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Connection via Passive Attenuator
Unlike common systems, the level is adjusted with the help of a passive step-by-step attenuator using a wafer switch with constant resistors. A standard potentiometer was found inapplicable because its inherent contact friction noise and high transfer capacitance heavily "impersonalized" and "smeared" the sound.
A passive attenuator with a balancing transformer is also available.
pic.1 Connection via passive attenuator
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Connection via Tube Transformless Buffer Amplifier
A better performance is assured by connecting the mics via a tube buffer amplifier with a passive attenuator at its input. The amplifier operates in the pure class "À" mode, with no negative feedback at all. The unusual circuit of the transformerless output cascade comprises two medium-power triodes with target impedance of the balanced output 200 Ohm (100 Ohm per arm). See details->
pic.2 Connection via buffer amplifier
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It goes without saying, however, that the best results will be obtained by connecting the microphones directly to an analog-to-digital converter or a similar device with an unbalanced input and a 47-200 kOhm impedance.
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The proposed microphone system was experimentally developed in recording studios for a few years, again and again delighting indescribably every single singer.
Interference immunity of the system was once given a severe test under highly exacting conditions of a large TV studio. No audible noise was noticed, even with a 20 m long microphone cable.
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