The Amplifier I Want to Make

[rose]

Hello，all

I want to ask you some advice or help for my amplifier.

I am interested in building a amplifier which is based on two darlington power transistor--TIP142 and TIP147. (This is the datasheet of TIP142 and TIP147: http://www.kynix.com/uploadfiles/pdf65976/TIP147.pdf ) Because It’s the cheapest 150 Watt amplifier circuit I can make. However,I am finding difficulty accepting the differential input should be driven between -45V and +45V. Meanwhile,I think that using PNP transistors for a differential input is quite uncommon today.

 

1) To meet my criteria I changed parts of the circuit so that the differential input is made of NPN transistors instead that are connected between 0V (common, ground) and the +45V.

2) The output stage has also been modified so that R3 and R5 are on the negative side of the supply (-45V). I moved the driver transistor Q3 to the other side, that is, the +45V making sure to keep the same resistor values. Naturally, Q3 has been replaced by a PNP transistor.

3) In the input stage, differential input, the signal ground has been made the same as that of the differential input stage.

 

I am attempting to build the amplifier with my modifications.Do you have any suggestions to give me?

Best wishes~

[djk]

Put up a link to your schematic.

[NOSValves]

You might want to move this thread to the Solid State or technical forum. Since they implemented all the various sub forums for SS and tubes the once mighty 2 channel area is a ghost town.... as DJK states a schematic is going to make it much easier for him help you.