what does everyone think of this amp?

lt cdr data · 18th May 2005, 08:59 AM

here

http://img.photobucket.com/albums/06...hemy_OM150.jpg

MikeB · 18th May 2005, 09:44 AM

Hmm, i think it's not functional at all ?
The biasing in the outputstage is not defined at any point,
collectors from predrivers connected to base of drivers
without any resistor defining a voltage ?
Also, i can't see how the vbemultiplier should work ?
Is the schematic incomplete ?

Mike

lt cdr data · 18th May 2005, 10:09 AM

hi Mike I think its complete, q208 is output biasing/vbe.

q216 is the pre driver, the collectors are obviously the voltage amplifiers

MikeB · 18th May 2005, 10:26 AM

But how should q208 set anything through the diodes which are closed ?
These collectors can't make any voltageamplification, they can only
supply full voltage (minus vce-sat) , then they enter reversebias.
So you supply near full railvoltage to the base of the drivers, blowing them up ?

Mike

Workhorse · 18th May 2005, 10:27 AM

Quote:

Originally posted by lt cdr data
hi Mike I think its complete, q208 is output biasing/vbe.

q216 is the pre driver, the collectors are obviously the voltage amplifiers

There is no collector resistor defining the pre-drivers as voltage amplifiers and nor is the VBE multiplier is adequately implemented.

The schematic lacks major key factors to act as an amplifier, is it really complete or you might forget something to draw.

sajti · 18th May 2005, 10:46 AM

Quote:

Originally posted by MikeB
Hmm, i think it's not functional at all ?
The biasing in the outputstage is not defined at any point,
collectors from predrivers connected to base of drivers
without any resistor defining a voltage ?
Also, i can't see how the vbemultiplier should work ?
Is the schematic incomplete ?

Mike

I agree. This schematic doesn't work. There are some missing connection, and/or missing parts.

I think that the anode of the CR202 should be connected to the collector of Q210 and 212, and the cathode of the CR203 should be connected to the collector of the CR211 and 213.
With this modification the bias will works, and I think the amp too.

sajti

destroyer X · 18th May 2005, 07:20 PM

The circuit is interesting.... and will work...some small changes only.

Carlos

mashaffer · 18th May 2005, 07:44 PM

Hi Carlos,

I have been away for a while. Good to see you are still here.

mike

destroyer X · 18th May 2005, 11:21 PM

Good old guys...always good to see them here...i miss a lot of them..... halojoy too.

regards,

Carlos

jacco vermeulen · 19th May 2005, 08:39 AM

At last, he is back.

Help me, Carlos, because you were gone they have been picking on the words in my posts.

18th May 2005, 08:59 AM	#1
lt cdr data diyAudio Member Join Date: Dec 2003 Location: earth	what does everyone think of this amp? here http://img.photobucket.com/albums/06...hemy_OM150.jpg

18th May 2005, 07:20 PM	#7
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	Remove diodes, and bias will work! The circuit is interesting.... and will work...some small changes only. Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!

18th May 2005, 07:44 PM	#8
mashaffer diyAudio Member Join Date: Jun 2004 Location: Indiana	Hi Carlos Hi Carlos, I have been away for a while. Good to see you are still here. mike

18th May 2005, 11:21 PM	#9
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	I am still happy to see you here. Good old guys...always good to see them here...i miss a lot of them..... halojoy too. regards, Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!

19th May 2005, 08:39 AM	#10
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, just under Rotterdam	At last, he is back. Help me, Carlos, because you were gone they have been picking on the words in my posts. __________________ Looks like Sponge Bob has killed another thread.


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18th May 2005, 09:44 AM	#2
MikeB diyAudio Member Join Date: Apr 2004 Location: Gütersloh	Hmm, i think it's not functional at all ? The biasing in the outputstage is not defined at any point, collectors from predrivers connected to base of drivers without any resistor defining a voltage ? Also, i can't see how the vbemultiplier should work ? Is the schematic incomplete ? Mike

18th May 2005, 10:09 AM	#3
lt cdr data diyAudio Member Join Date: Dec 2003 Location: earth	hi Mike I think its complete, q208 is output biasing/vbe. q216 is the pre driver, the collectors are obviously the voltage amplifiers

18th May 2005, 10:26 AM	#4
MikeB diyAudio Member Join Date: Apr 2004 Location: Gütersloh	But how should q208 set anything through the diodes which are closed ? These collectors can't make any voltageamplification, they can only supply full voltage (minus vce-sat) , then they enter reversebias. So you supply near full railvoltage to the base of the drivers, blowing them up ? Mike

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