Not long ago, the Signature Mk IIa was the finest preamplifier you could buy. In production since 2000, this enduring classic marked the introduction of the basic, fully balanced, zero-feedback, transformer-coupled Class A1 triode topology found in all contemporary VAC preamplifiers. Even from this early form, it preserves and reproduces the emotion and vitality of music and maximizes the performances of the associated source components and power amplifiers.



  • 3 sets RCA line input
  • 2 sets balanced/RCA selectable inputs
  • 1 set RCA tape monitor input
  • set RCA cinema bypass input
  • Optional 1 MM and 1 MC (or additional line input if phono is not fitted)
SIGNATURE MK IIA Optional MM/MC phono stage with user adjustable loading
Gain 12 dB
  • 2 sets RCA
  • 2 sets balanced XLR (EIA ‚Äúpin 2 hot‚Äù studio standard)
  • 1 set RCA tape output
Tubes 2x 12AU7
2x 8416, 7308, 6922, E88CC, ECC88, 6DJ8, (or 12DJ8 twin triodes)
Absolute Phase correct from all inputs to all outputs
Frequency Response Flat over audio band
–3 dB bandwidth 5 Hz – 210 kHz
THD <0.009% @ 1 kHz, 1 V RMS
Maximum Output > 8 V RMS
Output Impedance < 150 ohms, 20 Hz – 20 kHz, static (i.e., not dependent upon feedback)
Maximum Input Infinite signal (attenuation precedes the gain circuitry)
Recommended Output Load > 300 ohms
Power External power supply, detachable umbilical cable, detachable IEC power cord
Tape Output Unity gain from selector, non-inverting for archival integrity
Cinema Bypass Yes
Voltage May be ordered for 100v, 120v, 220v, or 23-/240v operation
Remote Control included
Illumination Illuminated logo may be switched off
Finish Black or silver
Warranty Two years parts and labor, excluding tubes (USA, see manual for full details)
Dimensions (H x W x D) Audio chassis (not including knobs and connectors): 5.5″ x 18″ x 14.5″ (14 cm x 45.7 cm x 36.8 cm)

Power supply (not including connectors): 4.3″ x 18″ x 14.5″ (10.9 cm x 45.7 cm x 36.8 cm)

Shipping Weight With phono: 61 lbs. (27.7 kg.)



6x 12AX7

Phono Stage (optional)
Gain 44 dB MM

64 dB MC

Frequency Response RIAA standard +/- 0.2 dB (20 Hz – 20 kHz)

-3 dB bandwidth 10 Hz Р• 80 kHz

Channel Seperation > 80 dB @ 1 kHz
Maximum Input > 130 mv @ 1 kHz, MM

> 13 mv, MC

MC Load Impedance selectable, 470, 300, 250, 200, 150, and 100 ohms
MM Load Impedance selectable, 47k, 30k, 25k, 15k, and 10k ohms
Overload 117MV @ 1kHz = 8 volts RMS output; 460MV @ 10kHz
Residual Noise Less than 3MV at output (s/n ratio greater than approx. 69db

*Specifications subject to change without notice.





Kevin Hayes has really outdone himself with the VAC Signature IIa preamp. A statement piece at a luxury price, it plays music with extraordinary finesse and drive, accurate timbres, spaciousness in the soundstage, swift attacks and aching decays, and an even spectral balance. Of all the preamps that have been in my system, it is the one that most wisely balances the ofttimes contradictory qualities of superior drive and great finesse. Completely versatile, it can be voiced by rolling tubes to suit just about any ear, has numerous inputs for a multitude of sources, can be fitted with an outstanding phonostage, and be run balanced or single-ended. It performed splendidly with three of my power amplifiers, both tubed and solid-state. Besides all this, it looks flat fantastic, a fancy piece of audio bling perched atop its own power pedestal.  Read More