Headphone support on ZVOX SoundBases:

Only the SoundBase 770, 670 and 570 are designed to support headphones. These three units support headphones only while the speaker itself is playing. No current ZVOX Audio SoundBase provides a headphone output that allows listening to headphones without the SoundBase also playing.

The recent and current SoundBase models that do not support headphones are the 220, 320, 420, 350 and 450. These models have no audio output.

Here are some guidelines about using headphones with a TV.  Most TVs have a digital audio output. Many TVs also have a analog audio output. ZVOX Audio SoundBase models usually connect to the digital audio output. If your TV also has an unused analog audio output, this can be used with wireless headphones. An analog audio output can also be used with a headphone amplifier plus passive headphones.  

Wireless vs passive headphones
Standard “passive” headphones (the ones with a wire with a plug at the end) REQUIRE a dedicated headphone output. These headphones will not play properly from an analog audio output on a TV. You have to connect a stand-alone headphone amplifier to an analog audio output on a TV to use passive headphones.