User manual SENNHEISER SK 1007

[. . . ] The Senn heiser condensor microphones MKH 105, 405, 415, 805 and 815 can be connected to the SK 1007 via the special cable KAM 1-5. In this case the microphones are powered from the transmitter. Power for the SK 1007 is taken from three 9 V Batteries (lEG No 6 F 22) eg Pertrix 438 or Daimon 333. For ease of operation all switches and sockets are mounted on the front panel. [. . . ] When fitting batteries care must be taken to ensure that good contact is made. If necessary the crown contacts of the batteries should ben pressed together a little. 2 shows the various stages of the transmitter in block diagram form. The third stage contains an RC combination in the feedback loop with which the 50 fl sec pre-emphasis is achieved. Following the microphone pre-amplifier come the clipping diodes, with which all voltage peaks which would cause a frequency deviation of more than :t 75 kHz are cut. To prevent an increase in the total distortion, which would normally happen when the diodes suddenly clip the signal, a limiter stage is incorporated. This stage varies, dependant upon the AF output voltage, the ratio of a voltage divider situated in the first stage. The lower resistance of this divider is the field effect transistor T 11 whose drainsource path resistance is such that limiting takes place only after a frequency deviation of :t 40 kHz has been achieved. A further 30 dB increase in the input voltage is then permissible before the distortion factor exceeds 1 %. Decay time approximately 2 seconds and the attack and delay amplitudes are very small. The four stage HF section contains the free running Colpitts oscillator (T 1), the frequency doubler stage (T 2), the driver stage (T 3) and the final amplifier (T 4). Both oscillator and doubler stages are, for stability reasons, fed from a regulated power supply. Therefore possible to use a relatively ~ small transistor which need not be cooled seperately, which contributes to keeping the transmitter as small as possible. The final stage is driven by a particularly non-retroactive A class amplifier. In order to keep the maximal interference level below 4, 10-9 Watt the final stage is followed by n filter, which also serves for aerial matching. Power for the AF section is taken from one 9 V battery whereas the HF section requires two 9 V batteries in series. Battery life, when the transmitter is used intermittently, is approximately 5 hours. Contrary to earlier models the screen of the microphone cable does not act as aerial but only as counterweight. The SK 1007 must therefore be operated with the aerial provided plugged into the aerial socket. For good results it is advantageous to let the aerial hang vertically, also it should be as high as possible. [. . . ] In this case the microphones are powered direct from the transmitter. This superhet receiver can be used on two set frequencies in the 8 m band. This receiver also operates on two set frequencies. Power is taken from a 9 V battery or accumulator. [. . . ]