Preamplifier
This VAC Statement dual mono triode vacuum tube phono (MM/MC, three gain modes, adjustable load, stereo/mono operation) preamplifier is designed for extreme applications. On the back panel there are two DC umbilical cords and large Amphenol aerospace connectors, a reminder of the massive dual mono power supply. There are inputs for four independent phone sources. In addition, each input may be of the conventional single-ended type or may be fully balanced.
Mechanical Design
The chassis is machined at VAC from high-grade, non-ferrous aluminum and with superior RF rejection properties across a wide range of radio frequencies. Similar care is taken around each of the six wideband audio transformers in each unit.The front panel features a large machined knob for the four-position selector switch. Another large knob selects overall gains of 52 dB, 70 dB, or 76 dB to match virtually all moving magnet and moving coil cartridges. Smaller knobs provide full control of load impedance, load capacitance, and stereo or mono operation.
Electrical Design
The audio chassis’ distinct isolated sections dedicated to certain signal functions prevent unwanted interactions among the circuits. Interconnecting wires are carefully routed and directed by spaced machined nonmetallic guides. The hand-wired vacuum tube audio circuit assemblies are bonded to massive brass loading plates, which in turn are isolation mounted to the main chassis. The eight twin triode vacuum tubes employed in the various Class A 1audio stages are made with the finest grade parts, such as ‘naked’ metal foil resistors. The RIAA equalization is achieved without negative feedback, preserving the organic nature of the sound. A wide range of magnetic core materials and magnet wires were tested and auditioned, including different winding structures, silver and copper magnet wires, and mu metal and amorphous cobalt cores, to determine the ideal combination for the world’s finest phono stage.Power Supply
The massive separate power supply is a dual mono design with substantial energy storage and high inherent regulation. Both resistive and inductive elements are used in concert with high-speed capacitor assemblies for the high voltage supplies, while active voltage stabilization is included in the four heater supplies and the 12-volt trigger supply.-
Tubes
6x 12AX7
2 x E88CC/6922, ECC88/6DJ8, or 7308
Gain
46 dB MM (low gain)
70 dB MC (medium gain)
76 dB MC (high gain)
Up to 6 dB greater gain available on special order
Frequency Response
RIAA standard +/- 0.2 dB (20 Hz - 20 kHz)
-3 dB bandwidth 10 Hz - 80 kHz
Channel Separation
> 84 dB @ 1 kHz
Maximum Input
> 130 mV @ 1 kHz, MM (low gain); >500 mV @ 10 kHz
> 16 mV @ 1 kHz, MC (medium gain)
> 8 mV @ 1 kHz, MC (high gain)
Load Impedance
MM, 47k Ohms
MC (medium gain), selectable 400, 300, 200, 150, 100, or 50 Ohms
MC (high gain), selectable 100, 75, 50, 38, 25, or 13 Ohms
Load Capacitance
MM, 1, 100, 120, 150, 180, or 220 pF
Residual Noise
Less than 3MV at output (s/n ratio > 74 dB)
Absolute Phase
Does not invert absolute phase
Maximum Output
> 8 V RMS
Output Impedance
< 150 ohms, 20 Hz - 20 kHz, static (i.e., not dependent upon feedback)
Recommended Output Load
> 300 ohms
Power
External power supply, dual detachable umbilical cable (dual mono design), detachable IEC power cord
Voltage
May be ordered for 100v, 120v, 220v, or 230/240v operation
Illumination
Illuminated logo may be switched to bright, dim, of 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): 7 x 17.7 x 16.15 in.
Power supply (not including connectors): 5.8 x 17.7 x 16.15 in.
Shipping Weight
Phono stage chassis 56 lbs.
Power supply 64 lbs
*Specifications subject to change without notice.
- Reviews
“As those of you who have been lucky enough to hear them at shows can attest, the results are phenomenally lifelike.”
Jonathan Valin - 2015 Golden Ear Award, The Absolute Sound