Marantz AV251 (c. 1985)

The Marantz AV251 is a compact audio/video controller from the mid-1980s. Home video was moving past simple TV hookups then, and people needed a hub to route signals cleanly. It was originally priced at ¥29,800 in Japan (around 1985), and a US retail listing from the era shows $200. The unit is slim - 420mm wide, just 37mm tall, and 192mm deep - and weighs only 1.8kg. It was clearly meant to sit on top of a VTR or in a rack.

Functionally, it's a video switcher with two VTR loops, two auxiliary video inputs, and one audio-only input. A monitor output handles both audio and video. The front panel has a copy switch so VTR-1 and VTR-2 can dub each other with one touch, and a stereo/mono selector for the VTR audio jacks. There's also an enhancer and a sharpness control for cleaning up dubs, plus a fader that fades video and audio in and out simultaneously, which is handy for editing onto tape. On the audio side, it has a Dynamic Noise Reduction (DNR) system. It uses a variable low-pass filter that shifts between 1 kHz and 30 kHz depending on signal content, and gives about 10 dB of noise reduction in quiet passages. A Spatial Stereo function converts mono sources into pseudo-stereo by manipulating mid and high frequency phase. There's even a microphone mixing input for layering voice over video.

Video specs are modest by today's standards but fine for the era: 1Vp-p/75Ω in and out, 70dB signal-to-noise, and a frequency response of 6 Hz to 8 MHz ±3dB. The audio section manages 85dB S/N and 50dB channel separation. A period equipment directory described it as a "video switcher with 2 VCR loops; 2 aux video inputs; selectable audio source; video fader; sharpness control; dynamic noise reduction; and misc mixing."

Dimensions: 420 x 37 x 192 mm
Weight: 1.8 kg
Video in/out: 1Vp-p / 75Ω unbalanced
Audio in: 150mV / 25kΩ; Audio out: 150mV / 250Ω
DNR noise reduction: 10 dB at silent portions

Little is documented about the AV251's place in the Marantz lineup or how it sold. A related variant, the AV251II, appeared around 1987 with front-panel VCR-2 jacks and an RF output for TVs lacking direct video inputs. The relationship between the two models is not formally documented. Service manuals and original catalogs do surface occasionally, which suggests the unit was sold widely enough to leave a paper trail. The record on production years, common problems, and collectibility remains thin.