Vertigo Sound VSP-2 Mic Pre is a two channel dual mono microphone preamplifier built around a fully discrete Twin Op Amp stage called the OPA 1976. The input is isolated by a microphone transformer with a low 1:2 ratio, which forces the discrete stage rather than the transformer to provide most of the amplification.
Gain you can write down and recall
Three singers in one session, each at a different level, and a week later you need a punch in that matches. The VSP-2 solves that in hardware: main gain sits on a ten position Grayhill switch in 6 dB steps across a 12 to 72 dB range, and fine trim runs on a separate 41 click Alps pot covering 0 to 6 dB. Both values can be noted and reproduced click for click, including across the two channels when you are working a stereo pair.
An instrument input with nothing in the way
The Instrument In socket is an unbalanced input wired straight to the Twin OPA stage with no circuitry in between, which makes it a genuine DI. Throw the switch and play; the output mutes briefly so nothing cracks through the monitors. For microphone work there is ramped 48 V phantom power, a 20 dB pad that does not change the input impedance, a polarity switch and a 12 dB per octave low cut filter at either 80 Hz or 120 Hz. The signal LED reads green across the usable range and red at +19 dBu, with no ambiguous orange state in between.
KEY FEATURES
- Two independent channels in dual mono configuration
- Fully discrete Twin Op Amp OPA 1976 gain stage
- Transformer isolated microphone input with a 1:2 ratio
- Gain from 12 to 72 dB on a Grayhill switch in 6 dB steps
- Fine gain trim of 0 to 6 dB on a 41 click pot
- Instrument input wired directly to the input stage
- Output muted when switching to the instrument input
- Low cut filter at 12 dB per octave, 80 Hz or 120 Hz
- Ramped 48 V phantom power
- 20 dB pad that does not affect input impedance
- Polarity reverse switch on each channel
- Two state signal and clip LED with no ambiguous middle
TECHNICAL SPECIFICATIONS
- Input impedance: 1.5 kOhm
- Gain range: 12 to 72 dB plus 0 to 6 dB fine trim
- Dynamic range: 116 dB at 36 dB gain
- Frequency response: 10 Hz to 35 kHz (±1 dB) at 36 dB gain
- Maximum input level at 20 Hz: +9 dBu
- Maximum output level: +24 dBu into 600 Ohm, balanced floating
- Noise: -81 dBu (20 Hz-22 kHz, unweighted, RMS) at 36 dB gain
- Electronically floating output, That 1646 type
- Clip LED threshold: +19 dBu at the output
- Linear power supply with toroidal transformer
- Mains voltage: 115 V or 230 V
- Steel chassis with electrostatic and magnetic shielding
