removed.

8. PCI Recorder, http://www.xs4all.nl/~fjkraan/digaud/elrad/pcirec.html
* "ELRAD published a successor to the Take Five card in the issues March , April and May of 1997. This card has both optical and coaxial in and outputs and is completely 'plug and play'." Click on the March/April/May links to access the articles, in German. As far as online translation can parse these pages, the articles seem to give a very nice discussion of audio PCI card issues.

9. Final Year Project Low Cost PC-Based Quad Channel Oscilloscope - Final Report, http://www.cmccord.co.uk/FYP/final_report.htm
* 8-channel 10-bit ADC, based on PIC16F877 microcontroller, serial communication to PC @ 9600 bps

10. Yamasaki Lab Reponsive Processor project, http://www.ny.ics.keio.ac.jp/research/resp/
* Contains a link to schematics of "PCI Board with external ADC/DAC", also "Explanation Documents" (in Japanese), as well as Linux drivers

11. Sound cards materials, http://www.kiarchive.ru/pub/misc/hardware/soundcard/
* Seems to have some interesting resources listed, among others DAC schematics for PC slot, http://www.kiarchive.ru/pub/misc/hardware/soundcard/dac/

12. Flashy acquisition board, http://www.knjn.com/board_flashy.html
* Some nice block diagrams, but is a commercial board, not DIY - to be used with Dragon PCI FPGA daughterboard [http://www.knjn.com/board_dragon.html]

13. Controlling The Real World With Computers, http://www.learn-c.com/hardware.htm
* Schematic and C software provided: "The hardware is a tinned, masked PC-based ISA data acquisition and control board that: accepts up to 8 analog inputs through its 8 channel, 8-bit analog to digital converter (one has a mike preamp); produces analog output through 2 8-bit digital to analog converters (one is connected to an amplifier complete with volume, bass and treble controls that will drive a speaker)"

14. Hardware project Audio DSP PCI Card [still in planning phase], http://www.opencores.org/projects.cgi/web/fac2222m/overview

15. "DIY Sound Card?", forum post, http://www.head-fi.org/forums/showthread.php?t=174326

16. "help!, diy sound card parts problems", forum post, http://www.diyaudio.com/forums/showthread/t-84267.html
* Schematic of DEM-PCM2902 evaluation board

17. PCM2902 USB DAC/ADC Project, http://web.archive.org/web/20070509135128/http://hepso.dna.fi/misc/pcm2902/PCM2902_usb_dac.html (offline, archive, schematic cached)

18. "usb dac" thread, http://www.head-fi.org/forums/showthread.php?t=51870
* There seems to be a project page on http://web.archive.org/web/20060220034206/http://www.mellowparenting.demon.co.uk/guzzler/usbdac.html (offline, archive, schematic not cached)

19. MWP's Audio DAC-3, http://www.overclockers.com.au/~mwp/dac3/
* 1U USB DAC, schematic provided

20. AdLib sound card on a parallel port, http://www.raphnet.net/electronique/adlib/adlib_en.php
* Interfacing an ISA sound card to the parallel port

21. PCM2706 High Fidelity USB Soundcard / USB Headphones project, http://electronics-diy.com/PCM2706_USB_Soundcard.php
* Schematic, PCB Layout

Well, that is all I have for now - I look forward to, hopefully, seeing some more links in this thread ! Thanks...

 

[voodooless]

If you want it simple: just look at the USB stuff. You won't even need to write any drivers (at least not with the burrbrown stuff). Just design and make the PCB, solder the componentes on, and you're there

 

[smidi]

Hi, thanks for your reply !!!!

The reason why I want to get "all" resources on soundcard I/O, also on older stuff and on DAC/ADC that does not necesarilly provide audio quality by todays standards, is mostly for educational purposes. I have an engineering education, and I understand the theory behind ADC and DAC processes - but *not* in the practical sense of usage (in particular, soundcards); so I'm looking for resources that would help me go through that.

For instance, earlier I knew the theory behind ADC , but on a mathematical level mostly; once I built the Flash ADC here (with discrete elements ), I think I understood way better the actual physical process.. I'd like to do the same with soundcards (although this will be much larger process).

Obviously, if one wants to do multichannel I/O, there has to be some kind of signalling between the card and the PC - and that is what I'd like to get a hands on experience with. In that sense, I think that the http://www.learn-c.com/hardware.htm project is perfect for a start - because it works with discrete elements, and I think the source code deals with some low level signalling (which is why actually I would like some discussion on writing drivers).. I'm seriously considering doing that project first - as I have access to a student lab, I just have a problem tracking down a "living" 486 with ISA slots

However, for any usable work, one has to progress towards PCI or USB, and I'm afraid for the time being I won't be able to afford the specs, so I don't know how well that will go... That is why I'd like some more resources dealing with that In the end, what I'd like is to understand - from practical experience - *why* doesn't one need to write any drivers for a USB DAC

So, any comments or links are much appreciated..