Edrum

E-drum : Overview

The Lost Treasure Little was known about the history of the E-drum up until mid 2000, as it was a product both the public and E-mu Systems wished to forget. In reality it is an interesting product that was not even designed by Dave Rossum and his Santa Cruz team. This is the first Internet article on the "lost" E-mu Systems drum pad or "Digital Percussion Module".

Overview The E-drum was launched in early 1984, after the highly successful Drumulator, but it turned out to be E-mu Systems one and only disaster of the 80's! It is a single pad drum module housed in a blue metal casing, which is triggered by hitting the large black pad surface which covers most of the top of the E-drum. This pad is touch sensitive, and it controls overall volume (40dB of volume range). The sound is generated from a removable cartridge which contains from 1 to 4 samples on a 16kbyte EPROM. The samples are 8-bit, and some are copies of the Emulator I samples. A variety of different sound cartridges could be purchased and interchanged in the E-drum.

Where did it come from ? The E-drum was not developed by E-mu Systems, but Clavia DMI in Sweden. During November 1983 Hans Nordelius and Mikael Carlsson worked in a basement in a south suburb of Stockholm to develop a pre-production prototype - called the 'Digital Percussion Plate 1'. This innovative new single drum pad could play 8-bit samples stored on removable EPROM cartridges. The product was showed to Greg Fitzpatrick, an entrepreneur and musician. He ordered the first 25 units as well as introducing the design to E-mu Systems in the USA (via their European distributor).

Stockholm to Santa Cruz The design specifications of the Digital Percussion Plate DP1, later to be known as the ddrum in Europe, were brought over to E-mu Systems in Santa Cruz - with the idea of putting it straight into production. However it soon turned into a major problem. The prototype design needed considerable work on both the electronics (a switch to US sourced parts, changes in design) and improved mechanical tolerances, before it could make it into production. In the spring of 1984 this is the last thing that E-mu Systems could afford, as they were running into cash flow problems due to the delayed Emulator II and the clever idea of Marketing to stop production of the Emulator I in the fall of 1983. Only the reducing sales of the Drumulator (the Oberheim DX was taking off) held E-mu Systems together, although 50% of the work force were laid off

E-drum is Not a Hit ! The production team at E-mu Systems got the E-drum to market in spring of 1984, whilst the vital development team continued with the Emulator II. Once launched the E-drum continued to be a major problem. The keyboard distributors that E -mu Systems were using were ill-placed (literally) to sell digital drums. They were simply in the wrong part of town, and never visited by drummers. They made matters worse by keeping the E-drum behind glass cases to stop theft of this $300 item. This meant drummers couldn't get to play with the extremely responsive pad, which was the major selling point. Even when the E-drum did get sold, it wasn't long before the US drummer bust off the control knobs and brought it back for a replacement.

E-drum II With all these problems it was obvious a more robust and improved Mark II could be developed. However although considered, this never happened, as the EII took off and the development effort went into the SP-12 instead, which was a much better product. Clavia DMI went on to develop a range of digital drums, and later DSP analog modelled synthesizers, both of these ranges remain popular to this day. The ddrum is almost identical externally to the E-drum, except it is bright red and the black rubber pad is slightly larger.

Technically The samples are replayed from the cartridge via two 12 bit counter/dividers and some TTL logic, and they are decoded with an 8-bit Micro Power Digital to Analog Converter. There is also some analog circuitry for the tone controls.

Verdict A very interesting and flexible drum pad which creates nice 8-bit crunchy sounds. Totally out dated by modern drum machines, but well worth hunting out for some unique sounds.

Controls (Front Panel)

• Pitch This rotary control varies the pitch continuously over a one octave range
• Pad Sensitivity This rotary control adjusts the pad's dynamic response to match playing style
• Sound Selector This control selects one of two sounds on multisound cartridges.
• Pitch Sensitivity This rotary control controls the degree to which pad dynamics affect pitch.
• Decay This rotary control controls decay from 50 milliseconds to cartridge maximum.
• Treble This rotary control adjusts the amount of boost or cut in the treble frequency range
• Bass This rotary control adjusts the amount of boost or cut in the bass frequency range.

Input/Output (Rear Panel)

• External AC Adapter Input Accepts 18VDC 200ma unregulated power via a 3.5mm phone plug with center positive polarity
• External AC Adapter Output When E-drum module is powered by AC adapter, this output supplies power for connection to additional modules. Up to 5 E-drum modules may be powered bya single AC adapter.
• Power LED Indicates power ON status, whether from the battery or AC adapter
• Battery On/Off Allows use of external AC adapter power when in OFF position, use of battety power in ON position.
• Trigger Input (1/4" phone jack) accepts standard DC gates and triggers (0.2 - 5 volts, 100ms or longer) as well as most audio sources. The dynamics of
the triggering signal are detected and duplicated by the E-drum module.
• External Pitch Adjust Allows voltage control of pitch via a powered footpedal or other DC voltage source (0 - 5V).
• Audio Output (1/4" phone jack) 4.7Kohm signal output.
• Cartridge Port Accepts E-drum sound cartridges. Cartridges are keyed to prevent incorrect insertion.