Audio Exklusiv P7 Valve (Tube) Line Level Preamplifier
The P7 is a valve (tube) line-level pre-amplifier. Each channel uses one ECC 803S for the amplification.
The power supply has even been provided with a valve (tube) type rectifier (EZ90).
The valves are closely selected in order to reach the best possible channel balancing, noise and distortion measured data. Should you ever experiment with other tubes we kindly ask you to notice that, due to the missing selection, the sound characteristics are likely to be modifed.
The chassis and board mounting have being optimised mechanically using our special techniques.
Concerning the circuit we chose a direct-coupled anode-/cathode-circuit. The advantage can be seen in the shortest signal path with only one final coupling capacitor. So possible sound interference can be kept extremely low.
The P7 is (including transformers) completely dual mono construction. Each channel works absolutely self-governed and is consequently not influenced by the other. This is of great importance - the consequence is the best possible stability and an optimal channel separation. The result is an extremely wide-ranging, airy and well structured sound pattern.
The power supply is built up with an “Resistor-Capacitor-Inductor-Capacitor-” filter, and in combination with the high quality line filter, most of the power line interference can be eliminated. The audio circuit therefore works under the best possible conditions.
The switching of the input, gain and also (adjustable) negative feedback are affected by means of gas-filled reed relays. The only remaining mechanical contact is the volume potentiometer. We use the best potentiometer currently available from TKD.
All components have been determined separately in cooperation with long lasting listening tests. Non-inductive resistors with only lowest tolerances, MKP, mica, oiled-paper capacitors and high quality internal wiring are just a few examples of the final selection of parts.
10 Hz - 79 kHz (-3dB)
S/N ratio weighted: 106 dB
S/N ratio unweighted: 98 dB
THD+N: 0,046 %
IMD: 0,059 %
Channel separation (10 kHz):
Input sensitivity: 142 mV
Input impedance: 105k Ohms
Output voltage max: 22 V
Output impedance: 857 Ohms
Gain (x): 3 / 5 / 7
Power consumption: 29 Watt
480 (W) x 465 (D) x 125 (H) mm
Weight: 16.5 kg
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