The budget end of the console market is dominated by companies anxious to offer every conceivable feature, from mute automation to extra virtual inputs — but there's no such thing as a free lunch and something has to suffer. DDA, on the other hand, have always prided themselves on very high-quality circuit design, producing some of the quietest and best-sounding desks around. They adhere to the minimum signal path philosophy, which dictates that as few components as possible should be placed in the way of the audio signal in order to preserve the integrity of the original sound. And with low-cost digital tape machines just around the corner, and Dolby S analogue machines already here, DDA reason that audio quality is paramount in today's marketplace.

Just as DDA are experienced in circuit design and console engineering, Dynacord (the builders of this desk) are experienced in large-scale production of music-related products; their involvement in the manufacturing process certainly shows in the finished package. Despite its compact size, the console is very substantial, the controls are smooth and positive, and the styling is immaculate.

The Interface can be configured to suit a variety of recording, installation and live sound applications; it is fully modular with a choice of mono or stereo input channels, and further modules are planned. All line inputs and outputs conform to the +4dBu standard, though internal jumpers offer the option of -10dBV operation on the aux sends, the mix output and the tape returns, to accommodate semi-pro tape machines and processors. All input channels, groups and the main stereo outputs have insert points on stereo jack sockets.

The stereo module is destined to include stereo mic inputs and the facility for M&S decoding. Another of the proposed modules contains six mic amps in a single channel strip, while a further stereo input channel is planned with digital inputs in both SPDIF and optical formats.

Unlike the many recent consoles employing inline monitoring, the Interface is designed along traditional split lines for ease of use and has a four group-bus architecture. This may seem limited, but an ingenious use of the channel direct outputs enables them to be used as multitrack feeds or individual sends, complete with level control. There is no MIDI muting and no level automation, though the circuit boards are designed with connectors for easy fitting of third-party systems if required.

A typical Interface will include, as well as a master module, four group modules, each having two return sections which may be used for off-tape monitoring during recording. They can also be used as additional line inputs for sequenced instruments or effects returns, as well as for adding pan and EQ to the subgroups. There were no dedicated aux return points on the review console, a 16:4:2 model, though a multiple aux return module could be added to the series later.

CONSTRUCTION WORK

Available in frame sizes to accommodate from eight to 32 input channels, the Interface is based around a heavy steel chassis with rigid foam sculpted side-cheeks and arm rest. All connectors are at the rear. Internal signal bussing is via ribbon cable, and the power supply is a separate 2U, fan-cooled rackmount unit.

A scribble strip is provided just above the arm rest and a pencil well thoughtfully included just below it. There is no meter pod, all meter functions being built into the various modules; the stereo master module houses the main stereo meters.

MONO INPUT

I can think of few applications which would not require at least some mono input channels, and in most respects, the channel design is quite predictable. At the top is the usual input section with switchable choice of mic or line and 48V phantom power for mic inputs. There's also a 20dB pad switch for use with the mic input, while the phase and LF roll-off switches apply to both the mic and line inputs. The same rotary control is used to set the mic gain and the line gain, with up to 76dB of mic gain available. A low-noise mic amp is used at the front end, with two stages of amplification cascaded when Microphone is selected. In Line mode, only the second stage of amplification is used.

The EQ section is based around existing DDA designs, and is a 4-band system with shelving high and low, plus a pair of sweep mids. All sections offer up to 15dB of cut or boost, with the high section operating at 12kHz and the low section at 50Hz. The mids have plenty of range, with the upper mid covering 470Hz to 15kHz and the lower mid covering 70Hz to 2.2kHz. An EQ bypass button is fitted to take the EQ out of circuit.

In the aux send department, there are four aux controls with sends 3 and 4 switchable as a pair to busses 5 and 6; as well as a Pre/Post-fader button (which affects sends 1 and 2 as a pair), Aux 1 has an additional button labelled Direct which isolates it from the aux bus and, instead, allows it to be used as a master level control for the direct output. When Dir is not selected, the channel signal still feeds the direct output, but without a level control. Using the direct out as a tape feed, the channel fader can be used to set the level to tape, so there's no real point in pressing the Dir button, as all you get is the channel fader and the aux pot in series. But if you choose to use the Dir facility as an individual aux send to an effects unit, then the ability to control the signal level feeding the effects unit is very welcome. As supplied, the direct output is processed by the channel EQ, but internal links allow the pre-fade feed to be either pre- or post-EQ. It's also possible to change internal links allowing aux 3 and 4 to be selected pre-fader or pre-EQ.

Routing is standard, with one button selecting the L/R mix and two more selecting group busses 1/2 and 3/4. The channel pan pot allows the signal to be steered between odd- and even-numbered busses, while a channel On button mutes the channel and kills any post-fade aux sends from the channel.

Directly below the On switch is the Pre-fade Listen button. This feeds the channel signal, post-EQ, to the loudspeaker output, the phones output, and also to the main meters. You can then optimise the input gain trim regardless of the channel fader settings, and without affecting the signal at the main stereo output. The faders on this desk are delightfully smooth and there is a 5-segment meter adjacent to each one, showing the channel signal level over the range -13dBu to +17dBu.

On the rear panel of the module are the mic input, the line input, the direct out and the insert jack. The line input is balanced, while the direct output is a ground compensated, unbalanced signal.

"Unlike the many recent consoles employing in-line monitoring, the Interface is designed along traditional split lines for ease of use"

MASTER MODULE

Right at the top of the Master Module is a BNC socket to take a gooseneck lamp; directly below are the meters. These are 10-segment LED bargraphs set for PPM characteristics, but internally changeable to VU. The module has masters for all six aux send busses, each of which has an AFL (After Fade Listen) button. Down the right hand side of the strip are the talkback (with latching switch), oscillator and monitor functions. There is an XLR socket which allows a standard dynamic mic to be patched in, though the internal link system allows phantom powering of a capacitor mic for talkback. A gain control is provided for the talkback input, which can be routed either to aux busses 1 and 2 or to all the console's main outputs simultaneously. In both cases, the monitor signal is killed to prevent feedback.

The Interface also includes a basic oscillator, which provides a 1kHz tone at a variable level. This is inadequate for serious machine alignment but is useful for general meter calibration and checking up when signals have gone missing.

Moving a little further down, the Monitor Level pot sets the signal level fed to the monitor outputs, which would normally feed the control room monitoring system. This control also affects the headphone output level, though when the headphones are switched on the speaker output is automatically muted. As with any studio mixer, there is provision to connect a two-track machine for mastering. The MIX/2 TRK switch is used to select the output for the two-track machine to play over the monitors rather than the stereo mix. This is overridden by any Solo, PFL or AFL switch.

The desk has a separate mono output, which is a simple sum of the left/right stereo mix channels. This can be switched pre or post the main faders, and has its own level controls; potentially useful in broadcast or installation setups. Separate left/right faders are fitted, with their 0dB position right at the top of their travel, so normally they'll be left flat out. The headphone socket is located at the bottom right hand side of the module.

The rear panel features electronically balanced XLR connectors for the Left, Right and Mono outputs, and 1/4" jacks for the monitor outs, tape returns and insert points, the latter being on stereo jacks wired tip send.

GROUP THERAPY

The group module follows the split console tradition in providing a group fader, above which are located a couple of return inputs for use as monitor/tape returns or extra line inputs for effects and sequenced instruments. However, there are a couple of not-quite-standard routing options which add to the flexibility of this mixer, as we shall see in just a moment.

At the top of the module is the group meter; an internal link allows a choice of VU or PPM characteristics. In PPM mode, the displays decay quite slowly, making it easy to read short peaks. The meter monitors either the signal level feeding the group output or the pre-EQ signal at the input of the Return B section. The PA/Record switch enables the signal feeding the Return strip to be selected as either the group output or the return input; this also means the meters can monitor either the signals being sent to tape or returning from tape. However, as there are only four group modules in a typical desk configuration, it is only possible to monitor up to eight tape tracks without resorting to using spare input channels, and only four off-tape signal levels can be metered at any one time. When reading the group output signals, the meter reads post-fader, giving a proper indication of the level appearing at the output. Conversely, when reading the tape return levels, the meter reads the actual incoming level before the monitor level control, which is as you would expect.

Return A, the upper section, is routed directly to the stereo mix; Return B may be routed to either the stereo mix or to the sub-group bus. The group output may be fed through the Return B section, giving the ability to apply basic EQ to a submix. There is an insert in the group output path; the line inputs for Returns A and B are on quarter-inch jacks, while the group output is via a balanced XLR connector.

Both return sections are similar in that they offer HF and LF shelving EQ, an Aux send feeding the Aux 1 bus, a pan control and a level control, though the routing options differ. Return A is equipped with an On button and a PFL button, both with status LEDs. Interestingly, the EQ frequencies are different from those used on the main channels — 15dB of cut or boost at 60Hz and 8kHz.

Return B has the same rotary controls but a different complement of buttons. At the head of the section is the Return/Buss switch which determines what signal feeds into the return section; in the Ret position, the return jack on the rear panel is active; selecting Buss routes the signal present at the return input socket directly to the group bus, effectively bypassing the controls. This is only true if PA is selected and in Record mode, this choice disables the Return B input entirely.

Below the Pan control is the PA/Rec button which dictates how the input to Return B is routed. Below the level control are the Return B On switch, a PFL button and a pair of Left/Right mix buttons relating to the group fader. Used individually, these buttons allow the group signal to be routed to the left or right side of the main stereo mix; used together, they enable the Return B Panpot to be used to position the group signal in the stereo mix. However, if this latter option is used, Return input B can't be used. This ability to pan subgroups during mixing is very valuable, but it does rob the console of a line input in the process.

MANY HAPPY RETURNS

To get the most from this desk, it's vital to understand the role of the Return source switching, which has been devised to make the desk as flexible as possible. This appears convoluted on paper, but is less of a headache in practice. The Ret bus switch determines what signal feeds the input of the Return B section, and in the Ret position, the input comes from the Return jack input. If Buss is selected, the group output signal is fed through the Return B section, enabling it to make use of the EQ, Aux 1, Level and Pan controls. In a normal recording setup, this switch can be used to swap between to-tape and from-tape monitoring, and the meters follow this source accordingly. However, with the desk set to Rec mode, when Buss is selected the external Return line input is isolated and cannot be used.

"For me, design high points are the excellent equaliser, the low noise and the simple layout, combined with very solid, practical engineering."

In PA mode, the metering always reads the group signal level, and with Buss selected the return input again picks up the group signal, while the input to the Return B connector routes directly to the corresponding group bus. This provides additional line inputs to the groups but without EQ, level or aux facilities. With Return selected, the Return input feeds the stereo bus, while the group output feeds the group out socket. This switching system allows you to equalise the subgroups if you want to, and to make use of an aux send to process them, but in doing so, some or all of the Aux B functions are sacrificed.

TESTING TIME

Having had a little experience of DDA desks, I was expecting something a little bit special, and I wasn't disappointed. The new input stage seems to work very well, being no noisier than a well-designed discrete front end, yet with a more useful range of gains at both the low and high end. I've always liked the sound of DDA equalisers, and given that this design uses sweep rather than fully parametric mids I think the Q value has been well chosen to provide the best compromise between musicality and precision of control. The fact that the lower mid goes right down to 70Hz makes the system really flexible when sorting out bass problems. The bypass switch is extremely quiet in operation and I could detect no subjective change in tone or level between the EQ flat and bypassed positions.

I like the ability to isolate the Aux 1 send on a channel-by-channel basis, not only because effects can be deployed more usefully, but also because the setup can thus be configured for minimum noise. All mix bus systems become noisier as more channels are routed to them, which is why unused input channels should be de-routed, not just muted. If you want to use an effects unit on a single instrument in a mix, it's so much better to be able to isolate the send from the rest of the bus so that no other channel is contributing to the aux output noise; the Interface gives you a means of controlling the send level during a mix if you need to.

Of course, the same applies when using the direct outputs to feed a multitrack, as the signal doesn't have to pass through all the routing and group circuitry. I know that some people will feel deprived with only four group busses, but when was the last time you recorded a take with more than four lots of mixed signals going to tape simultaneously? Using direct channel outs to record single mics or instruments to individual tape tracks makes much more sense. Having ranted about noise, I have to say that this console is about as quiet as they come, but it doesn't hurt to use it intelligently to get the best out of it. The degree of crosstalk is also very low, given that the system doesn't use balanced mix busses.

Having never previously had the means, I never missed the ability to equalise the group signals — but having tried it, I admit that the option of equalising something like a backing vocal submix without changing all the relevant input channel EQ settings is useful on occasions. This operation is made much easier by the 'split' console layout, though the obvious drawback is that you don't get as many extra inputs at mixdown as you would with an in-line design.

LAST IMPRESSIONS

Those used to working on consoles with every bell and whistle may dismiss the Interface as being sparsely equipped considering its price. I feel that such a judgement would be unfair. This console may not have every feature that you want, but my guess is that it has just about everything you need. To me, the Interface represents an affordable way of taking advantage of the very high sound quality offered by a DDA design, and it should prove very popular with those who put ease of use and sonic purity before sheer number of features.

Because of its professional performance, the Interface is a potential partner for the new generation of digital multitrack tape machines or Dolby S analogue machines, as well as the more usual multitracks. Its format appears to limit the Interface to 8-track use, but the 32-channel version could be used with 16 or even 24-track machines by monitoring back through the input channels. For anything over 4-track use, I'd strongly recommend a patchbay system to handle the insert points and the direct channel outputs at the very least — rear connectors keep things tidy but make impromptu patching fiddly.

For sequencer users, the shortage of extra inputs is a minus point. I would have preferred to see a couple of pairs of additional aux returns included in the design, but the existing return switching makes it easy to patch in a line mixer for keyboards or effects. There are a few lesser niggles, such as the non-latching talkback switch, the mutually exclusive speakers-or-headphone monitoring system, and the lack of provision for a second 2-track machine, but these points are relatively minor. The lack of MIDI muting may be considered more serious by some, but again, it's down to what you can live without if you want the best possible sound quality. One plea — how about a thermostat for the PSU fan? With that addition, it would only run when necessary; even the best fans can be distracting.

For me, design high points are the excellent equaliser, the low noise and the simple layout, combined with very solid, practical engineering. Because different people have different requirements, it's impossible to say that the Interface is ideal for all applications, but if you need something basic and good, rather than something fancy and average, it fits the bill. The styling is spot on, the standard of construction excellent, and the controls smooth and positive. Many of the switches are illuminated, which makes life a lot easier, especially in a live sound situation, while the metering is clear and effective. I foresee a significant amount of professional interest in this console for small video-post facilities as well as from the serious project studio owner. I've a feeling that if you sit down and think carefully about how you work and what you really need from a mixer, a great many of you will conclude that the Interface approach makes a lot of sense.

Further information

DDA Interface 8:4:2, £2,778.87; 16:4:2, £4,018.50; 24:4:2, £5,410.87; 32:4:2, £6,838.50. All prices inc VAT.

DDA, (Contact Details).