BitHead Headphone Amplifier
HeadRoom is a unique company that has been dedicated to improving the headphone experience by providing hi-end headphone solutions to audiophiles everywhere. Based in Boseman, Montana, HeadRoom offers a full range of headphone products that includes not only headphones, but the important electronics that drive them. Their latest product is the BitHead, which actually includes a USB 1.1 interface geared towards portable laptop computers. If you've ever listened to a laptop computer then you are probably aware of the rather poor sounding audio that is available at the headphone output. This poor sound is not only a result of the DAC (digital-analog converter), but can also be attributed to the poor drive circuit that follows the conversion. The BitHead can work as either a simple amplifier or can completely replace the laptop's DAC by using the USB interface built into this unit. The USB interface receives S/PDIF data from the source and converts the digital PCM stream into two channel audio. The BitHead design can use internal batteries for reduced noise or can simply power itself from the USB interface. The package includes a variety of different feet for various mounting options. Velcro stickers attach the unit to your laptop or other portable device. Rubber feet are also provided as another option. A USB cable and mini-stereo cable are included with the unit.
We then inserted the USB connection into the laptop and our Windows XP found the appropriate driver so that the digital audio could be sent directly to the BitHead, bypassing the laptop's DAC and analog electronics. This resulted in a much cleaner sound with greater detail. The downside was a decrease in the maximum audio level. We didn't find this to be problem with our in-ear Shure E3c earphones, but with the HD 555 headphones, users may want more volume. Much has to do with the impedance of the headphones as well as the design of the transducers. In the case of the E3c design, the efficiency is higher, but not quite up to the sound quality we experienced with the HD 555. In addition, the high sensitivity of the E3c's made background noise in the BitHead more apparent. Volume levels are also affected by the current battery state. Lower battery voltages will result in the signal reaching a maximum level and ultimately clipping and turning on the red LED. This happened to us during our review. However, with low ambient background noise the HD 555 headphones provided adequate audio levels and sounded great.
Plugging the analog input back into the BitHead immediately bypasses the active digital USB link and enables the analog connection. Doing so doesn't seem to affect the digital connection and the computer continues to recognize the USB link. We also ran through some tests with our Neuros Digital Media Player and the results were also positive, but not quite as drastic as with our laptop. However, the audio definitely improved when using the BitHead as an audio amplifier.
The sonic differences between the two BitHead models were subtle especially with our lower cost headphones. However, when using a pair of Sennheiser HD-600's, the difference between the two became somewhat more apparent with a smoother midrange revealed from the Total BitHead version. We feel that the Total BitHead will satisfy those audiophiles who want to squeeze the most out of their portable products. However, depending on the equipment used in the setup it may not be substantially different to justify the cost difference.
- Kevin Nakano
Sony - Vaio PCV-GRX550
|Review - At a glance|
Headroom - BitHead USB Headphone Amplifier |
BitHead Manual: PDF File
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