Info Guide #02

Железо     GRM 2 plus

Pentagon - The problem of poor sound at the Pentagon 2 + and a solution.

               Switch.
  AlCo


   Most likely, you will notice that some
melodies on your computer listens
with not the best kachestvom.Eto most often seen in the fact 
that, for example, "fart" bass notes, or "crunch" udarniki.Ne 
think is bad on your "stereo" as it is nothing vinovato.Vinovat 
that (we will not say who), who bred a fee for

"Pentagon's 2 +".

   The documentation for AY-3-8910
(YM 2149F) specified frequency range
chips, namely 1.2 MHz. In corporate
computer on board Cervus Elaphus (which
inserted into the socket of the processor), as well as
in all circuits used to connect AY
frequency of 1.75 MGts.No in the "Pentagon 2 + on AY
costs twice as much frequency - 3.5 MHz.

   Chip maintains this frequency.
This is understandable - even at school we were taught that 
when calculating the reliability needed to take into account 
the tolerance factor of two. But: 

   Musical effect arising from this
- Uvelichavaetsya twice the frequency of all music, noise, and 
the envelopes (which corresponds to an increase of sound by an 
octave), and the envelope of "0" (It is 1,2,3 and 9), used to 
smooth the sound attenuation, also works twice faster.


   In view of the prevalence of computers
This scheme is almost half the tunes
written under nee.A we, the users of conventional
computers are not able to enjoy
the beauty of the melodiy.No, on the other hand,
"Dvushniki" also can not assess our tunes.

   So I (AlCo) offers you absolutely lamerskuyu circuit 
switching frequencies, which can implement any who can keep the 
soldering iron. 

1.75 MHz ______ CLC AY8910/22 leg
 3.5 MHz (AY8912/15 leg)

All that has been previously supplied to CLC should
relentlessly peel.


   Connect this switch, you have finally
be able to listen to all the best quality,
that was ever written by AY.


   At the same time want to talk about other double standards 
associated with the musical interface. Two of them.


   The first standard is associated with mixing
kanalov.Esli you studied harmony at the music school, then you 
know that the tools in music must have a certain volume

relative to each other, and if this volume change, a piece of 
music will sound very different. The standard scheme of mixing 
channels for connection to a stereo amplifier is shown below: 


               5,1 k

           1k +
 A> VLF left channel
AY8910 / 4 2k
(8912 / 5)
 B 2k 10,0
AY8910 / 3
(8912 / 4) 1k +
 C> VLF right channel
AY8910/38
(8912 / 1) 5,1 k


   Sound is mixed to both channels via 4,7 k.

   What is this duality of the standard? And that on some 
computers secondary channel is not B, and C. As a result, when 
listening to these tunes, we not only according to stereo, but 
will not hear no harmony. (Even worse with the harmony of

me because I do mono.)

   If you are not lazy, you can put the switch and here.


   The second standard is sufficiently
featured in various publications (including Oberon
among others). It lies in the fact that all
wiring diagram AY is too full address decoding port, because of 
what is not running digital music in many demonstrashkah. The 
correct diagram below: 

                            BC2 AY8910/28

                                (8912/19)
A14 '+5 V CS1 AY8910/25

                o (8912/17)
 M1 Ucc AY8910/40
A15 1 (8912 / 3)

              'O BC1 AY8910/29
 A1 1 o (8912/20)
____ O GND AY8910 / 1
IORQ 1 (8912 / 6)
 __ O BDIR AY8910/27
 WR (8912/18)

                            CS2 AY8910/24

A13 in the decryption is not involved!
M1 is to be sure!


   If your scheme is already summed A13, and
All remodel - a pity (and laziness), then submit it instead of 
A13 +5 V, or, at worst, A15. 


   Finally let me remind you not to confused: AY8910 (YM2149F) 
- it's so big from 40 feet, and AY8912 - on the contrary, a 
small with 28, and one I / O port in her

no.