Simple Symetrical Amplifier - Page 40

Lazy Cat · 24th August 2011, 09:37 AM

According to my current needs and personal taste I will start to make something like this.

Nico Ras · 24th August 2011, 09:40 AM

Hi am most pleased with the L-MOSFET version and that is why I have not had any further contributions to the thread.

Those who want to run with the simplest of the suggestion would end up with an excellent product that will be very hard to beat.

I have compared to listening to the BJT version as well and cannot hear any difference that would make me prefer the more complex versions. The L-MOSFET version sounds absolutely superb, is unconditionally stable and currently used on 4 ohm speaker and 32VDC supply.

Kind regards

Nico

Nico Ras · 24th August 2011, 09:44 AM

Lazy Cat, well done, you have brought something superbly different to DIY audio, thank you.

Kind regards

Nico

Lazy Cat · 24th August 2011, 09:56 AM

My deepest gratitude for all your support Nico. I am pleased that you enjoy in music with your SSA amp.

Yes, two things I brought to this forum BIGBT and SSA front-end and some ideas how to implement these, that's all.

Best regards, Andrej

Lazy Cat · 10:54 AM

Quote:

Originally Posted by MiiB

One thing i have trouble seeing through is how to adjust the current through the input pair/cascodes

SSA front-end collector current:

Ic=Ie-Ic/β

Ie=((15V-0,6V-Re*Ie)/Rs)-((0,6V+Re*Ie)/(Rfo*Rfg/(Rfo+Rfg)))

Ic - desired cascode collector current
Ie - emitter current through input BJT
β - input BJT current gain
Re - input BJT emitter resistor
Rs - current supply resistor (resistor connected between 15V supply and emitter resistor)
Rfo - feedback resistor from OUT
Rfg - feedback resistor to GND

Simple as that.

MiiB · 24th August 2011, 10:46 AM

Thanks... I now run 3 mA through the input/cascode.. 20 mA through the VAS and 200 mA in the output sets...

Getting PCB's-done and will start assembling i app. 2 weeks time...looking forward...

AKSA · 24th August 2011, 10:54 AM

LC, you are being modest; no need for that, take a bow!!

I would say that your circuit is the fully complementary big brother to FetZilla, and one day I hope to compare the two.

I have a notion that the SE circuit will have higher even than odd order distortion.

Again, thank you,

Hugh

alex mm · 24th August 2011, 12:03 PM

......and now rev 1.5 for BIGBT variant ......

please check PCB for errors , not tested .
Alex.

Joachim Gerhard · 24th August 2011, 12:16 PM

Alex, so this is now schematic from post 217 ?

radio · 24th August 2011, 12:19 PM

Alex mm, well done!
By which schematic this was done PCB?
Regards

24th August 2011, 10:54 AM	#397
AKSA diyAudio Member Join Date: Sep 2001 Location: Melbourne, Australia	LC, you are being modest; no need for that, take a bow!! I would say that your circuit is the fully complementary big brother to FetZilla, and one day I hope to compare the two. I have a notion that the SE circuit will have higher even than odd order distortion. Again, thank you, Hugh __________________ Aspen Amplifiers P/L (Australia) www.aksaonline.com

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24th August 2011, 09:40 AM	#392
Nico Ras diyAudio Member Join Date: Nov 2005 Location: Amanzimtoti - East Coast of South Africa	Hi am most pleased with the L-MOSFET version and that is why I have not had any further contributions to the thread. Those who want to run with the simplest of the suggestion would end up with an excellent product that will be very hard to beat. I have compared to listening to the BJT version as well and cannot hear any difference that would make me prefer the more complex versions. The L-MOSFET version sounds absolutely superb, is unconditionally stable and currently used on 4 ohm speaker and 32VDC supply. Kind regards Nico

24th August 2011, 09:44 AM	#393
Nico Ras diyAudio Member Join Date: Nov 2005 Location: Amanzimtoti - East Coast of South Africa	Lazy Cat, well done, you have brought something superbly different to DIY audio, thank you. Kind regards Nico

24th August 2011, 09:56 AM	#394
Lazy Cat diyAudio Member Join Date: Sep 2007	My deepest gratitude for all your support Nico. I am pleased that you enjoy in music with your SSA amp. Yes, two things I brought to this forum BIGBT and SSA front-end and some ideas how to implement these, that's all. Best regards, Andrej

24th August 2011, 10:46 AM	#396
MiiB diyAudio Member Join Date: May 2005 Location: Denmark	Thanks... I now run 3 mA through the input/cascode.. 20 mA through the VAS and 200 mA in the output sets... Getting PCB's-done and will start assembling i app. 2 weeks time...looking forward...

24th August 2011, 12:16 PM	#399
Joachim Gerhard diyAudio Member Join Date: Mar 2009	Alex, so this is now schematic from post 217 ?

24th August 2011, 12:19 PM	#400
radio diyAudio Member Join Date: Oct 2009 Location: Bitola MACEDONIA	Alex mm, well done! By which schematic this was done PCB? Regards