Soundblaster Preamp

The Sound Blaster 16 PCI and Sound Blaster 16 ISA do not have a very sensitive microphone input. This little one transistor amplifier is powered directly from the microphone jack on the sound card and has LOTS of gain. Just put a 100uF bypass capacitor in parallel with the diode to increase gain even more.

Source: http://members.shaw.ca/novotill/SoundBlasterPreamp/index.htm

Pre MIC (microphone preamplifier) 3 CH by IC LM348

Circuit Pre MIC (microphone preamplifier) 3 CH by IC LM348

PCB Pre MIC (microphone preamplifier) 3 CH by IC LM348

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

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

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

Two Microphone Preamplifier by BC109

Read more and View Circuit
Two Microphone Preamplifier by BC109

Pre MIC 3 Transister ( C945 ) mono

This circuit Dynamic Microphone Preamp,Pre MIC 3 Transister mono.
By Transister Part C945= 3 part.(TR1-TR3) OR C828 OR C458
Supply Volt 12V - 24V.
Easy to build and low cost.
Circuit Pre MIC - 3 Transister (C945) mono
PCB Pre MIC - 3 Transister (C945) mono

Pre MIC - 3 Transister (C945) mono

This circuit Dynamic Microphone Preamp,Pre MIC 3 Transister mono.
By Transister Part C945= 3 part.(TR1-TR3) OR C828 OR C458
Supply Volt 12V - 24V.
Easy to build and low cost.

Circuit Pre MIC - 3 Transister (C945) mono PCB Pre MIC - 3 Transister (C945) mono

Pre MIC 2 Transister mono

This circuit Pre MIC 2 Transister mono.

By Transister Part C945.
Supply Volt 12V - 24V.
Easy to build and low cost.

View Circuit and PCB Pre MIC 2 Transister mono

Dynamic Microphone Preamp

Circuit : Andy Collinson
Email: anc@mitedu.freeserve.co.uk

Description:
A low noise pre-amplifier suitable for amplifying dynamic microphones with 200 to 600 ohm output impedance.

Notes:
This is a 3 stage discrete amplifier with gain control. Alternative transistors such as BC109C, BC548, BC549, BC549C may be used with little change in performance. The first stage built around Q1 operates in common base configuration. This is unusuable in audio stages, but in this case, it allows Q1 to operate at low noise levels and improves overall signal to noise ratio. Q2 and Q3 form a direct coupled amplifier, similar to my earlier mic preamp.

Source: http://www.mitedu.freeserve.co.uk/Circuits/Audio/dyn_mic/dyn_mic.htm