by Neil Bauman, Ph.D.
A man was having trouble making his new TV work with his loop system. He wrote,
I recently purchased a Panasonic Viera TV. It only has a Toslink digital audio output jack. I purchased a Monoprice digital to analog converter (DAC). This works very nicely if I supply an HDMI input to the TV. But if I use a coaxial input, either from a cable system (QAM) or off-air (8-VSB), I get a beautiful picture, but no audio output. What’s going on?
My friend Robert McPherson (the owner of the Yahoo group BHNews) explained,
Your problem is that the Monoprice DAC you purchased only works with standard stereo signals [what is known as Pulse Code Modulation or PCM]. It cannot convert a 5.1 surround sound (Dolby) digital signal.
Unlike many/most TVs today, there is no user selection of digital audio output signal type with the Panasonic Viera sets. Rather it is dependent on the signal delivered to the TV. The Viera owner’s manual states, “When an ATSC (digital) channel is selected, the output from the DIGITAL AUDIO OUT jack will be Dolby Digital. When an NTSC (analog) channel is selected, the output will be PCM.”
In case you can’t decipher the above, it plain English it means that if you have this TV, you need a digital to analog converter that can decode BOTH Dolby and PCM digital audio signals. You can order the DAC you need (has both PCM and Dolby) here.