Need education on transistor output circuits

Ken Wright · 12th March 2004, 06:41 PM

I have worked with tubes and transistors all my life, but never really understood the common everyday transistor power output circuit. I need a source of design and repair theory for the single power supply circuit where the speaker takeoff point is set to half the supply voltage using feedback to the input. Just don't have a good working knowledge of the circuits. Can anyone recommend a good url or publication I could use to enlighten myself? Thanks, Ken

Nelson Pass · 12th March 2004, 09:58 PM

Well, if you want to start with the dumbest example, try a
Zen amp at www.passdiy.com

maylar · 12th March 2004, 10:10 PM

What is it that you need to understand? Some questions can be answered right here. If you want to design your own amplifiers, you need more depth of understanding than if you're just trying to fix a broken one.

My favorite book for generic transistor amplifier theory is the RCA Solid State Power Circuits Designer's Handbook, long out of print. If you search Amazon dot com you'll find hundreds of "how to" books for repairing electronics stuff.

Christer · 12th March 2004, 10:14 PM

Maybe a start could be to post a schematic of some amplifier
you want to understand but don't, and try to ask somewhat
more detailed questions referring to that particular schematic.
That might provide a good starting point for people to try helping
you. There are so many different topologies that seem to fit
your description, so the question is somewhat to vague and
general.

a31_ford · 13th March 2004, 01:06 AM

Here, lets talk about this one, 400watts a side RMS into 4 ohms, a very common comercial power amp.

have a peak !

andy_c · 13th March 2004, 01:27 AM

Quote:

Originally posted by Ken Wright
(...)I need a source of design and repair theory for the single power supply circuit where the speaker takeoff point is set to half the supply voltage using feedback to the input.(...)

Ken,
Try this 1967 article by Bart Locanthi, the original designer of the most commonly used bipolar power amp output stage, originally called the "T circuit":

http://users.ece.gatech.edu/~mleach/.../tcir/tcir.pdf

Also see this page for schematics and detailed circuit description of a DIY amplifier that people have been building since the mid '70s.

http://users.ece.gatech.edu/~mleach/lowtim/

Nelson Pass · 13th March 2004, 05:08 AM

Jeez, why don't you hand this guy a vurrent Levenson circuit
and give him a heart attack?

lucpes · 13th March 2004, 08:25 AM

You may find these a good read:

http://www.iirg.org/ticom/neets/

especially module 7 & 8 for SS & basic amplifier circuits.

thanh · 13th March 2004, 11:46 AM

about feedforward ,please!
thanks a lot!

till · 13th March 2004, 12:58 PM

Quote:

Maybe a start could be to post a schematic of some amplifier

a detailed diskussion of every parts function in alephx would befine

12th March 2004, 06:41 PM	#1
Ken Wright diyAudio Member Join Date: Mar 2004 Location: Roanoke, Va	Need education on transistor output circuits I have worked with tubes and transistors all my life, but never really understood the common everyday transistor power output circuit. I need a source of design and repair theory for the single power supply circuit where the speaker takeoff point is set to half the supply voltage using feedback to the input. Just don't have a good working knowledge of the circuits. Can anyone recommend a good url or publication I could use to enlighten myself? Thanks, Ken

12th March 2004, 10:10 PM	#3
maylar diyAudio Member Join Date: Jun 2003 Location: Connecticut	What is it that you need to understand? Some questions can be answered right here. If you want to design your own amplifiers, you need more depth of understanding than if you're just trying to fix a broken one. My favorite book for generic transistor amplifier theory is the RCA Solid State Power Circuits Designer's Handbook, long out of print. If you search Amazon dot com you'll find hundreds of "how to" books for repairing electronics stuff. __________________ dave

13th March 2004, 01:06 AM	#5
a31_ford diyAudio Member Join Date: Feb 2004 Location: Manitoba, Canada	Here, lets talk about this one, 400watts a side RMS into 4 ohms, a very common comercial power amp. have a peak ! __________________ Greg, aka A31Ford Manitoba, Canada

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12th March 2004, 09:58 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	Well, if you want to start with the dumbest example, try a Zen amp at www.passdiy.com

12th March 2004, 10:14 PM	#4
Christer diyAudio Member Join Date: Sep 2002 Location: Sweden	Maybe a start could be to post a schematic of some amplifier you want to understand but don't, and try to ask somewhat more detailed questions referring to that particular schematic. That might provide a good starting point for people to try helping you. There are so many different topologies that seem to fit your description, so the question is somewhat to vague and general.

13th March 2004, 05:08 AM	#7
Nelson Pass The one and only Join Date: Mar 2001	Jeez, why don't you hand this guy a vurrent Levenson circuit and give him a heart attack?

13th March 2004, 08:25 AM	#8
lucpes diyAudio Member Join Date: Dec 2003 Location: Iasi	You may find these a good read: http://www.iirg.org/ticom/neets/ especially module 7 & 8 for SS & basic amplifier circuits.

13th March 2004, 11:46 AM	#9
thanh diyAudio Member Join Date: Jan 2004 Location: ho chi minh city	about feedforward ,please! thanks a lot!

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