Just briefly going back to the HA500.
I bought mine when it was new back in the early 80’s, costly yes but I don’t think it was super expensive. Bought to replace a home built head amp the figure of around £100 sticks in the mind, which I think in those days, was about the price of a budget integrated amplifier.
I still use it from time to time.
Marantz CD/DA12, HHB 'burnit', Yamaha CT7000, Magnum Dynalab FT101A, Garrard 401, SME 3009, Dynavector 100R and 30C, AT F7, Trichord Dino, Audio Research LS7, Quad 303 or Leak Stereo 20, Harbeth P3ESR, BK sub, DIY passive with PG faders, Quad II's, Quad ELS57's, Townsend Ribbons, Crown IC150, HH AM8/12, Tannoy Monitor Gold in Lancaster, Stellavox SU8, Nagra T-Audio, Dolby 361's, Sony D50, Pro Walkman, Dat Walkman, Slee Solo, Sennheiser HD650 + Equinox, Lambda Sig. Pro., SRM-T1, Sr001