ZX Club #04 16 сентября 1997

Железо

Covox - What is the COVOX (scheme).

            ONCE MORE ON COVOX


     In recent years, began to "slip" mention COVOX. They can 
be found in ZX-Review for 1996 and Format'ah. There

editors COVOX: Instrument v3.01,
Sample Tracker v2.1, DIGITAL-Studio. However, many do not even 
know that it is of itself represents. And this is only one port 
and sixteen resistors plus a bunch of wires.

This is the simplest LPT COVOX, having only
one channel. Wait ...


     So, COVOX enables you to listen digital music written for
eight-bit digitized instruments.
You can also listen to "capture" true -
long. It is a pity that such a device is not
gained popularity, because you can not
just cool to write music, but without
ANY CONVERSION carry digital-music with the IBM PC and AMIGA!


     The purpose of the article: to help all comers
have COVOX, as well as bonus issues ZX-CLUB will be 
digital-music (if Alex Rostov will write it.


SWdZ: If Alexander Rostov on any
why can not provide digital-music to the next issue, try 
"austere" ready to transfer music files from the IBM PC. 
Perhaps among the readers there musicians who wish to write 
music specifically for COVOX ... 


     There are three versions
COVOX. The first and most primitive, - LPT
COVOX, which has one eight-bit channel;
usually "cling" to port # FB. Second -
PROFI COVOX - has two vosmibitnyh channel. Following the name 
suggests, this was COVOX assembled for a computer PROFI, ie for 
his Printer Port VV55. The third modification

COVOX - most non-proliferation, although
has awesome sound quality - it
Sound Drive. On it, four (!) Channel that
conforms to the IBM PC and
AMIGA. Here are just for its construction needs
two VV55 ... I did not collect Sound Drive, but
all other COVOX'y - yes. From my own experience, I believe that 
despite the ease of assembly, LPT COVOX (especially for

Owners Pentacon 128, with port # FB)
collect is not necessary, because quality music
slightly higher than the same quality of music you are 
listening by AY. KSAT, digital-music you can listen to and 
muzykalnoi coprocessor. But the tools a eight-bit, while the 
coprocessor AY - four Bit ... Sound Drive just disappears 
because of complexity in the assembly. Remains PROFI COVOX.

If you have a 128K, then locate the Sample
Tracker and run the demo tune on AY.
PROFI COVOX goes something like this, but the sound -
deeper and purer.


     If you already have VV55, it is necessary
all-just connect the shawl with resistors, and if not - build a 
circuit that is shown in Figures 1 and 2. 



  D0 34 D0 10P DB0 18

  D1 33 D1 BB55 DB1 19

  D2 32 20 D2 DB2

  D3 31 21 D3 DB3

  D4 30 22 D4 DB4

  D5 29 D5 DB5 1923

  D6 28 D6 DB6 24

  D7 27 D7 DB7 1925


  A5 9 A0 DC0 14

  A6 8 A1 DC1 15

                                 DC2 16

  A7 1 January 1917 DC3
____
IORQ LL1 2 3 4 1 6 June 1913 CB DC4

                                 DC5 1912
 DOS 5 LL1 DC6 11

  __

  RD 5 RD DC7 10

  __

  WR 36 WR

              10mkF +5 B 26 5

          +5 B <35 R 7 B

                +


                      120kOm



          Figure 1. Interface BB55


     As can be seen from figure 1 - is a well-known printer 
interface. Signal is active in the DOS unit (joystick block - 
DOS). This signal can be taken with a floppy drive controller 
or proinvertirovat available. Separately, a RESET. Generally 
speaking, the right to connect it as shown in scheme, but - you 
can "tuck" to RESET'u processor, or simply to +5 V Option

will select themselves, because COVOX may "stall" during 
playback. The scheme does not shows the port A BB55. I repeat 
"a hundred times" said: this port can be connected

Kempston-joystick.


R1 = 15 ohms>
R2 = 7,5 kOhm


                        6200

        R1 R2


       DX7



        R1 R2


       DX6



        R1 R2


       DX5



        R1 R2


       DX4



        R1 R2


       DX3



        R1 R2


       DX2



        R1 R2


       DX1



        R1 R2


       DX0



                Figure 2. DAC


     Bunch of resistors (Fig. 2) - is the DAC
assembled chains of R-2R. Shows the DAC to
one channel. For the second channel of the DAC is identical. 
DX07 - signal ports B or C. Capacitor is optional, but without

it will the dynamics of "popping", which, in general, not scary.


     Some probably have questions like: "Why should I COVOX, if 
you can listen to digital music and AY?" And then, dear, that 
the co-processor is played strongly distorted sound rather than 
"kovoksnutaya" music. At COVOX'e, again, the music is more 
clear and extensive. 


     In principle, if lazy, you can collect and LPT COVOX. 
Player COVOX'a absolutely indifferent to drop bytes. This 
version suitable for gamers, which is unnecessary top quality 
sound, ie - Only would be cool to sound-effects were. However,

the sound here is better than AY.


     For PROFI COVOX quite possible to write
coolest Mouzon. Sound - a fairy tale. I think it is - the best 
option. 


     Fans can collect sound Sound
Drive and "drag" on this very "a pile of wires and resistors," 
well and good from kovoks audio, of course. 


     We would like to COVOX'y
become a habitual thing, like AY
(At least in Barnaul). Send
their views on this (and not just this one) about the letter or 
on a diskette TR-ISMS-DOS (the size is not important) to 
address Editorial ZX-CLUB.



     Or call in the evening (after eight)
articles directly to the author, Vitaliy, on the phone

                42-96-42.


     Yes, the main thing. Frankly, the existing digital-music 
editors clearly do not meet "the requirements of the era."

So, gentlemen, coders, not better
get the glory of the coolest music editor, than to release 
another Mega-Giga-DEMO? ..



       We invite to cooperation