Previewed as long ago as December 1982's Music Maker Equipment Scene, the KPR-77 is at last in this country, if only in prototype form. Widely available in March along with the SDD-3000 Digital Delay, this fully programmable rhythm machine featuring tape dumping facilities will retail for around £400. As Korg's first attempt at a programmable, it seems to be intended to fill a gap in the market somewhere between Roland's TR-606 Drumatix and the larger TR-808, having several of the better features of both.

Basically the KPR-77 offers three modes of use, Training, Write, and Play. In the training mode, the square tablet buttons for each sound can be operated by hand to create patterns — there are two identical buttons for most of the sounds to make this easier.

In the Write mode,and LCD display on the top left hand corner indicates the state of the program. A moving cursor can be set to scan the desired number of beats with any degree of resolution from 16th notes to 32nd note triplets available. Programming can be achieved in realtime, with the cursor moving slowly along the display and the ability to put in any number of sounds on a given beat if they are struck simultaneously; or in step time, with each instrument being programmed individually with the use of the 'Step Up' button for spaces.

In the Play mode, the KPR-77 skips from one memory to another only at the end of a bar, indicating before it does so which pattern number is 'Next'. Pattern changing can be done manually, or by arranging the individual patterns in chains as described below. At all times the LCD display indicates the Group letter, Chain number (I or II), Basic Mode of operation, Pattern Number and Bar Number in a Chain. It's a pity that a digital readout of tempo wasn't also included, although obviously this would have been an added expense; as it is, the usual Tempo knob and flashing LED will have to suffice. Most of the controls on the KPR-77 are multi-function. The instrument buttons are numbered 1 to 16, indicating 16 patterns in each of three Groups A, B and C, for a total of 48. All 16 patterns in each Group can be combined for longer rhythms; the maximum length in Chain Mode is 512 measures of 4/4. There are 6 Chain Banks in fact, each holding 256 measures of 4/4, but these can be paired if desired.

After chaining the basic patterns, a Da Capo or Del Segno function can be used to restart the total pattern. Alternatively it's possible to skip to another entire chain or a basic pattern while playing. The entire memory contents are stored during switch-off, or can be dumped to cassette simply by enabling the function using a rear panel switch and pushing 'Group A', which doubles as the Save control. 'Group B' activates Load and 'Group C' gives Check, or verify. Each function takes about a minute to operate.

Other back panel controls are DC9V in, Tape In and Out, Sync In and Out on a 5-pin Din socket (as on the Drumatix) High and Low Tom-Tom triggers out, Footswitch Start/Stop (shorts to ground), Headphones, and three audio outputs. The first of these is Mix: the second Stereo, which spreads the instruments over an internally preset stereo spectrum; and the third Snare Drum/Clap for individual equalisation or reverb.

Internally, the analogue voice card sits in the base of the unit, above which is the input/output interface board (see photograph).

The microprocessor (a TMS 1025), CMOS memory, flat-pack LCD driver and display are mounted along with the clock control circuitry on a single PCB. Connections between the boards being made with flexible in-line PCB connectors.

As this model is a prototype some of the boards may change for production versions. However, the quality of construction is up to the usual high Korg standards; the design of the control section puts the KPR-77 almost on a par with the vastly more expensive LinnDrum.

The sounds aren't up to this level of course, but without digital sampling that's only to be expected. The new sounds, handclap and Tom Tom flam (a fast double stroke) are excellent, and so disco rhythms at least are powerful and convincing. Bass drum, Toms and Snare are adequate, although it would have been interesting to have a Snare flam available; the Cymbals and Hi-hat are faintly metallic, with good differentiation between open and closed positions on the Hi-Hat but no really convincing decay characteristics.

Obviously a lot of thought has gone into the design of the KPR-77, and ergonomically and mechanically it's a great success, the controls being pleasant to use and precise in operation. The recommended retail price is around £400 including VAT; exactly what portion of the market the Korg will capture is unclear, but as a first attempt at a programmable rhythm machine it's certainly an interesting new product that's well worth looking at.

The Korg KPR-77 will be available via Rose-Morris, (Contact Details). The RRP will include a tape containing the factory rhythms.