High Pitch Squealing Sound from DAC

[ants]

Hoping someone can shed some light on the issue of a why I am hearing a high pitched squealing sound when trying to use the optical (toslink) input on my Audio Alchemy DAC-In-The-Box (an inexpensive DAC). All I want to do is connect my Apple TV's optical out or my TV's optical out to the DAC. Then run standard RCA cables from the DAC into my 2 channel amplifier.

 

However, regardless of whether the signal comes from the TV or the Apple TV, I constantly get a crazy high pitched sound. nothing else. Checked the Apple TV settings and the TV's audio settings, seems I have it set up correctly..but who knows.

 

Does anyone have any idea on a fix ? Are there incompatibility issues I am not aware of ?

 

cheers

Ants

[pacwin]

Hoping someone can shed some light on the issue of a why I am hearing a high pitched squealing sound when trying to use the optical (toslink) input on my Audio Alchemy DAC-In-The-Box (an inexpensive DAC). Does anyone have any idea on a fix ? Are there incompatibility issues I am not aware of ?

 

Toslink in theory is an ideal connection. In practice its not. You may need to try another cable preferably something with a hard tip and a firm connection. Of course it may be dusty dirty frayed or the unit may be faulty. Empirically swapping elements is the only option.

[CatManDo]

Are you sure you are outputting a PCM signal from these two devices?

 

Most hifi DACs don't accept a Dolby Digital signal and will make such a noise in that case.

 

Video playback devices and TVs usually have an option in the audio settings to choose between Dolby Digital and PCM at the digital output, and Dolby is generally the default, as most users connect them to a home theatre receiver.

[Julf]

Toslink in theory is an ideal connection. In practice its not. You may need to try another cable preferably something with a hard tip and a firm connection. Of course it may be dusty dirty frayed or the unit may be faulty. Empirically swapping elements is the only option.

 

A bad toslink cable should not cause "a squealing sound and nothing else". If things get that bad, you won't get signal lock at all.

[GrahamJohnMiles]

Are you sure you're not playing Kate Bush?

[Raym87]

Are you sure you're not playing Kate Bush?

A man after my own heart. Well said Sir. :-)

[ants]

Are you sure you are outputting a PCM signal from these two devices?

 

Most hifi DACs don't accept a Dolby Digital signal and will make such a noise in that case.

 

Video playback devices and TVs usually have an option in the audio settings to choose between Dolby Digital and PCM at the digital output, and Dolby is generally the default, as most users connect them to a home theatre receiver.

 

I've set Dolby Digital to off on the Apple TV and also tried turning the Apple TV's audio output from auto to 16-bit, no difference. Will try another firmer fitting cable and also try disabling the speakers on the TV.

[ants]

Are you sure you're not playing Kate Bush?

 

No, Klaus Nomi's Lightning Strikes !

[xyz]

If switching the cable dosen't work, try using a transport that the dac was designed for in the first place; a CD player. That will at least tell you if you have a compatability issue, or if the thing is broken. Does the AA have coax or i2s as well? If it does, I would try those too.

[ants]

Well I've tried different cables that lock into place and it does not work. I hear a faint audio signal when connecting the TV to the DAC but there's so much noise, it's unbearable. The Apple TV connection does not work at all. Oddly enough, it works when connecting my MacBook Pro via a mini-toslink (3.5mm mini connector) to toslink, however that's not how I want to use the DAC.

 

Will have to find another solution and DAC. thank you for the replies and suggestions.

 

cheers

Ants

[xyz]

It's a compatability or settings issue. Nothing is broken. You have conformation that the AA works when you use your computer as a transport. The AA is 2 channel stereo only. That means your computer was putting out a stereo data stream to the dac. I don't have an Apple TV so I checked their web site to see what types of audio formats it supports. I'm pretty sure all the formats listed weren't even out yet when your dac was made. So unless you can send the dac a redbook data stream, or trick the dac into thinking its getting a redbook signal (probably what you computer is doing if you are playing something other than a CD), its time to upgrade.

[ants]

Yes, the DAC works, the previous owner used the coax inputs but I only require the toslink. I purchased this DAC at a reasonable price, so will try to sell it or give it to someone who can use it. Might just get a simple optical to stereo audio converter from monoprice, that should do the trick.