The VBA Pro signal chain starts with a dual channel input which is configurable as parallel A/B or bi-amped with crossover control (40Hz to 8kHz). The identical A and B channels are split into three sections: Compressor, Preamp and Power Amp.
The compressor has a single 'amount' knob that works in conjunction with the attack control to create a good deal of sustain and 'beef' without roaming into pumping territory.
Placing the compressor here helps keep a consistent level for the gain stage where plenty of growl is available via the Gain knob and Boost switch. Though the channels can be kept clean the distortion characteristic is a real joy to play with, from subtle fuzzing of the edges to a ripping valve overdrive, especially in conjunction with the dual channel architecture.
Each preamp has a standard three band EQ with fixed bass and treble shelving filters and a sweepable mid (40Hz-4kHz). This provides a good quality of broad brush tone shaping that really enhances the possibilities afforded by the dual channel/bi-amped signal path.
The power amp sections sport drive and limiter clipping controls which provide a second stage of gain and distortion performance. The power amp drive and clipping are less subtle and forgiving than the compressor and preamp so pushing them hard can create some nasty crackling and spitting, while the softer clipping characteristic can round off to a mellow rumble.
The lower half of the interface offers up a 12-band graphic EQ, Deep and Bright tone controls, a five-way cabinet selection, the final volume slider and two effects (reverb and chorus).
The graphic EQ has a good deal of range in both amplitude (+/-12dB) and frequency (30Hz-15kHz) and makes a huge difference in frequency manipulation without upsetting the balance of the input channels.
Though good tones can be made without engaging the graphic EQ we find it nearly always has the last word. Having said that, the Bright and Deep controls add that quick and easy high/low contouring that doesn't dismantle the preceding balances.
The three speaker cabinet models come courtesy of impulse specialists Red Wirez and use an Ampeg SVT 8x10, Hartke 4x10 and Ampeg B15 (miked with U47s). The 8x10 has a dominating boom and presence that can make the other two seem a little weak, but with some graphic EQ work the latter two easily come up with the goods.
The DI setting features a useful HF roll off making for a softer tone than the full frequency pass through provided by the 'off' cabinet setting.
The reverb and chorus effects are a simple affair with the former capable of adding a little air and room around the bass to place it in a mix. The chorus we found less useful, but then again we don't like chorus on bass. That said the cutoff control means it can apply chorus, if it is so desired, to the upper frequencies only, without upsetting the bass.
The easy to use interface provides plenty of level feedback via (virtual) traffic light LEDs strategically placed along the signal path. The range of tones available is excellent and the flexibility of EQ sculpting and gain staging/harmonic distortion makes this plug-in a pleasure to use.
Bass guitars may be the target instrument, but we had great results using it on guitars, electric pianos and, in particular, synth basses. The overall sound is such that the most thunderous bass tones can be achieved without losing the punchiness that a good bass lives or dies by.
For those in need of a dedicated bass amp plug-in, be it for stringed basses or synths, this is a fairly big contender for a fair price, and if you like a good bit of growling distortion to boot, then you're on to a winner.