High voltage Opamp with power transistors

[sivan_and]

Hello all..
I have a couple of high voltage opamps like BurrrBrown 3583JM lying around..these r capable of high voltage upto (+) & (-) 140 volts and load currents upto (+) & (-) 75ma..i am thinking of adding some transistor drivres to boost current..the idea is to use as a sub amp with an output of around 200 to 300 watts...any suggestions ?
thx in advance

 

[sivan_and]

http://www.electro-tech-online.com/...ed-way-boost-op-amp-voltage-output-opampb.gif

 

[jaycee]

To be honest, by the time you have gone so far as to add the neccesary output stage to an opamp, you may as well have built a fully discrete power amplifier.

 

[east electronics]

come on guys ....

there is similar applications also related with lm 12clk .....

i wonder why they exist in the books ....there is got to be a reason

all these circuits look so simple to construct so if your target is simplicity ,power and average quality i dont see any reason why not ....

i dlike to work on this a bit more

i recall the lm12 application saying 90 volts swing and +- 10 amps ... thats a hell of a lot of power .....

i thing i will have to construct to see what is going on there

 

[east electronics]

many people seen

this but no replies ....

its been in the forum before ....i wonder why ???

 

[woody]

That circuite is not a power amp. It is intended to drive a 2,000ohm load not a loudspeaker. Few people need a line
stage that will swing that kind of voltage.

 

[av-trouvaille]

Hello,

Many years ago in the French diy magazine LED (now integrated with Electronique Pratique) there used to be a series of articles with such a design for power amplifiers. The high voltage IC directly drove one high voltage transistor or MOSFET (the ‘real’ class A, some say), which was biased by a currents source.
These designs were highly regarded for the way they sounded. On the site of Bonavolt there used to be a copy of such a design, but I did not visit it lately.

Best, Arjen.

 

[Juergen Knoop]

LM12 and LF357 are low voltage opamps.
How do their applications apply (LOL!) to the BB type? 😕
Those BBs are expensive. I would sell them.
Regards

 

[scott wurcer]

http://www.electro-tech-online.com/...ed-way-boost-op-amp-voltage-output-opampb.gif

That intermediate stage is full class B I don't think it would be too good for audio. These things are often used to drive electrostatic actuators.

 

[Juergen Knoop]

These things are often used to drive electrostatic actuators.

exactly what we used the BB for in the past. Then we switched to Apex which was cheaper.
regards

 

[bear]

There's a nice trick that was in a National or Signetics app note years ago that put the driver transistor's drive coming from the PS of the opamp - obviously driven by the current drawn... the output of the opamp was a resistor to ground... that was the input/VAS method... might work nicely here.

_-_-bear

 

[sivan_and]

Thats what am looking for...the high volt capabilities should be fully utilised.. its for sub-woof applications.

 

[ostripper]

Here is what might become my next sub amp.. only 7$
and it IS the highest voltage OP-Amp I have seen.
(+- 100V military version)...

An externally hosted image should be here but it was not working when we last tested it.

[Lm4702/lme49810]
With a standard EF output stage (2sa1837/2sc4793 driver - n/MJL X - 281/302 outputs ..even thermal-traks) a 25$
sub amp can be had.(125+W/8 - 200+W /4)

This is my next endeavor ,.."frugalamp 4" HT sub...
1 week into 2009 and all will be done..
OS

 

[sivan_and]

Dear "ostripper"
What r those 4 Series connected diodes inside the Output transistors...r they inbuilt diodes or externally placed close to the case...a sort of temp feedback the quiescent current ?