17
Nagra
–
CLASSIC PHONO
Maintenance
Tube ageing
The Nagra CLASSIC PHONO tubes are selected by Nagra according to exacting
criteria. Their theoretical minimum useful life is 5
’000 hours. Actually, some tubes
operate consistently for more than 10
’000 hours.
Thus, the useful life of the tubes is somewhat unpredictable. Rather than
replacing the tubes arbitrarily after 5
’000 hours, we suggest that you identify the
signs of ageing:
The distortion gently increases to an audible level;
Presence of clicks (dry and short noise, like breaking dead wood);
Presence of pops, short noise in the low frequencies;
Presence of hiss, higher background noise.
As soon as one of these signs appears, please contact your Nagra dealer to order
a Nagra CLASSIC PHONO replacement tube kit, reference 7055034030.
Case cleaning
Clean the Nagra CLASSIC PHONO casing using a soft, non-fluffy, slightly damp
cloth. Do not use any cleaning products which could have a corrosive effect.