Astro MixAmp Pro

[Spazturtle]

I was looking for a DAC that could take TOSLINK from my mac and turn it into 3.5mm

I wanted a DAC that had Dolby surround, so I could hear surround sound though my headphones.

I cam across this: http://www.astrogaming.co.uk/mixamp™-pro/3AM99-HBU9X-975.html

If I understand it correctly it can take in TOSLINK and out put surround 3.5mm.

Am I missing anything here? Would this be good buy?

My budget is around £100.

I use Fostex T50RP headphones.

 

[Spazturtle]

Seams it does, apparently the 2011 version is better then the 2013 version so I went with that.

 

[Syphon Filter]

For the MixAmp to run Dolby Headphone it needs to receive a 5.1 Dolby Digital signal over the optical connection. If you're feeding it with 2-channel PCM then it doesn't really work (it does but not properly as it doesn't have a full set of info).

What is your source? On board audio over optical? If so check that your system can do on the fly Dolby Digital encoding.

I've just gone through this and found that the drivers for my on-board audio DO NOT support real-time DDL encoding which means when I use my MixAmp (wireless from 2011) all I get is 2-channel audio up-mixed to surround which is NOT the same as Dolby Headphone working on a 5.1 Dolby Digital signal.

What I've ended up doing is going for a Sound Blaster Z and a new set of headphones (I currently have the Astro A40).

 

[Spazturtle]

As for as I know you only need DDL for games, normal 5.1 optical out will work for movies.

This is because movies and tv shows have each speaker on a different channel.

But games have to dynamically generate the sound in realtime.

My macbook pro 2011 has a mini toslink port hidden in the 3.5mm jack and can output 5.1 audio.

Should I want 5.1 in games, I would get a Creative Soundblaster X-Fi Surround 5.1 Pro which would work with both my PC and Mac.

I can't use PCI-e sound cards anyway on my PC. Then Intel Sandy Bridge CPU is shit at isolating noise on the PCI-e bus.

My 7990 would cause large amounts of noise in a pci-e sound card.


My setup will be Macbook -> Toslink -> MixAmp -> 3.5mm -> Headphones.

 

[Syphon Filter]

Ah I see...

Yes, so in that event what will happen is that any content that is already encoded as DDL or DTS should pass through to your optical output. Everything else will come out as 2-Ch PCM.

The MixAmp will ONLY decode DDL and 2-Ch PCM I believe. If you pass DTS you will get nothing but silence.

 

[Spazturtle]

Follow up:

Connected the USB from my Macbook Pro to the Mini USB on the Mix Amp, this powered it an enabled USB audio 2 channel.

Connected the Mini Toslink from my Macbook Pro to the Toslink on the Mixamp, this enabled 5.1 audio.

In Applications > Utilities open Audio MIDI Setup

Now if you want all Audio to go though the Optical then click on Built-In Output.

Change it to 48000.0Hz and 2Ch-32bit Float.

This means all audio will be passed though the optical port, when it detects 5.1 audio it will automatically change to Encoded Digital Audio.

It supports AC3 but not DTS.

When the DD light on the mixamp is on it will make all audio 5.1 even only 2Ch audio, this is not good but can be disabled by pressing the DD button to disable it and pressing it again to enable it.


Or

If you change Built-In Output to 48000.0Hz and Encoded Digital Audio only 5.1 audio will be passed though, and 2Ch audio will go over the USB connection.

If you do this you will need to tell apps which audio output to use, for example in VLC click Audio > Audio Devices > Built-In Output (Encoded Digital)

Then VLC will pass audio via the optical connection and you will be 5.1 audio.

You can convert DTS to AC3 so thats fine, but you won't get 5.1 in games.

The 5.1 quality depends on the source, if the source doesn't separate the channels well then it won't sound that good, but for most 5.1 it sounds very good.

It takes the sound out of your head and puts it where it should be.

Overall it is good, and works will with my Macbook Pro.