Bel BD80 Digital Delay Line
Though I'd not heard of Bel before the BD80 arrived, I am reliably informed that they are a small firm who build all their units lovingly by hand; high-quality studio accessories. Part of this story rang true when I telephoned Bel for various technical details, and was put through to "the person who makes them." At least he knew what he was talking about.
Another part of this story did not ring true: the BD80 came into the One Two office accompanied by a manual and a letter, which specified the unit's price as £600 + VAT. On examination of this new digital delay, my eyebrows raised themselves so far they nearly permanently damaged my hairline: only £600 for over eight seconds of delay? Surely not. And with the option of doubling the delay to 16 seconds at the press of a switch? Impossible at that price.
I was right. It is impossible at that price. The BD80 is an expandable digital delay: with the addition of extra memory space using cards supplied by Bel, the standard machine's maximum echo of 2047mS is advanceable in steps (4095mS, 6143mS) up to a maximum maximum of 8191mS. The price quoted is for the basic 2047mS delay model. The full 8191, which Bel had kindly lent me, will cost around £1000. Oh well, another economic miracle down the dumper...
Not really though: £600 for more than two seconds delay, and all the other facilities the BD80 offers such as modulation for ADT/flange/chorus effects, looping, memory hold, and trigger, mean that it is still competitively priced in relation to such alternatives as the Korg SDD3000 and the Roland SDE3000. Frequency response is good at 15kHz (7.5 if you use the "x2" control), though the BD80 generates a fair amount of hiss on its own, even when just resting. The 15kHz holds good for the full 8191mS, giving a bright, clear, typically digital reproduction.
If this echo were a person, it could euphemistically be described as "generously proportioned"; although it is a rack-mounting, standard 19in wide, its 3in height makes it look shorter and fatter. The bright blue control panel is dominated by an enormous and very bright red LED, placed centrally amidst the knobs, buttons, and lights. On the far left is an input level bar graph, graded from -20dB (green), via -15 and -6, to 0dB (red). Though the manual recommends setting the input level with the adjacent knob to peak occasionally into the red, I found this caused distortion far too readily. The input is really only safe when peaking around -6dB. The input itself is through a balanced/unbalanced jack socket in the back of the BD80, next to the direct, delay, and mix outputs. Shame there's no front socket for easy access in moments of panic.
There are standard "Mix" and "Feedback" control knobs, for altering the relative signal/echo levels, and the number of repeats. At full, the Feedback gives an almost infinite repeat. Though this enables you to build up a mighty barrage of sound, it does prevent those wonderful over-the-top dub effects. A small quibble, though.
There are no tone controls on the Bel, though tonal variation is possible through judicious manipulation of the phase buttons. These enable you to change the phase of both input and treated signals, permitting subtle variations in the quality of The Noise. This proved effective on keyboards, though it made vocals sound rather nasal. A filter is provided, which gradually muffles the echoed signal as it dies away.
Delay time, as displayed on the hypnotically large LED, and as indicated by the flashing "point" in the right-hand corner (it flashes at the rate of the delay), is variable throughout its range by units of 1mS. It is changed by the four buttons under the display, fast and slow, up or down.
To the right of the numbers are the "x2" control and the modulation section. Above the on/off switch the LED (it glows to indicate the speed of the oscillations) are knobs for speed and depth of modulation. I found these rather insensitive under my sausage-like fingers, and relocating previously successful settings proved an awkward chore. They don't half work though, giving the full range of effects as (ahem) effectively as you could wish. At less than 10mS, glorious, grinding, ring-mod sounds can be extracted from any signal; decrease the feedback and you are left with gentle ADT. As the delay increases above 15mS, you can notice a wide sweeping flange that grows into chorus around 70mS. The flashing LED is of very little assistance in helping you to judge the speed of the modulation as it seems to spend more time off than on. Above 300mS, the oscillation becomes a bit too wacky to be generally useful, unless you're into roller-coasters.
On the far right of the BD80 is its "memory-hold-and-edit" facility (or so the manual tells me). This piece of electronic trickery enables you to load a signal into the memory (length as specified on the LED), then replay it either as a loop, endlessly repeating, or as a triggered signal. It can be triggered either by the start/stop button on the front of the BD80, or by an audio signal fed into the External Sync socket in the back panel. This means that the BD80 can be used to substitute drum sounds; given the audio-out of a machine like the TR808, it can turn a weedy tom-tom into any noise you care to feed the memory with. But one important thing to note is that the BD80 will not repeat itself every time it is triggered; the recorded information must play out before it can be retriggered.
The edit facility enables you, by decreasing the delay time, to inch the front edge of the memory up to the start of the recorded signal, thus making the BD80 trigger both in time and on beat. It's not possible to edit off the end of the memory, which means that care must be taken to prejudge the length of your recorded signal. Too long, and the end of the memory will chop it off; too short, and the extra space will prevent rapid triggering. It's clever, but not infallible. And if you hold the start/stop button down whilst triggering, it over-rides the trigger, giving a great impression of an electro-beat disco mix drum-break — powpowpowpowpowpow.
Lurking round the back of the BD80 (as one does at reviewing time), I located another jack socket, next to the External Sync, marked CV Socket. Fresh from my recent experiences with digital sampling devices such as the Electro Harmonix Super Replay (see page 10), my eyes lit up with glee; these new machines enable the consumer (me and you) to sample sounds, and then play them back with a keyboard, giving cheap monophonic sampling à la Emulator. Given the excellent bandwidth/frequency response of the BD80, the idea that this Control Voltage input would permit high quality sampling of a keyboard-controllable kind was not far from my mind.
Not having suitable synthesisers immediately to hand, I phoned the nice persons at Bel to enquire as to the feasibility of this little wheeze... "That's a good idea," quoth the man, "I think we'll look into that." Muttering incredulously to myself, I pushed the matter further, only to discover that the CV input was there to provide access only to the modulation circuits. Mike at Bel admitted that it would be possible to make the unit "keyboard-controllable" with the help of a simple interface. At least I tried.
Using the BD80 in the studio proved a bemusing experience. The problems I had found with noisy incrementors bleeping whenever the delay was changed disappeared, but then so did all the wonderful chiming chorus effects I had tweaked up from the modulation. The speed and depth knobs are too insensitive by far, particularly when the BD80 does not have the luxury of a read-out for them, or even the use of programmable memories like the Roland SDE's.
Apart from these quibbles, the Bel was easy and interesting to use, especially in view of the clarity and enormity of the available memory space. And the idea of an expandable echo unit is a sensible one, providing extra space when you can afford it. Until you can, the basic machine sounds good for the price.
BEL BD80 digital delay: £690
One Two Testing - Jul 1984
Donated & scanned by: Simon Dell
Review by Jon Lewin
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