Preamplifier
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.
The Signature’s line stage has no coupling capacitors to detract from the purity and detail of the hand-wired circuit. With no loop feedback, the output is stable and free from dynamic interactions with the load. Six standard line inputs (five when phono is fitted) are present, as well as a fully balanced Cinema Bypass input.
The optional six-tube phono stage is sensitive and quiet, compatible with low-output, moving coil cartridges. Gain is adjustable, as is resistive loading. Electrostatic decoupling prevents the heater circuits from “talking” to each other, a common cause of lost detail. A separate power transformer is used, eliminating any disturbance of the delicate phono signal by the powerful line stage.
The VAC logos are backlit in an elegant blue in normal operation, and display red when the mute is activated. These are set in the heirloom-quality sculpted 3/8” faceplate.
The Signature SE (Special Edition) input transformers are the premium designs used in the Statement and Master ranges.
-
SIGNATURE MK IIA Optional MM/MC phono stage with user adjustable loading Gain
11 dB
Inputs
- 3 sets RCA line input
- 2 sets balanced/RCA selectable inputs
- set RCA cinema bypass input
- Optional 1 MM and 1 MC (or additional line input if phono is not fitted)
Outputs
- 2 sets RCA
- 2 sets balanced XLR (EIA “pin 2 hot” studio standard)
Tubes
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 kHzTHD
<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
Cinema Bypass
Yes
Voltage
May be ordered for 100v, 120v, 220v, or 230/240v operation
Remote Control
included
Illumination
Illuminated logo may be switched off
Finish
Hand-rubbed gold-flake gloss black lacquer with chrome knobs standard.
Hand-rubbed metallic gloss silver lacquer with chrome knobs special order with additional cost.
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.)
Phono Stage (optional) Tubes
6x 12AX7
Gain
44 dB MM
68 dB MCFrequency Response
RIAA standard +/- 0.2 dB (20 Hz - 20 kHz)
-3 dB bandwidth 10 Hz - • 80 kHzChannel Separation
> 80 dB @ 1 kHz
Maximum Input
> 130 mv @ 1 kHz, MM
> 13 mv, MCMC 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.
“The Valve Amplification Company's Signature SE preamplifier is the most significant audio product I've ever hooked up to my reference system. It was flawless.”
Robert J. Reina - Stereophile, June 5, 2015
“It opened my eyes to the potential that was still hidden in my digital and vinyl collections. State of the art industrial design, superb build quality and cutting edge performance... The best compliment that I can give the Signature is that I purchased it. Very highly recommended!”
Robert S. Youman - Positive Feedback, June 10, 2020
“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.”
- The Absolute Sound, September 2012
“"The sound is gorgeous - capable of handling rock, jazz, or classical music equally well."”
- 2012 Editors Choice Award, March 2012 - The Absolute Sound
“That’s pretty much how it goes with VAC gear – whatever it is connected to sounds about as good as it’s going to get! ... The Signature Preamplifier Mk 2 is suitable for the most exquisite of audio systems, and thus is recommended without reservation!”
- Doug Schroeder, DaGoGo, March 2010
“A Music-Lover’s Delight ... imaging isn’t good or even very good, it is out of this world; and it’s out of the speakers. I wouldn’t call it three-dimensional, I’d call multi-dimensional with instruments on the (invisible) soundstage in revealing focus ... its dynamic range — was beyond compare and it was quite evident that the VAC’s presence heightened the system’s musical caliber.”
- The Inner Ear Magazine, February 2010