Introduced in 1959 at the start of the stereo era, the HF-81 is still the EICO most often rebuilt and the one Stereophile revisited as a bargain alternative to boutique valve units.
Valve chassis: HT rails stay live after switch-off; never power up on original electrolytics. Check the output transformers and the power transformer for overheating - replacements are unobtainable.
Marks that can be entered for this maker: Model / catalogue number, Model / catalogue number, British capacitor code (Hunts, Mullard), Japanese capacitor code (Nichicon, Chemi-Con, ELNA), EIA component code.
Nothing predates 1959; components only push the date later.
Sold-price aggregates are not collected yet, so the archive gives no figure — condition, originality of the transformers and a documented recap move this model more than any list price.
Evidence: Stereophile — EICO HF-81 review · Vintage Instruments & Radio — EICO kit catalogues