Hi Curt,
First up thank _you_ for sharing the details of your rigs on your
site. It's a brilliant resource!! The timber I could get is somewhat
smaller than what you used - 19mm x 90mm vs 25mm x 100mm but still
seems to work quite well. I've also made up a wire mesh cage and fake
"arctic fox" furry which has really helped with wind protection.
I've been pretty happy with the preamp since I finished it - it works
pretty well for something built on perf board! I've found that the
line-in on the RH1 is really quite good. With the line inputs
terminated with a 150ohm resistor and at full gain I can hear (and
see on a spectrogram) very, very faint traces of the motor noise but
it is a pure motor noise rather than the more obvious broadband hash
you get on the mic inputs. The preamp gives a maximum of 60dB gain so
I can run the record levels at about 14-20 which is effectively
attenuating the line-in signal. So all-in-all I'm really quite happy
with the results I'm getting via the line in.
I've made a really short test file comparing the self noise at
typical recording levels. Based on the figures on wildlife-sound.org
I figure that at "17" on line in I'm attenuating the 60dB preamp gain
by 7db so get 53dB effective gain. The same data would suggest that
"22" on "hi" gives roughly 53dB gain. No guarantees on how accurate
these figures actually are!! I've terminated all mic inputs with
200Ohm resistors. The file has the internal pre first and the
external second.
http://www.mactrix.com.au/files/recordings/preampcomp.wav
That said and done I'm about upgrade to a HD-P2 as I have been
finding the preamp/RH1 combination fiddly to deal with in the field.
This mainly due to the preamp being quite bulky, but there are a
number of things about the RH1 which I find less than ideal. The
display is virtually impossible to read in any kind of sunlight, so
it makes setting levels extremely hit and miss. I also find setting
levels on the RH1 to be a bit clumsy when trying to make quick
adjustments.
cheers
Paul
On 10/10/2007, at 12:33 AM, Curt Olson wrote:
> Very nice, Paul. Thank you for sharing this beautiful recording!
>
> Your mic rig sounds great, as I would expect. And you certainly did a
> nice job on the preamp. Are you satisfied with the line input to your
> MZ-RH1?
>
> Curt Olson
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