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Digital to analogic converter

For the "die-hard", it is also possible to play sounds without a sound card (and the speaker) via a digital to analogic converter (DAC) on any of the three possible parallel ports. Depending on the board (and the money you want to put in it) you can have mono or stereo sound.

Basic DAC

Taken from Tomi Engdahl (look there for pictures). If you are not afraid of a little bit of soldering, here is the electronic circuit for the most simple one :

         Parallel Port:

          signal   pin        20k   20k
          D0       2      >---###-+-###--0v
                              20k # 10k
          D1       3      >---###-|
                              20k # 10k
          D2       4      >---###-|
                              20k # 10k
          D3       5      >---###-|
                              20k # 10k
          D4       6      >---###-|
                              20k # 10k
          D5       7      >---###-|
                              20k # 10k
          D6       8      >---###-|
                              20k # 10k
          D7       9      >---###-|
                                  # 10k  10uF
                                  +-------][----> To amplifier
                                  # 10k
          Ground  20      >-------+------------->

- There is a driver (8Kb) for using DAC connected to parallel port as Windows 3.1 sound output device for playing back sample and sound effects. The driver was originally written for Covox Speech Thing, but works nicely with this compatible circuit.

- I have not tested myself the drivers with Win95/98, but some other have tested vith varying results. For some people the Windows driver above works nicely, but for some people the sound quality is very bad (many breaks in sound) or the driver does not seem to work at all.
Jodi Davidson ( reported a way to make the driver to work on Windows 98. Here are the tips for that:

Installing the Software
You are now ready to use your sound card. For those of you that have to install the software on your computers copy the zipped driver files to your local drive. Unzip them in a temp sub directory. Then:
Go under control panel and select add/new hardware
Click next and next again to let it search for new hardware
When it comes up with no new items click select from list
Choose Sound, Video and Game cards
Select Have Disk and browse to the directory you unzipped all the files for the drivers in.
Select the oemsetup.inf file and click ok.
Click ok, and click ok again.
Select the Covox Speech Wave Driver
Choose the Port your sound card is plugged into (Most cases this will be LPT 1)
Then you are done and you can restart the machine. The next time you login and want to use your sound card go through the configuration listed at the bottom of this page.

Configuring The Device
Like all the other devices on your computer, our sound card needs some drivers to make it work. The driver we are using is called the Covox Speech Thing Driver. At camp the drivers are already installed for you, you just need to select that sound media to play our music. You can do this by selecting:
Start Menu --> Settings --> Control Panels --> Multi-Media -->
Under the audio tab select
Playback: Preferred Device to be "Speech Thing Waveform Output"
Then select the check box at the bottom that indicates to only use the preferred device.

Here are also the drivers for Windows 9x (8Kb).


Taken from Henrik Haftmann. There is a lot of info (not only in german but english too) on DAC (program source, circuits, ...). Here is what Henrik says about it :

LPTDAC.386: LPTDAC Waveout Driver Version 1.0
 = SoundBlaster Emulator on LPTDAC base for Windows and its DOS boxes
 - LPTDAC  Digital-Analog-Converter on printer port. In the easiest way
   one R-2R-network ("16 singing resistors") in a dongle case
 - My first great experience in case of 32 bit, protected mode, and
   device driver programming. I want to demonstrate, that there is
   more than 1kHz available on my 386/25. Without kernel programming it's
   impossible (fixed 8kHz from the real time clock excluded)

System Requirements:
 - 386 DX 25 (faster --> better results)
 - MS-Windows 3.1 Enhanced Mode (I don't know how it works under Windows95)
 - SB20SND.DRV as multimedia driver for Windows or SNDBLST2.DRV (only 22kHz;
   this is a standard Windows driver named "Creative Labs Sound Blaster 1.5")
   (You can write a well-suited driver for this in Turbo Pascal...)
 - The LPTDAC Speech Thing

Missing Functions in LPTDAC.386 Version 1.0
 - proper device contention management
  + one VM could set the sample rate and interference another VM
 - device contention management while printing via same port
  + You should avoid playing sound and printing at the same time:-)
 - Some API-Funktionen are not implemented
 - Setup values for SB port, IRQ level, and DMA channel
You can get the whole thing at LPTDAC-Projekt.

Players using DAC

The whole point of the exercice is that with a DAC you should have a better sound than with the original PC speaker.

Usually the player that can play with the speaker can play with DAC so just have a look under the DOS section. On the internet search for the older MOBOBJ and MODPLAY or newer Optical Player and Inertia player.

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