The QR-666 was produced between 1974-1976 by Trio-Kenwood Electronic Inc in Japan. It´s a solid state all wave receiver that followed the popular valve/tube model Trio 9R-59DS. It can be powered via 100/117/220/240 VAC, with DC by internal batteries (R20/D*8) or from external power source 12-15 VDC. The physical dimensions are, 362*165*330 mm, and it wights 7.3 kg.
This receiver was in good shape when I got it, there was only need for cleaning and new bulbs. The unit has been cleaned in detail, and now looks like new, with intact lettering and clear scale and meter glass. But the original S-meter bulb is a frosted incandescent lamp soldered directly on the lampwire, like the AC/Standby bulb. For easier maintenance, the first one was replaced with a frosted flickering free AC/DC LED and the second one with a frosted LED including protective resistor/diode.
It receives on all bands when tested, and sounds good both on the internal speaker and in headphones. There are 6 bands, covering 0,17 MHz up to 30 MHz. This unit has not been equipt with the option for the FM-band, but as can be seen on the front the buttons for that option are there on the basic model.
Now this receiver has been sold (april 2017) to a radioamateur living in a small town west of Gävle, ca 150 km northwest of Stockholm. He longed to see the warm glow from the scaledrum of this receiver.
References:
https://medxr.blogspot.com/2016/04/retro-receiver-6-kenwood-qr-666.html
https://www.radiomuseum.org/r/trio_kenwo_qr_666.html
http://www.rigpix.com/kenwood/qr666.htm