Firmware
Last known revision for S900 is 1.2C. Multiple variants of 1.2 are known but the Akai S900 1.2A EPROM binaries are available for repair and updating purposes.
Additional Features of v1.2
– One Shot mode (page 14 of Edit Program)
– Previous Sample Bandwidth display
– MIDI Program Change enable/disable
– MIDI loudness send/receive (MIDI channel volume?)
– Sustain previous voices while changing patches
– Boot OS from floppy
Note: Burning the ROMs requires an EPROM programmer and two 27128 type EPROMS.
Akai S900 Disks
S900 OS Disks
(requires v1.2 / 1,2 firmware; update using the above firmware, if necessary)
Operating System v2.1
Operating System v4.0
Additional Features of OS 2 and 4
1. Pre-trigger recording
– retains 2000 samples prior to transient (preserves attack)
2. Special one shot mode
– auto-handling of drum machine MIDI
3. Crossfade looping
– page 13 of Edit Sample
4. Dynamic Filtering
– ADSR control, no resonance; page 17 of Edit Program
5. Automatic locating of start point
– trims gaps; page 6 of Edit Sample
6. Velocity release by note on
– page 10 of Edit Program
7. Combine two samples for velocity crossfade type samples
– page 15 of Edit Sample
8. Changing the velocity mix curve for velocity crossfade
– page 4 of Edit Program
9. Time skew for velocity
– page 14 of Edit Program
10. Key group copy function
– page 3 of Edit Program
11. Disk mode: Compression of sampled data (OS4 only)
– saves disk space; enable/disable via Disk menu
S900 Bundled Floppy Disks
(see page 23 of the Operator’s Manual for more details)
S900 Operation Guide Disk
SL501 – Grand Piano #1
SL502 – Chopper Bass
S900 Sound Library (SL5xx)
Note: See premium content information at the bottom of the page.
SL503 – Drum Kit #1
SL504 – Voices, Flute, Vocal
SL505 – Orchestra #1
SL506 – Strings #1
SL507 – Brass #1
SL508 – Harp Gliss, Cello-Viola, Pan Pipes
SL509 – Pizz Strings, Eastern, Kalimba
SL510 – The Stick
SL511 – Bells, Strings, String Bell
SL512 – Guitars #1
SL513 – Effects #1
SL514 – Clarinet, Brook, Harp Pluck, Glock Harp
SL515 – Glass Bell, Choir, Voice Strings
SL516 – Ooos (Chorus)
SL517 – Acoustic Guitar, Classical Guitar
SL518 – Ring Mod 1/2, Solo Guitar
SL519 – Violin Cellos
SL520 – Acoustic Bass, Bass1~7, Fretless 1/2
SL521 – Strings #2
SL522 – Strat Guitar
SL523 – Choir 1/2/3
SL524 – Choir 4
SL525 – Choir 5
SL526 – Les Paul, 12 Strings
SL527 – Les Paul VS
SL528 – Solo Violin, Slow Violin, Violin Sect
SL529 – Cello #1
SL530 – Ethnic Percussions
SL531 – Harp #1
SL532 – Violin #1
SL533 – Contra Bass, Cello, Violin
SL534 – Viola
SL535 – Vibraphone
SL536 – Pan Flute
SL537 – Flute, Piccolo
SL538 – Bass Flute, Alto Flute
SL539 – Ocarina
SL540 – Recorder
SL541 – Bass Recorder
SL542 – Fretless Bass
SL543 – Brazilian Guitar
SL544 – French Horn
SL545 – Church Bell, Church Organ
SL546 – Tenor Sax, Trombone, Flugelhorn
SL547 – The Islands, Marimba, Vibraphone
SL548 – Rolling Timpani, Gong
SL549 – Synthe Bass 1~7
SL550 – Guitars #2
SL551 – Effects #2
SL552 – Harpsichord, Tubular Bells
SL553 – Orchestra Hit #1
SL554 – Latin Percussion, Conga
SL555 – Effects #3
SL556 – Orchestra #2
… (number and titles 557~580 are unknown and unverified) …
SL581 Multi Sound 1
SL582 Synth Sound 1
SL583 Dry Kit
S950 (SL50xx) Sound Library (also backwards compatible with S900)
Note: Unavailable.
These disks utilize the maximum capabilities of the S950 and have been recorded with a sampling rate of 48kHz for sound that surpasses CD quality. They can also be used with the S900 and the S1000 series samplers.
SL5001 – Off Mic Piano
SL5002 – Electric Piano
SL5003 – Rich Strings
SL5004 – Violin Pizz & Marc
SL5005 – Viola Pizz & Marc
SL5006 – Real Choir
SL5007 – Brass Section #2
SL5008 – Trumpets
SL5009 – Saxes
SL5010 – Wind & Mallet
SL5011 – Chopper Bass #2
SL5012 – Wood & Fretless Bass
SL5013 – Bass Variation
SL5014 – Nylon Guitar
SL5015 – Synthe & Techno Kit
SL5016 – Kick & Snare
SL5017 – Percussion #3
SL5018 – Percussion #4
SL5019 – Ethnic Percussion #2
SL5020 – African Percussion
PSL9xxx Library for S900/S950
Note: See premium content information at the bottom of the page.
PSL9001 – Orchestra
PSL9002 – unknown
PSL9003 – Grand Piano
PSL9004 – Gigging Piano
PSL9005 – Moog/MKS/Emu Basses
PSL9009 – Mixed Choir
PSL9010 – unknown
PSL9011 – Live Drums 1
PSL9012 – Drums & Percussion 1
PSL9013 – Electronic Drums
PSL9014 – unknown
PSL9015 – unknown
PSL9016 – Special Strings
PSL9017 – unknown
PSL9018 – Songwriter
PSL9019 – unknown
PSL9020 – unknown
PSL9021 – Collection 1
PSL9022 – unknown
PSL9023 – unknown
PSL9024 – unknown
PSL9025 – Linn Drums
PSL9026 – unknown
PSL9027 – Trombone / Alto Grr Sax
PSL9028 – Trumpet / Jazz Tenor Sax
PSL9029 – unknown
PSL9030 – unknown
PSL9031 – Trumpet Classic
PSL9032 – unknown
PSL9033 – String Orchestra
PSL9034 – Cello
PSL9035..43 – unknown
PSL9044 – Grand Choir
PSL9045 – Dual Bah Choir
PSL9046 – Hammond 1
PSL9047 – Hammond 2
PSL9048 – Electric Guitar with Chorus
PSL9049 – unknown
PSL9050 – Acoustic Picking Guitar
PSL9051 – Sitar
PSL9052 – Banjo Dobro
PSL9053 – unknown
PSL9054 – unknown
PSL9055 – Trumpet II
PSL9056 – Sax ‘n’ Flute Set
PSL9057 – Marimba
PSL9058 – Humour
PSL9059 – Classical Flute
PSL9060 – Band Disk
Akai S900 Bad RAM (D-RAM) Bit Codes
These are verified and definitive codes; no guesswork involved.
IC45 = DJ0
IC46 = DJ1
IC47 = DJ2
IC48 = DJ3IC49 = DJ4
IC50 = DJ5
IC51 = DJ6
IC52 = DJ7IC53 = DJ8
IC54 = DJ9
IC55 = DJ10
IC56 = DJ11
IC57 = DJ12
IC58 = DJ13
IC59 = DJ14
IC60 = DJ15IC61 = DK8
IC62 = DK9
IC63 = DK10
IC64 = DK11
IC65 = DK12
IC66 = DK13
IC67 = DK14
IC68 = DK15IC69 = DK4
IC70 = DK5
IC71 = DK6
IC72 = DK7
Service Manual
An all new, high-quality scan which includes the rare CPU addendum is now available — see premium content information below.
ASK90 Information
Once an Akai S900 is fitted with the ASK90 expansion board, pressing that oh-so-mysterious Utility button will show various information and settings regarding the drum inputs.
Page 1 (Global Settings) — The ASK90 drum triggers can be enabled or disabled via the DRUM INPUTS ON/OFF menu option. Global input sensitivity can be set to either high or low.
Page 2 (MIDI Settings) — MIDI channel, note/pitch, and on-time can be set per trigger input. The on-time parameter has a range of 1-9,999 milliseconds. A MIDI note off event will be generated if any given input is triggered twice within the duration set by the on-time parameter. MIDI data is generated using these settings by the ASK90 during trigger input events, and the data is then relayed to the S900 MIDI output.
Page 3 (Input Settings 1) — Each of the eight inputs has a capture time parameter which sets the signal detection time within a range of 1-20 milliseconds. Higher times provide greater signal detection accuracy, but will necessarily increase the trigger latency. MIDI velocity is based upon the peak audio level detected within this capture time. Recovery time (1-99ms) can be reduced to 1 for very rapid response, or increased to prevent false re-triggers.
Page 4 (Input Settings 2) — A bar graph is presented to monitor the trigger level currently being adjusted. Unlike the global input sensitivity setting on Page 1, the gain parameter in this menu is per channel and ranges from 1 to 99. Likewise, trigger threshold is also set per input with a maximum ceiling of 40 and minimum of 1.
The ASK90 configuration data can be saved or loaded using the Disk menu. A newly accessible ninth page contains a LOAD/SAVE DRUM SETTING command so the ASK90 does not have to be calibrated or readjusted at every reboot or power off event. There is no way to store multiple configurations for the ASK90 on the same disk, but this can be worked around by using additional disks, if necessary.
The ASK90 came with one floppy disk featuring drum kit samples (bass, snare, three toms, rimshot, cowbell, metal, open/closed hi-hat, ride, and crash cymbal. These are arranged into three drum kits: small dynamic range, large dynamic range, and no cymbals.
Floppy Emulator Installation and Setup Guide (Gotek/HxC specific)
The correct and easiest way to install a Gotek with HxC firmware into an Akai S900 — with pictures, explicit instructions, and all the configuration, update, and disk image files needed to get started with an HxC-flashed Gotek.
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Note: Not all disks listed above are available. The library archives are currently incomplete, but will be updated if/when the missing disks are obtained.