I guess the Cary's are just gonna have to go for service and upgrade - I'm thinking maybe the power caps are shot but I'm no Jez arkless. Unless you've seen and lifted an 805c it's difficult to understand the over engineering that's in them. The trannies are the biggest I've ever seen and they weigh in at 45k each monoblock. They make most other amps look puny and fragile. They are however a dog's dinner internally. With bench time and upgrade components I'm looking at around €1500 - the price of a good second hand alternative.
As regards the Hiraga - I do wish Jez lived in sunny Spain so I could get it checked out and any components changed - but it sounds great, revealing new details in well known tracks, and giving pin point imaging that the Cary's don't.
Technics SP10 mk2
Jan Allaerts MC 1 Boron mk1 cart
Miyajima Shilabe cart
Hashimoto HM-X SUT
Siggwan (gimballed not unipivot) Cocobola 12"
Aurorasound Vida LCR Phonostage
The Truth linestage
Dave Slagle Autoformer Volume Controller
Cary 805c SET amps
Audio Note ANe-SPX speakers
Townshend Isolda speaker cables
Cardas Golden Presence interconnects