K3 external amp relay (key out) question

Posted by Robert Sands on Feb 06, 2011; 8:40pm
URL: http://elecraft.85.s1.nabble.com/K3-external-amp-relay-key-out-question-tp5998485.html

My K3 "key out" relay works fine with my SB220 (uses positive 110DC volts to ground when keyed). When I use it with another home brew linear (negative 15 V to ground to key) it leaves the linear in keyed ON condition so can't be used. Is the negative 15 volts incompatible with the "key to ground" relay in the K3? My Icom 775 has no problem with the negative 15 volt relay and it works fine with this linear.