[Elecraft] KX3 with external speaker

[Walter Underwood]

The KX3 “PHONES” jack is for headphones. It produces 100 mW. —wunder, K6WRU

> On Feb 16, 2026, at 3:44 PM, Jim Brown via Elecraft <elecraft at mailman.qth.net> wrote:
> 
> On 2/16/2026 3:15 PM, Phil Hystad via Elecraft wrote:
>> Can someone give pointers on this?
> 
> The K3, K3S, and K4 have separate audio power amplifiers for headphones and speakers, each with their own individual output jacks. I haven't studied the schematic, but I suspect that the KX3 has only the amplifiers for headphones. Speakers require considerably more power.
> 
> The headphone output could probably drive a powered speaker (that is, one with its own built-in amplifier), but powered speakers are notoriously bad for RFI, both generating noise and being susceptible to nearby transmitters, so are unlikely to be a solution.
> 
> 73, Jim K9YC
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