DIY cheap microphone preamp for Canon DSLR #3 case build and putting it together
27Part #3 of a step-by step tutorial on how to build a cheap microphone preamplifier for Canon DSLR cameras. Here the plastic housing is being made, the cables soldered and finally the PCB built into the case, and the unit first tested.
From 26:20 you can hear the microphone preamp, and you can notice the difference in the quality of the audio recording compared to the first portion of the video. The noise of the DSLR preamp is totally cut off, and the audio sounds a lot better and cleaner, though one need to speak with a really even voice.
Still, this is not yet tweaked, because the quality can be made better by tweaking the software settings in Magic Lantern and by adjusting the potentiometers and resistors.
The preamp very much improves the audio quality, reduces the hissing noise and also flattens the piercing S sound in your videos.
The quality is better than what I can get via software post-processing, so I do like the result.
The build is rather simple, so it can be easily put together by hobbyists. Total costs around 20-25 Euros including the battery.
Component lists:
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Microphone: clip-on lapel microphone of an old Samsung mobile phone headset
The headsets from old mobile phones are good and inexpensive options.
You just need 2 minutes to figure out which leads are going to the microphone with a multimeter.
Conrad microphone preamplifier kit: 11.99 Euro
http://www.conrad.com/ce/en/product/197688/Conrad-mono-microphone-preamplifier-kit
Plastic case: 2.69 Euro
http://www.conrad.com/ce/en/product/522066/Module-casing-64-x-53-x-28-Polyamide-Black-AMG-2-1-pcs
Schielded audio extension cable, optional: 2.5 meters, 6.99Euro
http://www.conrad.com/ce/en/product/325051/Jack-Audiophono-Extension-cable-1x-Jack-plug-35-mm-1x-Jack-socket-35-mm-250-m-Black-SpeaKa-Professional
3.5 mm audio jack Socket with fixing screw: 2.09 Euro
http://www.conrad.com/ce/en/product/738619/35-mm-audio-jack-Socket-vertical-vertical-Number-of-pins-3-Stereo-Black-Lumberg-KLB-4-1-pcs
3.5 mm audio jack Plug: 1.99Euro
http://www.conrad.com/ce/en/product/738920/35-mm-audio-jack-Plug-straight-Number-of-pins-3-Stereo-Black-Lumberg-KLS-40-1-pcs
9V battery: 2.5-4 Euros, depending on location/manufacturer
9V battery leads: 0.35Euros:
http://www.conrad.com/ce/en/product/490660/T-Style-9V-Snap-Clip-With-150mm-Wire-Leads
Power On/Off switch with a slider switch: 0.79Euro:
http://www.conrad.com/ce/en/product/708046/Slide-switch-50-Vdc-02-A-1-x-OnOn-SS-12-05-1-pcs
Optional for power indication:
LED for indicating PowerON, and a series resitor for the LED.
However, it will deplete the battery faster. Instead, I use Magic Lantern, where I can visually see when the preamp is turned on from the audio bars at the top of the screen during recording.
Audio setting in Magic Lantern for my Canon T3i, aka Rebel 600D:
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Override audio settings: ON
Analog gain : 0dB
Mic Bosst: 0dB
Digital Gain -- go inside the submenu
Record Effect Mode: Notch filter
Record digital volume: 0
Left digital gain: 0dB
Right digital gain: 0dB
AGC: OFF
Input source: External stereo !do not forget to select this!