NAGRA – CLASSIC PREAMP
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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 CLASSIC PREAMP replacement tube kit, reference
7055764000.
Case cleaning
Clean the CLASSIC PREAMP casing using a soft, non-fluffy, slightly
damp cloth. Do not use any cleaning products that could have a
corrosive effect.
