Poor sound from Macbook Pro via Total Bithead (Headroom) USB out

[Thomsen]

Hello, I am new to CA and the forum and I am not much experienced with computer and audiophile. I recently purchased a Macbook Pro and use it as a music server with my hifi or headphones.

I purchased the Total Bithead DAC/Amplifier by Headroom some time ago and used it with my pc laptop (before my macbook pro) via USB connection. It worked well. Now I try to use the Bithead DAC with the Macbook via USB connection but the sound is very noisy and not powerful. Using the headphone line out via DAC sounds much better and clearer. Now I am not sure if there is much difference between DAC and no DAC when using headphone line out?

Does the Bithead actually improve the signals coming from the headphone line out?

Is there something that can be done to use the Bithead via USB connection from my MacBook in good sound quality?

Thank you for any help and suggestions.

Thomsen

[DSJR]

Have a look at the HDD forum. In this case, there are many members using macbook pros as main sources and they should advise you best.

http://hddaudio.net/punbb/index.php

If you get a satisfactory outcome, perhaps you could tell us?

[Thomsen]

Thanks for the advice. I'll check the website and let you know the outcome.

Cheers, Thomsen

[Marco]

Hi 'Thomsen',

Welcome to AOS :)

Could you please pop into the Welcome area and introduce yourself to our community by supplying your first name, basic geographical location, system details and music tastes, as this is the requirement for all new members joining AOS.

Cheers! :cool:

Marco.

[roob]

Have you been in the Audio Midi section in Utilities and set the output to digital out also set sampling rates to 24 bit and 44.1 also make sure digital out is selected in System Preferences sound tab, if using usb then set the output to usb in Audi Midi etc
If you are using iTunes make sure volume control is up full and sound enhancer is not switched on.
My experience is that the optical out outperformed usb with a macbook into my dac.

[roob]

Update.
I have done a bit of Googling on you amp/dac, it does not have any digital inputs so you have to connect it via usb to your mac, connecting any other way will not improve the sound from your mac. Just make sure you have the Audio midi settings set as mentioned earlier. From what I have read don't expect to much of an improvement, it's good for ipod listening but not really for high end.

[Thomsen]

Hello,

Thanks for your tips and ideas. :) I tried the 2 USB ports on my Macbook with the DAC. One sounds a bit better than the other but compared to the headphones out both sound weaker.

I went to the Audio MIDI Setup section of my Macbook to change the settings. The DAC USB out I can only set 48 kHz/16 bit whereas the headphones out can be set up to 96 kHz/32 bit. But even when I set the USB and headphones out to the same settings, the headphones out sounds rounder, more powerful, and more detailed and I don't need a high end system to hear that.

So I assume that if I want to improve the sound from my macbook I need a better DAC. Or maybe the fire wire out would help?

Thanks again for help and comments.

Tom

[Vincent Kars]

I'm not an OSX user so I can't help you with the specifics.

When playing a song, the audio file is decoded into PCM.
This is the input of the internal DAC of the Mac.
The output of the DAC is beefed up by the internal headphone amplifier of the Mac.
If you connect your headphone to the headphone out of the Mac this is where you are listening to.
If you put the Bithead in between, you add a second amp to the circuit.
Of course the Bithead can't improve on the quality of the internal DAC/amp (sound card) of the Mac. It can only add more power.

You can set the bit rate of the headphone out because it doubles as an optical out.
You can use a (mini) Toslink cable to connect a DAC.
As you are using the analogue part, this setting won't have any impact.

In case of USB, the PCM audio is routed to a USB port.
This is of course digital.
If you connect the Bithead over USB, you are listening to the DAC and amp of the Bithead.
The sound card of the Mac is bypassed completely.

If the USB sounds 'weak', check the settings in the audio midi panel.
A good setup guide: http://www.ayre.com/usb-apple.htm

USB ports might make a difference as internally the DAC might share a hub with another device or is the single user of a hub.