Raimund,
This is very helpful. I am in exactly the situation you described. Limited =
funds, and I already have a small recorder and an inexpensive portable prea=
mp, and I want to get the best out of them that I can.
Both of your predictions seem to be correct!
I tried a few experiments, yours of just using pins 2 and 3 from balanced t=
o unbalanced and another of inserting a transformer (from a Hosa adapter ca=
ble) between the balanced and unbalanced signals. Both of these had the exp=
ected effect on the signal level, but also on the noise level, so the end r=
esult was the same whether the signal was carried by unbalanced, balanced=
=3D>transformer=3D>unbalanced, or Pins 2/3=3D>unbalanced. The unbalanced si=
gnal level dropped 6dB but I just boosted it in post and the results were i=
dentical to my ear.
The preamp balanced output did yield a 2-3dB improvement in s/n over the un=
balanced output when I routed it through a studio mixer that accepts either=
balanced or unbalanced line connections, but that is not an option in the =
field. Given the equipment I have for field use, it doesn't seem to matter =
whether I use the balanced or unbalanced outputs.
I seem to be going through a lot of gyrations just to prove that I'm alread=
y getting the best I can out of the equipment I have!
many thanks,
John
--- In "Raimund" wrote:
>
> > I don't think that this is going to be a problem in any of these device=
s, because their balanced output signals have already been amplified at thi=
s point. A drop of 6 dB would therefore not make a difference in terms of n=
oise (one can easily compensate for that by increasing the gain of the prea=
mp or the recorder).
>
> John,
>
> I just realized that my previous reply was not correct (it is really a co=
mplex issue ;-).
>
> Taking only one of the two (amplified) balanced output rails could still =
lead to a degradation of the noise performance. So, I believe that feeding =
the difference of the two into the unbanlanced input would be better in ter=
ms of noise. I seems to me however that this kind of "unbalancing" is not a=
vailable on the SoundDevices preamps.
>
> One thing that one might try is to connect the unbalanced line input of t=
he recorder to the XLR pins 2 and 3 of the preamp output (rather than to gr=
ound and pin 2 or 3). Such a floating arrangement might work if at least on=
e of the units (either the preamp or the recorder) is battery powered. That=
way, one would just record the difference between the two rails. But I hav=
e never tried that and I'm not sure if it really works in practice...
>
> Regards,
> Raimund
>
--- In "Raimund" wrote:
>
> > I don't think that this is going to be a problem in any of these device=
s, because their balanced output signals have already been amplified at thi=
s point. A drop of 6 dB would therefore not make a difference in terms of n=
oise (one can easily compensate for that by increasing the gain of the prea=
mp or the recorder).
>
> John,
>
> I just realized that my previous reply was not correct (it is really a co=
mplex issue ;-).
>
> Taking only one of the two (amplified) balanced output rails could still =
lead to a degradation of the noise performance. So, I believe that feeding =
the difference of the two into the unbanlanced input would be better in ter=
ms of noise. I seems to me however that this kind of "unbalancing" is not a=
vailable on the SoundDevices preamps.
>
> One thing that one might try is to connect the unbalanced line input of t=
he recorder to the XLR pins 2 and 3 of the preamp output (rather than to gr=
ound and pin 2 or 3). Such a floating arrangement might work if at least on=
e of the units (either the preamp or the recorder) is battery powered. That=
way, one would just record the difference between the two rails. But I hav=
e never tried that and I'm not sure if it really works in practice...
>
> Regards,
> Raimund
>
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