OPAMP with Transistor Output

polsol · 9th September 2004, 09:12 AM

Anyone any recomendations for a power amp using low power op-amps driving conventional transistor)s) output stage?
Links to any available designs would be much appreciated.

Regards,

mik · 9th September 2004, 10:24 AM

http://audio.lukar.net/forum_wpisy.h...mat=5755&all=1

http://shell.sinuspl.net/~igod/pdf.zip_ password is abcd1

mandat · 9th September 2004, 11:08 AM

Here you are the recent address of this forum.

http://www.audiostereo.pl/forum_wpis...mat=5755&p=5#k

When you want to know another projects of this author press the links below.
http://www.q-audio.pl/
http://q-audio.dis.pl/gallery/

li_gangyi · 9th September 2004, 11:29 AM

maybe you guys read the question wrongly...but he wanted BJTs as outputs...not MOSfets...hmmm but it does seem interesting though...there were some posts by Circltron on Current damping afterburners on Power opamps...

mandat · 9th September 2004, 11:44 AM

>li_gangyi
Hey Mr, look at the gallery and you find such a project, too.

li_gangyi · 9th September 2004, 12:08 PM

since we're on this topic...I wanted to ask if there is any possibility of power outputs of over 200W...into 4 ohms that is...using this kinda configuration...

mandat · 9th September 2004, 02:13 PM

Specification of the amp mentioned by mik.

PSU: +/- 28V,
gain: +41V/V
load: 4 Ohm
quiscent current:120mA
THD+N: 0.008% (22Hz to 22kHz, P =1 to 10W)
THD+N: 0.014% (22Hz to 22kHz, P = 11 to 40 W)
THD+N: 0.6% (22Hz to 22kHz, P = 41 to 75W)
SR: +22/-18V/us

About a specification of other amps from mentioned gallery you should mail to dariuszkulesza@wp.pl

polsol · 11th September 2004, 05:39 AM

Thanks for the info. Unfortunately i don't speak Polish but have still managed to glean some info.
I have also found an Amp on the ESP site plus "Op-Amp Boosters" are also covered in an application note on the National Semiconductor site plus I found an old JLH reference in his articles in ETI 1986 (from memory).
As for power output, this is limited by the drive capability of the opamp (available output current and voltage swing) i would imagine.
The reason for looking into this aspect of amp design is that I'm not too happy with trying to use a "one chip" power amp as i don't think that the thermal properties of the chip/heat sink would be too good and BJT's should be better. Also using a "front end" of known characteristics allows one to then look at the ouput current gain topology more closely.
Regards

tino96 · 8th February 2007, 02:47 PM

Quote:

Originally posted by mandat
Here you are the recent address of this forum.

http://www.audiostereo.pl/forum_wpis...mat=5755&p=5#k

When you want to know another projects of this author press the links below.
http://www.q-audio.pl/
http://q-audio.dis.pl/gallery/

damn.. q-audio links are both dead....
I've found new realase of project.
unfortunately I don't speak Polish...
someone have info, PCB and docs about this very interesting project?

tino96 · 8th February 2007, 03:56 PM

re-arranged...: good http://forum.akustyka.info/viewtopic...hlight=drakula

9th September 2004, 09:12 AM	#1
polsol diyAudio Member Join Date: Aug 2004 Location: Cape Town and Kuwait	OPAMP with Transistor Output Anyone any recomendations for a power amp using low power op-amps driving conventional transistor)s) output stage? Links to any available designs would be much appreciated. Regards, __________________ Tony M

9th September 2004, 11:29 AM	#4
li_gangyi diyAudio Member Join Date: Jun 2003 Location: Woodlands Circle	maybe you guys read the question wrongly...but he wanted BJTs as outputs...not MOSfets...hmmm but it does seem interesting though...there were some posts by Circltron on Current damping afterburners on Power opamps... __________________ Kids in the back seat cause accidents...Accidents in the back seat cause kids...

9th September 2004, 12:08 PM	#6
li_gangyi diyAudio Member Join Date: Jun 2003 Location: Woodlands Circle	since we're on this topic...I wanted to ask if there is any possibility of power outputs of over 200W...into 4 ohms that is...using this kinda configuration... __________________ Kids in the back seat cause accidents...Accidents in the back seat cause kids...

11th September 2004, 05:39 AM	#8
polsol diyAudio Member Join Date: Aug 2004 Location: Cape Town and Kuwait	Thanks for the info. Unfortunately i don't speak Polish but have still managed to glean some info. I have also found an Amp on the ESP site plus "Op-Amp Boosters" are also covered in an application note on the National Semiconductor site plus I found an old JLH reference in his articles in ETI 1986 (from memory). As for power output, this is limited by the drive capability of the opamp (available output current and voltage swing) i would imagine. The reason for looking into this aspect of amp design is that I'm not too happy with trying to use a "one chip" power amp as i don't think that the thermal properties of the chip/heat sink would be too good and BJT's should be better. Also using a "front end" of known characteristics allows one to then look at the ouput current gain topology more closely. Regards __________________ Tony M

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9th September 2004, 10:24 AM	#2
mik diyAudio Member Join Date: Dec 2001 Location: Serbia	http://audio.lukar.net/forum_wpisy.h...mat=5755&all=1 http://shell.sinuspl.net/~igod/pdf.zip_ password is abcd1

9th September 2004, 11:08 AM	#3
mandat diyAudio Member Join Date: Oct 2003 Location: Gliwice	Here you are the recent address of this forum. http://www.audiostereo.pl/forum_wpis...mat=5755&p=5#k When you want to know another projects of this author press the links below. http://www.q-audio.pl/ http://q-audio.dis.pl/gallery/

9th September 2004, 11:44 AM	#5
mandat diyAudio Member Join Date: Oct 2003 Location: Gliwice	>li_gangyi Hey Mr, look at the gallery and you find such a project, too.

9th September 2004, 02:13 PM	#7
mandat diyAudio Member Join Date: Oct 2003 Location: Gliwice	Specification of the amp mentioned by mik. PSU: +/- 28V, gain: +41V/V load: 4 Ohm quiscent current:120mA THD+N: 0.008% (22Hz to 22kHz, P =1 to 10W) THD+N: 0.014% (22Hz to 22kHz, P = 11 to 40 W) THD+N: 0.6% (22Hz to 22kHz, P = 41 to 75W) SR: +22/-18V/us About a specification of other amps from mentioned gallery you should mail to dariuszkulesza@wp.pl

8th February 2007, 03:56 PM	#10
tino96 diyAudio Member Join Date: Mar 2003 Location: .	re-arranged...: good http://forum.akustyka.info/viewtopic...hlight=drakula

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