Replacing IGBTs with BJTs in Elektor IGBT design!

[Shahriar]

Hi

I read Reviews about IGBTs, MosFETs and BJTs uses in Audio Power amplifiers.
I want to build the Elektor 50W Compact AF IGBT power amplifier. I want to replace IGBTs with BJTs.
I have two questions:

1- which components should I change?
2- What is the best BJT to use? (part Number)

P.S. I know how to replace it with MosFET. But I do not know about BJT replacement.

Here is the Original Design.
http://www.4shared.com/file/10820796/362d5b1f/CompactIGBTPowerAmp.html

Here another design with BJT from the same designer. maybe it could help. (I don't know the supply Voltages)
http://www.4shared.com/file/10820833/b7f40027/ne5534pa.html

ThanX
Shahriar

[audioguru]

Hi Shahriar,
The schematic with IGBTs is a fuzzy JPG file type and its details cannot be seen even when it is zoomed. It is too bad it wasn't saved as a very clear GIF or PNG file type.

The circuit in the 2nd schematic is unusual because its output transistors don't have emitter resistors.

[Shahriar]

The original design is from Elektor Magazine, may 1997issue
fortunately I have another schematic which a nice guy has redraw it.

http://www.4shared.com/file/10940178/f870121/giesigbt.html

The circuit in the 2nd schematic is unusual because its output transistors don't have emitter resistors

This designer have many designs that the output is connected to Power transitors Collector instead of Emitter via resistors. This is why there is no resistor.

ThanX
Shahriar

[audioguru]

Hi Shahriar,
Look in Google at Sziklai Pair to see the complementary transistors connected to operate like a high power single emitter-follower. Usually an emitter resistor is used to match the transistors at the top and at the bottom and for thermal stability to avoid thermal runaway.