12
Nagra –
VPA
Tube ageing and replacement
845 tubes are supposed to operate for around 5’000 hours.
Internal tubes can last about the same.
As a rule, you should replace all tubes at once on both units.
Internal tubes must be replaced by a Nagra dealer.
It is normal to adjust the bias once in a while. From time to time,
before listening, check the bias and eventually adjust it to make sure
you get 100% performance out of your amplifiers.
Tube compatibility
Nagra selected 845 tubes go through a rigorous selection: 24 hour
burn-in, individual measurement and selection and are paired using a
Nagra unique process. Using 845 from other suppliers will void
warranty.
Tube bias adjustment
Please refer to the instructions found in the tube package to learn how
to set-up the bias.