The latest version is red color amplifier module:
Ultra-miniature electret amplifier module, ultra-small size, support 5 ~ 12V DC power supply, input can be directly connected to the electret microphone without any bias circuit, the sound can be fine-tuned on-board trimmer, the output OUT can drive 8 ~ 32 European (0.5 ~ 35W) speakers, the output power of 750mW, very suitable for DIY various vocal amplifier, pickup, amplifiers, cable walkie-talkie and so on.
(Note: New version module does not require series resistance and capacitance in use. This module does not contain speaker, microphone, battery.)
Parameter:
1. Operating voltage: 5V-12V (voltage below 5V sound will be significantly reduced, the limit voltage can not exceed 15V);
2. Operating current: 1mA (static) ~ 150mA (max);
3. Output speaker impedance: 4 Ω-32 Ω(impedance high-sound, high efficiency);
4. Support the speaker power: 0.5W-25W (In fact, any power speaker can be used, the volume and the speaker power is not much relationship, as long as greater than the power amplifier output rating on the line);
5. Output power: 750mW (max);
6. Input support: electret, microphone, condenser microphone, moving coil microphone, audio signal.
7. Volume: 22.7 (L) * 13.5 (W) * 7.4 (H) mm;
8. Used for microphone preamplifier effect good , noise and AC ripple is very low, the output signal voltage greater than 1V or more, to promote the power amplifier signal strength.
Instructions:
1. Amplifier board IN and GND use shielded cable access electret microphone, access to the attention of the polarity, the electret after the reverse will be very little or no sound;
2. Amplifier OUT board connected speakers, speakers away from the microphone, in order to avoid self-excited noise;
3. Power amplifier board positive and negative access 5 ~ 12V DC power supply, please do not reverse, otherwise it will burn out the module;
4. Amplifier board comes with a volume trimmer potentiometer, if you feel the sound is too large or too small can try to adjust.
Precautions:
1. Soldering must be grounded when the soldering iron;
2. Do not reverse the polarity of the input power supply;
3. Output speakers away from the microphone;
4. Try to use the battery power, if you use the adapter, it is best in the power supply in parallel with the appropriate capacity of the capacitor in order to eliminate the introduction of power interference. Mituto input to make use of shielded wire, can effectively reduce the interference signal.
Applications: (old version wiring picture)
Package Included:
1x Ultra-miniature Electret Microphone Amplifier Board
Positive Feedback will be much appreciated from you.
or negative 
feedback.
