At 10:56 PM +0200 8/30/06, Klas Strandberg wrote:
>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 th=
e
>one I had been using for years in the EM23, the voltage went down below 0,=
Message: 7V.
Subject: >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 th=
e
>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.
Hi Klas--
I regret the frustrations you're facing in keeping your excellent PIP
products on line. No other mic manufacturer has pushed the
capabilities of PIP mics as far as you have. Your EM-23 is the only
PIP mic I can think of that has less than 16dB(A) self-noise, the
great majority have over 20dB(A)
Did you see Richard's "heads-up" on the AK-5356VN-L
ADC/Pre/PIP/Regulator used in the Sony Hi-MD's?
http://bioacoustics.cse.unsw.edu.au/archives/html/naturerecordists/2006-07/=
msg00192.html
download the .pdf of the AK-5356VN-L spec sheet here:
http://www.asahi-kasei.co.jp/akm/en/product/ak5356/ak5356_f00e.pdf
discussion:
http://www.analogzone.com/avp_0804.htm
Your experiments and modifications show that that the PIP circuit has
become compromised, but the ADC and preamp circuit in the Hi-MD's may
be better than any $<350USD recorder to date. Richard's and Bruce's
bench tests suggested that the noise of the Hi-MD's pre becomes
audible when using an MKH-40 with 12dB(A) self noise. I tested this
by ear and felt the HiMD pre performed a little better than this.
It seems that with the exception of the EM-23, those interested in
low noise recordings in quiet locations would not consider PIP mics
among the best options. Of course, another option is to use
conventional, phantom powered condenser mics with a portable phantom
power supply unit. Eric Benjamin ran a noise test on the $70 Rolls
PB224 and found it's noise to be safely below that of the Hi-MD's
pre.
I'm very sorry to hear about the R-09 woes. The AK-5356VN-L link
above proves your claim that a low-noise, high-gain pre circuit costs
less than a few bucks! Yet, as readers on this list, we know one
cannot assume manufacturers understand how important it is to build
in pre quality.
Maybe its time to package the EM-23 for phantom? I know folks want to
see the EM-23's become more available here in the States. Could a
simple in-line power supply as Richard suggested possibly work with
an EM-23, to get around PIP? Rob D.
--
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