• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

NPN only class AB power amplifier

Status
Not open for further replies.

Benito

New Member
I was wondering if it was possible to use two identical NPN transistors instead of an NPN-PNP pair.
I was thinking that if you could flip the signal, apply the original signal to one NPN and apply the inverted signal to the second NPN and gave both a slight bias current, you could do it.

I just wanted some feedback as to the feasibility of the idea.
If it won't work, I guess I'll order some PNP transistors or just make a class A amp.
Thanks in advance!


P.S. I'll add some schematics later if needed.
 
Last edited:

audioguru

Well-Known Member
Most Helpful Member
Quasi-complementary amplifiers were made in the 60's. I still have one. They used NPN output transistors and complementary driver transistors.

The MC3317x and MC3407x opamps have all-NPN outputs. The circuit is very complicated and relies on the good matching of the transistors and their matched temperature inside an IC.

Class-AB amplifiers use NPN and PNP complementary outputs. A class-A amplifier sounds the same but heats your entire neighbourhood.
 

crutschow

Well-Known Member
Most Helpful Member
The first circuit I saw of one was in the old GE Transistor Manual.

Here's an example Simple 60 Watt Power Amplifier.

Edit: I also built (and am using it now to power my PC speakers) a Dynakit Stereo 120 60W/channel stereo amp way back in the 60's which used a very similar circuit. Still sounds great.
 
Last edited:
Status
Not open for further replies.

EE World Online Articles

Loading
Top