Name: Kenwood TS-520/520S
Brand: Kenwood

80m – 10m

Bands

100 W

Output

1973

Introduced

Frequency	TX/RX: 80–10 m (amateur)
Bands	160m (520S only), 80m, 40m, 20m, 15m, 10m
TX power	100 W (200W PEP input SSB, 160W DC input CW. ~100W output. Hybrid: tube PA finals.)
Modes	USB, LSB, CW
Weight	16 kg (35.3 lb) - 16 kg (35 lb) per specs (TS-520S). Built-in AC power supply; also runs on 13.8 VDC.
Connector	SO-239
Year	1973

Connectors

antenna	SO-239
mic	4-pin locking connector (50KΩ)
key	key jack
phone patch	phone patch connectors
ext spkr	external speaker
ac in	AC mains (built-in PSU)
power req	120/220 VAC (built-in PSU); also operates on 13.8 VDC.

Kenwood's mid-70s hybrid HF, predecessor to TS-830S, tube finals, the Japanese 'Drake killer' TS-520 (1973, 80-10m) → TS-520S (adds 160m + 15 MHz WWV) → TS-520SE (final); the hybrid line continued with the TS-820 (1976), then the TS-830S (1980) HYBRID design: solid-state receiver + tube PA finals (like TS-830S successor) SSB and CW ONLY (no AM, no FM) ham bands only, NOT general coverage double-conversion superheterodyne (1st IF: 8.295-8.895 MHz, 2nd IF: 3.395 MHz) receiver sensitivity: 0.25 µV for 10 dB S+N/N (excellent!) selectivity: 2.4 kHz at -6 dB / 4.4 kHz at -60 dB SSB optional 500 Hz CW filter: 0.5 kHz at -6 dB / 1.5 kHz at -60 dB image rejection: 50 dB VOX noise blanker 25 kHz calibrator phone patch connectors built-in AC mains power supply spurious emissions: better than -40 dB 50 KΩ microphone impedance, 4-pin locking connector 1W audio output (8Ω speaker) succeeded by the TS-820 (1976), then the TS-830S (1980); the TS-530S (1981) was a lower-cost TS-830S sibling one of Kenwood's most popular radios, the radio that established Kenwood in HF VINTAGE. DISCONTINUED 12BY7 driver + pair of S2001A/6146B finals 200W PEP input / ~100W output double conversion, 0.25 uV sensitivity 2.4 kHz SSB filter (optional 500 Hz CW)

Strengths

Excellent receiver sensitivity (0.25 uV). Hybrid design (solid-state receiver + tube PA: a 12BY7 driver and a pair of S2001A/6146B finals), with the warm tube audio that comes with it. Built-in AC power supply, phone patch, optional CW filter. Affordable used. The radio that established Kenwood (Trio) in HF.

Weaknesses

VINTAGE (1973). SSB/CW ONLY. No general coverage. No WARC bands. TS-520 lacks 160m (520S adds it). Tubes need periodic replacement. No DSP. No digital display.

Verdict

Where Kenwood HF began. The TS-520 established Kenwood (then Trio) as a serious HF manufacturer: good sensitivity, hybrid tube finals, and a built-in supply at a price that undercut the American competition. The TS-520S added 160m. The hybrid lineage ran TS-520 → TS-820 → TS-830S, with the TS-530S a lower-cost 830S sibling.

The Kenwood TS-520 is one of the most beloved and successful HF transceivers ever made, the radio that established Kenwood (then also branded Trio) as a major force in amateur radio. It is a 'hybrid' design, mostly solid-state but using vacuum tubes in the final amplifier (a 12BY7 driver feeding a pair of S2001A tubes, equivalent to 6146Bs) for 100 watts of output, covering the 80 through 10 meter amateur bands in SSB and CW.

The hybrid approach gave it a forgiving, easy-to-load output stage and a clean signal, while keeping the rest of the radio modern and compact, and the result was a reliable, great-sounding, affordable station radio that sold in enormous numbers. It launched a long line of Kenwood hybrids that ran for nearly 25 years. Plentiful, well documented, and still a pleasure to operate, the TS-520 remains a quintessential and highly recommended vintage HF transceiver.

It is a discontinued classic. See the WARC-equipped TS-530S and the higher-end TS-820S.