The SDE-2000 is a typical studio-quality DDL unit in a standard 19" rack-mounting format. It has a built-in modulation section capable of controlling the delay time, and can produce a wide variety of echo, reverb, flanging, phasing and chorus effects.

Input and output sockets are located on the back of the unit, although there is a power switch on the right hand side of the front panel. Other front panel controls are described in order from left to right below.

Input Stage

The input to the unit can be routed directly to the output using the Bypass switch. Input impedance is nominally 56kohms, and a four-stage LED display shows input levels of -20dB, 0dB, +3dB and +6dB.

Feedback and Output

The degree of feedback, and thus the number of echoes or degree of reverberation obtained, is continuously variable using the Level control. However, there is also a Single control with an associated LED indicator which effectively disconnects the internal feedback circuit. The Delay Output has a Level control for echo volume and gives +4dBm into a 600ohm load or -20dBm into a 10kohm load. The Delay Output section also has a Phase Invert switch with LED, which changes the quality of flanging and other effects by reversing the phase of the DDL's output.

Delay Section

The Delay section features a three-figure LED display to give the delay time. This can be from 0 to 320 mS, or by pressing the Delay x2 button, from 0 to 640 mS in 1 mS steps. Delay time is altered, not by a rotary or stepped control, but by a pair of momentary buttons marked Up and Down. An additional LED indicator shows whether the delay is On or Off.

Modulation

A push-push button chooses between Triangle and Sine Wave modulation. Modulation speed is stated as 0.1 Hz to 10 Hz, and Depth is variable from 1 to 10.

It's also possible to produce modulation or fix the delay time using an external control voltage into a rear socket. The operating voltage is 0 to +10V, but the unit can withstand levels of plus or minus 20V. Impedance is 90k ohms.

Design and Specifications

The SDE-2000 design is based on an 8049C single-chip 8-bit processor and the 416 Dynamic RAM chip. Frequency Response is quoted as 10Hz-16kHz at 320 mS delay between +0.5 and -3dB, and 10Hz to 7.2kHz at 640 mS delay between the same levels. Signal to Noise is kept to 90dB using compression and expansion circuitry, and THD at 1kHz should be 0.08% on the delayed sound and should not exceed 0.2%. Power consumption is 30W and, as previously mentioned, the unit fits into a standard 19" rack at a height of 1 unit.

The modulation options on the SDE-2000 make it a versatile unit and specifications indicate that it should display sound quality to match. 640 mS will produce a very respectable repeat echo in addition to the wide range of other delay effects available, so the SDE-2000 should be suitable as the central processing device of any semi-professional or even professional studio.

The SDE-2000 is available via Roland dealers at a recommended retail price of around £600 incl. VAT.