The one place impedance might be important is with regard to frequency response. Some of the early K3 headphone circuits has smaller value coupling capacitors than the current production. With low impedance (< 16 Ohms) headphones the low value coupling capacitors resulted in a low frequency roll off that bothers some operators.
I like the CM-500 and the *old* Heil Pro Set with 200 Ohm headsets for that reason. However, the my Heil is gone ... the mic housing broke and Heil would not sell repair parts (more specifically they wanted as much for the repair parts as it would have cost to buy a new Pro Set HC-5!). I bought two x CM-500 for less than one Pro Set. 73, ... Joe, W4TV On 8/14/2011 9:52 PM, Jim Brown wrote: > On 8/14/2011 6:16 PM, rich kennedy wrote: >> Is headphone impedance a critical factor in choosing your headphones? >> Thanks, 73, Rich, K3VAT > > NO! The more important number is the "voltage sensitivity," which is > usually expressed in dBSPL (acoustic loudness) for a standard driving > voltage. Any decent headphones will work fine electrically with the K3 > unless you happen to have VERY SERIOUS hearing loss (like some of my > friends). I'm 69 years old and have moderate hearing loss, and I've yet > to see decent phones that aren't loud enough. > > 73, Jim K9YC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html