amplifier circuit from eleccircuit.com

Thread Starter

ntetlow

Joined Jul 12, 2019
24
I tried to simulate the amplifier posted. below with ltspice.
It doesn't work. Can anyone say why? The centre line should be zero volts but is close to -38 volts!
It seems that the connection in the lower left corner between the MPSA06 transistor and resistor R24 is pulling the centre line voltage down
when it surely should not.
 

Attachments

AnalogKid

Joined Aug 1, 2013
8,100
It seems that the connection in the lower left corner between the MPSA06 transistor and resistor R24 is pulling the centre line voltage down
when it surely should not.
R23, R24, R16, and Q3 form a constant current source (along with the GND connection at the bottom of C3) that is the collector load for Q5. That all looks fine.

Note the square box at the bottom of C3. That usually indicates an unconnected pin or wire. Are you sure C3 is connected to GND? If it weren't (and there were no other problems), the circuit would revert to unity gain, not negative saturation, so it's probably not your main problem. Still, something to check.

ak
 

AnalogKid

Joined Aug 1, 2013
8,100
The power supplies limit the power into 8 ohms to something less than 90 W, but it looks like the current limiters come on at around 200 W. What are the design parameters?

ak
 

Ylli

Joined Nov 13, 2015
765
Specified a value for the Zener diode, and 'balanced' the VAS with it's CC source.
 
Top