I just spotted this in the online archive which wasn't emailed to me. I apologize in a advance for others who post replies without getting a response from me. If the list server doesn't send me a copy, I may not spot it in the archive. The original message is at the bottom. First is my reply:
Hi Walter, Thanks for your feedback. I appreciate it. Yes, I'm aware of that amplifier. It would be appropriate for driving bookshelf HiFi speakers, as your writeup demonstrates - cool project, by the way. Aside from 15W being overkill for driving the 2W/3W driver in the SPX3, it wouldn't fit in the enclosure, and would need to be modified by hand to work as needed even if it did fit. Most transceiver external speakers put out 2-3W, as that's all that's necessary for listening to voice and CW at close range. Plus, when taking the SPX3 portable, it needs to last a long time on a battery. 15W per channel (30W) would drain a battery mighty quick. I turned the prototype on this morning when I got up, and it's still running after more than 15 hours on the same battery charge. The SPX3 sports features specific to what the KX3 needs, such as a low pass filter, built-in battery and charging circuitry, a shielded enclosure to eliminate RF from the antenna affecting the audio, works great outdoors, the speaker cone won't get damaged if it gets wet, and more. Plus, it matches the KX3 and supports KX panels and covers (already in talks with the SIDE KX folks). You might want a pair yourself to take on the road. Thanks and 73, Robert (AG6ZZ) --- Walter Underwood [1] Fri, 13 Apr 2018 11:58:12 -0700 [2] I use this 12 V audio amp. It would be easy to put it inside a speaker. It seems to vary in price a bit. Today it is $8.50, on the low side. "DROK TDA7297 15W+15W Audio Power Amplifier Module AC/DC 9-18V 2.0 Dual Channel Stereo Amp Board" https://smile.amazon.com/DROK-Amplifier-Amplify-Digital-Portable/dp/B00C4MT274/ At home, I stick it to the top of one of the speakers with velcro. Writeup is here: https://observer.wunderwood.org/2017/03/04/speakers-for-my-elecraft-kx3/ wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) Links: ------ [1] https://www.mail-archive.com/search?l=elecraft@mailman.qth.net&q=from:%22Walter+Underwood%22 [2] https://www.mail-archive.com/search?l=elecraft@mailman.qth.net&q=date:20180413 ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
