I continually research methods and products to improve sound quality, music server performance, and convenience all with audiophiles in mind. This research includes, among other things, talking to many manufacturers, engineers, dealers, and CA readers from around the globe. It's always nice to hear what other people are doing to improve their music listing experience. As some readers know I've been researching isolation devices to isolate the computer from audio components, shared power sources, and noisy switching power supplies. Like everything else in life I found there is more than one way to get the isolation job done. My conversations with engineers have ranged from those who recommend as much isolation as possible to those who recommend virtually no isolation other than what's built into the components. Using these conversations and my own searches I've put together a handful of products Computer Audiophile readers may want to investigate. As always, don't take any one person's word about the effectiveness or ineffectiveness of these products. Read information from as many sources as possible and try out the products for yourself if feasible.
HyperMac External Battery $200-500
This external battery connects to a MacBook / Pro via the laptop's standard power port. Using a HyperMac external battery enables the MacBook to remain disconnected from a wired power source for 30+ hours. There's nothing better at isolation than completely disconnecting from the wall outlet. This alleviates all possibilities of ground loops and power related computer noise getting into the audio system. I've done several listening tests and believe in my system running on battery power results in improved sound quality. I hear the improvement even though I have a dedicated power sub-panel and circuits for my listening room and a copper ground rod going directly into the earth from my sub-panel. The HyperMac batteries come in four sizes with varying watt-hour capacity.
Oyen Digital MiniPro Portable Hard Drives $100-245
I've been using an Oyen Digital MiniPro 750GB hard drive connected to my MacBook Pro for a few weeks. I have nothing but great things to say about this portable drive. I'm using a FireWire 800/400, USB model that receives power from a FireWire or USB port, or an external power supply. I power the drive via FireWire or USB (single USB port) without any issues. One great thing about this is it removes a noisy switching wall wart power supply from the system and keeps my music server completely isolated from the power source used by my audio system. Again, complete disconnection is the best isolation available. The Oyen Digital MiniPro portable series drives use all 2.5" (laptop) disks and range in size from 160GB to 1TB with speeds of 5200, 5400, and 7200 RPM. The smaller 2.5" disks use less power and produce less noise than standard 3.5" (desktop) disks. The solid aluminum enclosure is well built, looks nice, and dissipates heat first and foremost. The drive enclosure does heat up during periods of heavy use, but hopefully this means the enclosure is dissipating the heat well. The MiniPro series does not require a fan to stay within the specified operating temperature range. In addition to these nice features the MiniPro uses the Oxford 934 chipset (OXUF934SSA). More geeky audiophiles will realize the significance of this chipset. The 934 chipset is featured in many external drives used by engineers with applications like ProTools and Avid that have very exacting external drive performance requirements. The MiniPro series drives also spin up/down depending on the computer's status (awake or in sleep mode).
The drive works equally well on Windows and Mac platforms. I currently have music storage for a J River Media Center library and an iTunes library on the 750GB version. My complete library doesn't fit on this drive but a large number of my "most listened to" albums do fit on the drive. Maybe I need the 1TB version. I could also purchase a couple of these drives and daisy chain them together using this built-in capability of FireWire interfaces. During my review of the Weiss DAC202 I connected this drive to my MacBook Pro's FireWire 800 port and the DAC202 to this drive's other FireWire 800 port with a FW800/400 cable. I didn't experience any show stopping performance issues. I also brought this drive with me to local coffee shops and connected it to my MacBook Pro via FireWire while my Wavelength Proton was connected via USB. This is a great combination for the audiophile on the go.
NOTE: Oyen will release a USB 3.0 version of the MiniPro drives very soon.
Oyen Digital MiniPro Product Page Link
Opticis Optical USB Extender M2-100-XX $189-345
Opticis FireWire Repeater M4-200 $795 & Fiber Cable $35+
The next two products not only provide an additional layer of isolation they also enable USB and FireWire devices to be placed far beyond the limits of standard USB and FireWire cables. A few high end manufacturers have used the optical USB extender at audio shows with very good results. Using the USB extender with an asynchronous device is ideal because the clock is located after the signal has traversed the optical link, thus does not increase the jitter. The USB extender consists of four internal glass fiber cables with a single USB port on each end. The computer is totally isolated from the DAC and offers mmunity from EMI and RF signals, but there is no free lunch. The extender does require a small power supply on the DAC end of the cable. I talked to a couple well respected audio engineers who have used this device. One simply built a linear power supply to replace the stock switching supply. The other said the switching power supply was better than the power derived from the computer's USB port and was not a show-stopper. Opticis does offer a USB extender (M2-200-XX) with USB power eliminating the need for the external power supply but as I said there is no free lunch. This device removes the galvanic isolation between the computer and the DAC. Thus, it's only an extension not an isolation device. NOTE: These USB extenders are USB 1.1 compliant and will not work correctly with USB 2.0 devices.
The Opticis FireWire Repeater is somewhat simulate to the USB repeater but the cost is several hundred dollars more than the USB device. This repeater is RF and EMI resistant as it uses industry standard fiber optic cables with LC terminations. The FireWire repeater can be daisy chained in a number of configurations with optical cables up to 500 meters each. The FireWire repeater may require the included external power supply if the FireWire device opposite the computer requires bus power from the FireWire port and the built-in power indicator is not illuminated. The FireWire repeater is completely compatible with FireWire 400 and 800 chipsets. I haven't' used this device yet so I can't comment on any performance benefits or issues. This is simply an FYI to readers looking to try some possible system enhancements using solid engineering principles.
Both devices work with Most versions of Windows, Apple OS X, and Linux.
USB Optical Extender Product Page Link | USB Data Sheet PDF | USB Applications PDF
FireWire Repeater Product Page Link
<b>Baaske Network Medical Isolator 5kV MI 1005</b> $190
This last product definitely uses the belt and suspenders approach. It's built for the medical industry to filter out "leakage currents and voltages" over a standard copper based network. This network isolator is the only one I could find that is fully 10/100/1000 Gigabit Ethernet certified without cable length limitations. Even though twisted pair Ethernet cables have built-in galvanic isolation (belt) one never knows when they'll need up to 5000 volts of AC isolation (suspenders) <img src="http://images.computeraudiophile.com/graphics/2010/0705/me.png">. I believe the device is more beneficial for use with shielded Ethernet cables as the shield itself is not galvanically isolated. Use of shield cables is a rare occurrence in a home network.
Product Page Link | Additional Product Page Link
General Information PDF | Technical Information PDF
There you have it, a few products that have at least peaked my interest when it comes to isolating my audio components from my music servers. Fortunately most of these products are less expensive than the sales tax on many audiophile cables :~)
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