Доброго времени суток форумчане, подскажите пожалуйста как переделать канал фет донного усилителя под другой транзистор? Я в этом не очень силен, нашел только вот что:
- Use a 2n5457 instead of the NTE452. It's available, cheap, and has low noise. The ones I have used have a Vgs(off) of ~1.5V and Idss of ~3mA. You should measure the Vgs(off) and ensure that it's at least 1.4V, or you will clip the input with a strong hit from humbuckers. Note that the pinout of this FET is different than that of the 452 - look at the datasheet.
- Drop the gate resistor from 1M to 10k.
- Remove the gate resistor bypass cap.
- Drop the source resistor to less than 1k. In my case, best bias was at 670R. I'd suggest using a scope to set the bias here.
- Raise the operating voltage to ~22V by changing the lower resistor of the divider to ~27k.
- Change the output level pot to 250K. I run this at about 3/4 for a strong boost over the normal input.
- Remove the source resistor bypass cap. It's not needed. With these values, this circuit will produce clean gain up to the voltage limit of the FET. Also, removing it removes phase shift, which makes it easy to set the bias by setting my scope in x-y mode and watching for departure from linearity.
- Optionally, add a 150pF cap on the input to simulate more Miller capacitance. This flattens out the response nicely.
На это ссылался EaNot с gtlab-а, там же он привел две ссылки
1и
2 только я не до конца понял как именно измениться схема.
Сообщение отредактировал berty: 13 октября 2011 - 02:54