| 1,2 |
Hardwarebuffer (2 * 2 kByte) to prevent
accidently stopping Playback and Recording
Melody 1200 plus makes use of 128 kByte RAM for Playback
which results in about 5 Seconds when playing back MPEG-Audio
Layer 2 at usual bitrates. |
| 3 |
X-tal driven clockgenerator for different
samplingrates |
| 4 |
Output connector (SubD-9pol,EMI) for plugging
the adaptor which results in 6 external RCA connectors
(female)
As a replacement for the cover used at the Sub-D a bracket
may get used or the board may get mounted to the backside
of your Tower directly. |
| 5 |
internal connector for CD-Reader as an example
|
| 6 |
active analogous input filters
They remove HF-noise with has no place in audiosignals.
By the way: The parts used are used with a reason! It's
not possible to use cheaper stuff like some people recently
told ous. Melody 1200 is not cheap trash! It's known other
new boards for Amiga have got the filters removed...judge
yourself please! |
| 7 |
active 2-stage filters for clean output
(4..20kHz) |
| 8 |
20 Bit AD/DA-Converter.
This high performance chip is usually used for Dolby (R)
Pro-logic (TM), THX (R), Dolby Digital AC-3 (TM) and better
DSP-based stuff. Its Signal to Noise Ratio of 108 dB is
much better than known from cheap "16 Bit Multimedia Audio"
CODECs offering about 86 dB (each 3 dB step means
doubling the ratio). Please don't have
a closer look at such numbers they're not usefull. At
least you may recognice the chip is playing at different
League! |
| 9 |
Connector for serial control- and audiodatabus
between analog and digital part of Melody 1200.
Via the audiobus data is transceived using a professional
standart (TTL-Digital-IO). Only by using exactly this
design it's possible to get the seperation to the agressive
digital lines and emmission of the computer. Another important
advantage to poor designs,
which need to transport analog
lines through the machine is the possibility for nice
extensions. A separated design like this is very intensive
in development power and electronic parts needed. Because
of this not cheap but very nice in performance. |
| 10 |
strong filtering of the supply for getting
really clean voltage routed to the analog circuits. User
of Melody 1200 will be able to recognice a bit of this
filtering in hearing a special switch-off sound. This
will happen several seconds after switching of power!
|
| 11 |
Space for upgrading it with a DSP to be
a Melody 1200 plus oder pro
(Melody 1200 pro is shown at this example) |
| 12 |
The EPLD, a programmable logik chip.
This is the heard of Melody 1200. The complexive Control
of the board is located in it. The programm loaded into
it is differend for the variants of Melody 1200 and is
the goal for easy upgrading from Melody 1200 base to plus
or pro. The basic functionality includes f.e. access of
the CODEC and generation of signals needed to support
a RS232-Modul and even includes logic needed to connect
a Digital-IO expansion. At Melody 1200 with DSP (plus
or pro) its even responsable for giving data to it. For
sure it controlls the buffering and various serial <->
parallel conversations required. |
| 13 |
Main connector whitch connects to the Clock-Port
of the Amiga 1200
The port is routed through the board (with some signals
modified) to make it possible to use another expansion
on top of it. Boards done by Kato Development will work
witout trouble. Others like Hyperc*m1 may need a small
modification (a cut and a wire). They were not done with
respect of getting other boards work at the same connector.
|
| 14 |
Fehler bzw. Peak-LED (neben der SubD-Buchse)
The LED shows misbehaviour of the board and things like
overloading the inputs (clipping). Skilled electronics
should better move the LED to another place in A1200's
housing (warranty will not void!) to make better use of
it. |
