Used HOT HOUSE S400 Pro Sound Product

Hot House S400 Stereo Hi-Current MOSFET Control Room Amplifier

Estimated Year: Early–Mid 1990s 

Made in: USA 

Used Hot House S400 Stereo MOSFET Amplifier

Overview 

The Hot House S400 is a stereo hi-current MOSFET control room amplifier designed for studio monitoring and high-fidelity applications. Built in the USA, this rackmount power amp features a minimalist front panel and substantial external heat sinks for efficient cooling and clean power delivery.

Rated with 30dB gain and 51k ohm input impedance (non-inverting), the S400 is built to deliver stable, high-current output for nearfield or control room monitors. The rear panel includes 1/4" inputs and binding post speaker outputs for each channel.

A solid vintage studio power amp with classic MOSFET warmth and punch—ideal for project studios, hi-fi setups, or rack-based monitoring systems.

Features 

- Stereo hi-current MOSFET power amplifier 

- Control room / studio monitoring design 

- 30dB gain 

- 51k ohm input impedance 

- Non-inverting design 

- 1/4" inputs 

- Binding post speaker outputs (per channel) 

- 5 Amp Type 3AG fuse 

- 120V AC, 60Hz operation 

- Heavy-duty external heat sinks 

- Made in USA 

Condition 

Good condition. 

- Powers on and tested for output 

- Cosmetic wear and rack marks on faceplate 

- Heat sinks in good structural shape 

- Original attached power cord included 

Store Policies 

- All items are tested before listing and again before shipping. 

- Orders typically ship next business day. 

- Shipping is available to the continental U.S. only. 

- We do not accept trades on shipped items. 

- Returns are accepted within 48 hours of delivery. The buyer covers return shipping, and a 20% restocking fee applies. If you have any questions before buying, feel free to message us—we’re happy to help.