While "134 better" isn't a standard technical term in the Harman Kardon AVR 51 service manual , it likely refers to a comparison with the newer AVR 134 receiver
You now have a working replica of the , with specific enhancements tied to the “134” code – whether that firmware, error correction, or user preference. harman kardon avr 51 user manual 134 better
: Features preamplifier outputs for all channels, allowing you to use it as a dedicated processor with more powerful external amplifiers. Essential Setup Tips from the Manual While "134 better" isn't a standard technical term