"Is it best to use a buffer send/ptt device like the Ameritron ARB-704 with the K3?"
Not necessary. The ALS-600 keying input has an open circuit voltage of 12VDC, and requires you to sink 100ma (or 70ma with the QSK mod) to key the amp. Easily handled by the K3 amp-key RCA output. If you have a new ALS-600, ALS-500 or ALS-1300 with the ARI-500 for auto-band switching, the K3 band data output works great. You do need the K3 TTL band data mod if you have an early K3 as the ARI-500 does not have pull-up resistors. The K3 TTL band data mod is also required for the THP HL-1.5 amp, but not for the HL-2.5 (the HL-2.5 has internal pull-up resistors). As I recall, the SPE EXPERT amp has internal pull-up resistors as well - but I'm not 100% certain about this. Phil - AD5X ______________________________________________________________ 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
