opamp input based power amps

[sparkle]

i remember i found few years ago some amplifiers that have inputs based on opamp's .....also some of the opamps were bootstrapped to increase the voltage swing....

does anyone have high quality schematics of power amplifiers that have opamp in the input - preferably bootstrapped and they could have mosfets or bjt at the output doesn't matter....power needed 50-100W /8ohm....
regards
daniel

 

[sparkle]

 

[Symon]

Take a look at this

http://www.pi.infn.it/~federico/PSE.htm

 

[sparkle]

thank You Symon....

anybody else?

 

[Chucko]

QSC Audio uses NE5532 chips in the front ends of many of their PA style power amps. See the support area for PDF schematics.

 

[paulb]

http://sound.westhost.com/project76.htm

 

[Minion]

Or this one (18w into 8ohms or 30w into 4ohms)


http://www.redcircuits.com/Page1.htm


Or this one(10w):

http://www.redcircuits.com/Page61.htm

 

[AKN]

Hi,

See also this earlier thread

 

[Bone]

Here's one with PCB and alternative BJT and MOS versions - http://skory.gylcomp.hu/25wamp/25wamp.html
With the right heatsink you can get over 40w from one of these


Tony

 

[sparkle]

oh man - thank You all.....nice - a lot of nice schematics....
anybody else that have something nice to contribute here is very welcomed.....
thank You again...
high quality is my priority

 

[Christer]

Of course, there is the Alexander amp
http://www.analog.com/UploadedFiles...211.pdf&fterm=alexander&fterm=alexander&la=en

 

[Juergen Knoop]

or elektor pa-300
regards

 

[sparkle]

thanks guys - much appreciated....

 

[jerluwoo]

Thought this may be of interest.

 

[sparkle]

it is - thanks

 

[peranders]

http://www.audio-circuit.dk/LYNX_3-0_main.html
http://www.sjostromaudio.com/hifi_files/misc/AN211_better_text.pdf
http://sjostromaudio.com/_unsql/hifi/qrv03/index.html

 

[sparkle]

Thanks Per-Anders......your QRV can be adapted to be a power amp.....topology is what is interesting )
i completely forgot that you have nice projects there...
thanks

 

[unclejed613]

jerlwoo, you don't need to bring the center line back to the drivers. as a matter of fact, with the center line going back to the drivers, should you ever blow the amp up, guarantees the damage will include the drivers and VAS....

also.... is there any bias on this amp?

op amps make great input stages, as long as most of your voltage amplification comes later.... i like jerlwoo's op amp to VAS transition using common base.....

 

[jerluwoo]

this may give better "hifi" results as the first one is geared toward minimum disapation class b bass amp.

 

[djk]

Simple 100W amplifier.

http://www.qscaudio.com/support/library/schems/Discontinued/Series One/1100.pdf

They made this same amp up to 600W by just adding more output pairs and raising the supply voltage.