Slightly out of the ordinary, this versatile unit is particularly effective for producing textural treatments.

A curiously named little beast this Madrack. The penny finally dropped when I observed the legend 'Multi-tapped Analogue Delay' on the very attractive front panel.

In the digital age it's all too easy to reject an analogue unit such as this, due to the generally accepted idea of digitals scoring on their quiet operation and better frequency response but at short delay times, analogue units can offer first rate performance.

The Madrack, however, is more than just a delay line; it offers a smooth sounding hybrid echo/reverberation and competes well with other analogue units offering tapped delays, the most similar being an American cousin which is considerably more expensive. The circuit features 2:1 compander noise reduction which results in a commendably low background noise.

Facilities

The densely packed 1U front panel has a generally attractive appearance with white lettering on a mid-blue background. The top is printed with a table of the various settings needed to achieve the different effects, but experimentation should be regarded as the key to getting the best out of it. The treatments are variously described first in mono; flanging, drainpipe, reverb 1 and 2, chorus/ADT; and in stereo; vibrato, short tape echo, bounce echo, stereo multi-chorus 1 and 2, stereo reverb/echo and mono to stereo simulation. It's up to your imagination as to how the controls should be used, and it can sound pleasant on an acoustic guitar or can add depth to any dry synthesiser.

"Where this unit comes into its own is in the production of short delay effects such as chorus, flanging and stereo simulations..."

What sets this stereo unit apart from a standard ADT (Automatic Double Tracker) or a same ratio interval multidelay, digital or otherwise, is the feature of tapped feeds with varying ratios giving a more realistic reverb rather than a simple echo. The tapped feeds are separate points in the signal path where a number (in this case seven) of direct links are made to the outputs. On the Madrack the taps are assignable to either channel. The inputs and outputs are ¼" jack sockets on the rear panel and a further socket is provided for an effect on/off footswitch which is especially useful for stage work.

The front panel may at first glance appear daunting with its many controls, but in practice it rapidly becomes a familiar straightforward operation. One set of pots control input and output level and another pair the mixing of each channel's treated and dry signals, permitting treatment of programme material in more simple recording setups without auxiliary sends. I found it possible to create audible distortion on the delayed portion of the programme before the peak reading LED indicated overload so you need to use your ears. Next to each of the mix controls is a toggle switch. The left output can operate in Normal mode which is stereo, or from right mode which represents mono selection. The other switch affects the left channel delay, and is either set to Normal or Invert which treats the signal to simulate a stereo effect enriching a mono signal quite well by simulating the reflections from the walls of a confined space.

The delay taps are selected by a matrix of buttons, the upper seven for the left channel and the lower seven for the right. The tap assignments are indicated by green LEDs. A second matrix has four buttons, three with associated LEDs; one to switch the delay on or off and another to cancel all the tap selections, and two other unusual effects. The button titled Pan automatically spreads all seven taps across the stereo field and cyclically changes them over. Although the rate of pan is not slow enough to provide any obvious (read 'psychedelic') consciousness shockers, it is a real bonus in giving a very rich texture to a range of signals and can be further enhanced by manually selecting taps to emphasise the effect. The rate of pan is affected by the length of delay and to a degree by the modulation pots. The final button, Sum 7, is a preset which mixes taps 1-6 and feeds them to tap 7 which must be selected to give a nice echo/reverb. These small buttons are closely packed, so if you have a chunky index finger you'll find yourself selecting an adjoining tap, so use your pinky or a pen top. However, if larger buttons were used it would necessitate a deeper panel, consequently taking up more of that valuable rack space. The buttons have a light but positive action.

"The difference between this unit and a conventional chorus unit is comparable to the difference between a standard chorus unit and no chorus at all..."

The real versatility of the Madrack D7 is the variation one can apply with the tapped delays, the Pan and Sum 7 features. It becomes additionally impressive when used in conjunction with the two feedback controls which allow a variable amount of signal to be applied to the delay input stages. This can be selected from any single tap or all taps from either channel, but care needs to be exercised if undesirable oscillation is to be avoided.

Equalisation can be applied to the delayed signal by the high cut (low pass) control. In the minimum setting (fully clockwise) the higher frequencies are slightly boosted, useful in both overcoming bandwidth limitation inherent in bucket brigade based delays, avoiding tying up outboard equalisation to simulate different acoustics.

The modulation is set by the usual two controls, on for depth, the other for the rate of sweep over 3½ octaves of the delayed signal's frequencies. The rate is indicated by an LED which pulses synchronously. A wide range of flanging, chorus and vibrato effects is attainable and this will probably lead to many sessions lasting well into the small hours, since time spent experimenting is extremely rewarding. An obtrusive noise was noticed on the delayed signal when the depth of modulation was set to minimum even without sweeping it, but by turning the depth pot a little it disappeared with no audible detrimental effect on the treated signal - possibly just a gremlin on the review sample.

"...it is still cheaper than most of the serious competition in this area."

The delay length control affects all taps simultaneously. The panel of the review unit was calibrated to read X½ at the maximum delay setting and in excess of X3 at the minimum. Initially I wondered at the logic of Tamtec. Is there a gap in my maths education? Was I asleep during that crucial lesson? In fact it is an error that has been corrected in the present units and X3 will now mean an increase in delay intervals! The maximum delay available is 145mS from the standard setting, which is short on paper never mind the ears, but don't forget the feedback which extends the repeats available.

It's true that if you are seeking large room reverb sounds then this unit is not for you. Where this unit comes into its own is in the production of short delay effects such as chorus, flanging and stereo simulations and the textural depth afforded by the multi-tap arrangement is well worth listening to. The difference between this unit and a conventional chorus unit is comparable to the difference between a standard chorus unit and no chorus at all, it's that impressive.

Conclusions

I initially wondered about the 8kHz bandwidth and whether it would be a problem, but in practice it was bright enough for most applications. As most effects contain a significant proportion of the direct signal, this also helps to create the illusion of a better bandwidth than is really the case. The unit is not exactly cheap at around £482 but it is still cheaper than most of the serious competition in this area.

The treatments that this unit can produce can benefit both electronic and acoustic instruments and are also effective for enrichening the voice, so you won't be short of things to try it out on. The Madrack D7 is not however capable of producing true reverb but it will give you chorus, flanging and stereo ambience with a tremendous impression of depth and its rich textures are well worth exploration.

Further details are available from: MTR, (Contact Details)