Microphone Preamplifier | Electronic Project Circuits

Posts Tagged ‘Microphone preamplifier’

6 Input Mixer by IC 741 , LF351 ,TL071

Description:
A simple mixer with 3 line inputs and 3 mic inputs using commonly available parts.

Notes:
The mixer circuit below has 3 line inputs and 3 mic inputs. The mic inputs are suitable for low impedance 200-1000R dynamic microphones. An ECM or condenser mic can also be used, but must have bias applied via a series resistor. As with any mixer circuit, a slight loss is always introduced. The final summing amplifier has a gain of 2 or 6dB to overcome this. The Input line level should be around 200mV RMS. The mic inputs are amplified about 100 times or by 40dB, the total gain with the mixer is 46dB. The mic input is designed for microphones with outputs of about 2mV RMS at 1 meter. Most microphones meet this standard.

The choice of op-amp is not critical in this circuit. Bipolar, FET input or MOS type op-amps can therefore be used; i.e 741, LF351, TL061, TL071, CA3140 etc.

Source :: http://www.zen22142.zen.co.uk/Circuits/Audio/6ipmix.htm

Be the first to comment - What do you think? Posted by admin - June 25, 2007 at 1:26 pm

Categories: Audio diagram, Pre Amplifier Tags: audio mixer, LF351, Microphone preamplifier, TL071

Mini Stereo MIXER MIC-LINE for PC Audio Card

Source : http://users.otenet.gr/~athsam/audio_mixer_pc.htm

Most cards of sound in computer, are deprived stereo input for microphone, on the contrary have stereo input for high level [ Line ]. The circuit uses the input Line of card of sound, in order to we place a two mono stereo microphone, in the input of card of sound. Simultaneously he is more functionnal, after we have the possibility of regulating the gain of stage of microphone and regulating the final level of sound externally and independent for each channel of microphone. This solution was selected in order to we can if we want mixing two mono microphones. Also exist the classic supply for Electret microphones. Simultaneously exist stereo input Line, with two choices plugs of input and regulation level of input with the RV4, making him mix of sounds from the microphones and the input Line, easy affair. The input A, use two plugs RCA [ JF3-4 ] and input B, use a classic stereo plug jack 3.5 mm of nail. The IC2A-B, make the addition of signals and they drive the stereo output, that becomes from the JF6 jack. In JF7, we can give the supply, bigger than + 9Vdc, from a simple external power pack. This voltage is stabilised in + 5V, from the IC3. This low voltage was selected in order, to does not exist danger overdrive of card of sound. If the level, is not in the level that we want, we can change the prices of resistors R14-19 and R21 until R24, with other smaller or bigger, so that we change also the percentage of gain of proportional stage.

Part List

R1-8-31-32=3.3Kohmsï¿½ C1-4-7-9-12-17=10uF 16V IC1=TLC274
R2-7-27-30=100ohmsï¿½ C2-8=470nF 63V MKT IC2=TLC272
R3-4-9-10=1Mohmsï¿½ C3-24-27-28=100nF 63V MKT IC3=7805
R5-11-21-22-23-24=10Kohmsï¿½ C5-10=10pF ceramic D1=1N4007
R6-12-15-17=1Kohmsï¿½ C6-11=1uF 16V D2=LED 3mm
R13-14-19-20-28-29=47Kohmsï¿½ï¿½ C13-16-20-21=47pF JF1-2-5-6=female jack 3.5mm stereo
R18-16-25-26=22Kohmsï¿½ï¿½ï¿½ C14-15-18-19=1uF 63V MKT JF3-4=RCA female plug
RV1=2X100Kohms Lin.ï¿½ï¿½ï¿½ C22-23-25=100uF 16V JF7=female jack 3.5mm mono
RV2-3=47Kohms log.ï¿½ï¿½ï¿½ C26=4.7uF 16V
RV4=2X47Kohms log. C29=470uF 25V All the Resistors is 1/4W 1% metal film

Be the first to comment - What do you think? Posted by admin - May 28, 2007 at 9:47 pm

Categories: Circuit com, Pre Amplifier Tags: Circuit com, Circuit diagram, Microphone preamplifier, Pre Amplifier

Pre MIC (microphone preamplifier) 2 CH by IC NE5532 or LF353

This be Pre Mic circuit or Microphone preamplifier circuit model 2 CH. By this circuit uses integrated number circuit NE5532 or LF353. It perform enlarge sound signal from Dynamic Micro phone give the power goes up for subsequently submit to go to still stereo power amplifier circuit next. This circuit be of good quality good sound, because of use the integrated circuit decreases the noise, but should use the fire feeds +12V GND -12V with. The VR1 and VR2 perform fine decorate the sound. The detail is other and PCB see in a picture below.

Circuit Pre MIC (microphone preamplifier) 2 CH by IC NE5532 or LF353