Dynaco Dynakit Stereo 70 (ST-70) Vacuum Tube Stereo Power Amplifier – 35 Watts Per Channel – Legendary Vintage Tube Amplifier

This item will be thoroughly checked, tested, and serviced one last time before shipping to ensure this amplifier is performing as it should.

Classic American tube engineering. Timeless musicality. Legendary Dynaco performance.

Some amplifiers become popular because of their specifications. Others become legends because of the way they make music sound. The Dynaco Dynakit Stereo 70 belongs firmly in the second category.

Introduced in 1959, the Dynaco Stereo 70, commonly known as the ST-70, became one of the most successful and influential vacuum tube power amplifiers ever produced.

Designed by legendary audio engineer David Hafler, the ST-70 helped make high-quality tube amplification accessible to music lovers everywhere. Its combination of excellent engineering, reliable circuitry, quality transformers, and impressive musical performance made it an icon of American hi-fi.

Delivering a genuine 35 watts per channel RMS, the Stereo 70 uses four EL34 output tubes in a classic push-pull configuration to produce a rich, detailed, and engaging listening experience.

At the heart of the amplifier are Dynaco's famous A-470 output transformers, engineered for excellent frequency response and signal reproduction.

The ST-70 also features Dynaco's patented Dyna-Bias adjustment system, designed to make setting the output tube operating conditions straightforward.

Its beautifully exposed vacuum tubes, substantial transformers, and classic metal chassis give it an unmistakable vintage appearance.

Decades after its introduction, the Dynaco Stereo 70 remains one of the most respected and sought-after vintage tube amplifiers in the history of audio.

WHY YOU WANT THIS AMPLIFIER

• Classic tube amplification: 35 watts per channel RMS, delivering the natural musical presentation that made vintage tube amplifiers famous.

• Four EL34 output tubes: A proven push-pull amplifier design known for its musicality, dynamics, and rich tonal character.

• Legendary A-470 output transformers: Dynaco Super-Fidelity transformers designed for excellent bandwidth and signal transfer.

• Patented Dyna-Bias system: Individual channel bias adjustments help maintain proper output tube operating conditions.

• Selectable speaker impedance: Compatible with 4, 8, and 16-ohm loudspeaker connections.

• Stereo or mono operation: Can be configured for approximately 70 watts of mono output.

• Classic American engineering: Designed by David Hafler and built around a proven, serviceable circuit.

• Iconic vintage appearance: Beautiful exposed vacuum tubes, substantial transformers, and classic Dynaco chassis styling.

• A collector-worthy classic: One of the most influential and recognizable tube amplifiers ever made.

TECHNICAL SPECIFICATIONS

Amplifier

• Power output: 35 watts per channel RMS

• Mono operation: 70 watts

• Rated speaker impedance: 4, 8, and 16 ohms

• Frequency response: 10Hz–40kHz (±0.5dB at 1 watt)

• Total harmonic distortion: Less than 1% at rated output

• Intermodulation distortion: Less than 1% at rated output

• Damping factor: 15

• Signal-to-noise ratio: Greater than 90dB

• Input sensitivity: 1.3 volts RMS

• Channel separation: Greater than 55dB

• Push-pull vacuum tube amplifier design

VACUUM TUBE COMPLEMENT

• 4 × EL34 / 6CA7 output tubes

• 2 × 7199 driver tubes

• 1 × GZ34 / 5AR4 rectifier tube

• Selenium rectifier in the original bias supply

FEATURES & CONNECTIONS

• Stereo operation

• Mono operation

• Independent left and right bias adjustments

• Dyna-Bias adjustment system

• 4, 8, and 16-ohm speaker connections

• Left and right RCA inputs

• Auxiliary power connections for compatible Dynaco preamplifiers

• Classic A-470 output transformers

• Nickel-plated chassis

• Removable protective cover

PHYSICAL SPECIFICATIONS

• Width: 13 inches

• Height: 6-1/2 inches

• Depth: 9-1/2 inches

• Net weight: 32 lbs (14.5 kg)

• Packed weight: Approximately 38 lbs (17.2 kg)

WHY BUY FROM FACTORY HI-FI?

At Factory HiFi, we appreciate equipment that was built to last and designed to reproduce music the way it deserves to be heard.

Every amplifier we sell deserves attention to detail, proper testing, and the care necessary to bring classic audio equipment back to life.

The Dynaco Stereo 70 is not just another vintage amplifier. It is a legendary piece of American audio history, combining classic vacuum tube technology, exceptional transformer design, and musical performance that continues to impress audiophiles decades after its introduction.

Whether you're building a dedicated two-channel tube system, upgrading your current amplification, or adding an iconic Dynaco to your collection, the Stereo 70 is an amplifier worth owning.

35 watts of classic tube power. Legendary Dynaco engineering. Timeless musical performance.

Factory HiFi – Bringing Great Audio Back to Life.