They talk about vibrant soundstage and deeper blackness when describing the improved audio performance achieved by breaking the USB ground loop. So USB isolators/ground loop eliminators are extremely popular among audiophile and pro audio circles. According to my internet research, numerous issues involving artifacts and dynamic range of digital audio can be traced to USB ground loops. I learned that the USB ground loop problem existed after stumbling upon a number of pro audio websites and blogs that discuss this as a major problem in the recording industry. Additionally the locking tactile feel of a high retention industrial connector ensures proper insertion and prevents it from coming loose. Industrial strength connectors for general electronics applications are constructed with higher reliability contacts specified for at least 1,500 mating cycles. There are also multiple grades of connectors from cheap consumer types to heavy-duty industrial. While a Type B connector with the same pinout but different style is common for peripheral connection, the type of connector used by a SDR can vary in pinout, shape, and size between several standard types. The standard USB 2.0 connector at the host computer is Type A pin 1 = +5 VDC, pin 2 = D-, pin 3 = D+, pin 4 = ground. A high power USB 2.0 peripheral can draw as much as 500 mA (2.5 watts at 5 volts), while a USB 3.0 device may demand 900 mA (4.5 watts at 5 volts). A low power peripheral requires up to 150 mA of current (0.75 watts at 5 volts). The USB 2.0 high speed power supply voltage specification is +5 VDC nominal, +5.25 maximum, and minimum +4.40 at the peripheral to allow for voltage drop across the cable. If the host sends an instruction to the peripheral and it doesn't receive a reply in time due to excessive cable delay, then USB operation will fail. The cheapest USB 2.0 low/full speed cables aren't shielded, and may only consist of three wires, combining the data return line and power supply ground via the same wire - stay away from these! Maximum high speed cable length is specified at 5 meters to limit 'round-trip delay between host and peripheral. Cheaper cables may not have a black wire, instead using the shield as the power supply ground. The more expensive high-end USB 2.0 high speed cables are typically shielded, sometimes including a ferrite bead at each cable end for common mode choking of RF emissions. The differential data lines of the USB serial interface are green (D+) and white (D-). The power from the host is via red (+5 VDC) and black (ground) wires. The typical USB 2.0 high speed cable for connecting a SDR receiver peripheral to a host computer consists of four wires. Some of the extra wideband SDR's for FM broadcast spectrum capture such as the Elad S2 and S3 units may require USB 3.0 super speed. Software defined radio (SDR) receivers covering LW, MW, and SW, such as the Microtelecom Perseus and WiNRADiO Excalibur, typically require USB 2.0 high speed. USB 3.0 supports data transfer rates up to super speed, 3.1 to 10 Gbps, and 3.2 to 20 Gbps super speed plus. USB 2.0 can operate at low, full, and high speeds, but not all USB 2.0 devices are capable of high speed. The USB 1.1 data rate is specified for low and full speeds. USB data transfer rates, specified in bits per second (bps), are low speed 1.5 Mbps, full speed 12 Mbps, high speed 480 Mbps, super speed 5 Gbps, and 'super speed plus' at 10 to 20 Gbps. In other words, the USB connection can be safely plugged in and unplugged from the peripheral and host without powering down the device or computer. It's an internationally standardized specification designed for easy plug-and-play hot connection between peripherals and a host computer. USB Isolators/Ground Loop Eliminators for Software Defined Radio Applications USB Isolators/Ground Loop Eliminators for Software Defined Radio Applications
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