Sony ST A40
A compact FM/AM tuner featuring Sony's Acute Servo Lock tuning system and LED-based signal indicators.
Overview
The Sony ST A40 is an FM/AM tuner manufactured by Sony. The unit uses an advanced Acute Servo Lock mechanism for precise and stable FM tuning, indicated visually by a green LED at the optimal tuning point, flanked by red LEDs. It includes a 5-segment LED signal strength meter and incorporates a CAL-TONE circuit along with a pilot signal cancellation circuit for improved stereo reception quality.
Specifications
| Product type | FM/AM tuner, Acute Servo Lock FM/AM Tuner |
| Practical sensitivity | 1.8 μV |
| Stereo distortion factor | 0.15% |
| Effective selectivity | 80dB |
| Separation | 50dB |
| Power consumption | 8W |
| External dimensions | Width 430x Height 80x Depth 275 mm |
| Weight | 3.3kg |
| Original price | ¥34,000 |
Design
The ST A40 features a newly developed Acute Servo Lock mechanism designed to accurately locate the lowest tuning point for stable reception. The front end uses J-FET transistors, while the IF stage employs a uniphase filter and the MPX section uses a PLL-IC. The tuning status is displayed via a green LED that lights at the optimal point, with red LEDs on either side indicating deviation. A 5-segment LED bar provides signal strength feedback. The circuit configuration is nearly identical to the ST-A40, with the front end matching that of the KT-900/990 models.
Market
A user manual and marketing brochure for the Sony ST A40 are available through online resellers, with the brochure listed for £4.99 and the manual offered via buyee.jp.
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