Marantz 170DC vintage power amplifier, 86 WPC — front view, silver faceplate with twin illuminated power meters

Marantz 170DC vintage power amplifier — angled front view, silver faceplate, dual VU meters and finned heatsink top

Marantz

Marantz 170DC Vintage Power Amplifier – 86 WPC, Level 2 Service

$1,995.00

✔️ Marantz Model 170DC stereo power amplifier — 86 WPC into 8Ω, 108 WPC into 4Ω, 170 WPC into 2Ω
✔️ True DC-coupled complementary OCL topology, shared in architecture with the legendary Model 250
✔️ Iconic blue-illuminated peak-reading VU meters, –40dB to +3dB with peak hold
✔️ ESP energy-sensing speaker protection and four-second turn-on delay — no thump
⚠️ No power switch by design — needs a preamplifier with a switched outlet, or a switched power bar

1 in stock

Description

Designed in the USA and built in Japan during Marantz’s most celebrated era, the Model 170DC is a genuine Golden Age stereo power amplifier — seriously built, beautifully presented, and still commanding respect among vintage audio enthusiasts decades after it left the factory.

What the “DC” Actually Means

The 170DC’s name is more than a model designation. “DC” refers to a true direct-current coupled amplification circuit that carries the audio signal through all gain stages without AC coupling capacitors in the signal path. Marantz’s engineering team adopted this approach with a specific goal: eliminating TIM — transient intermodulation distortion — which they had identified as a key degrader of musical transients and dynamic accuracy in conventional designs of the era. The result is a purer waveform with minimal phase shift, and a sonic character many describe as tube-like: warm, full-bodied and musical despite being solid state.

The circuit is a pure complementary OCL (output capacitor-less) parallel push-pull three-stage Darlington configuration, with a fully independent symmetrical layout identical in architecture to the legendary Model 250 — a topology chosen for load stability and power linearity. The first stage uses a differential cascode bootstrap circuit built on audio-specification low-noise dual FETs, minimising temperature and time drift so DC operation stays stable across the amplifier’s working life.

Power Supply and Protection

The supply is muscular and well considered: a large transformer paired with 18,800µF × 2 filter capacitors delivers the headroom and current that 86 watts per channel demands — and that dynamic peaks well above rated power actually require. The amplifier will deliver 108 WPC into 4Ω and 170 WPC into 2Ω when the programme material calls for it.

Protection is drawn directly from Marantz’s flagship Model 510M. The ESP (Energy Sensor Protection) circuit monitors output current, voltage and DC generation simultaneously, measuring total energy rather than instantaneous values — so it protects speakers without interrupting music during brief transient peaks. A four-second relay delay on power-up eliminates turn-on thump.

Those Blue Meters

The 170DC’s signature is its pair of large blue-illuminated VU meters — logarithmic peak-reading instruments spanning –40dB to +3dB with peak hold indicators. They earn their place twice over: you can confirm balanced channel operation at a glance, and they give the unmistakable Golden Age Marantz look that reads across a room. A DC/AC coupling switch on the rear panel adds flexibility when pairing with different preamplifiers.

It Needs a Preamp With a Switched Outlet

Worth knowing before you buy: the 170DC has no power switch of its own. It was designed to be powered from the switched AC outlet of a matching Marantz preamplifier such as the 3250B or 3300, which makes it a natural partner in a vintage Marantz separates system. It pairs equally well with any quality preamplifier that has a switched outlet, or with a switched power bar. If you are building the system from scratch, our Marantz 3800 preamplifier is an American-built Golden Age match with exactly the switched outlets this amplifier expects.

Condition & Service

This unit presents in very good vintage condition — the classic black faceplate and silver chassis show normal patina consistent with careful use over decades. The blue VU meters illuminate brightly, all controls operate smoothly, and the gold-plated RCA inputs are clean. It has undergone our Level 2 service and testing, which should ensure many more years of reliable performance ahead.

Owners describe the sound consistently: “Sounds like a tube amp. Bassy, controlled, musical and smooth… definitely on the romantic side of sound. Great for vintage LPs and Jazz.” Another long-time owner: “I own several solid state integrated and standalone power amps and this is by far my favourite one… it can sing!”

Specifications

Type: Stereo power amplifier — designed in USA, made in Japan (1977–1980)
Circuit topology: True DC-coupled, pure complementary OCL parallel push-pull three-stage Darlington
Power output: 86 WPC into 8Ω · 108 WPC into 4Ω · 170 WPC into 2Ω
THD: 0.03% at rated output, 20Hz–20kHz · IMD: 0.03%
Frequency response: 20Hz–20kHz (+0 / –0.2dB)
Damping factor: 60 (8Ω)
Input sensitivity / impedance: 1.5V / 30kΩ, gold-plated RCA
Residual noise (IHF-A): 0.046 mV
Metering: Blue-illuminated logarithmic peak-reading VU, –40dB to +3dB, peak indicators
Protection: ESP circuit (current / voltage / DC / energy sensing) plus four-second relay turn-on delay
Power switch: None — powered from a preamplifier’s switched outlet
Semiconductors: 53 transistors, 49 diodes, 4 dual FETs
Dimensions: 16.4″ W × 5.75″ H × 11.9″ D (416 × 146 × 302 mm)
Weight: 31.1 lb (14.1 kg)

Completing the System

A 31 lb amplifier with a large transformer benefits from being decoupled from the shelf it sits on. The IsoAcoustics zaZen II platform is rated to 40 lb, which gives real margin over this amplifier’s 31.1 lb — we are an authorized IsoAcoustics dealer and happy to advise on fit. For speaker cable, build exactly what your run needs with our Custom Speaker Cable Builder, made to order in our own shop.

Why Buy From Radique

This amplifier is backed by our Bumper to Bumper Warranty and our Perpetual Trade-Back Program, so you can buy today and move up later without losing your investment. Audition by appointment at our Kanata North location in Ottawa, or order online for local pickup or shipping. Every order ships in our 275 lb-test double-wall packaging, engineered to protect your gear in transit.

⭐ Don’t Just Take Our Word For It

Radique Audio holds over 600 customer ratings averaging 4.97 stars across six public platforms — Facebook Marketplace, Kijiji, Canuck Audio Mart, Google and others. Every rating lives somewhere we don’t control, so you can read the originals yourself, including the less flattering ones. See what our customers say. 👉

Additional information

Weight	34 lbs
Dimensions	15.9 × 20.4 × 9.95 in

About brand

Marantz at Radique

Marantz began in 1953 in Queens, New York, where Saul Marantz built tube preamplifiers and amplifiers, and by the 1970s it was making receivers with champagne-gold faceplates, blue-lit dials and flywheel tuning. We carry Marantz receivers, amplifiers and preamps, turntables, tuners, CD players and cassette decks. We've had more than 150 Marantz listings so far, covering nearly 100 different models. Every used Marantz here is inspected, tested and serviced as required, then photographed in-house and covered by our Bumper-to-Bumper Warranty and Perpetual Trade-Back Program. Many Marantz components were sold without their wood case, so we also make new cherry WC-22 and WC-10 style cabinets. Don't see the model you want? Tell us on First Dibs and we'll email you when one arrives.

Our five best-selling Marantz models so far: the SR4023 stereo receiver, the vintage 2225, the SR7000 AV receiver, the SR4320 stereo receiver and the vintage 2238B.

The Marantz story, 1953 to today

Saul B. Marantz founded the company in New York in 1953. His first product, the Audio Consolette preamplifier, became the Model 1, and Marantz dates the first Consolettes to 1952–53. Marantz says the early factory was in Woodside, Queens.

The tube years. Through the late 1950s and early 1960s Marantz built a small run of tube separates in New York that collectors still chase: the Model 7 preamplifier (1958), the Model 9 power amplifier (1960) and the Model 10B tuner (1964).

Superscope and the move to Japan. In 1964 Superscope, the company that also distributed Sony tape recorders in the US, bought Marantz, and Saul Marantz resigned at the end of 1967. The Model Eighteen of 1968 was the first Marantz receiver, rated at 40 watts per channel. Under Superscope, design moved to California and, from the late 1960s, production moved to Japan through Standard Radio, which became Marantz Japan in 1975. Receivers such as the 2230 and 2270 are listed as designed in the USA and produced in Japan.

The power race. After a 1974 Federal Trade Commission rule tightened how amplifier power was rated, receiver makers competed on watts. Marantz's Model 2500 of the late 1970s was rated at 250 watts per channel and had an oscilloscope tuning display.

Philips, Denon and today. In 1980 Philips bought Superscope's stake in Marantz Japan and the brand outside the US and Canada. Marantz says its CD-63 of 1982 was one of the first CD players, and its "KI Signature" models carry the initials of Ken Ishiwata, who joined in 1978. In 2001 Marantz Japan bought the trademark back from Philips, and in 2002 it combined with Denon to form D&M Holdings. In September 2025 HARMAN, a Samsung company, completed its purchase of Sound United, the parent of Marantz and Denon.

Which Marantz is which?

Tube separates (1950s–60s): the Models 1, 7, 8B, 9 and 10B, built in New York. Rare collector pieces.

First receivers (from 1968): the Model Eighteen, followed by the Nineteen at the end of 1969.

22xx receivers (from 1972): the first set was the 2215, 2230, 2245 and 2270, with the champagne-gold faceplate, blue-lit dial and "Gyro-Touch" flywheel tuning. A higher number generally means more power: the 2230 is rated at 30 watts per channel, the 2270 at 70. Later "B" versions such as the 2220B and 2285B followed.

Big late-1970s receivers: the 2325 (125 watts per channel), the 2500 flagship and four-channel "Quad" receivers.

1000-series integrated amplifiers: for example the 1060 (30 watts per channel, from 1971), the 1070 and the 1150 (75 watts per channel). The slim 1030, 1040, 1060 and 1070 share their case size with tuners such as the 104, 105 and 112.

Tuners: from the tube Model 10B to solid-state models such as the 2130, with its oscilloscope display.

Wood cases: Marantz sold its wood cases separately: the WC-22 for the 22xx receivers, the WC-10 for the slim 1000-series amplifiers and 100-series tuners, and the WC-1 for larger models such as the 1200. That is why so many turn up bare. A customer who sold Marantz in Ontario in the 1970s told us the cases his shop ordered were built here in Canada, by Westinghouse. Our own cherry WC-22 and WC-10 style cabinets are made in Canada too.

CD players: from the CD-63 of 1982 to the KI Signature versions.

Buying used Marantz: what to check

Dial and meter lamps. Burnt-out bulbs are common on 1970s receivers and are often replaced, sometimes with LEDs. Ask which, if the look of the dial matters to you.

The dial itself. The diffuser sheet behind the dial ages and can dull the glow. Check that the Gyro-Touch pointer moves smoothly and tracks the stations; dial cords are a common replacement part.

Controls and switches. Crackle when you turn a control or work a switch usually means dirt. Try every input, and walk away from a unit that drops a channel.

Capacitors and bias. Electrolytic capacitors in 1970s gear are often past their best, and full restorations replace them. Restorers also set the bias and DC offset.

Cosmetics. Pitting on the faceplate points to damp storage, and dents or water stains to rough handling.

Everything we list is inspected, tested and serviced as required here, and comes with our warranty.