Audio Research VT100mkII

Commentary

This is a stereo power amplifier which is the renewal model of VT100.

The energy storage capacity of the power supply has been doubled, and the enormous capacity of 540 joules has improved the ability to follow music signals and the audibility output.

A large beam power tube 6550C is used for the final stage of the signal system, and stable high power is obtained by parallel push-pull operation with sufficient allowance for the maximum rating.
In addition, the dual mono configuration separated from the input terminal to the output eliminates interference and crosstalk between the left and right channels.

The output terminal has 2 systems of 8 Ω and 4 Ω.

Audio Research's unique balanced circuit for all stages supports both balanced input and unbalanced input. There is no change in load condition or input sensitivity regardless of whether you use either.
In addition to the tube type preamp, it is also designed to be suitable for combination with a semiconductor amplifier, and the original transmission quality can be maintained even when a semiconductor type channel divider is connected.

In order to increase dynamic stability against music signals, the power supply of the voltage amplifier stage is fully constant voltage, and a constant current source is added to the input stage to suppress drift and aging.

The vacuum tube of the first stage is equipped with a clear damping ring to eliminate adverse effects of mechanical vibration.
In addition, a cooling fan has been installed at the bottom of the chassis to ensure stable operation and high power and to extend the life of the vacuum tube.
A detachable power cable with an IEC connector has been newly adopted.

Model Rating

Type	Stereo power amplifier
Rated output	100W + 100W (continuous, 20 Hz to 20 kHz)
Output bandwidth	15 hz to 80 khz -3dB
Total harmonic distortion factor	1% or Less (1 kHz, 100W)
Frequency characteristic	1 Hz to 100 kHz -3dB (1W)
Input sensitivity	1.9 Vrms (both balanced and unbalanced)
Input impedance	Balance : 200k Ω Unbalanced : 100k Ω
Output terminal	4 Ω / 8 Ω
Damping factor	About 11
Signal-to-noise ratio	95 dB (at IHF, input short, rated output)
NFB	10dB
Slew rate	15V/ms
Rise dime	3ms
Vacuum tube used	4 x 6550C matched pair 6922x8
Pwer	100 VAC, 50Hz/60Hz
Power consumption	300W (No Signal) 750W maximum
External dimensions	Width 483x Height 222x Depth 533 mm (Including Handle)
Weight	29.5 kg (Body) 37.7 kg (when packed)