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New noisy mic amps!

Subject: New noisy mic amps!
From: "Klas Strandberg" klasstrandberg
Date: Wed Aug 30, 2006 2:43 pm (PDT)
Hello everybody, bad news again:

Here on this list I claimed for a long time that ordinary MD mic inputs
were good enough if only the microphone had a reasonably high output, like=

the Telinga EM23.
Rob and others took up this thread and found it basically correct. (??)

Then something happened:

Suddenly some recorders could not provide enough plug in power! The first
model was a Sharp MD released 2003. When using a low-noise FET IC, like the=

one I had been using for years in the EM23, the voltage went down below 0,7=
V.
I thought it was only this Sharp, and warned about it at this list.
Then .... it seemed as all new Sony HiMD's were the same...

Some wise guy in Japan seems to have realized what was happening, and
re-designed the FET-IC into a version using less current. I got hold of it,=

I could test it and all was well. Now this low-current FET-IC is in all
EM23's and the HiMD plug in power is high enough.

But of course I didn't like this new "Sony-style" of having such low
current capacity of the plug in power voltage.
iRiver, for example, went the other way and stepped up the 1,5v battery
voltage up to some 3v.

Then came the new Edirol R-09! Worse than anything before it!
I tried every possible way to make a plug in power mic which had juice
enough to compensate for the low sensitivity and terrible noise level.
In vain.
You need an extra mic amp stage and a output stage providing low impedance=

and external battery voltage, at least some 6 volts, preferably 9.

Making very thorough experiments, I found that two other recorders were the=

same - the Edirol R-1 and MT 24/96. Noisy, but more acceptable than the
R-09. With maximum output voltage from the EM23's internal FET-IC, the
recorder mic amp noise is louder than the self noise of the EM23.
A extra mic amp, output buffer and battery in a little plastic box solved
the problem.

But: What about other new recorders??
Before: Most recorders were very alike, having good mic amps.
Now: There are good ones and really bad ones. I hate it!

Isn't it true any longer that "MD mic inputs are good enough"??

Rob?? Others?

Klas.















At 17:16 2006-08-30, you wrote:
>Hi, can anybody recommend me an low noise external stereo mic for
>recording soft ambiances with
>the Edirol R-09?  I would prefer it worked with the PiP of the R-09,
>which as I am told is about
>2,6V. For me, the recording of louder ambiances with the internal mic
>works fine.
>
>I've red here about two Shure WL183 modifying them so they work with
>PiP, which is quite
>interesting for making binaural recordings.
>Would this also be possible with two Sennheiser ME2? I can have two of
>them but I don't
>know if they perform better or worse then the WL183.
>
>Thanks,
>
>Igor.
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>

Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email: 
website: www.telinga.com







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