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How To Upgrade Your Akai S900

What do you do when your 12-bit Akai S900 sampler starts to seem a little underspecified in comparison with the latest models? Upgrade it with a '16-bit injection' from Marion Systems. David Mellor reports.

Q: What do you do when your 12-bit Akai S900 sampler starts to seem a little underspecified in comparison with the latest models?

A: Don't sell it. Upgrade it with a 'bit injection' from Marion Systems. David Mellor reports.

Wouldn't it be nice if your equipment never got out of date? Once upon a time, studio equipment was kept until it wore out. Now, it is only useful as long as it is current technology. The pace of change in musical expression, and the equipment that makes this change possible, is rapid. That's what makes studio life fun.

Just over two years ago, the Akai S900 sampler was the machine to have. Musicians all over the world were selling their grandmothers to get hold of one. Now, those same musicians are looking wistfully at the new S1000 16-bit sampler and wondering which members of their family are similarly expendable.

Let's suppose, for the sake of argument, that you are an existing S900 owner, and you can afford to buy an S1000 (I'm envious). What do you do with the old S900? Sell it on the secondhand market might be one answer, but how much do you think you will get? Its 'preowned' value is plummeting faster than the price tag on a Sierra carefully used by a sales rep. But it is still a very worthwhile piece of equipment, even though it is no longer the latest thing. I certainly don't intend getting rid of mine for a long time yet. Perhaps if there were some way of giving its performance a boost up to current standards, that might be a much better option than losing an old friend.


Enter Tom Oberheim. If the name sounds familiar, think of those excellent analogue synths which bear the same monicker. Now he calls himself Marion Systems - or rather that's what his new company is called. Their first big assault on the market is an upgrade for the S900, called the MS9C, which is claimed to raise performance standards to the 16-bit level. In several ways, this could be an acceptable alternative to giving the old S900 the big heave-ho. Let's examine this upgrade in more detail...

What you get for your money is a large, square printed circuit board (PCB), which is a complete replacement for the voice circuitry of the original machine. Just throw the old one away (or sell it to an electronics enthusiast!).

This is the point where many might take fright, but installing the new board doesn't look too difficult. Those who have been on the Territorial Army training course, 'Dealing with personal panic situations when modifying audio equipment' will get along fine. Seriously, all you need do is to remove the 13 top cover screws. Disconnect the cables going to the topmost circuit board (they are all on push-on connectors, so no soldering) and unscrew the board. Follow these steps in reverse order with the new board and it's done - the only tool you need is a Phillips screwdriver.

Here comes advantage number one over selling the S900 and buying something more modern. The MS9C is designed to appear exactly like the original voice board to the existing control circuitry of the S900. In other words, there is no change to the operation of the sampler, everything appears as it was before, but with the benefit of 16-bit sound. In fact, you could operate an upgraded S900 and not know that half of its innards had been changed. There is the added advantage that any future software upgrades to the S900 will not find themselves in conflict with the modification.


Looking at the specifications of the MS9C, you might notice something odd. The standard 12-bit S900 gives a maximum full-bandwidth sampling time of 11.7 seconds. With the MS9C upgrade, the 16-bit S900 gives a maximum sampling time of... 11.7 seconds. How can this be unless extra memory is added - which it isn't? Surely 16 bits will generate more data than 12? Never fear, all will be revealed.

What you get for your money on the MS9C are 16-bit analogue-to-digital and digital-to-analogue convertors. What you also get is a clever device which converts the 16-bit data into 12-bit data, so that it can be stored in exactly the same way as it was before. To the S900, there appears to be no difference. But if you shrink 16 bits down to 12, there must be some information lost somewhere, surely?

About halfway down Page 1 of the 'Rulebook Of Life', a publication that most of us missed out on somehow when we were small, is a short paragraph explaining that you never get something for nothing. It's true here, too. What the MS9C does is to compress the data in the top 40 decibels of its dynamic range to make it fit into the available sample memory space. Note that this is not compression as found in compressors and limiters, but digital manipulation of the data generated by the A-to-D convertor at the input. Below the —40dB level the MS9C performs true linear 16-bit conversion; above this it acts, in effect, like a non-linear convertor.

I have to say here that this is not the same as linear 16-bit conversion, as used in the Akai S1000. If I said that the process used here was as good as the S1000, that would be unfair and misleading. The drawback to non-linear conversion is that it produces something called 'modulation noise' - a hiss that rises and falls in level as the signal level rises and falls. The effect of modulation noise is very subjective. For example, there is one famous tape noise reduction system that produces modulation noise to an extent that makes it unusable for me, yet many other people hardly notice it. If I say that in the case of the MS9C I find the mod noise occasionally noticeable, but hardly even slightly troublesome, that might put it into perspective. But I have to mention it, because true 16-bit linear sampling is better.


This could be a very short paragraph, because hardly anything is changed. The main point of interest is the swap between 12-bit and 16-bit modes. You did want to play your old sample disks, didn't you?

On the Marion Systems upgrade board, there is a little gadget called a 'jumper'. It's not woolly in the slightest, but links two pins on the PCB. It has two positions: one makes the upgraded S900 power up in 16-bit mode automatically, the other does the reverse and places the machine in 12-bit mode at switch on. Changing modes during use is done by inserting a special 3.5" toggle disk. Loading this disk (it takes just a couple of seconds) switches the S900 alternately from one mode to the other. It's not possible to use 12-bit and 16-bit samples simultaneously, but that isn't much of a disadvantage.

The only other difference the new board makes is that the S900 meter operates slightly differently when you take a sample. Because the top 40dB's worth of data is effectively compressed, the segments are slower to move. This actually seems to make it easier to set a sample level, although I'm half convinced it's an optical illusion.


The big question about the MS9C upgrade, since it costs a fair hunk of cash (£595 plus VAT), is what does it sound like? Does it sound noticeably better than the original S900?

Well, even before I started playing about with samples I noticed that the output noise was lower than on my own S900, so that's a good start. One of the hardest things for a sampler to do is to capture accurate reverb tails, so I sampled some Microverbed drum machine beats. Once again the upgraded S900 was noticeably quieter than the original, although the decay of the reverb wasn't as clean as on the S1000 I also tested. Incidentally, Marion Systems claim that the frequency response of the original S900 isn't all that it could be, and that they have improved it. This is a subtle difference that you would need to hear for yourself before deciding that it was an advantage (and if you preferred the original response, there is a jumper on the new PCB to allow you to select just that!).

To try and summarise the benefits of the MS9C, I would put it like this. You get improved audio performance, but not up to S1000 standard. Operation is the same as before, so there is no time spent on a new learning curve. Old sample disks can be used without difficulty. Additionally, new sample disks can be created at less cost than when 16-bit linear sampling is used, because the MS9C retains the same, more compact, data format as on the 12-bit machine.

And what are the drawbacks of the MS9C? Well, if you have considered all the options and it seems an appropriate step forward, there are none.


£682 inc VAT.

Synton Electronics BV, (Contact Details).


(supplied by Marion Systems)

AKAI S900 S900/MS9C
Dynamic range (unweighted): 68dB 85dB
Frequency response (-3dB): 80Hz-16kHz 18Hz-18kHz
Input filter: 6-pole switched capacitor 7-pole voltage controlled
82dB S/N 92dB S/N
Analogue to Digital convertor: 12 bit 16 bit
70dB S/N 92dB S/N
Digital to Analogue convertors (8): 12 bit 16 bit
72dB S/N 96dB S/N
Output filters (8): 6-pole switched capacitor 7-pole voltage controlled
82dB S/N 92dB S/N

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Orla Master Keyboard

Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - Dec 1988

Donated & scanned by: Mike Gorman

Gear in this article:

Expansion Board > Marion Systems > MS 9-C

Sampler > Akai > S900

Gear Tags:

12-Bit Sampler

Review by David Mellor

Previous article in this issue:

> Shape of Things to Come - AE...

Next article in this issue:

> Orla Master Keyboard

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