Rockbox mail archive
Subject: Re: External Mic preamp?
From: Ronald Teune (rtwolf_at_gmx.net)
hey... _you_ are limbus :-P
anyway, i have tried quite a nice, small preamp which seems to be from
velleman (www.velleman.be) which amplifies quite a bit too
i could try finding or drawing the schematic. It's spec'd to work at 9-27
volts. But now I'll just sleep :)
On Tue, 7 Sep 2004 23:25:32 +0200, Manuel Dejonghe <limbus_at_gmail.com>
> me too I am currently making some experiments with that.
> The main problem is, as you already recognised, this is a line in, and
> not for mics.
> I bought an electret condenser microphone from sony (ECM-TS125) which
> already has some kind of preamp. Unfortunately, this preamp is rather
> a driver for the ecm. A normal ecm without that element would be very
> weak on a mic in too.
> I hoped, this element would raise the level high enough to get it
> working on the line in. And it does, but still not high enough: If I
> set up the gain to the max (+19,5 db) I still can normalize the
> recorded file without having to cut out the peaks.
> There are many preamplifiers, but not so much that are battery
> powered, which is a not negotiable option for me.
> There are some within high-professional-range with balanced xlr-plugs
> as well as a digital breakout, but that's not what I need. Ok, it
> would be fine, but it makes it not affordable anymore.
> There are some around 50-100 euro on ebay, even within semi-professional
> One of the cheapest solutions (30 euro) seems to be to buy the archos
> microphone, which has a real amplifier and seems to be of a fair
> quality, see the list for more comments.
> I'll let you know if I am making progress.
> One option is to design a small circuit myself. I'm not good with
> that, but it may be the cheapest solution that meets my needs. I don't
> specially need high quality.
> regards, Manuel
> On Tue, 7 Sep 2004 15:06:40 -0400, Shervin Riahi <shervin_at_gmail.com>
>> Hey guys, I have a nice sony stereo microphone, but I notice (with
>> much dismay) that it barely picks up any sound when I use it to record
>> via my AJBR (running today's daily build). As a control, I plug my
>> _headphones_ into the same port (the Line In socket), and voila, the
>> device receives sound input and I can record (albeit at a very poor
>> quality level). As such, I guess I need to buy some sort of preamp in
>> order to boost the incoming signal, right? Any suggestions on an
>> affordable one?
>> Thanks in advance!!
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