Join Date: Jun 2002
Location: Melbourne, Australia
Use power semi as low noise amp?
Years ago I read a construction article for a moving coil cartridge preamp and they made the statement that it was possible to use a power device (they suggested a 2N3055) as a low level low noise preamp because the current density in the die would be very low seeing you would only be trickling milliamps through it, not tens of amps like normal. This was said to contribute to very low noise performance. Do mosfets / hexfets exhibit this same quality? Does anyone have any experience that they would like to share?
The article did not pursue this approach; they went with about 10 paralleled BC549C's on the idea that the individual noise of each transistor is random and therefore not additive with the rest, in fact they tend to cancel somewhat, but the gain is ten times as high as one transistor (I think).
A thought just popped into my head... If a Hexfet is really jillions of paralleled cells then maybe, just maybe it would have super duper low noise performance as per the previous paragraph???