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. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
