how about bridge 2 lm7402 they can have +- 75v supply is that enough?
http://www.national.com/pf/LM/LM4702.html
but for low current output you would not use the transistors that they have in the datasheet
http://www.national.com/pf/LM/LM4702.html
but for low current output you would not use the transistors that they have in the datasheet
Operation
The maximum power of the amplifier is primarily set by the supply voltage (18V). The maximum output voltage is approximately 16V. With 8 ohm speakers, the power rating is 16 Watts per channel. With 4 ohm speakers, the power rating doubles (32W per channel). Continuous power output equals the peak power output since, except for the supply voltage, power supply is "over-dimensioned".
Each LM6171 opamp is able to deliver up to 150 mA of current, we have 6.6 Amps per channel.
With 16V output, the amp should drive loudspeakers down to 2.5 ohm. In this case, the output impedance effectively seen by each separate opamp is 44 x 2.5 + 10 = 120 ohms and does not represent a major problem (LM6171 is specified for impedances down to 50 ohms).
This amplifier uses 44 op-amps LM6171 in parallel
An externally hosted image should be here but it was not working when we last tested it.
more info A Precision Preamplifier-Power Amplifier System
Bazukaz said:I need an output voltage of around 200V Rms and very low current. I need it to drive audio signal
200 Vrms needs a power supply of +300Volt, 0 Volt and -300 Volt
I think you should forget Op-Amps
Think high voltage transistors or tubes for this.
Bazukaz said:I don't want to use output trannie generally,
so an Op-amp with high voltage transistor would be OK.
It could operate in class A mode, but where to find a schematic ?
Maybe an OP-amp with high volt transistor output stage.
You need a transformer with at least secondary 2x200 Volt, anyway.
And another trafo for OP-amp supply.
I can say for sure, you will not find any such schematic.
But if you tell exactly what you are trying to do,
maybe someone here could try to design a circuit for you.
I guess a few here know about high voltage circuits, for television.
A good Output Transformer to raise the voltage might be the best idea ....
Bazukaz said:Hi,
Is it possible to bridge more than 2 op amps , lets say , 8 ?
I need higher voltage and low current at output. I would use LM833 or similar op amps.
Yes, you can bridge more than 2, but you will need floating power supplies. For 4 op-amps bridged you will need two 'grounded' and two floating supplies. I don't think it is very good idea though.
regards
Hi,
Thanks a lot,
I am thinking about driving electro-static headphones directly with a transistor amp.I have found one circuit diagram for it .
Few questions :
Could take out first two op amps ? And substitute BUK456 with something else , like IRFBG30 ? What changes to other components may be required ?
Regards ,
Lukas
Thanks a lot,
I am thinking about driving electro-static headphones directly with a transistor amp.I have found one circuit diagram for it .
Few questions :
Could take out first two op amps ? And substitute BUK456 with something else , like IRFBG30 ? What changes to other components may be required ?
Regards ,
Lukas
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