I need a regulated solid state PSU to drive a preamp based on two 12AX7.
I need for a variable voltage because I have to try different settings.
My project is based on Marantz M7 that requires a 265V and 280V.
I'm looking for a very small ripple PSU project that use BJT or MOSFET.
Any suggestions ?
I need for a variable voltage because I have to try different settings.
My project is based on Marantz M7 that requires a 265V and 280V.
I'm looking for a very small ripple PSU project that use BJT or MOSFET.
Any suggestions ?
I'd go with the already mentioned TL783C if you have around 15 extra milliamps to spare. It is simpler to build.
As long as your source (unregulated B+) is 125 volts less than your wanted B+ out this is a very nice regulator.
As the input cap ramps up in voltage when you turn the PS on, the TL783C's output follows and it won't exceed the 125v max differential even with an output voltage of 270 volts...as long as the input voltage is below 390 volts.
The adjust resistor should be 82 Ohms, and for 270 volts out, an adjust resistor (or resistor string) of about 17.5k will do the trick. This adjust resistor/resistor-string will have to dissipate around 4 watts so it should be 10-12 watts or higher total total dissipation.
As long as your source (unregulated B+) is 125 volts less than your wanted B+ out this is a very nice regulator.
As the input cap ramps up in voltage when you turn the PS on, the TL783C's output follows and it won't exceed the 125v max differential even with an output voltage of 270 volts...as long as the input voltage is below 390 volts.
The adjust resistor should be 82 Ohms, and for 270 volts out, an adjust resistor (or resistor string) of about 17.5k will do the trick. This adjust resistor/resistor-string will have to dissipate around 4 watts so it should be 10-12 watts or higher total total dissipation.
Antonix said:
You can use the Supertex LR8N3 to provide base drive to a MJE3439 (although you should check the SOA to make sure that you aren't over-taxing the pass transistor.) The voltage on the device is set by the ratio of two resistors just as in an LM317 or TL783, but it will regulate to 450V.
I have a bunch of LR8N3's purchased from Mouser -- email me if interested.
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