Alesis Andromeda A6 analog polyphonic synthesizer


Last Update 05-26-2019

Alesis built WHAT?
Different Knobs/Buttons?
Front Panels
Custom Jobs

Disclaimer: I was a member of the beta test/sound design team for the Andromeda, but was never an Alesis employee so any comments herein are my own and have no representation of Alesis.

Alesis really came out of left field when they introduced the Andromeda A6 polyphonic analog synthesizer in 2000.  They were known for their consumer level digital effects and professional multitrack recorders, which made home studios a reality.  Prior to the Andromeda, Alesis first dove into keyboards with their QS series which were a success.  Some of the team members who worked on the QS series happened to be fans of vintage analog synthesizers, which were coming back with a vengeance at that time.  They noted the demand for vintage polyphonic analog synthesizers and the lack of new machines on the market.  A new music genre - EDM - emerged which made extensive use of analog synthesis.  Alesis by then had extensive experience in fabricating custom ASIC chips for their home recording products, which made them very affordable.  That put Alesis in a position to fill the void for a new polyphonic analog synth.  No doubt the Alesis marketing department were skeptical.  While the team members pushing for a new polyphonic synth undoubtably had a hard sell ahead of them... they started the project to spite management.

Wisely, the Andromeda team recruited more analog synth fanatics for the development effort.  The key people at Alesis who brought the Andromeda into existence were Mike Peake, Dave Bryce, Taiho Yamada, and Keith Barr.  If Alesis founder Keith Barr supported the project then management could hardly say no.  The market for vintage synthesizers revealed certain makes and models trading at high values so they focused on the best features of those units.  And focus they did... a real analog audio path with real VCOs, real VCFs, and real VCAs, all the way to the final output.  The VCOs were patterned after the Moog 921 VCO module from the Moog modular synthesizer, chosen for its big sound.  The VCOs could generate triangle, sine, variable pulse, and rising/falling ramp waveforms as well as suboscillators.  They could also be cross modulated, ring modulated, and soft or hard sync was available.  Alesis borrowed a trick from the Yamaha CS-80, offering the sine wave in the post filter mixer which can add a strong fundamental.  The VCFs chosen were the Moog ladder filter and the Oberheim multimode SVF from the SEM heritage, both widely acknowledged to be the most useful filters ever designed without much redundancy in timbre and they co-existed very well in a mix.  The VCOs and VCFs, with their associated VCAs, were shrunk down into an itsy bitsy teeny weeny microscopic four square millimeter substrate ("Honey I shrunk the synth").  With such a small footprint, Alesis was capable of supplying sixteen voice polyphony into a compact package.  With the custom ASICs at their disposal, they could include a world of features and still meet a competitive price target that few manufacturers could match.  The model name was a play on words "A6" = "ASICs".  Virtual synthesizers were still in their infancy at the time and did not yet approach the sonority of real analog circuits.

The "golden era" of analog polyphonic synth design produced a few high density machines.  In 1980 Emu made one prototype Audity that harkened the Andromeda feature set, but its retail price of $69,000 (!) and very large footprint made it an impossible sell.  Emu saw the Fairlight sampler at a trade show and dropped the Audity project to change their market strategy to make affordable samplers, for which it was very successful.  The Rhodes Chroma of 1982 (originally birthed by the maverick designers of ARP) was the first commercial analog synthesizer to offer sixteen voices.  While it had multimode VCFs, each voice only had a single VCO but several architectures were available other than the VCO->VCF->VCA chain.  The Oberheim Matrix-12 of 1985 was the peak of analog polyphonic synth design from the "golden era" offering twelve voices each with dual VCOs, single multimode VCF, and impressive modulation capability.  All of these were large machines before the advancement of SMT.  In 1994 the OBMx made by Gibson guitars - who owned the Oberheim trademark by then but employed none of the original design staff - offered maximum twelve voices each with dual VCOs, dual VCFs, and a decent modulation system.  But the OBMx was a difficult birth which left behind a trail of legal battles and was allowed to die a miserable death (a sad saga reserved for another webpage).  By 2000, Alesis really upped the ante by shoehorning sixteen voices into a smaller lighter package, giving each voice dual VCOs and double the filters, complete sixteen voice multitimbrality (read: each voice could be a completely separate patch), digital effects, and many more features.  At the same time the Andromeda was announced, Studio Electronics released an eight voice analog polyphonic rackmount MIDI module that sounded very good, but its feature set was nowhere near as extensive as the Andromeda.

When the Andromeda was released it was hardly a toy - it was a professional machine.  In addition to the core feature set it included three multi-stage envelope generators that were loopable, flexible routing of the VCFs (bypass or parallel or series, with all four modes of the SVF), four MIDI syncable LFOs (one fixed to S&H), three noise sources (white, pink, red, and can be modulation sources), arpeggiator, sixteen stage step sequencer, analog distortion, digital effects, ribbon controller, key aftertouch (mono), very comprehensive MIDI implementation, a very extensive modulation system, multiple audio outputs (stereo mix, auxiliary stereo mix, and separate outputs for each voice).

These block diagrams can help you visualize the VCO and the various modes of the VCF:

VCF Mix mode (parallel) VCF Bandpass
VCF overall
VCF Notch

All of this with a panel full of knobs and buttons that was a sound designer's dream.  In the beginning, synthesizers had a panel full of one-function-per-knobs that made immediate tweaking a joy.  By 1985 just about every new keyboard had a user interface that was a menu system consisting of an LCD display and either up/down data buttons or a single data controller, which made sound design so difficult that owners resorted to using factory presets.  Menu systems are only feasible for shallow feature sets like a simple monophonic synth, not complex systems like polyphonics.  Back then the market was very aggressive for price competition, and eliminating the expensive knobs was the usual tactic to marketing less and less expensive keyboards to stay competitive.  Analog synthesis had fallen out of favor.  As musicians re-discovered analog synths with a panel full of knobs, they cried to bring back that interface and analog synthesis (the major makers outside the US were VERY slow to respond).  Alesis wisely resisted a large user interface for their extensive feature set, opting to reserve the one-function-per-knob system for the primary functions (72 knobs, 144 buttons) while the remaining features were put in the menu system with eight "soft" knobs that were multi-purpose.  This is a very good compromise; immediate access to often-used controls, while the parameters that are seldom manipulated were relegated to the menu system.  The knobs made it possible to manipulate patches in real time during a performance.

This webpage is far from a comprehensive list of the Andromeda's features, and I'm not going to re-write the owners manual here.  The owners manual is still available at Alesis website if you want to learn more.  top

The announcement of the Andromeda raised a lot of eyebrows.  Many skeptics found it hard to believe that Alesis could build a polyphonic analog synthesizer.  Then when the curtain was pulled back and the names of the sound design team became known, many of the skeptics became believers.  Not every owner embraced the A6; if you're a preset surfer this isn't your machine.  With all those controls, the A6 BEGS to be tweaked.  If you know your way around analog synthesis and love to program them, they don't get much better than the Andromeda.  Many fans label the A6 as a polyphonic modular due to its programming power, and today it is considered "classic" and is trading for high dollars (to date it is not considered "vintage").   top

What kind of sounds can the A6 do?  It is a very flexible machine.  I call it my "chameleon" synth because I have successfully duplicated many sounds from my Memorymoog and old Oberheims, so I just gig my A6 and leave the old stuff at home.  Others have duplicated Roland, ARP, Korg...  There are some factory patches that do a really good emulation of vintage keyboards like the ARP String Ensemble which had defied sampling.  While it can do reed and pipe organs, it falls short on Hammond organ sounds.  Strings?  Horns?  Synth FX?  Pads?  Prog?  80s Rock?  Techno?  Hip Hop?  EDM?  Oh yeah.  This demo isn't my work but it represents a lot of what the A6 can do.  The monophonic lead sounds just don't have the power of a vintage synth like a Minimoog.  The A6 can go beyond typical analog synth timbres.  Thanks to its zippy envelopes and flexible filtering, it is very good at analog drums and percussion.  It has a MIX mode where you can layer/split sounds, and the factory MIX patches show off the EDM heavily-influenced stuff - almost a complete song on the keyboard.  I even created a respectable acoustic piano - uncanny for an analog synth - for the factory library.

Disclaimer: yes, I was a member of the beta test/sound design team for the Andromeda.  There were about a dozen of us on the team, including some professional musicians.  I am forever grateful to Mike Peake for extending the invitation to be involved in this historic instrument.  Alesis allowed me to keep my beta unit (serial #9) in exchange for my work, and since 2001 it has seen steady use.  Many of my patch submissions wound up in the factory library - "Frankensteinwhey", "MeltsInYourMouth", "TawrusBassPedal", "Stereo Strings", "Lucky You", "Modern Day Warrior", "Deep Abyss Bass", "Old Man Winter", "Molasses In Winter", "Shawk The Monkey", "Diamond Rain", "Sea Bells", and many more.

Learning the tricks of the Andromeda can be a daunting task, even for me.  Fortunately for A6 owners, a user on the A6 discussion email list collected a lot of good information and compiled it in a "tips-n-tricks" document, and it is conveniently sorted.  This document and many shared patches can be found on  Even for a seasoned programmer like myself, I learned a bunch of tricks I did not know.

Alesis chose the Fatar tp9 keybed that had semi-weighted keys, velocity sensing, and an aftertouch element.  Many keyboards from 1985 on - in their race to stay competitive - had cheap featherlight keybeds that I never liked.  The Andromeda keyboard is very pleasant to play.  I wish more synths used this keybed, and the Moog Voyager was one of the few that also used a similar keybed.  top

Sharp-eyed surfers will notice the different knobs on my Andromeda.  When I used to work contract engineering, I had a contract job at a fabrication shop that built measurement acquisition modules.  These modules looked like synthesizer modules and I thought I had stepped out of a time machine into a synthesizer factory of 1972!  They had piles of Rogan knobs that they no longer used, so I arranged to purchase a bunch for my A6.  Rogan knobs were used on Moog synthesizer products starting about 1975 (Minimoogs and modulars continued to use the classy Cosmo knobs).  The A6 used large, medium, and small size knobs so I made sure the Rogans I purchased were likewise.  The Rogan knobs have a better feel and I find it is easier to adjust the small Rogan "soft" knobs over the stock ones with the A6.

Even sharper-eyed surfers will notice the different color buttons.  While I was working on beta test/sound design for the Andromeda, one of the staff gave me a bunch of buttons of different colors that did not get used for production units.  I swapped these around and I really like the different colors I put on them, especially the gold colored buttons.  top

To expand the patch memory, there is a card slot for a PCMCIA type 1 SRAM card but these cards are obsolete and hard to find.  Flash memory cards will not work.  A 2MB card gave you six additional banks of 128 patches each and four additional banks of mixes - far more than enough.  I was fortunate enough to acquire one when they were still available and I am glad that I did.

If there is any weak point about the Andromeda, it is the digital effects.  The effects engine is the same as the Alesis Wedge.  There is a large variety of effects - various digital reverbs, chorus, flangers, delays, rotating speaker, pitch shifter - with a healthy set of parameters for each.  Single and multiple effect configurations are available.  The weakest are the rotating speaker and pitch shifter.  The digital reverbs aren't Lexicon quality but aren't terrible (they're FAR better than the piece-of-sh!t ART Multiverb I used to own).  I tend to favor ambient room algorithms, and seldom use reverbs with long tails.  Delay-based effects are the most useful for analog sounds.  Thankfully there is a dedicated button to enable/disable the onboard effects.  I exploit MIX mode a lot for my stage work but only one digital effect can be active in a MIX configuration - the auxiliary outputs allow me to route synth patches to my own effects system where the onboard effects are not enough.

There were a few panel variations.  Alex Hartmann designed the graphic art on the panel, with the "constellations" sections.  The standard panel almost everyone has seen is silver with blue constellations.  The prototype Andromedas had a dark blue panel with black constellations, and only a few of those exist and they may not be able to accept production OS firmware due to circuit differences.  Alesis made a special edition silver panel with maroon constellations.  They only made 250 of those.  When I started on the beta test team I really wanted the red panel unit but there weren't any available.  A third party in recent years has made panel overlays that were all black.  But the overlays did not include the constellations and I like the fact that the stock Andromeda stands apart from almost every other keyboard because it is not all black.  top

And what is this Alesis "Aurora"?!?  Well, someone had a prototype panel for their production Andromeda and commissioned a shop to build a case where the panel was tilted up instead of laying flat.  Alesis even provided a customized OS where the power up splash screen displayed AURORA.  There was an ambition to add I/O jacks on the top of the case but this was never carried out.  Another custom case job was similar except with the black panel overlay and a new set of silver/gold knobs.  Have to admit that gold knobs on a black panel looks classy.

A rackmount Andromeda was on the drawing board, until Alesis ran into financial trouble and was acquired by Numark the DJ supply company.  Numark continued the manufacture of Andromedas but ceased all development work so the rackmount A6 never got off the drawing board.  Numark also ceased all OS development, so the promised MIDI reception of polyphonic aftertouch never became reality.  By then most of the design team for the Andromeda had left Alesis.  This image of the rackmount panel isn't the actual unit conceived at Alesis, it was a mockup done by an internet citizen - and what could had been.  Shortly after the Numark acquisition Keith Barr passed away, and since he was responsible for the custom ASIC designs that was the end of Alesis studio products.  With Barr and the original design team gone, Numark/Alesis management were clueless about promoting the Andromeda, but the buzz around the internet was still alive.  Production was steady until about 2005 when they were made in infrequent small batches, then by 2008 Numark ceased all synthesizer and studio processor/recorder production.  But a production run from 2001 to 2008 is very respectable and an eternity compared to most other keyboards.  Today the only Alesis products are MIDI controllers, MIDI drum sets, powered monitors, and DJ accessories - products that do not need custom ASICs.  A far cry from the original Alesis company...  top

Seems that a lot of misinformation about the A6 gets perpetuated on the internet.  One infamous former owner sold his A6 admitting he couldn't (or wouldn't) learn how to program it, then on every discussion forum he bashed the A6 whenever it was mentioned.  He couldn't be bothered to learn the machine then somehow believed that gave him license to trash it.  I don't have a problem if people don't like certain products.  I do have a problem when people dismiss products while admitting that they did not want to learn how to operate it, yet are boisterous about spreading all kinds of outright lies about the machine then use personal slurs against anyone who dares to contradict them.  Many former A6 owners wanted an instant gratification machine where they could rely solely on the presets.  A poor craftsman always blames his tools...  Others spread the myth that the A6 does not sound "warm".  I've been programming analog synths since 1981 and frankly if you can't get good warm sounds out of an Andromeda then you'll never get good sounds out of any analog.

Some claim that the A6 is "buggy".  This is both false and true.  I can attest that after heavy editing sessions and gigging my A6 regularly since 2001, it is far from "buggy".  The beta test team put a lot of work to uncover the bugs during development and the OS that was released was very mature and free of bugs.  As a member of the beta test team, the subsequent releases of the OS added new features and I know of no bugs that needed to be resolved.  The last OS version was v1.40.13.

As for claims of "buggy", there were foibles later uncovered that could cause the A6 to malfunction but they are not related to the OS.  One is the widely reported "self edit" bug.  This is not a bug; the root cause is oxidizing contacts on the ribbon connectors for the front panel boards.  The oxidization wreaks havoc on the voltages from the knobs, and the OS thinks that a user is manipulating a control.  THAT'S what causes the "self edit".  I had similar issues with other synths.  The problem can be fixed by re-seating the ribbon cable connectors (WARNING make SURE the connectors are NOT offset from the header pins - I did that once and blew the FX ASIC).  But the connectors oxidize again over time; I had to re-seat the connectors every 2-3 years.

Another foible later uncovered is a component substitution on the LCD circuit board.  There is a crystal on the board that generates the timing clock signal.  Later units substituted the crystal with a capacitor, and this caused the clock signal to fail.  This clock signal is crucial to the operation of the A6.  The OS does a self-test on power up and if it cannot detect the LCD clock signal then it will not operate the system.  Many people encountered this in a store and then called it "buggy" not knowing any better.

There were claims of a "bad batch" production of Andromedas but there is no known serial number range for these units.  Today Alesis has no spare parts and service centers that can work on SMT components are few and far between.  The custom ASIC ICs are extremely hard to find today.  A website claims to have spare parts for the Andromeda, but this is not the case and the website hasn't been updated for years.  The service manual can be found online.  top

I am currently playing in a classic rock band that is performing a lot of 70s/80s songs that are heavy on keyboards.  I have a lot of sounds to cover, especially analog sounds.  I have many MIDI modules in rackmount format to cover traditional sounds (Kurzweil 1000xx for pianos, brass, strings, etc), percussion (Alesis DMPro), lead synths (Moog Voyager RME), and bass pedals (Moog Minitaur) all prewired to minimize setup and teardown.  I had been bringing four keyboards, but am now only bringing three; weighted action MIDI controller, Hammond clonewheel, and Andromeda.  That's it!  I succeeded in duplicating the patches I used on my Oberheim OBX into the Andromeda so I can now leave the OBX at home.  Handy performance tip - set the knob mode to PASSTHRU in the GLOBAL menu.  Loud PAs can vibrate the knobs and put the A6 in "edit mode".  Configuring to PASSTHRU means that the instrument does not go to edit mode unless a knob position "passes through" the programmed value.  I exploit the MIX mode heavily to access sounds, splits, layers, and remote MIDI control and the Andromeda has been performing like a champ!  top

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