What is the input impedance of the four?
Olympus says 2k.
I was told that Sony is 22k. is that right?
What was the input impedance of the old Sony MD=B4s and later the HiMD=B4s?=
?
Klas.
At 05:33 2009-08-22, you wrote:
>[resent to correct table formatting; sorry!]
>
>None of the recorders were behaving at all like CC sources, at least
>with loads drawing anywhere around .5mA. They behaved much more like
>The current was pretty linear with the load, more like an ordinary
>voltage supply with a resistor in series.
>
>I just measured the PiP current supplied into a dead short for each
>recorders. That's the maximum current that they can deliver. Here's
>a revised table showing that as the last column:
>
>MODEL V (unloaded) V @ 0.50 mA Load (Ohms) mA (0 Ohm)
>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>Sony D50 2.82 0.52 1030 0.61
>Zoom H4n 2.84 1.82 3606 1.38
>Olympus LS10 3.02 1.93 3828 1.40
>Nagra ARES-MII 2.81 1.78 3580 1.37
>
>This suggests that the H4n, LS10, and ARES-MII use an internal series
>resistance of about 2.2K Ohms, while the D50 uses about 4.7K Ohms,
>with each having a roughly 3V voltage source.
>
>-matt
>
>On Aug 21, 2009, at 21:54, umashankar wrote:
>
> > somewhere i remember reading that many new plug in power sources are
> > constant current, which of course changes the way we measure. it
> > should be possible to identify the constant current sources quite
> > easily.
> >
> > it would make sense to provide constant current rather than voltage
> > when working with very low voltages.
> >
> > umashankar
> > i have published my poems. you can read (or buy) at
> http://stores.lulu.com/umashankar
> >
> >
> >
> >
> > ________________________________
> > From: Klas Strandberg <>
> > To:
> > Sent: Saturday, August 22, 2009 7:12:29 AM
> > Subject: Re: [Nature Recordists] Plug in power voltage?
> >
> > Great Matt! Thank you!
> >
> > This needs some consideration.
> >
> > You have to load the Sony 3 times as much to squeeze the 0,5 mA out
> > of it because the voltage drops..?
> > Do you see any other interpretation?
> >
> > Klas.
> >
> >
> >
> > At 18:22 2009-08-21, you wrote:
> >> On Aug 21, 2009, at 7:07, Klas Strandberg wrote:
> >>
> >>> Hi folks!
> >>>
> >>> It would help me and users if I better knew about the plug in power
> >>> voltage that different recorders provide.
> >>>
> >>> This is the test:
> >>>
> >>> 1/ Connect a potentiometer and a mA meter in series between input
> >>> and ground.
> >>> 2/ Set the potentiometer so that the mA meter shows 0,5 mA.
> >>> 3/ Measure the voltage between input and ground.
> >>>
> >>> For the moment I am specially interested in the voltage that Sony
> >>> PCM-D50 provides at a given current, like 0,5 mA.
> >>>
> >>> Klas.
> >>>
> >>>
> >>>
> >>
> >>
> >> OK, I just did the LS-10, too: 1.93V
> >>
> >> To summarize (view in a monospace font):
> >>
> >> MODEL V (unloaded) V @ 0.50 mA Load (Ohms)
> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> >> Sony D10 2.82 0.52 1030
> >> Zoom H4n 2.84 1.82 3606
> >> Olympus LS10 3.02 1.93 3828
> >>
> >>
> >> So the Sony is an outlier here.
> >>
> >> Note that my 0.50 mA current adjustment was only approximate -- I set
> >> the load resistor to get as close to 0.500 mA to flow as I could, but
> >> really got only within +/- 1 % or so. So the loaded voltage isn't
> >> exactly R * .0005, because the current wasn't exactly 0.5000 mA.
> >> It's
> >> just close. Ohm's law still applies in Philadelphia, in spite of
> >> what
> >> the numbers above might suggest!
> >>
> >> V measurements were done with a recently calibrated Fluke 189.
> >> Current was measured with a Fluke 289, also recently calibrated.
> >>
> >> -matt
> >>
> >>
> >> mab blogs at http://www.crypto.com/blog/
> >>
>
>
>
>mab blogs at http://www.crypto.com/blog/
>
>
>------------------------------------
>
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>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause
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