Amplifier with single 60v ps

[IRSound]

does anyone have a schematic for an amplifier that will work with single 60v power supply ?
something like this , but more output device and higher output power.

2N3055 Power Amplifier

[homemodder]

For higher output power youll need higher supply voltages for the same speaker impedance. More output devices at the same supply voltage will only improve the circuits linearity.

Electric power - Wikipedia, the free encyclopedia

Thats a nice single supply design BTW, with modern transistors it could be a very design.

[IRSound]

i want to used it for 2 ohm loads.
can i use 2 pair of 2SC5200 for output ? also using BD139-140 for driving stage ?

I've also find this on web : MJR7-Mk5 Mosfet Power Amplifier

[IRSound]

can i use 2 pair of 2SC5200 for output ? also using BD139-140 for driving stage ?

can anyone help me about that ?!

[john_ellis]

Hi
You should be able to use 2SC5200 outputs and BD139-BD140 drivers but why not use PNP output (2SA1943) for a complementary pair?

For 2 ohm load you will need at least two pairs in parallel to reach a maximum current of 30V (clipping) / 2 ohms=15A.

You will need, probably, a BD139-BD140 driver pair for each output pair. In principle a single driver pair should be able to drive two 2SC5200-A1943 outputs but at 300-400mA peak that's getting near their limit.

With two BD's the gain should be around 63 min at 300 mA (comfortable) so the VAS load stage should be at least 10 mA. I'd use 2x 1k load resistors in the bootstrap.

But you will also need a huge output capacitor if you are to get any decent bass. 1500 uF isn't enough for 8 ohms. As a minimum I'd recommend 22mF but you may need 47-100mF - do you really need AC coupling?

BTW the simple amp you referred to isn't good IMHO! Too big a Miller capacitor, unnecessarily high feedback resistors, but it is simple.

[John Luckins]

You could try one of the old Nytech designs. There's this one, the CA252 which runs off 60 volts

http://i869.photobucket.com/albums/a...chca252pwr.jpg

Their bigger amp the CPA602 uses 80v supply and T03 output devices but could be made to work on 60 volts quite easily. I have the circuit and board layout somewhere. Notice the clever AC only feedback around the output cap through R113.

John

[sgrossklass]

For a 2 ohm load, the output coupling cap would have to be in the order of 6800µ..8200µ at least, rated 63 V or higher. The amp may very well end up with more capacitance tied up there than in the power supply...

[nigelwright7557]

I would forget the 2n3055 amplifier and go for something more modern.
Also go for a split power supply to get rid of the output coupling capacitor.