With this circuit it is possible to retrofit Lake People and Violectric D/A converters with a USB input with 24 bit and up to 192 kHz. Here a "Tenor" chip-set is used, therefore this article is best suited for Windows applications. The USB type-B input can be used to connect a PC or Smart-Phone. It will be automatically detected as an audio device. The USB input is 2.0-compatible and needs a proprietary driver (for PC applications which can be found here in the downlowd area. Audio files are received whereas audio formats up to 24 bit with 44.1, 48, 88.2, 96, 176.4 and 192 kHz are supported. This item is best suited for Windows applications. For MAC OS the USB X-Mos variant is recommended. The following operating systems are supported: - Linux, - Windows XP, Vista, 7, 8, 8.1, 10 - Mac OS-X "Yosemite" or "El Capitan" (upgrade required) - Android devices from 5 upwards ("OTG" adaptor requiered) - I-phones from 5 ("Lightning to USB 3 Camera-Adapter" requiered) This USB input supports the so called "asynchronous" mode. The USB receiver is powered by the external device and is handling over the digital audio data by means of a transformer to the input circuitry of the following circuitry. This means that the external device and D/A converter are completly galvanically isolated to avoaid any hum or noise issues from the external device. Rretrofitting is easily done and consists of pluging and screwing. The installation manual can be mailed in advance on request.