Hi,
My K3 last arrived last week and I have been getting to grips with it.
However, I think I may have an issue with noise in the mic amp /adc.
The headset I hoped to use is one that I have successfully used with my
FT1000MP, a Sennheiser HMD25-1. This has a 200 ohm dynamic mic insert.
With the K3 I find that I need to use the high gain setting and a
relatively high mic gain level (30 -40) to get anywhere near the
required 4-5 bars of ALC. With that much gain I hear more noise than I
would expect to. The noise is mostly white but has a distinct whine
which I estimate to be at around 1500Hz. The situation is the same using
the front or rear mic sockets.
I have also tried a number of other headsets. A Bayer DT190 with a 200
ohm dynamic mic insert gives similar results to the HMD25-1. A
Sennheiser HME25-1 which has an electret mic insert is a little better
(probably because it has a higher output level) although still requires
fairly high gain.
The best results so far have been with a low cost computer headset or a
£1.00 electret mic capsule. With both of these I was able to use the low
gain setting and a mic gain less than 20.
So, some questions...
What sort of gain level should I expect to use for a dynamic mic?
Are other K3 mic amps as noisy as the one I have, if not then where
should I start looking for the noise issues?
Does anyone else hear the tone in the noise with the mic gain turned up?
73
Ian.
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Jun 29, 2010; 8:45am
