Denon PMA-451 (circa 1977)

Name: Denon PMA-451
Brand: Denon

The Denon PMA-451 is a two-channel integrated amplifier from around 1977 (though one source places it in the mid-eighties). It sold for ¥49,800. Denon positioned it in its affordable amplifier segment, and it inherits technology from the earlier PMA-701 and PMA-501. The record on this model is thin - mentions on enthusiast resources are rare - but what survives points to a well-engineered, dependable budget integrated amp.

The most distinctive documented feature is the PCC (Phono Crosstalk Canceler). It adds reverse crosstalk to cancel the crosstalk inherent in phono cartridges. With the supplied adjustment record and two knobs, the listener could improve separation in the most audible frequency range to approximately -40 dB. The power amp section is a direct-coupled OCL circuit with differential amplification throughout, a low-impedance power supply, and output transistors with double epitaxial and triple diffusion structures. A fast protection circuit and a specially structured relay are also noted. The preamp and power amp sections run on separately wound transformer windings, and the phono input connects directly to the equalizer amp to reduce stray capacitance.

Rated output is 45W + 45W into 8 ohms (20 Hz-20 kHz, both channels driven), or 55W + 55W into 4 ohms at 1 kHz. Dynamic output (IHF) is listed at 140W (70W + 70W, 8 ohms). THD is 0.08% or less at rated output, and output bandwidth (IHF) spans 5 Hz to 50 kHz. Phono S/N is 75 dB or better, and line inputs are rated at 95 dB or better. Tone controls offer ±10 dB at 50 Hz (bass) and 20 kHz (treble). It weighs about 10.5 kg and measures 430 × 142.5 × 310 mm.

The few owners who have written about the PMA-451 describe it as reliable and predictable - a unit that works for decades with minimal care. Typical age-related issues are noisy controls, a worn protection relay, and tired electrolytic capacitors in the power supply. It's regarded as an amplifier for a small room. It pairs well with entry-level bookshelf speakers and suits jazz, vocals, chamber music, and lighter orchestral material.

Audio-Database (accessed 2026) documents the full specification sheet and the PCC circuit description.