On Fri, 25 Jun 2010 13:50:30 -0700, John Merrill wrote: >I have a ProSet and it is fine at around 10 o'clock. I wonder if it an >impedance thing?
It's a combination of impedance and sensitivity. Headphone output stages are essentially constant voltage devices -- that is, they have a low output impedance -- but good designers add a small value of resistor in series so that the output devices don't fail when accidentally driving a short circuit. Headphones are made in a range of impedances from about 8 ohms to about 600 ohms. Most pro headphones are in the range of 50-200 ohms. The higher the inpedance, the more voltage it takes to drive them. But the higher the impedance, the less current the headphone amp needs to supply. In other words, 600 ohm phones need much more VOLTAGE to get the same power as 100 ohm phones. In general, a headphone output will be happy with any headphone impedance equal to or greater than its rated load. The bottom line question is, can you make the headphones loud enough with the audio gain control to satisfy your ears without audible distortion? If the answer is yes, be happy. If it isn't consider buying a new set of cans. The Yamaha CM500 is a winner, under $50. 73, Jim Brown 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
