FWIW: The cat Eye tube upfront as output level indicator. If that cat’s eye ever blinks shut while you’re playing your tunes, you’ve reached full power from the Cary 805 amp.
Below is from Stereophile measurements:
Cary 805 amp voltage gain averaged 23.2dB at 5dB feedback (into an 8 ohm load, slightly less into a 4 ohm load, slightly more into a 16 ohm load). With 0dB of feedback, the gain increased to 25.2dB; with 10dB of feedback it dropped to 18.2dB (all into an 8 ohm load).
Mike