Jan 032018
C and PAS tools to play MOD's.
File MODOBJ-1.ZIP from The Programmer’s Corner in
Category Music and Digitized Voice
C and PAS tools to play MOD’s.
File Name File Size Zip Size Zip Type
HARDWARE.DOC 12763 4175 deflated
MOD-OBJ.DOC 9654 3660 deflated
MOD-OBJ.OBJ 13076 7223 deflated
TCMOD.C 1373 658 deflated
TCMOD.PRJ 22 21 deflated
TPMOD.EXE 14880 8630 deflated
TPMOD.PAS 1764 787 deflated

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Contents of the HARDWARE.DOC file

MODOBJ ********* (C) Mark J Cox
MODOBJ ** 1991-2
MODOBJ *******
MODOBJ **************

Hardware devices for great sound output!


How to make:
Mono output from a parallel port for about 5 pounds
Mono output from a parallel port for around 1 pound
Stereo from one parallel port for about 12 pounds
A +5v power supply
A 22W amplifier

This document has been supplied with MODOBJ. You may distribute
this file freely with any program you include MODOBJ in as long as
it remains unaltered.


MODPLAY will play modules through the PC Speaker as mentioned above, via
an D to A converter on any of the three possible parallel ports, in stereo
if you have an D to A converter on both LPT1 and LPT2 (this sounds really
good) and also through a special board that plays stereo from one
printer port ("stereoon1")


A simple circuit for HiFi quality sound needs only a few components (and
this circuit will work with other software). It even sounds better than
a Sound Blaster for sampled output!

You need:

IC1 a ZN426E (about 3 pounds) (Ferranti or Plessey are UK manufacturers)

C1 a 10micro-farad electrolytic capacitor (10V or greater)

C2 a 4.7micro-farad electrolytic capacitor (10V or greater)

R1 a 380ohm resistor (5%, 1/8W)

CON1 a phono socket for connecting a lead to your amplifier

CON2 a 25 way male D-type connector for your parrallel port

A bit of 10 way cable - or 10 short wires.

A +5v supply

Zn426e +5V
D-type pin no \
(2) D0 9 14
(3) D1 10
(4) D2 11 390
(5) D3 12
(6) D4 13 5
(7) D5 1 6 +
(8) D6 2 4> TO AMPLIFIER
(9) D7 3 7 10F
+ (may not be needed)

(25) GND GND


Lots of people have found that they cannot get the ZN* chips outside
the UK - so heres a circuit that will do the same as above..
Use a DAC0800 or DAC0801 or DAC0803 from National Semiconductors...

DAC 080x
Parallel Port Pin 0.01F 0.1F
(2) D0 12 16 GND
(3) D1 11
(4) D2 10 155k
(5) D3 9
(6) D4 8 145k
(7) D5 7 13
(8) D6 6 2 +5V
(9) D7 5 3 1 4> TO AMPLIFIER
0.1F + 10F
(may not be needed)

(25) GND GND

The 0.01uF and 2x 0.1uF capacitors are Ceramic. Resistor values
not critical


Catalogues such as MAPLIN (uk) provide simple circuits for obtaining
a +5v power supply (it only has to be 100mA maximum). Alternatively
you could tap +5v off the keyboard connector or use 3 1.5volt
batteries (or even 4 1.5volt batteries with two diodes in series to
drop the voltage). In fact, anything that produces a voltage in the
range 4.5 5.5 volts. (in fact you can even tap +5v from the game
port). Don't forget to connect the 0v of your power supply to the GND
rail shown.

Heres a simple circuit for +5v from mains. Mains voltage is lethal
so always get a qualified person to make this if you are unsure. Make
certain that the mains voltage is completely isolated from the computer
side and that it is impossible to touch - If you don't want to take the
risk then don't make this circuit.

B 7805 +5V
Step down R + +
Mains transformer 6V I C1 C2 C3
to 6VAC AC D
E 0V

C1 1000 F electrolytic capacitor (Circuit from Kenneth
C2 0.1 F ceramic capactitor Aaron, Israel)
C3 100 F electrolytic capacitor
BRIDGE any diode bridge


For the price of 20 1% resistors and a plug, with no power supply
needed you can make a D/A converter that sounds close to the IC
one above (it seems only the UK can get a Plessey ZN426E)

You need one plug for your amp, one for your parallel port and
9 20k and 9 10K resistors
Use 1% resistors if possible and 20k sound much better than 22k

Printer 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 >
20k 10k 100nF
GND 20 >>

Thanks to Harry Stox for the above circuit. Again, make sure all
the 0v lines are connected together. The 100nF capacitor may not
be needed, try removing it if this circuit sounds poor.


It is possible to play in stereo with only one parallel port (MODPLAY
version 2.00 onwards) using the circuit below. MODPLAY will
automatically detect this circuit if it is present and work out what
address it is at so you can plug it into any of your parallel ports.
MODPLAY needs no further options and will default to playing through
this device. The +5v supply can be anywhere between 4.5 and 5.5 volts
so it could be run from three 1.5v batteries. (Or from four
rechargable batteries as these are only 1.2v)

* Stereo-on-1 works from MODPLAY 2.03 onwards where it did not in 2.00 *

You can use your stereo-on-1 board with other programs that require
a single D/A on the port as follows:

Find out what address your port is at (LPT1 = 0378, LPT2 = 0278) and
add 2 (LPT1 = 037A, LPT2 = 027A). Go into DEBUG and type
o 37a,3 (replacing 37a with the port address)
Then all sound directed to the parallel port will come out of both

11 6+5v
12 7
13 3NC
14 + 10F
15 5> Left out
16 0v>
20 >0v 1 10+5v
2 90v
14 >4 8

11 > ZN428 + 1F
9 >11 D7 VRIN 6
8 >12 D6 VROUT 7 NC
7 >13 D5 NC 3 NC
6 >14 D4 + 10F
5 >15 D3 OUT 5> Right out
4 >16 D2 0v>
3 >1 D1 +V 10+5v
2 >2 D0 0v 90v
1 >4 !EN 0v 8
25 pin male D connector


Make sure all the 0v lines are connected together and connected to the
0v line of your power source. Also, make sure the +5v lines are
connected together. The lines marked 'NC' do not need to be connected.

If a ZN428 is not available, any D/A with input latches will work -
the D/A should latch the data bus when pin 4 (!EN) is low.

= No connection, = joined

The above circuit (Stereo-on-1) is (C) Mark J Cox 1991, 29 Lundie Close
Stenson Fields, Derby DE2 3AN; and is supplied for personal use only.
For any other use, please contact the author at the address above. If
this circuit is abstracted or incorporated into any other document or
circuit then that document or documentation supplied with that circuit
must contain this paragraph of text. Any commercial use where not
agreed by written contract with the author (Mark J Cox) is prohibited.


For those of you who have built a stereo DAC and haven't enough
inputs to your Amplifier - Kenneth Aaron has supplied this
circuit which is designed to give a high power (11W per channel)
high quality, low interference, single rail supply amplifier!

> +12v
0v 7 13 3 1 Left
Left 470nF 4 2 Speaker
5 TDA 7370 14 Right
Right 470nF 11 15 Speaker
+6 8 9 10NC


Make sure that 0v of the +12v supply is connected to all the 0v
connections on the main circuit. The enable line has to be tied
to +12v to 'switch on' the amp


Mark J Cox Electronic Mail:
29 Lundie Close [email protected]
Stenson Fields
Derby, UK If that fails - try:
DE2 3AN [email protected]

 January 3, 2018  Add comments

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