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Diy mic pre-amp
  • First a background. I wanted to mic my actors for my film using a lav on each actor and some portable recorder. Some scenes had 5-6 people talking. I first started with iriver ifp recorder with the Giant Squid mics - about 35 bucks per setup. This gave me pre-amp noise as the iriver uses cheap pre-amps. It was recorded as 160kpbs mp3 mono 44.1khz sampling. Then I tried a bunch of used Sony Hi-MD recorders, about 50-75 each. These default to AGC, and I had to buy a MZ-RH1 (M200 actually) in order to transfer the recording using USB2.0 (the older Hi-MDs come with USB1.1). The pre-amps on the older NetMd and MD were crap. Now I have the Tascam DR-05, which fixes all the problems related to pre-amps and gives 96khz sampling. However, it is still too big to carry in a pocket.

    I found that the biggest problem for human conversational voice is not sampling (44.1khz vs 48khz) or compression (PCM vs 160kbps mono mp3) but pre-amp noise. Resampling can be done easily via command-line using soX.

    I also found the form factor of the iriver ifp series to be most convenient for micing actors.

    So I looked around for circuits for a simple battery powered electret mono pre-amp for a iriver ifp. BTW the iriver was found to have very low distortion using the line-in setting.

    I found these DIY battery powered mic pre-amp kits. - 11.95/- ~ 10/- each

    Has anyone used these, any comments ?? BTW I am looking for something to be powered from a 9V or a AA battery, a portable device.

  • 2 Replies sorted by
  • As I remember. Some guys used Yamaha Pocketrak recorders.

    I really suggest to try different small recorders.

  • Vitaliy.. VERY nice suggestion. I dont know how I missed this.