This is a very serious problem and in my opinion the QMX should NOT be used with headphones as there is a very real risk of hearing damage.? The first time it happened to me, I was using some JVC headphones (32 Ohms).? I was probably on 40m and I must have had the "volume" up quite high when trying to hunt a weak POTA station.? The next station that transmitted was a powerful station which was EXTREMELY loud!? It was so loud and intense that I reared back in my chair and swatted the headphone clean off of my head and they ended up on the floor.? I felt pain in my ears for over an hour after that so it is likely that I suffered some degree of hearing damage.? It's hard to quantify exactly, but I would say the volume level felt about the same as someone screaming in your ear from and inch or two away!
I shelved the QMX until version?1_00_014 of the firmware was released.
I decided to give the radio another try.? This time I was using a more expensive set of headphones which I normally use with my FTDX10.? Unfortunately, the same thing happened to me again.? This time I managed to rapidly yank the headphones off of my head in a somewhat controlled manner but I very nearly ended up damaging an expensive pair of prescription glasses.
I do CW POTA activations and I prefer using a headset as the Morse code can be quite annoying to other park users.? My QMX is going back on the shelf until this issue gets sorted out.? In the mean time, I am investigating various AGC / limiter circuits, both passive and active.? In addition to the simple diode circuit described earlier, I have found a couple of other circuits which I will attach to this post.? I would very much appreciate any other recommendations or information.
Kind Regards, Lyndon
