With the audio industry finally old enough to see its experts finding new alliances and opportunities, DAV's mic preamp draws Dave Foister back to the heyday of Decca
DECCA'S LOSSES ARE AUDIO'S GAINS--in some areas, at least. It's certainly no secret that the closing of Decca's R&D department brought us the Genex M-O disc recorders, the first fruit of an in house Decca project. On a smaller scale, ex-Decca maintenance-design engineer Mick Hinton is behind the launch of a new range of outboards under the DAV banner. First off the production line is a microphone preamplifier known, in honour of the location of the old Decca studios where he began in 1969, as the Broadhurst Gardens No. 1. During his time at Decca's Belsize Road complex, Hinton designed 4-channel microphone preamps which are still in use by ex-Decca engineers at Classic Sound, and the new range is based on Decca circuits from around 1977.
In appearance, the No. 1 closely resembles the Canford Audio (Studio Sound, February 2000) mainly because it is built in the same style of off-the-shelf extruded black case. One end carries the output and mains connectors while the other carries the inputs and controls, and the most obvious difference is that the DAV is considerably longer and a good bit higher. The resulting impression is of a piece of equipment whose function is far more important than its appearance, being just a notch or two up from good home-brew. The facilities are also remarkably similar to those of the Canford, although this appears to be no more than coincidence.
DAV places its emphasis heavily on the quality of the electronics inside, and its lack of cosmetic pretension and fairly basic set of controls mean that it can also be made more affordable than its quality would suggest. Each channel has only one knob, for switched setting of the gain (26dB-59dB in 12 steps), and a few small push-button switches with indicator leds where appropriate. The labelling for the controls is silk-screened in blue and red on a black panel and is not easy to read.
Each channel has a fairly hefty pad (-26dB) and two switches for low-cut filters, giving a choice of three cut-off frequencies. The lowest is usefully low at 40Hz. In line with the consideration that quality comes first, there is no attempt to reduce the audible effect of operating these switches, and consequently they thump quite a lot. I don't have a problem with this, as it's not hard to mute the following chain before making changes, and it means that the only capacitors in the signal path are the carefully chosen phantom power decoupling capacitors.
Phantom power is not individually switchable for the two channels, indicating that the unit, despite its excellent crosstalk figures, is perhaps primarily intended for use with a straight stereo pair. This might also be suggested by the fact that only Channel 1 has a phase reverse switch, which is fine if a stereo pair through here is all you're using although it doesn't allow absolute phase to be corrected on both channels for those who feel this is important.
The final feature, also curiously found on the Canford model, is a switch for routeing Channel 1's input to both outputs, allowing the preamp to be used as a simple distribution amplifier. There is very basic metering in the form of two leds on each channel, a green one lighting at -3 and a red marked Over. The specs reveal the levels indicated by these to be +18dBu and +21dBu, with a clipping level of +29 giving plenty of headroom even with the lights flashing. The small difference between their indicated levels means that the greens are rarely on, making them less useful than they might be.
The emphasis in the specs is on low noise and low distortion, with a frequency response quoted as 10Hz to 70kHz (no tolerance given). This character is very much in evidence in practice, showing that the guts of this ordinary-looking box are on a par with far more fancy-looking devices at far more fancy-looking prices. It's a full, open sound, clean and quiet, doing the deceptively simple job of neutral amplification very well indeed. It handled a particularly problem microphone I use without difficulty; many preamps go unstable with it as there's some problem with its output impedance, but the DAV was perfectly comfortable with it.
The Broadhurst Gardens No. 1 is uncompromisingly a tool to do a job; no client is going to take any interest in it whatsoever and it does nothing for the aesthetics of your control room. Yet it's an excellent tool that will fit comfortably into many situations at a remarkably low price. DAV promise three more units, all from the same era of Decca design: a mic-line amp with EQ and filtering, a stereo limiter-compressor, and a stereo mastering unit whose facilities remain a mystery for now. If the No. 1 is representative of what is to come, we should all be looking forward to them with great interest.
DAV Broadcast, UK. Tel:+44 20 8892 9334. Fax:+44 20 8892 9300. Email:email@example.com Web:http://www.davelectronics.com/