S-400 II vs ST-85
The ST-85's power @ 8ω is 60W against the S-400 II's 300W, its signal-to-noise 95 dB against 90 dB, and its thd 3.000% against 3.500%. Both share class (AB).
AI-generated product photo — not official manufacturer imagery.
AmplifiersPower AmplifiersTube AmplifiersDiscontinued
Estimated price (community-sourced)
$2,995
Around — community and catalog average, updates slowly
About the S-400 II
The VTL S-400 II is a reference stereo tube power amplifier from Vacuum Tube Logic, introduced as a Series II redesign of the original S-400. It uses a fully balanced differential architecture, zero global negative feedback, auto-bias with fault sensing, and a user-adjustable damping factor control to tailor amplifier output impedance and loudspeaker matching. It is rated at 300 watts per channel in tetrode mode or 150 watts per channel in triode mode, and was described in review coverage as a high-end stereo amplifier priced at $33,500.
Specifications
Power Specifications
Amplification power output and characteristics
- Power @ 8Ω
- 300W @ 8Ω
- Amplifier Class
- AB
- Minimum Impedance
- 4Ω
- Input Sensitivity
- 1.5V RMS
- Input Impedance
- 48000Ω
Analog Output
Analog signal output specifications
- THD
- 3.500%
- SNR
- 90 dB
Connectivity
Input and output connections
- Bluetooth
- No
- Wi-Fi
- No
- Ethernet
- No
- Analog Outputs
- 5-way binding posts
Physical Dimensions
Size, weight, and appearance
- Dimensions
- 610 × 290 × 610 mm (W × H × D)
- Weight
- 113 kg (249 lbs)
Key Specifications
Power: 300W
Specifications are community-contributed and may not be accurate or complete. Verify all details with the manufacturer before making purchasing decisions. Terms & Conditions