Scott 399 (1969)

The Scott 399 is a solid-state stereo amplifier, reportedly introduced in 1969 by H.H. Scott, Inc. It is not as widely documented as some of its contemporaries, but vintage audio people respect it for its technical sophistication, conservative design and build quality. It came as part of Scott's push into the solid-state era, and it sits between tube amplification and transistorized circuitry.

Design and Engineering Philosophy

H.H. Scott, Inc. was founded by Hermon Hosmer Scott, an MIT-trained engineer who pioneered the concept of the "communications receiver" and emphasized measurable performance in audio equipment. The company's products were known for scientific design principles, low distortion, and wide frequency response. The 399 continues that tradition.

The 399 is a dual-mono, two-channel power amplifier designed for stereo operation. It delivers 18 watts per channel into an 8-ohm load, with less than 0.1% total harmonic distortion (THD) across its operating range. That was substantial for its time, given the efficiency of speakers available in the late 1960s. The amplifier is believed to operate in class AB, a common and efficient configuration that balances heat dissipation with linearity.

The 399 is a fully discrete solid-state design. Unlike later amplifiers that used integrated circuits, it relies on individual transistors, resistors, and capacitors laid out on point-to-point or eyelet-based circuit boards. This construction makes it reliable and easy to service, which was typical of Scott engineering. The power supply is heavy duty, with a large toroidal transformer (in later revisions) or a high-quality EI-core transformer, so voltage stays stable even under dynamic load conditions.

Technical Specifications

Power Output: 35 watts RMS per channel (8Ω, both channels driven)
Frequency Response: 10 Hz – 60 kHz (+0, -1 dB)
Total Harmonic Distortion: < 0.1% at full power
Slew Rate: ~25 V/μs (estimated based on circuit topology)
Damping Factor: > 100 (at 1 kHz)
Input Sensitivity: 1.5 V for full output
Input Impedance: 47 kΩ
Signal-to-Noise Ratio: > 90 dB (A-weighted)
Protection Circuitry: Thermal overload and DC offset detection
Dimensions: 19" (W) × 6.5" (H) × 14" (D)
Weight: Approximately 38 lbs (17.2 kg)

The amplifier features balanced (XLR) and unbalanced (RCA) inputs, a rare inclusion for consumer amplifiers of the era, suggesting that the 399 was marketed toward semi-professional and high-end audiophile markets. The front panel is minimalist, with a large central power meter (VU-style), channel indicators, and a recessed power switch. The meter serves both as a power output indicator and a diagnostic tool, helping users monitor clipping and channel balance.

Sound Characteristics

The Scott 399 is often described as having a neutral, transparent sound. It lacks the coloration of tube amplifiers but avoids the clinical sterility that plagued some early transistor designs. Its wide frequency response and high damping factor let it control speaker cones well, giving tight bass and detailed treble. The midrange is clear and articulate, which suits vocal and acoustic recordings.

With low distortion and high linearity, the 399 reproduces complex musical passages without congestion. It pairs well with high-efficiency speakers such as the AR-3a, KLH Model Eight, or Advent Large. Its 35-watt output may struggle with low-sensitivity or difficult impedance loads, so speaker matching is important.

Build Quality and Reliability

The Scott 399 was built to last. The heavy steel chassis shields well against electromagnetic interference, and the aluminum front panel and knurled control knobs feel industrial. Internally, components are generously sized and conservatively rated. It uses metal-film resistors, polypropylene capacitors, and high-gain output transistors.

Many 399 units still work today with minimal servicing. Aging electrolytic capacitors and dried-up thermal paste on the output transistors are common maintenance issues. Replacement parts are generally available, and the service manual, when you can find one, gives detailed schematics and alignment procedures.

Market Position and Legacy

In 1969, the Scott 399 retailed for approximately $450, which, adjusted for inflation, equates to over $3,500 today. That put it in the premium segment, competing with amplifiers from McIntosh, Marantz, and Fisher. It was not as visually striking as some of its contemporaries, and it appealed to engineers, scientists, and critical listeners who valued performance over looks.

The 399 never reached the status of the Scott 222 receiver or the 299 preamplifier. That may be partly because it came out during a period of rapid technological change, and partly because of H.H. Scott, Inc.'s gradual decline in the 1970s. The company changed ownership several times and eventually ceased production of high-end audio gear, though the brand name has been revived intermittently for consumer electronics.

Today the Scott 399 is a sought-after collector's item, especially among those who like understated, measurement-focused design. It is valued for its sound quality and as a piece of the early solid-state era. Restored units regularly appear on audiophile forums and vintage audio marketplaces, often at prices between $600 and $1,200 depending on condition.

Conclusion

The Scott 399 stands as a testament to the engineering rigor that defined H.H. Scott, Inc. at its peak. While overshadowed by more famous models, it delivers exceptional performance, reliability, and musicality. For the vintage audio enthusiast, the 399 offers a window into a time when high fidelity was pursued with scientific discipline and uncompromising standards. Whether used as a daily driver or preserved as a collector’s piece, the Scott 399 remains a worthy representative of American audio excellence in the late 1960s.