CCS Biased Class A

[davidallancole]

I have been playing with this for a while. What do you guys think. I am going to go to work today to build it and see how it sounds.

 

[Tube_Dude]

I have been playing with this for a while. What do you guys think.

The CCS is biased at 6 amps?...

But, some like it hot ...😉

 

[davidallancole]

Not quite. In the simulation it draws 1.8 A. It puts 12 volts out nicely into 8 ohms, with a 1 V input.

 

[Tube_Dude]

Not quite. In the simulation it draws 1.8 A. It puts 12 volts out nicely into 8 ohms, with a 1 V input.

0,6 Volts (one diode drop ) across 0,1 Ohms is 6 Amps...me thinks...😉

 

[davidallancole]

You must have not noticed the 2.5k resistor after the diodes reducing the current.

 

[Tube_Dude]

You must have not noticed the 2.5k resistor after the diodes reducing the current.

That way your CCS is not thermally stable.

Why not simply , to use a 0,3 Ohms emitter resistor..

 

[davidallancole]

I built a rough one of these at work two weeks ago. That 2.5k resistor I used was a pot so I could adjust the bias current. The transistors are on some pretty big heatsinks. They barely come above room temperature.

 

[Tube_Dude]

I built a rough one of these at work two weeks ago. That 2.5k resistor I used was a pot so I could adjust the bias current. The transistors are on some pretty big heatsinks. They barely come above room temperature.

That's ok! ...🙂

 

[davidallancole]

I just ran some temperature simulations on PSPICE and it showed as it gets warmer the bias current dropped by a few milliamps.