External tranformer usage
You can use the VPS with an external transformer. In this case, you must set the
jumpers to disconnect the internal transformer (on an MC card).
Here is the required setting: 1 B, 3 B, 4 A, 5 B.
On an MM card, you can connect the transformer directly to the input connectors.
The jumpers are already in the correct position.
Tube ageing
The Nagra VPS tubes are selected according to exacting criteria. The theoretical
minimum useful life of these tubes is 5000 hours. In real life, some tubes operate
consistently for over 10 000 hours.
Thus, the useful life of the tubes is somewhat unpredictable. Rather than
replacing the tubes arbitrarily after 5000 hours, we suggest that you learn to
identify the signs of ageing:
- Increase in distortion to reach 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, you must change the tubes to maintain
the standard of performance of your Nagra VPS.
Nagra VPS replacement tube kit, order number 7055767000.
Case cleaning
Clean the VPS casing using a soft, non-fluffy, slightly damp cloth.
Do not use any cleaning products which could have a corrosive effect.
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Nagra –
VPS
