QUASI Amplifier for Beginners

[A square]

hello sir ...

pls tel me how can i add clip led in my amp..??

 

[tantang]

Hello Mr APEX, i have many transistors PNP. What can be able modfication from emitor follower to colector fllwr this final.....???

 

[apexaudio]

hello sir ...

pls tel me how can i add clip led in my amp..??

Use this circuit

 

[apexaudio]

Hello Mr APEX, i have many transistors PNP. What can be able modfication from emitor follower to colector fllwr this final.....???

Do You want QUASI PNP output stage?

 

[sanju21]

thanks for the amplifier schematics. i am new to building amps.i have some queries
1 what are the rail voltages for driving 2 ohm load & using 4 pairs of o/p transistors per channel.what else i have to change.( i will be bridging two such channels to drive 4 ohm load ).
2. what will be resulting power in bridge mode when driving 4 ohm load

plz look at this link
http://www.electronica-pt.com/circuitos/en/audio-amplifiers/44-audio-amplifier-90-100w-with-2n3773.html
3. is the above ckt class b or class ab?
4. what is the differnce in qualitywise between the above design & ur design

plz dont be offended i am only a mechanical engineer
please reply to all my queries

 

[echobase]

The schematic that you mentioned, I did it and it goes out into smoke. I check and recheck with the schematic and the PCB layout, but is just didn't work. Try it for yourself! maybe you could get it right!

Best regard
Albert

 

[echobase]

I am now in the process of the making of the amplifier that shown in post #1. I'll post the result soon.

Albert

 

[echobase]

Is my bad





Is my bad not to include the images. So these are the images:

 

[djk]

I don't think the BD139/140 are rated at high enough voltage to work at ±65V, nor are the TIP 41C/42C.

 

[noobie]

mje15032/33=TIP???

I don't think the BD139/140 are rated at high enough voltage to work at ±65V, nor are the TIP 41C/42C.

for +-75 to 80v any substitute for mje15032/33?

 

[djk]

"for +-75 to 80v any substitute for mje15032/33? "

That's a pretty good part, and it shouldn't be too hard to find.

The NJW 0281/0302 would make a good substitute. The ON Semi price reference is $0.93 vs $0.61 for the MJE 15032/33.

http://www.onsemi.com/pub_link/Collateral/NJW0281-D.PDF

 

[AndrewT]

post228 will not be reliable with +-65Vdc.

Most of the transistors are the wrong type or wrong voltage rating.
The maximum voltage I would recommend is +-40Vdc.

 

[apexaudio]

I don't think the BD139/140 are rated at high enough voltage to work at ±65V, nor are the TIP 41C/42C.

Yes, but with MJEs will work at +/-65V, only I suggest 2N5551 instead BC546.

 

[AndrewT]

MJE350 are not the correct type for VAS duty.

 

[echobase]

I don't think the BD139/140 are rated at high enough voltage to work at ±65V, nor are the TIP 41C/42C.

Yap! you're right. it is 40V to be precise. Thanks for correcting.

Best regard

 

[djk]

"MJE350 are not the correct type for VAS duty. "

Sure, there are better types. Consider that it speeds up to 60Mhz around 20mA (use a heatsink), it may be adequate for this type of amplifier.

 

[boytaho]

driver

what do you think is the suitable driver for this amp on this site???
Crown - The Professional Choice

any suggestions?

 

[djk]

No T/S parameters that I can see.

 

[noobie]

pnp output

Do You want QUASI PNP output stage?

care to share your quasi pnp output.

thanks

 

[apexaudio]

care to share your quasi pnp output.

thanks

You can use same circuit for quasi pnp output, just replace all pnp transistors with npn and all npn replace with pnp, revert diode polarity and use revert +/- rail voltage polarity and you get quasi pnp amp.