Mutchus

Microphone Pre-Amplifier 9-12Volt Discrete This is a microphone pre-amplifier ambit that use detached components. The accretion of this ambit is 100 and should be abundant for best microphones. It is set by the arrangement of the 10k resistor to the 100R. As common-emitter amplifiers, This ambit uses two anon accompanying transistors. Here is the schematic diagram of circuit: Please agenda that this ambit has no bent voltage source, so you can’t use with condenser blazon microphones. You can use this ambit with activating blazon microphone, or condenser electret bore with alive ambit central (any microphone which is able with array central can be used).

Wireless am microphone Transistor Ql and its associated components comprise a tuneable rf oscillator. The rf signal is fed to transistor Q2, the modulator. Operational amplifier ICl increases the audio signal and applies it through resistor R4 to the base of Q2. Tune an Wireless am microphone AM radio to an unused frequency between 800 to 1600 kHz. Tune Ll for a change in the audio level coming from the radio. Peak the output by adjusting L2 If Ll is disturbed, it may be necessary to readjust L2 for peak performance. Depending on the impedance of the microphone audio sensitivity can be increased by decreasing the value of RIO and vice versa. Wireless am microphone. Wireless am microphone

Description: This circuit takes an ordinary loudspeaker and allows it to be used in reverse, as a microphone. Circuit diagram Notes: This circuits allows you to use a cheap loudspeaker as a microphone.Sound waves reaching the speaker cone cause fluctuations in the voice coil. The voice coil moving in the speakers magnetic field will produce a small electrical signal . The circuit is designed to be used with an operating voltage between 6 and 12 volts dc. The first transistor operates in common base mode. This has the advantage of matching the low input impedance of the speaker to the common base stage, and secondly has a high voltage gain. The second stage is direct coupled and operates in emitter follower. Voltage gain is slightly less than unity, but output impedance is low, and will drive long cables. Speech quality is not as good compared to an ordinary or ECM microphone, but quite acceptable results can be obtained. Speaker cones with diameters of 1 inch to 3 inches may be used....

Description This relatively simple mixer was designed for three dynamic microphones, but can be re-designed for more or less. Level and tone controls are available to tailor the sound to your needs.  Circuit Diagram Parts Part Total Qty. Description Substitutions R1, R2, R3 3 1K 1/4W Resistor R4, R5, R6 3 10K Logarithmic Pot R7 1 1Meg 1/4W Resistor R8, R10 2 10K 1/4W Resistor R9, R11 2 100K Linear Pot C1, C2, C5, C6 4 0.1uF Ceramic Disc Capacitor C3, C4 2 22nF Ceramic Disc Capacitor U1, U2 2 741 Op Amp J1, J2, J3 3 Input Jacks Of Your Choice MISC 1 Board, Wire, Knobs, IC Sockets Notes  Email Anatoly I. Shikhatov with questions, comments, etc. R1-R3 are level controls. R9 and R11 control bass and treble, respectively. Since the circuit draws such low current, two 9V batteries can be used for a power supply. Building the mixer in a metal case will cut down on noise. Source -  http://www.aaroncake.net/circuits/mixer2.asp