For now, I will try this on myself, I will publish the graphs and the simulator settings, and hope for comments on how to improve the settings.
And 'Simulators are just that simulators', Nico, I totally agree, and it is also the reason that I was looking for help (on the simulation parameters). The numbers that I am getting are 'too good to be true' and if so should be distrusted.
But it’s all great fun
and maybe ‘Simulators are stimulators’ also 
What is this, a LDA? (low drop amplifier ), rail to rail within 97%
It took some doing, but it has been done, the ‘New class A’ is now running with 6 pairs of IRFP 9240/240’s, the bias current is set to 5.14Amp (857mA per device) good for 105Watt class A. power dissipation in each device is about 39Watt. Later I will show the new performance graphics, but first some absolute maximum values.
The graphics shows the amplifier running at absolute maximum output (there is some distortion showing up due to clipping in the driver stage). V(max) and V(min) on the output connector V(out) are at 43.61Volt (97% of the rail).
At V(pos) +45Volt, V(gen) 2.1752, R(load) 8Ohm
V(rsp) = 44.71Volt
V(nfb) = 43.76Volt
V(out) = 43.61Volt
), rail to rail within 97%It took some doing, but it has been done, the ‘New class A’ is now running with 6 pairs of IRFP 9240/240’s, the bias current is set to 5.14Amp (857mA per device) good for 105Watt class A. power dissipation in each device is about 39Watt. Later I will show the new performance graphics, but first some absolute maximum values.
The graphics shows the amplifier running at absolute maximum output (there is some distortion showing up due to clipping in the driver stage). V(max) and V(min) on the output connector V(out) are at 43.61Volt (97% of the rail).
At V(pos) +45Volt, V(gen) 2.1752, R(load) 8Ohm
V(rsp) = 44.71Volt
V(nfb) = 43.76Volt
V(out) = 43.61Volt
Attachments
The amplifier will not deliver more than the 5.14Amps until it goes into AB witch it will not (42Volt(peak)/8Ohm(load)=5.14Amps).
This is what I am thinking about (see the LA14-300 or LA15-300).
http://www.fischerelektronik.de/fischer/uploadfischerfcool/Fischer/D03_D.pdf
I'm sure they will be pricy
But it will do in 8Ohm
(5.14*.707)*(5.14*.707)*8 = 105.34Watt(rms).The simulation shows that the amp will deliver 10+Amps in 4Ohm and I did not test with lower loads, but I am sure (if the power supply will) it will, the Rds value is very low. But then it will be in class AB.
Hi Frank,
I looked at your old construction; it reminds me of the way Quad constructed their 405 amplifier: pretty compact, with bundles of all sorts of wire (signal, power supply...).
When you start constructing your new amp, give it a bit more space, and don't share all wires in bundles for the sake of a good look because there will be quite some capacitive coupling between these wires as long as they are not screened. This is what you don't see when simulating but might be the cause of HF oscillation, hum and so on.
Verslik je niet in de oliebollen!
I looked at your old construction; it reminds me of the way Quad constructed their 405 amplifier: pretty compact, with bundles of all sorts of wire (signal, power supply...).
When you start constructing your new amp, give it a bit more space, and don't share all wires in bundles for the sake of a good look because there will be quite some capacitive coupling between these wires as long as they are not screened. This is what you don't see when simulating but might be the cause of HF oscillation, hum and so on.
Verslik je niet in de oliebollen!
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The current commercial amplifier, see Signature Origin | Home of Signature Quality, is based on a current conveyor design that has not been published here. Maybe one day
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