Sony TA-1120A

At 11 kilograms and bristling with silicon transistors, this 1967 flagship hums with the ambition of a company staking its claim in high-end audio.

Overview

The Sony TA-1120A isn't a subtle machine. From the moment it’s lifted—its 11 kg mass demanding respect—it broadcasts seriousness. Released in 1967, it marked Sony’s first major push into the upper echelon of home audio, a deliberate statement that Japanese engineering could rival the best from the West. This isn’t just an amplifier; it’s a premain design, meaning the preamp and power amp sections are fully integrated but engineered with enough independence to allow for modular use if needed. The entire signal path uses silicon transistors, chosen specifically for their stability under temperature swings and strong high-frequency behavior—critical for maintaining clarity at the extremes. Despite its age, the circuitry feels forward-thinking: a quasi-complementary SEPPP OTL configuration in the power stage, fully discrete design, and a parts list headlined by 46 transistors and 23 diodes, many of them now long out of production. It was never meant to be discreet.

Specifications

Manufacturer	Sony
Product Type	All-silicon transistor stereo premain amplifier
Original Price	¥ 96,000
Power Amplifier Unit Output	Non-clip music Power: 160W (8 Ω, both channel operation); Music Power (IHF): 60W + 60W (8 Ω, both channel operation); Rated output: 60W + 60W ± 0.5 db (4 Ω); Rated output: 50W + 50W ± 0.5 db (8 Ω); Rated output: 35W + 35W ± 0.5 db (16 Ω)
Harmonic Distortion Factor (Power Amp)	1kHz: 0.05% or Less (at Rated Output); 1kHz: 0.01% or Less (at 10W Output); 20 Hz to 15 kHz: 0.1% or Less (at Rated Output); 20 Hz to 15 kHz: 0.06% or Less (at 25W output); 20 Hz to 15 kHz: 0.03% or less (at 500 mW output)
Cross Modulation Distortion Factor (Power Amp, SMPTE standard 60Hz:7kHz=4:1)	0.2% or Less (Rated Output); 0.05% or Less (at 25W Output); 0.02% or Less (at 10W Output)
Frequency Characteristic (Power Amp)	7 Hz ~ 180 kHz + 0 -1dB (at Rated Output)
S/N Ratio (Power Amp, IHF standard Closed circuit)	110 dB or more
Input Impedance (Power Amp)	100k Ω or more
Damping Factor (1 kHz)	180 or More (8 Ω); 360 or More (16 Ω)
Sensitivity (Power Amp)	1 V (at 50W output)
Residual Noise (Power Amp)	0.1 μ W or Less (8 Ω)
Preamplifier Section Output	Pre-out: 2V/10k Ω; Headphone: 6V/10k Ω; Rec out: 150mV
Harmonic Distortion Factor (Preamp, at rated output)	Tuner, Aux, Tape: 0.03% or less; Mic: ≤ 0.05%; Tape head: 0.05% or less; Phono1/2: 0.05% or less
Cross Modulation Distortion Factor (Preamp, 60Hz:7kHz=4:1)	Tuner, Aux, Tape: 0.1% or less; Mic: ≤ 0.1%; Tape head: 0.1% or less; Phono1/2: 0.1% or less
Frequency Characteristic (Preamp)	Tuner, Aux, Tape: 10 Hz to 100 kHz + 0 -2dB; Phono1/2: deviation from RIAA curve within 0.5 dB; Tape head: Deviation from NAB curve within 0.5 dB; Mic: 10 Hz to 30 kHz + 0 -2dB
Sensitivity (Preamp)	Tuner, Aux: 150mV/100k Ω; Tape: 150mV/100k Ω; Phono1/2: 1.2mV/47k Ω; Tape Head: 1.2mV/500k Ω; Mic: 1.2mV/500k Ω
Maximum Undistorted Allowable Input (1 kHz, Preamp)	Phono1/2: 100mV; Tape head: 100mV; Mic: 100mV
Signal-to-Noise Ratio (Preamp)	Aux, Tuner: 90 dB or more; Phono1/2: 70 dB or more; Tape head: 70 dB or more; Mic: 65 dB or more
Tone Control	Bass: 100 Hz ± 10 dB; Treble: 10 kHz ± 10 dB (2 dB Step 11-Stage Switching)
Filter	Low Filter: 50 Hz or less, 12dB/oct.; High Filter: 9 kHz or higher, 12dB/oct.
Semiconductor Used	Transistor (46 pcs) 2SC401: 25 2SC293: 8 2SA527: 2 2SC318: 3 2SD45: 8; Diode (23 pcs) DS2M: 4 pcs 1T22: 2 SV-03: 2 SV-05: 4 SV-31: 10 1S332: 1
Power	100 VAC (Switchable to 117 V, 220 V, 240 V) ± 10%, 50Hz/60Hz
Power Outlet	Power switch interlock: 2 systems; Power switch not linked: 1 system
Power Consumption	No signal: about 40W; Rated output: approximately 260W
External Dimensions	Width 400x Height 145x Depth 310 mm
Weight	Approximately 11 kg
Attachment	Short plug Pin plug Connection code Silicon cloth 5A fuse
Sold Separately	Eurasian Cheek Finish Wood Case TAC-1 (¥ 4,600); Mounting Bracket MB-5 (¥ 2,800)

Key Features

Quasi-Complementary SEPPP OTL Power Circuit

The TA-1120A’s power amplifier relies on a quasi-complementary SEPPP (Series Push-Pull, Paralleled) OTL (Output TransformerLess) design. This configuration was a sophisticated choice in 1967, avoiding the coloration and bandwidth limitations of output transformers while delivering high current into low impedances. The use of silicon transistors throughout ensured better thermal stability than germanium alternatives, critical in a high-power, tightly packed chassis. The result is a measured 180 or more damping factor into 8Ω—exceptional for the era—giving owners tight control over speaker cones and a rock-solid bass foundation.

Lever-Operated Quick-Access Input Switch

A distinctive mechanical feature is the front-panel lever switch that allows instant toggling between two preset inputs, typically Tuner and Phono1. If other inputs are pre-selected via the main rotary switch, the lever effectively creates a three-input quick-select system. This wasn’t just a convenience; it reflected Sony’s focus on usability in a high-performance context, letting users switch between their most-used sources without fumbling through a knob.

2 dB Step Tone Control with Flat Cancel

The tone controls offer precise 2 dB increments across 11 steps, allowing for surgical adjustments. More unusually, a dedicated tone cancel switch returns the signal to flat regardless of the knob positions. This meant users could dial in a favorite EQ curve but instantly bypass it for critical listening—no need to visually align knobs to a center detent.

Independent Preamp and Main Amplifier Operation

Though housed in a single chassis, the preamp and power amp sections are functionally separable. The pre-out and main-in jacks allow the TA-1120A to act as a standalone preamplifier driving an external power amp, or as a power amp fed by another preamp. This flexibility was rare in integrated units of the time and speaks to Sony’s intent to position this as a modular component within a larger system.

Kooky Red Capacitors

Inside, the amplifier retains its original red-bodied capacitors—components that have become a visual hallmark. While their electrical performance degrades with age, their presence is a point of authenticity for collectors. Their failure is a common restoration hurdle, but their distinctive look is often preserved when possible during servicing.

Historical Context

The TA-1120A arrived in 1967 as a direct successor to the TA-1120, building on its foundation with improved circuitry and tighter specifications. It represented Sony’s serious entry into the high-fidelity market, a domain then dominated by Western brands. Its design language and engineering priorities—modularity, precision, and measurable performance— The aesthetic evolution from this model to the early 1970s TA-1130 reflects Sony’s shift toward a more refined, minimalist front panel, but the TA-1120A remains a bold artifact of late-60s Japanese industrial confidence.

Collectibility & Value

While specific market values aren’t documented in the primary source, owner reports indicate increasing demand on secondary markets, with some expressing surprise at rising eBay prices. The unit’s collectibility stems from its status as an early Sony flagship and its advanced-for-the-time engineering. However, it is not without issues: common failures include noise, DC offset voltage at the outputs, and capacitor degradation—particularly in units manufactured before 1968. The main RC snubber capacitor has been known to fail catastrophically. Service and user manuals are available through niche vendors, aiding in proper maintenance.

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