> On the other hand, plug a Heil ProSet with its 200 Ohm elements > into an unmodified K3 and the -3dB point is 80 Hz ... low enough > for communications use without being overly sensitive to hum and > other low frequency noise...
That would be a good choice for the stock K3. One thing to note is that most coil-based headphones and speaker elements do not have a flat impedance curve as a function of frequency. Some can vary considerably from their rated impedance rating. The Z at 50 Hz can be vastly different than at 5 kHz. Also, moving the C9 & C13 headphone coupling capacitors up in value will allow for grabbing most any headphones.without worry as to how response will be affected. I used an old set of Koss Pro4/AA for testing but use Sennheiser PCX300 or Bose Triports headphones when operating my K3. 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
