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Digital to Audion convertion.

3K views 16 replies 4 participants last post by  ExDilbert 
#1 ·
Four years ago I got a new Samsung smart TV. To watch TV late at night without disturbing anyone, I hooked up some Sony wireless headphones to the headphone output jack. Planning to eventually hook it up to external speakers, I found it only had optical audio output, so I bought an inexpensive converter, a Toslink cable and a long RCA cable set to connect t my AVR. Everything worked and I never checked on the audio output again until I decided on another pair of speakers.

So a couple of weeks ago the 50" Samsung crapped out, showing a spider web pattern in the bottom LH corner, which soon deteriorated to no picture at all. I learned from the local TV Repair that this wasn't economically fixable, so I got a new TV, this time a 55" Samsung Smart TV. To my dismay I discovered it had no headphone output jack for my wireless headphone setup, so I hooked the DAC output to it, but all I could hear was a rattling sound. I connected the DAC back to the AVR RCA cables, same thing. So either the DAC had gone bad, or the new Samsung optical output was defective. I ordered another DAC which looked identical to the one I had, just a different brand name, and today I received it. Hooking it up, all I got was silence, not even a rattle like the old one.

So my question is, could this new DAC be defective or mis-labeled, or could my TV have a problem and requires warranty work? How reliable are these inexpensive DACs?



 
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#3 ·
Under Sound Output on the TV I have the choice of TV Speaker, Audio Out/Optical and Bluetooth Speaker List. I do set it to Optical. It worked with the previous TV but not with the new one. I'm just wondering if the old DAC went bad or new TV optical output is defective or the old DAC went bad and the new one is defective. The old DAC outputs a rattling sound and the new one is silent. It's not the Toslink cable because I tried both.
 
#6 ·
This digital to audio converter only works with PCM digital audio. It's likely that the former TV output PCM but the new TV outputs Dolby Digital, an incompatible format. The noise heard with the older DAC often indicates an incompatible digital audio format. The new DAC may simply mute the incompatible signal.

If possible, the resolution will be to change the TV's digital audio output to PCM format. That may be an option in the TV settings. If not, changing the signal going to the TV to PCM may be possible in the TV receiver box menus. The downside to that will be that the AVR will not receive Dolby Digital surround sound and audio quality will be reduced. If that's not possible, is undesirable or it doen't work, it will be necessary to get a Dolby Digital compatible DAC or headphones that handle Dolby Digital.

I found an Wiistar digital to stereo audio converter on Amazon that works with Dolby Digital and is reasonably priced. Wireless headphones that handle Dolby Digital input are also available.
 
#7 ·
Well, I tried the DAC on my son's older Samsung UN50H5203AF Smart TV and it worked fine. I didn't try the previous DAC I had that made a rattling sound on my new TV.

That's interesting @ExDilbert. Is this the Wiistar 5.1 Audio Decoder you mean?
https://www.amazon.ca/Wiistar-Decod...pID=41C0Wl8sXeL&preST=_SY300_QL70_&dpSrc=srch

It does not seem conceivable that my new TV would have non-functional optical audio output out of the box. It's model UN55MU6300F. Can anyone confirm the optical output of this model would be different from previous models?
 
#10 ·
The UN55MU6300F TV manual is here.

From the manual:

Page 10:
The UN55MU6300F has an 1/8" mini-plug for analog audio output. It is the second connector above the SPDIF optical audio connector. That might work with the wireless headphones. It's probably a fixed level output so the headphones will need a volume control.

Page 19:
In order to get sound out of the digital or analog audio connector, set Speaker Select to External Speaker under the Audio menu. (The TV speakers will be turned off.)

When using SPDIF, select the Digital Audio output (SPDIF) format from the options to PCM . Note that the IR carrier (AKA the red light) may be on even though no sound is present.


The DAC I found is this one. It's going to be simpler to set up. The other DAC has a lot more features but may not work as well with stereo headphones. It probably won't be needed though.
 
#11 ·
When using SPDIF, select the Digital Audio output (SPDIF) format from the options to PCM .
Doesn't this imply that there are more options than simply PCM? If there are more, you may wish to try switching to another like DD or RAW, then back to PCM...

It's very strange that your DAC worked on your old TV, works on your son's TV, but doesn't work on the new TV. I still suspect a setting issue, not a hardware issue.
 
#12 ·
From page 19 above I paraphrased:
Audio Format
: During the reception of a digital TV
broadcast, you can select the Digital Audio output
(SPDIF) format from the options
PCM or Dolby Digital.
That implies that if the signal is not digital then digital audio output may not be available. So, no digital output with analog audio and video input or analog TV stations?

Edit: Samsung seems to be cutting a lot of corners on some of their lower end TVs so I wouldn't expect a lot in the way of special audio handling.
 
#13 ·
That manual is not for the UN55MU6300F but the UN55C6300SF. Here is mine
The settings are very simple and dumbed down.

I got a set of Bluetooth headphones when I could not get my wireless ones to work due to this problem. That Wiistar AC3/DTS/Dolby Toslink adapter looks similar to the ones I have, but the specs are more detailed, so I'll give it a try.
 
#15 ·
Monoprice D/A Convert ONLY outputs LPCM (aka PCM, 2-Channel STEREO):
https://www.monoprice.com/product?p_id=6884

I suspect that your Samsung is STILL set for (DEFAULT) Dolby Digital.....

Under "Settings/Sound/Expert Settings" there should be a menu for Digital Output Audio Format, per eManual pg69:
http://downloadcenter.samsung.com/content/UM/201711/20171113111128155/ENG_US_KTMATSCL-3.0.6.pdf

"● Digital Output Audio Format
If you use a receiver that does not support Dolby Digital Plus, you will hear no sound if you select Dolby Digital+
The Dolby Digital+ option is only available via ARC(HDMI) for external devices that support the format."

NOT very useful Manual Entry...doesn't even tell you it ALSO applies to OPTICAL Output....they only comment on the EXCEPTION case. So there should ALSO be entries for (regular) Dolby Digital [DEFAULT]....and PCM (aka LPCM), which is what YOU want for compatibility with Monoprice D/A Converter.....or use another D/A Converter compatible with (regular) Dolby Digital.
 
#16 ·
Problem solved!

I went back in the Sound Expert Settings. As I said earlier, the Digital Output Audio was PCM with no other choices. But the HDMI Input Audio Format was Bitstream and I didn't think anything of it. But then I saw the other choice was PCM. As soon as I changed that to PCM I had sound from my AVR speakers when using Audio Out/Optical.

Oddly, when using the TV speakers the sound also comes out of my AVR speakers when the receiver is on. Since my AVR speakers are behind me, I now have "surround sound". :smile
 
#17 ·
Glad you solved it. It looks as if the TV is telling the TV box what type of audio it wants sent. That's a new one on me but not surprising due to the way HDMI is designed. The TV must just pass through whatever digital audio it receives. As I said before, downgrading the audio to stereo PCM will result in poorer quality sound to the AVR. That's not that big an issue with most TV content but might be noticed with movies that have a lot of sound effects.

It looks like Bluetooth might be another option for listening with headphones. See page 70.

I still coudn't find the right manual online. Samsung kept sending me to a C6300 from 2010. The link holl_ands posted finally brought up the right manual. And yes, that's an odd manual. There isn't much detail at all, unless it's designed with some new features that Foxit Reader doesn't have. It looks like there are some buttons that should do something but don't.
 
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