Active DIs are fairly complex, require power (usually in the form of +48Vdc «phantom power»), and are ideally suited for hi-Z signals such as those from passive guitar and bass pickups. Max output level from balanced XLR before clipping: +4 dBu/1,2 volt over 1 kohm load. Apologies in advance if some of the maths becomes a bit baffling and causes more confusion rather than less. This is an original schematic, never seen before, of a h-end no feedback design. WM8740 in MONO To view the bottom of this simple board click here. Скачать статью в формате PDF Назад Условия статической устойчивости синхронного двигателя с постоянными магнитами Вперёд Конструктивно-технологические особенности MOSFET транзисторов Сообщить об ошибке.
The dynamic range could be increase using for the BUF634 a power supply near to +-18V. MEASUREMENT RESULTS Follows a new comparing table for these DAC chips about measurement results. The first order approximation suggests a 1:10 ratio would give us 5mV. Does that still hold true if we also consider the cartridge’s 5 ohm source impedance and the load impedance presented by the transformer? Other transformers There are lots of other good mic transformers with ratios around 1:5 which can be used backwards in 5:1 configuration for this DI-box design. One my friend (Mon) (different from both previous tests) with a lot of experience on music reproduction were present at the test.
These DAC chips does not have a current output so in mono configuration (differential) is necessary to add resistors on analog output to merge these. In the schematic there are 2k 1% but I have used a parallel of 2 x 4k 1% to reduce their inductance. The WM8740 have internal pull-up or pull-down resistors on configuration pins so are not necessary other external resistors. They sound good. A good passive DI will thicken and smooth the sound in a way that a transformerless, active DI will not. Follows some measurements with BUF634 or with a 2sk216 connected on transformer’s secondary to reduce output impedance and load headphones. Passive DIs are extremely simple, require no power, and are best suited for lo-Z inputs such as synthesizers and active pickups (however, they have been known to sound great on passive sources such as the «Billy Jean» bass line). Why Go Passive?