Manley Voxbox is a 3U all-valve channel strip combining a microphone preamplifier, an ELOP optical compressor, a passive Pultec style equaliser, a de-esser and a limiter. The whole path is valve based, with no op-amps in the signal chain.
A vocal that is finished on the way in
Tracking a vocal through an ordinary preamp leaves you with a take that has to be rescued later with plugins: sibilance, level jumps, no bottom end. The Voxbox does all of that on the way to the converter, while the signal still has full headroom. The de-esser and compressor sit ahead of the equaliser, so lifting the top does not sharpen the sibilance you have just tamed. Compression runs at 3:1 with up to 16 dB of reduction, and switching to limiting turns that into 10:1 and 32 dB when a level jump has to be caught without riding a fader.
Passive equalisation with valve make-up gain
The equaliser section uses genuine inductors and the passive Pultec topology, with gain recovered by a Class-A valve stage. The trick that defines this circuit, boosting and cutting the same low band at once, produces a curve you cannot build on a parametric equaliser. The inputs handle microphone, line and instrument at 2000, 4000 and 100,000 Ohms respectively, so an electric guitar or a synth enters the same path as the microphone.
KEY FEATURES
- 3U all-valve channel strip with no op-amps
- Microphone preamplifier with up to 60 dB of gain
- Line and instrument inputs with their own impedances
- ELOP optical compressor at 3:1 with up to 16 dB of reduction
- Limiting mode at 10:1 with up to 32 dB of reduction
- Passive Pultec style equaliser on genuine inductors
- De-esser placed ahead of the equaliser section
- Compression attack 4 to 70 ms, release 0.3 to 5 s
- Limiting attack 2 ms, release 0.5 s
- 12AX7, 12BH7 and 6414 or 5965 valves matched in pairs
- Universal supply, 90 to 254 V
TECHNICAL SPECIFICATIONS
- Maximum gain: 60 dB mic, 23.2 dB line, 23.4 dB instrument
- Input impedance: 2000 Ohm mic, 4000 Ohm line, 100 kOhm instrument
- Frequency response: 20 Hz to 60 kHz
- Equaliser section response: 10 Hz to 68 kHz (±1 dB)
- Maximum preamp output: +30 dBu
- Maximum equaliser output: +33 dBu
- THD+N: 0.008% at 1 kHz, A-weighted
- Noise floor: -83 dBu, A-weighted
- Dynamic range: 113 dB
- Dimensions: 19 x 5.25 x 10 inches, 3U
- Weight: 14.5 lbs; power consumption 31 W
