Deanvard VA 30K
Deanvard's V-amp range is new to the UK, but may become highly popular because it's consciously aimed at a particular market — the amateur or semi-professional keyboard player. There are in fact eight V-amp guitar combos as well, but the VA 30K examined here, along with the VA 10K and VA 60K, are specifically designed for Casio, Yamaha or Technics keyboards and perhaps reaching up to the Juno 6 or Polysix market.
The VA 10K is described as 'the ideal amplifier for expanding the sound of any mini-keyboard instrument'. It comes in a red or white finish and has a single 8 inch speaker delivering 10 to 17 watts RMS. There are two inputs with sensitivity stated as 100 mV, together with Treble, Middle and Bass controls. The Treble control gives minus 24 dB or plus 15 dB at 10 kHz, the Middle control gives 20 dB variation at 1 kHz, and the Bass control gives plus or minus 14 dB at 100 Hz. It's intended to be suitable as a practice amplifier for larger keyboards as well, and shares the 16 gauge welded steel mesh plastic-coated grille common to the other amps.
The largest keyboard amp can deliver 60 to 70 Watts RMS into 8 ohms, and has Treble, Bass and Parametric controls. The Treble control gives minus 28 dB or plus 15 dB at 10 kHz, the Bass control gives plus or minus 14 dB at 100 Hz. The parametric control gives 35 dB variation at any point between 120 Hz and 1.6 kHz. There's a built-in spring reverb with level control and footswitch socket, and the two inputs can be balanced against one another to set relative volumes of two keyboards or a keyboard and a microphone. The speaker is a 12 inch dual cone cambric-edged design with a response claimed to be an octave above that of the guitar combo speakers.
The VA 30K itself, then, is the mid point of the range of V-amps, and features the same controls as the VA 60K while having a smaller speaker and a power output of 30 watts into 8 ohms. It's quite hefty, weighing about 25 pounds, and is just over eighteen inches tall. The finish is extremely rugged; the cabinet is made from 15 mm birch ply, bonded to 18 mm chipboard which is both glued and pinned. There is a choice of five colours, black, grey, red, white and blue, in each case with a black leather handle — a comfortably rounded one with no sharp edges — carefully bolted into the centre of the slight indent in the top of the amp. This should allow V-amps to be stacked, incidentally. The cabinets themselves are built by the Packhorse Case Company, who have made a very good name for themselves in many years of producing cabinets and flightcases. The speaker grille, as previously mentioned, is in heavy plastic-coated mesh affixed by six cross-head screws to the cabinet.
The first features are the two input channels, identical plastic quarter inch jack sockets marked 1 and 2. Next to these are two large black knurled control knobs, for Master volume (graduated from 0 to 10) and for balance between the levels of inputs 1 and 2 (marked 1 at the fully anticlockwise position and 2 at the fully clockwise position). Each knob has a silver spot on the cap to indicate its position; this could have been clearer, as the knobs themselves can appear silvery under bright lighting.
Next to these Gain controls are the Equalisation controls, comprising four knobs identical to those already mentioned. These are Treble (marked minus 10 to plus 10), Parametric Gain (minus 10 to plus 10), Parametric Frequency (not marked except by the figure 1000 at the halfway position) and Bass (minus 10 to plus 10). The Parametric controls comprise the Middle band of equalisation.
Finally, there is another knob for Reverb depth, marked 0 to 10, a plastic quarter inch Footswitch socket, and a neon-illuminated Power On switch. The amp's overall appearance is extremely clean and simple, with no back panel controls and an integral mains lead (rather short on the review model) which can be hidden away inside the amp through a back panel cutout if desired.
Removal of the amp head is quite easy — it slides from the cabinet once four crosshead screws have been removed. There's a single PCB with EQ and the dual-ganged Parametric Frequency pots directly mounted, and the power transformer is bolted and glued to the inside of the control panel, although well insulated from it by a layer of rubber. The power supply, for which all the other components are on the board, uses two 50V 1000 microfarad electrolytics for smoothing, and diode rectification; the power amp design is based on two BD 357 power transistors. These are generously heatsinked, and the rest of the design is fairly standard, using 741 op-amps in both the mixing and equalisation circuitry. PCB quality is very high and there is a minimal use of wire links or confusing bunches of cable.
The speaker can be removed by unscrewing the grille and the four heavy black clamps secured with quarter inch screws driven into sockets inside the cabinet. It's a Fane 1015 8 ohm model, a beautifully finished dual-cone design with plastic shielding over the magnet and very thick braided tag wire. Beneath it on the base of the cabinet sits the spring line reverb, a pretty standard dual 6 inch spring design from OC Electronics, Wisconsin. There are some nice additional touches though; phono sockets and plugs for connection to the amp circuitry, complete suspension of the transducers and spring lines on four smaller springs to reduce handling noise, and careful sealing of the location points for the small springs to avoid airflow from the moving speaker cone. The spring line is insulated from the cabinet by a thick rubber sheet to further reduce stray vibrations.
Although the Deanvard's designed for non-professional keyboards, the standard of construction seemed very high, so it appeared to be worth testing it with a fairly powerful synthesiser capable of covering the entire audio range. One obvious contender was OSCar, a new programmable monophonic from the Oxford Synthesiser Company. Since it's capable of covering 13 octaves (more with pitch bend) it seemed the ideal choice. The Deanvard didn't appreciate its full output, which shows one of the disadvantages of identical input sockets — no choice if distortion is produced. It was quite happy at about two-thirds however, and the first test was of its bass response. A highly resonant bass twang at 32 feet on the synth was reproduced very well, even with Bass full up on the amp and the Mid set to 120 Hz as well. Although the speaker cone was exhibiting a very long travel there was no sign of mechanical noise or vibration in the cabinet.
The Treble control was adequate, with some breathing effects noticed at high volumes in the treble range, but the Parametric Mid more than made up for any shortcomings, and would be invaluable in altering the overall tone colour of portable keyboards. The Bass was very full, within the obvious limitations of a 10 inch speaker, and the Balance control between the two inputs is a brilliant idea. The time and money saved in fiddling with small mixers and differing impedances when all you want is a quick rehearsal with two keyboards, or a keyboard and a microphone, could be enormous.
Finally, the Reverb, which is quite deep and full and produces no detectable hissing or buzzing, it reproduced bass notes well and reached quite high into the treble range before any sign of distortion
A beautifully constructed amp with a finish to last a lifetime. Certainly an enormously valuable upgrading to any portable keyboard, and quite suitable for the recent flock of cheaper polysynths. The input balance is a clever idea for musicians on a budget or in favour of simplicity, and the Reverb and Parametric Mid features are good. Not really suitable for amplifying an entire keyboard stack including organs or deep bass monophonics, but no doubt a reliable purchase which would give long service to very many amateurs and semi professionals alike.
Further details from Deanvard Ltd., (Contact Details). Recommended Retail Prices including VAT are as follows: VA 10K £69.52, VA 30K £137.25, VA 60K £165.77.