Magazine Archive

Home -> Magazines -> Issues -> Articles in this issue -> View

Simmons SDS EPB

If the sound of your kid sister hitting a biscuit-tin lid is your idea of what a snare drum should sound like, Simmons' new EPROM blower should make your sampling dreams come true. Paul White reports.

As the sound-sampling war hots up, Simmons strike another percussive blow for Britain.

After months of superhuman patience on behalf of E&MM staff, the long-awaited EPB finally arrived in the editorial office last week. Designed primarily to complement Simmons' SDS7 electronic drum kit, the EPB enables the musician to store natural sounds on EPROMs so that they may be used later as percussive elements within the SDS7. It's not inconceivable, however, that the EPB will find applications other than as an add-on to the SDS7, as stored sounds may be triggered from a sequencer, click-track, or indeed Simmons' own newly-developed SDS1 pad, making the EPB a useful device for studio applications.

Either the 2764 (8K) or 27128 (16K) type EPROMs may be used, giving maximum sample time of 0.8 seconds and 1.6 seconds respectively.

Whilst not being long enough to capture entire party political broadcasts (and let's face it, who'd want to capture them in the first place?), the EPB's capacity does allow it to accommodate a wide range of percussive sounds and, using the larger EPROM, ambient effects such as reverbed snare drum, for example.

The EPB has a single input channel which incorporates a peak LED for level matching purposes. Once it's been fed into the unit, the sound is digitised into eight bits and stored in an area of RAM (up to 16K), and it's at this point that whatever it is you've sampled may be replayed so that its relative worth may be evaluated before it is immortalised in EPROM form. Once the EPROM has been programmed, it may be played back via the EPB or used to replace one of the existing EPROMs in an SDS7, should you be lucky enough to possess one.

A computer interface is also provided, and this allows samples to be transferred between the EPB's memory and that of the computer, making the editing of sounds (or even the creation of new ones from scratch) quite feasible. The catch is that if you want to take advantage of this facility, you'll have to write your own software, but it shouldn't be long before some enterprising soul starts to market a suitable package.


This is a functional bit of gear, and its 320 x 210 x 75mm steel case makes few concessions to fashion. All the switches and pots are mounted on the top surface, along with the zero-insertion-force EPROM socket, whose nomenclature is conveniently and charmingly shorted to 'zif'. The rear panel contains the computer interface connector, the input and output sockets, and the trigger input socket. No surprises there.

For the enlightenment of those readers who have never encountered a zif, it's simply an IC socket into which a chip may be plugged without whoever's doing the plugging having to use force. The clever part is that once the chip has been fitted, a lever clamps the IC's legs, thus holding it firm and ensuring good contact. This is obviously desirable in situations where an IC needs to be inserted and withdrawn on a frequent and regular basis, as otherwise the socket would wear out and half your EPROMs would be walking around with wooden (non-conductive) legs.

Mode D'emploi

Didn't know I could speak Serbo Croat, did you? The first item on the agenda is to decide whether you're going to record the sample live (using a microphone), or whether you're going to sample something you've already recorded on tape. You'll need to plug the EPB's output into a monitor system of some kind in order to check the sound quality of your handiwork, and the output monitors the signal after it has been through the digitisation process, so you can check for side-effects that might be caused by the sampling rate you're using. Sadly, this facility is only audible during sampling.

Whatever you decide to record, it must first be stored in the RAM section of the EPB, and the Record RAM button is used to select this function. The input level should be adjusted so that the clip LED just glows if you want to obtain the optimum signal-to-noise ratio without distortion.

Depending on which EPROM size you intend to use, 8K or 16K should be selected, and recording may then be initiated by pressing the Start button.

In order to obtain the highest quality of recorded sound, the sample speed should be set as high as is possible without cutting off the end of the sample. If there's a hefty chunk of silence recorded after the sound has died away, you're sacrificing bandwidth and signal quality to no purpose. So stop it at once.

The beauty of being able to store the sound in RAM first is that all these finer points can be optimised before the end result is burned into the EPROM. Of course, trying to synthesise the exact beginning of a percussive sound to the pressing of the Start button can be a bit of a pain, to say the least, so Simmons have wisely built an auto-trigger facility into the EPB.

Pressing the Ready button puts the EPB into this automatic mode, and recording starts as soon as an input signal is present. A variable threshold helps to ensure reliable triggering and this is best set empirically.

Finally, the moment of truth. You plug an EPROM into the zif, pausing only to check that the Safe/Blow switch is in the former position. Pin 1 of the EPROM must be next to the lever, ie. the indent at the end of the EPROM should point towards the rear of the case. Moving the lever down locks the EPROM into place, and the Safe/Blow switch can then be moved into the Blow position.

At this point, you simply press Save followed by Start and wait for the Start LED to go out (between 40 and 80 seconds). When this event has come to pass, the Select switch can be thrown back to Safe and your handiwork checked by pressing Play PROM followed by Start.

A Loop facility is also incorporated, and this causes the stored sound to cycle indefinitely (at a rate set by the Sample Speed control), enabling you to set up repeated signals and thereby create that mystical entity we call A Rhythm.

If you find that you loathe your latest sample with an intensity normally reserved for tax inspectors, your EPROMs can be erased and reused by subjecting them to half-an-hour of electronic brainwashing in an ultra-violet eraser supplied as an optional extra. To give you some idea of what this implies, half-an-hour in one of these things is equivalent to a week or so in the Sahara, only without the sand.

Sound Quality

This really depends on the sample speed set during Record mode, though for every sample I made while the EPB was in my possession, a certain amount of quantisation noise was always evident. This is generally unobtrusive in the context of percussive sounds, but where it does become a problem is when the sampled sound is so short that you end up storing a little of the following silence or ambience. In this case, the noise really shows up directly after the beat, and I can't help but wonder if Simmons would have been better off opting for a shorter sample time with better quality. Even sampling at the fastest possible rate, a snare drum beat wastes a fair amount of memory, and all this does is generate unwanted noise.

At the maximum sample time, it's only possible to get something like a 4kHz bandwidth, so bright sounds such as snare drums or cymbals suffer rather badly if things are stretched too far - but a one second sample using the 16K setting is both bright and long enough to capture any ambience that may exist, whether acoustically or artificially.

Used in conjunction with the SDS7, even the EPB's low-bandwidth samples are useful, as analogue stick-click or pitch-bend can be added to liven things up. However, it's worth noting that the SDS7 cymbal sound takes up two 16K EPROMs, and I can't think of any simple way of replacing that.


The EPB may be considered as being something of a luxury, particularly if your musical endeavours are being sponsored by no greater a benefactor than the Department of Stealth and Total Obscurity, but SDS7 owners and recording engineers may well feel that the added flexibility justifies the unit's high initial cost.

It does mean that recording studios and musicians alike can build up a library of sounds for future use though the cost of EPROMs shouldn't be ignored: a 16K (27128) job will cost around £12 or more.

I have some reservations about the quantisation noise, but the EPB does its job in an efficient and user-friendly manner, and if you do use it in conjunction with the SDS7's analogue processors, the noise side-effect should all but disappear.

The EPB retails at £392.04 including VAT.

Further information from Simmons Electronics, (Contact Details).

Also featuring gear in this article

(IT Dec 84)

Browse category: Drums (Electronic) > Simmons

Previous Article in this issue

Casio CZ101

Next article in this issue

Powerful Combinations

Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.


Electronics & Music Maker - Jan 1985

Scanned by: Stewart Lawler

Gear in this article:

Drums (Electronic) > Simmons > SDS EPB

Review by Paul White

Previous article in this issue:

> Casio CZ101

Next article in this issue:

> Powerful Combinations

Help Support The Things You Love

mu:zines is the result of thousands of hours of effort, and will require many thousands more going forward to reach our goals of getting all this content online.

If you value this resource, you can support this project - it really helps!

Donations for August 2022
Issues donated this month: 0

New issues that have been donated or scanned for us this month.

Funds donated this month: £112.00

All donations and support are gratefully appreciated - thank you.

Magazines Needed - Can You Help?

Do you have any of these magazine issues?

> See all issues we need

If so, and you can donate, lend or scan them to help complete our archive, please get in touch via the Contribute page - thanks!

If you're enjoying the site, please consider supporting me to help build this archive...

...with a one time Donation, or a recurring Donation of just £2 a month. It really helps - thank you!

Small Print

Terms of usePrivacy