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Subject: Re[2]: Microphone.
From: Uwe Freese (mail_at_uwe-freese.de)
Date: 2002-10-19


Hello M.,

M. OReilly wrote on Saturday, October 19, 2002, 12:05:31 AM:

MO> I wanted to do some microphone recording with my AJBR20, so I bought a nice
MO> Sure mic. Problem is that the Archos seems to be expecting a 0dB input, and
MO> the mic is only outputting -20dB (or something like that, I don't know). I
MO> found that in order to get a usable audio signal, I have to run it through
MO> an AC-powered mixer to boost the line signal to the point where the Archos
MO> can use it.

MO> Is there a way to get the Archos to use a "regular" music microphone without
MO> needing an AC power source? I would like some sort of line signal amplifier
MO> that uses battery power or something of that nature. I don't know if it's
MO> feasible - I've been looking for a while and haven't found anything yet.

I had the same problem: I wanted to connect an electret condenser mic
capsule / such a mic to the AJB. I think the only way is to connect a
mic amplifier to the AJB.

I soldered one with an operational amplifier in it - that means it needs
power, which I took from a 9V battery. The mic capsules also needs power
(>1,5V, ~2mA).

A dynamic mic has a greated output power, so it works with a smaller
amplification (or maybe without an amplifier?). There exist simple
amplifiers with transistors. So I think that's why the Archos mic is a
dynamic mic.

Bye, Uwe.



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