It's been maintained! Sony's pure Class A mono amplifier, reference model. It is famous for saying that it is not profitable to make it, and it is a supreme item that is very elaborate on parts and assembly. It drives woofers for large systems such as B&W (Yoichi Murakoshi)
Maintenance Information:2022.6.9 Maintenance (large capacity electrolytic capacitor, output relay RCA jack replacement, solder correction, input switch check screw tightening, bias and offset (Check, output sound check, interior and exterior cleaning.)
Accessories: instruction manual (copy)
Main specifications: Mono pure A class amplifier 100W (8Ω) 200W (4Ω) 400W (2Ω) 550W (1Ω) W470 × H190 × D455mm 47.5kg