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Low Volume from Digital Coaxial Output

post #1 of 8
Thread Starter 
Hey all,

Here is the situation. I have A) An old surround system that only inputs and outputs LINE audio. I also have a 46" Philips that (unfortunately! only outputs audio via digital coaxial or toslink.

So I bought this small powered converter unit that converts digital coaxial to line audio. I interfaced it with the old surround unit and I get volume but it is pretty low.

I have the volume maxed out on the unit and I still can't get that loud 'in your face' booming sound. If I play a CD through the unit, it sounds great!

My guess is that the TV is sending a weak signal to the unit. Does there exist any possible way I can amplify this signal before it hits the surround unit?

Thanks
post #2 of 8
Hi Reminisc,
Quote:
Originally Posted by reminisc3 View Post

So I bought this small powered converter unit that converts digital coaxial to line audio. I interfaced it with the old surround unit and I get volume but it is pretty low.
I suspect that device to be the problem - It may be defective.

The digital signal from the TV is in LPCM format, and typically has no "volume" associated with it. It is either on or off. The TV could be capable of controlling the volume, but that would be unusual. Does the volume change at all when you adjust it from the TV?

If not, then it appears that the analog signal that is being produced by that DAC is anemic. Try exchanging it, and if the replacement has the same problem, post back here and tell us which one it is.
post #3 of 8
Thread Starter 
The volume does not change on the surround unit when changing the TV volume. So the output must be isolated.

Nonetheless, not the answer I wanted to hear frown.gif I ordered the converter unit on Amazon for like $20+ so returning it is just kind of a pain. Maybe I will see if RadioShack has one and I'll try it and just return it if there is no difference.

This is the unit I bought:
http://www.amazon.com/Analog-Digital-Audio-Converter-Adapter/dp/B005F20756/ref=cm_cr_pr_product_top
post #4 of 8
Quote:
That device appears to be made specifically for converting analog line-level input to 2 channel LPCM digital output. Analog to digital. Are you sure it is supposed to work the other way, too? If not, it might still be working for you, just not too well, as it is not made to do that.

Maybe this will work better. Digital to analog.
http://www.amazon.com/Digital-to-Analog-Audio-Converter/dp/B002KY4SQ6
post #5 of 8
Hi Reminisc,

Are you sure that is the unit? Could it be THIS one? They look identical.

As Sivadselim said, the unit you linked to converts in the opposite direction. You shouldn't hear anything from it.

I've used a similar unit, and it worked fine. But the issue with those low-cost imports is that quality-control barely exists.

EDIT:
Here is the Radio Shack equivalent.
Edited by MarkHotchkiss - 4/24/13 at 9:19pm
post #6 of 8
Quote:
Originally Posted by reminisc3 View Post

Hey all,

Here is the situation. I have A) An old surround system that only inputs and outputs LINE audio. I also have a 46" Philips that (unfortunately! only outputs audio via digital coaxial or toslink.

So I bought this small powered converter unit that converts digital coaxial to line audio. I interfaced it with the old surround unit and I get volume but it is pretty low.

I have the volume maxed out on the unit and I still can't get that loud 'in your face' booming sound. If I play a CD through the unit, it sounds great!

My guess is that the TV is sending a weak signal to the unit. Does there exist any possible way I can amplify this signal before it hits the surround unit?

More likely would be that the converter is receiving an adequate digital input, but that its analog output is relatively low. Looking at the online documentation for it, I find no specifications relating to this. The converter may not be defective, but merely malassigned.

Consumer audio gear lacks standards for analog signal voltages. For example European audio gear DIN connector inputs is often about 5 times more sensitive than other inputs via RCA jacks.

If you find a device like this with a specification for analog output with a full scale digital input, you are probably looking for something around 1 volt.
post #7 of 8
It is amazing that there is ANY output, since it is the wrong device and you are using it backwards. It is the wrong type of converter.

It is for converting analog to digital, not the reverse.

You need a converter that converts a TOSLINK input to analog output signals, such as the Fii0 D3, which you can get at Amazon for $25.

You can probably return the one you got if it is still within Amazon's time limit for a return.

Quote:
Originally Posted by reminisc3 View Post

The volume does not change on the surround unit when changing the TV volume. So the output must be isolated.

Nonetheless, not the answer I wanted to hear frown.gif I ordered the converter unit on Amazon for like $20+ so returning it is just kind of a pain. Maybe I will see if RadioShack has one and I'll try it and just return it if there is no difference.

This is the unit I bought:
http://www.amazon.com/Analog-Digital-Audio-Converter-Adapter/dp/B005F20756/ref=cm_cr_pr_product_top

Edited by commsysman - 4/25/13 at 6:59am
post #8 of 8
Quote:
Originally Posted by commsysman View Post

It is amazing that there is ANY output, since it is the wrong device and you are using it backwards. It is the wrong type of converter.

It is for converting analog to digital, not the reverse.

You need a converter that converts a TOSLINK input to analog output signals, such as the Fii0 D3, which you can get at Amazon for $25.

You can probably return the one you got if it is still within Amazon's time limit for a return.
redundant much? rolleyes.gif
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