> I don't know about the big Icoms or their new 7600 and would be interested > to hear from anybody who has one.
The Icom '7700 and '7800 are nearly hiss-free at the minimum AF setting. My K3 is totally silent using Sony MDR-7506 and Bose Tri-Port headphones. There's generally only one time when I hear hiss from my K3 -- and that's right after a F/W flash. I have now become accustomed to turning power off after the flash is complete, then wait > 5 seconds and re-start. If I do not wait ~ 5 seconds, I oftentimes hear slight latent hiss. But it's cured 100% by this off-on sequence. The rig tried here with the highest latent AF hiss was the TS-950. In fact, the hiss level was so high that VS designed a special relay "cut off" circuit to kill the hiss (and all audio) when the AF control is turned full CCW. On the TS-950, the hiss comes into play when the AF control is just slightly advanced. IOW, at full CCW, a relay opens up the headphone line. And when the AF control is advanced, the relay closes and the hiss becomes apparent. That's the first attempt I've seen by a manufacturer to mask a design problem by using a relay as an audio 'knife switch." Anyone owning a TS-950 can try this test without wearing headphones: Turn the AF control CCW and repeatedly advance and retard the control slightly. Hear that relaying clicking inside the cabinet? That relay's sole purpose is to mask hiss. Paul, W9AC ______________________________________________________________ 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
