Rack-mounting digital delay lines are now more common than ever before, but it's taken some clever technological space-saving by Roland's Boss division to produce a pedal-based alternative. Paul White weighs up the pros and cons of the new format.

Digital delays have been with us for quite some time now, but this is the first one I've come across that actually fits into a pedal. Boss pedals have a reputation not only for quality but also for their small physical size, yet even so, it was hard to believe that anyone could squash the relatively complicated circuitry of a digital delay into such a tiny volume.

Featuring a maximum delay time of 800ms, the DD2 has a bandwidth of 7KHz - rather better than most comparably priced analogue units - while the residual background noise is a staggeringly low -95dBm.

Construction

The DD2 is identical in shape and size to the rest of the Boss range, and is finished in an attractive metallic pearl effect with blue legending. Like all Boss pedals, the battery fits under the foot-switch and can be changed easily in a matter of seconds, which is just as well because the circuitry consumes 55ma and so gobbles up batteries even faster than Bruce Grobbelaar gobbles up Liverpool's opponents' crosses. Because of this unavoidable shortcoming, the Boss PSA power unit is recommended and this will run the unit all week for about ten pence, I should think. Internally, the pedal is surprisingly uncluttered due largely to the use of a custom IC which replaces a lot of conventional circuitry.

Controls

Apart from the pedal itself which turns the effect on and off, there are four rotary controls which regulate the relative levels of direct and delayed sound, the amount of feedback used, the delay time and the delay range. This control sets the range over which the delay time control will operate, the maximum delay times being 50ms, 200ms and 800ms, with a fourth position dedicated to the hold function. When hold is selected, the pedal becomes non-latching so that no effect is heard unless the pedal is held down. Depressing the pedal causes the previously played phrase to be repeated continuously until the pedal is released, the length of the phrase depending on the setting of the delay time control.

An extra socket is provided for stereo use which enables the direct and delayed sounds to be routed to different destinations, and the usual LED indicates effect status and battery condition.

In Use

Although there are digital delay units with a wider bandwidth than the DD2, tests with electric guitar and synthesiser produced clean echoes that were virtually impossible to distinguish from the original sound. One of my personal quibbles with many digital systems is the inordinate amount of quantisation noise they produce. This can usually be heard on low frequency sounds and takes the form of a background sizzling noise, but in the case of the DD2, I could not detect any noticeable problem in this area, probably due to the 12-bit conversion system which utilises an analogue companding technique to make efficient use of the available dynamic range, without having to match the input level to the circuitry.

Another absent nasty was aliasing on high frequency signals. This unpleasant side effect is produced when harmonics of the input signal, not fully removed by the input filters, beat with the clock frequency of the delay circuitry and produce sum and difference frequencies, the lower of which may fall into the audio band and manifest themselves as non-harmonically related distortion.

Try as I might, I could find no fault with the DD2's sound quality, and any criticism that can be made of the unit must be levelled at its design philosophy, which forces the user to bend down to adjust the controls: it can look a mite unprofessional at gigs. I particularly like the hold effect which tempts the user to indulge in Fripp-like excesses with the minimum of required effort, the pedal system being ideally suited to the control of this function.

Conclusion

At a recommended price of £175, this is quite frankly the cheapest and most vice-free digital delay I have yet encountered in the under £300 range.

Having said that, the DD2 provides no modulation facilities or external modulation input, making chorus and flanging effects out of the question. Additionally, there is no facility for storing and triggering sounds, but at this price, I am neither surprised nor disappointed at this omission.

The pedal format does make it difficult to alter parameters in a live situation, while the tiny control knobs can make precise setting a fairly tricky operation but, on the other hand, the pedal is easy to use in the hold mode and costs about half the price of a comparable rackmounted unit.

Although the DD2 is obviously intended for live use, its low price and high sound quality will undoubtedly attract users from the home studio fraternity as well as keyboard players, guitarists and PA operatives. It seems that Boss have done it again, and it will be interesting to see how long it takes rival manufacturers to follow suit.

RRP of the Boss DD2 is £175, including VAT.

For further information, contact Roland UK, (Contact Details).