--- Don Wilhelm <[EMAIL PROTECTED]> wrote: > As stated many times by Wayne B., the K2 design criteria was for low > receive current consumption and that is one reason that the K2 has > limited audio power output. The current consumed by a higher powered > audio stage could likely take more current than the rest of the receiver.
For a linear, class AB audio amplifier, I would agree. However, there are some very efficient Class D audio amplifiers on the market now that deliver an amazing amount of audio power from very tiny packages. Check out: http://monolithicpower.com/prd_05_classd_amp.htm They have a 20-watt amplifier in an 8-pin DIP package. It's rated at 24 volts, and can operate down to 9.5. The quiescent current at 24 volts is a whopping 1.5 mA, and efficiency is 93% at 20-watts! (I'd assume the power output at 12 volts into 4 ohms is 20/4, or 5 watts.) The challenge, of course, will be in preventing the switching noise from the amplifier from destroying the noise-floor of an already very quiet receiver. As far as getting more volume from an 8-ohm speaker, there may be small 4-to-8 ohm matching transformers available that can do the trick. An old audio output transformer with 4 and 8-ohm taps on its secondary can be wired as an autotransformer to achieve a similar effect. 73, de John, KD2BD Visit John on the Web at: http://kd2bd.ham.org/ . . . . __________________________________________ Yahoo! DSL Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com