SONY TA-NR1

Commentary

A monaural power amplifier with carefully designed and carefully designed structure while realizing electrically 1 Ω load continuous drive.

The power supply section is equipped with a large and heavy power transformer and high-performance electrolytic capacitor.
The transformer employs an EI-type transformer with a power supply capacity of 750 VA and a weight of 14 kg. The entire transformer core is hardened with a hardening filler. The smoothing capacitor employs a multi-element electrolytic capacitor with a stacking structure, in which the distribution of characteristics is made uniform and sound quality is improved by dividing and laminating electrode foils. It is equipped with 6,800 μ Fx2/3,300 μ Fx2 for the voltage amplifier stage and 22,000 μ Fx2 for the power amplifier stage.
In addition, we have adopted the STD (スポンティニアス Twin Drive) system, which cuts off interference at high power by separating the supply to each stage from the rectifier circuit.
The outer casing of the transformer and condenser is velvet-processed. This is made of ultra-fine and strip nylon pile blown away by the power of static electricity and coated with epoxy adhesive. It dumps the surface of the casing well, eliminating the influence of external vibration and effectively suppressing the vibration of itself.

The chassis is made of high-carbon steel with a maximum wall thickness of 21 mm and a weight of 10.5 kg.
This chassis is made of cast iron, which is used as the base of machine tools, and has very high rigidity and excellent vibration damping characteristics.

The circuit of the output stage is a pure A-class operation in which crossover distortion and switching distortion do not occur in principle, and an output stage configuration which emphasizes low impedance driving capability is adopted.
The output device uses 20 Hi-ft power transistors with a collector loss of 200W and a maximum allowable current of 17A for 10 parallel push-pull operation. This provides a wide current supply capability and enables 1 Ω load continuous drive.

Aluminum die-cast with a base thickness of 18 mm is used for the heat sink, which is naturally air-cooled.

The input terminal is equipped with XLR terminal balanced input in addition to pin-jack unbalanced input.
In addition, it is equipped with both positive - and negative-phase inputs of pin-jack specifications. By connecting two TA-NR1 units by bridge, it is possible to increase the effective output power from 100W at 8 Ω load to 400W, and from 200W at 4 Ω load to 800W.

The front and rear panels are made of 7mm-thick extruded aluminum material, the corner posts are made of the same extruded aluminum material, and wood is used for the side plates.
In addition, only parts that are empirically reliable are used in consideration of acoustic characteristics.

The balanced input transformer uses a large permalloy core with high magnetic permeability due to uniform material characteristics, and realizes low distortion over the entire signal band.

The speaker terminal is a gold-plated brass machined speaker terminal. It is specially designed as a vise type and can be connected with very thick speaker cables with conductor cross section of 100 square mm.

Equipped with an analog temperature meter, the operating temperature of the power amplifier can be monitored from the time of warm-up. It also comes with a backlight.

Model Rating

Type	Monaural power amplifier
Circuit system	First stage : FET differential input cascode bootstrap current mirror load Second tier : Cascode bootstrap Final stage : 3-stage Darlington connection
Effective power	100W (20 Hz ~ 20 kHz, 8 Ω Load) 200W (20 Hz ~ 20 kHz, 4 Ω Load) 400W (1 kHz, 2 Ω load) 550W (1 kHz, 1 Ω load)
Total harmonic distortion factor	0.003% (at 8 Ω load, 10W output) 0.05% (8 Ω Load, Effective Output) 0.05% (4 Ω Load, Effective Output) 0.05% (2 Ω Load, Effective Output) 0.05% (1 Ω Load, Effective Output)
Cross modulation distortion factor (60Hz:7kHz=4:1)	0.05% (at 8 Ω load, 10W output) 0.05% (at 4 Ω load, 10W output) 0.05% (at 2 Ω load, 10W output) 0.05% (at 1 Ω load, 10W output)
Damping factor	50 or More (1 kHz, 8 Ω)
Residual noise	30 μ V or less (IHF-A network)
Signal-to-noise ratio	120 dB or more (IHF-A network)
Frequency characteristic	5 Hz ~ 50 kHz + 0 -3dB
Input Sensitivity / Impedance	Unbalanced : 1.1V/47k Ω Balanced : 0.55V/600 ohm
Pwer	100 VAC, 50Hz/60Hz
Power consumption	460W
External dimensions	Width 470x Height 190x Depth 455 mm
Weight	47.5kg