Very quiet audio when output through TV's SPDIF to DAC (1 Viewer)

[miketimberlake]

Nice to join you all on this forum!
I have a little problem
I recently started selling these DACs:
http://www.ebay.co.uk/itm/MUSE-24Bit-192Khz-Digital-Optical-Coaxial-to-Analog-RCA-Audio-Converter-DAC-/190709809264?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item2c6730c070
I've sold a few without problems, but today I've got a customer who reports that the volume level is very low when he uses it with his Samsung PS43E490B1W TV.
He's not communicating with me very clearly, but I've bust my balls trying to fix the problem, to no avail
Obviously there could be a problem with his unit, but it seems much more likely that his TV is set up wrong, or that this device is not entirely compatible with his TV. I've tested the same device (same model, different unit) with my computer and it has the same output level as my USB soundcard.
I've read the manual for his TV, and it seems the only option that might fix that is the change the audio output format to PCM. The manual does not actually list the formats available, but this says the TV has only 2 types of dolby output, not PCM or LPCM.
I'm a home theatre enthusiast myself, but so far I'm still using a large monitor as my screen, so have no experience of TVs with optical outputs, etc.
Could anyone please explain to me why the output would be so quiet?

 

[Al.Anderson]

Those devices don't amplify the signal, the user needs to connect the output to a amp/receiver. My guess is he's trying to connect it to a pair of headphones and the device wasn't meant to do that.

 

[miketimberlake]

Hi Al,
He was definitely connecting it to his amp, which he appeared to know how to use, and this DAC has no headphone output anyway. He said that compared to a CD the volume was extremely low. Of course it's possible he connected it wrongly, somehow...

 

[schan1269]

IF the TV has a variable audio output...maybe he doesn't have the volume all the way up. Simple thing a lot of people miss.
It "appears" that with this TV, which makes zero sense...if you choose "external speaker" it turns the internal off and bypasses volume and mute controls(meaning you automatically get fixed).
But external is "live" regardless of whether external is picked or not. ???? (that makes no sense)

 

[miketimberlake]

From what I understand, only a small minority of TVs have volume control over the optical out. I didn't actually broach this with him as I couldn't find anything in the manual that referred to that.
My question really is; are there any codec or compatibility issues that could cause low volume? I'd have thought the thing would either work, or not, and the only issues I came across during my searches were with a Sky box.

 

[schan1269]

As long as 5.1 isn't being output by the tv...
Every single DAC/adapter works. But, it is possible(if he's comparing this against a CD player) the TV just has a weak output.

 

[miketimberlake]

and what would happen if 5.1 were being output by the TV? Could this result in a very quiet signal?

 

[schan1269]

You are selling the thing. You should know the answer to that.

 

[miketimberlake]

I know I should know the answer to that, that's what I'm trying to find out! I don't have a TV to test it with, and even if I did I probably wouldn't experience the same problem...

 

[schan1269]

So, you don't have a DVD/BD player that outputs DD over toslink?
Or DTS for that matter?
And "that information" isn't included in the instructions for this thing???

 

[miketimberlake]

My HTPC system is XBMC on Linux, with optical output via Behringer UCA202 to Beresford TC-7510 DAC. When I first set this up I had NO sound until I switched off the DTS output in XBMC. The Beresford can't handle it, and as far as I'm aware neither can the Behringer..
As for instructions, there are none, but these Muse DACs do have a good rep for the price. I tested one compared to my USB soundblaster (using the optical out from the soundblaster) and they sounded nearly identical. Ok, I know that's not audiophile quality, but what would one expect for $30?
I'm guessing my customer's TV had the digital out volume lowered somehow, as I can find nor see any other explanation for this weird lack of volume. I'm gonna test it on my XBMC system when it comes back to see what happens, it's the best I can do without buying a TV identical to his!
Having read a lot about these kind of issues a few days ago, it seems the general consensus is that although the new breed of digital TVs are ok for most average consumers, for nerds like me most seem to lack in some areas.
Any advice about what is generally the best brand for digital TVs would be appreciated, as I think I'll be upgrading soon..