superbridge ??

Stormo · 14th May 2004, 05:31 PM

Hi all,

What if i wanted to make a high power, bridged amplifier - could this outputstage work ?

I know a lot is missing, bias, feedback, thermal protection etc, but just for the idea ? How about it ?

Any comments ?

Kind regards,
Stormo

Holger Barske · 14th May 2004, 05:36 PM

I can't see any differences from the classical bridge amplifier approach. You are generating two signals with opposite phase to drive comlementary output stages with the speaker in between them. This is how each "normal" bridge amplifier works.

thanh · 15th May 2004, 03:04 PM

wow!I think your amp is normal bridge

jewilson · 15th May 2004, 03:34 PM

Bias stage needed......

Elso Kwak · 15th May 2004, 04:02 PM

Hi,
Sumo Nine seems to be a more clever design.

Centauri · 16th May 2004, 03:55 AM

This is fairly classic bridge designed commonly implemented in chip power amps. Has dissadvantages of (1) distortion generated in first opamp is increased by second opamp, and (2) output DC offset voltage of first amp stage is inverted by second stage. Thus in the event of a fault in upper section output transistors, the output DC voltage is inverted by the lower section, resulting in twice the destructive force to the load (your speakers). I prefer separate inverter stage as suggested by Stormo in the first post.

Cheers

djk · 16th May 2004, 04:31 AM

"This is fairly classic bridge designed commonly implemented in chip power amps. "

Name one using this circuit.

It doesn't work the way you think it does, its a Circlotron.

"Has dissadvantages of (1) distortion generated in first opamp is increased by second opamp, and (2) output DC offset voltage of first amp stage is inverted by second stage."

No one is holding a gun to your head, change the loop.

The X circuit (feedback scheme) from Pass will work well too.

Circlotron · 16th May 2004, 12:04 PM

Quote:

Originally posted by djk
It doesn't work the way you think it does, its a Circlotron.

So it is! Fancy me not noticing that...

See that it has NPN transistors on the bottom row as well as the top, but it's not a quasi-complementary. Also, on the lower power supply rail the main filter cap just to the left of the bridge rectifier is reverse polarity;

it should be positive to bottom as per the diodes feeding it.

johnnyx · 16th May 2004, 01:38 PM

There is another problem;
Inverting amp gain is 33k/1k
non - inverting amp gain is 1+33k/1k
So it's not exactly balanced as it stands, but it can be made to.

djk · 16th May 2004, 08:59 PM

"There is another problem;
Inverting amp gain is 33k/1k
non - inverting amp gain is 1+33k/1k
So it's not exactly balanced as it stands, but it can be made to."

Have no idea what you are looking at.

The schematic clearly shows 300R + 3K0 for the non-inverting half and 300R + 3K3 for the inverting half, 26.84dB of gain.

14th May 2004, 05:36 PM	#2
Holger Barske diyAudio Member Join Date: Jan 2001 Location: Ruhrgebiet	I can't see any differences from the classical bridge amplifier approach. You are generating two signals with opposite phase to drive comlementary output stages with the speaker in between them. This is how each "normal" bridge amplifier works. __________________ Best regards: Holger www.holgerbarske.com

15th May 2004, 03:34 PM	#4
jewilson diyAudio Member Join Date: May 2002 Location: Plano , TX	Bias stage needed...... __________________ Jim W.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

15th May 2004, 03:04 PM	#3
thanh diyAudio Member Join Date: Jan 2004 Location: ho chi minh city	wow!I think your amp is normal bridge

16th May 2004, 03:55 AM	#6
Centauri diyAudio Member Join Date: Jul 2003 Location: Newcastle, Australia	This is fairly classic bridge designed commonly implemented in chip power amps. Has dissadvantages of (1) distortion generated in first opamp is increased by second opamp, and (2) output DC offset voltage of first amp stage is inverted by second stage. Thus in the event of a fault in upper section output transistors, the output DC voltage is inverted by the lower section, resulting in twice the destructive force to the load (your speakers). I prefer separate inverter stage as suggested by Stormo in the first post. Cheers

16th May 2004, 04:31 AM	#7
djk diyAudio Member Join Date: Feb 2001 Location: USA	"This is fairly classic bridge designed commonly implemented in chip power amps. " Name one using this circuit. It doesn't work the way you think it does, its a Circlotron. "Has dissadvantages of (1) distortion generated in first opamp is increased by second opamp, and (2) output DC offset voltage of first amp stage is inverted by second stage." No one is holding a gun to your head, change the loop. The X circuit (feedback scheme) from Pass will work well too.

16th May 2004, 01:38 PM	#9
johnnyx diyAudio Member Join Date: Jan 2004 Location: manchester	There is another problem; Inverting amp gain is 33k/1k non - inverting amp gain is 1+33k/1k So it's not exactly balanced as it stands, but it can be made to.

16th May 2004, 08:59 PM	#10
djk diyAudio Member Join Date: Feb 2001 Location: USA	"There is another problem; Inverting amp gain is 33k/1k non - inverting amp gain is 1+33k/1k So it's not exactly balanced as it stands, but it can be made to." Have no idea what you are looking at. The schematic clearly shows 300R + 3K0 for the non-inverting half and 300R + 3K3 for the inverting half, 26.84dB of gain.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)