Help the Apex 550W Class-B?!

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radio

radio

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Joined 2009
Hello all!
I want this amplifier 550W class-B to be processed into kalass-AB, and instead of diodes D3 (1N4148) and D4 (1N4148) for the bias, to put the transistor for bias, ... such as BD139 or similar?:(:rolleyes:
That's why people help you do that changes the pattern of this amplifier?
thanks
 

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NMOS

NMOS

Member
Joined 2010
radio said:
Hello all!
I want this amplifier 550W class-B to be processed into kalass-AB, and instead of diodes D3 (1N4148) and D4 (1N4148) for the bias, to put the transistor for bias, ... such as BD139 or similar?:(:rolleyes:
That's why people help you do that changes the pattern of this amplifier?
thanks
Click to expand...

please check amplifier basics knowledge....

this amp is working in class AB

but you can add class AB +B for more output power
 
radio

radio

Banned
Joined 2009
AndrewT said:
Radio,
if you don't know about ClassAB and ClassB biasing and can't determine how a Vbe multiplier works and why two diodes determine the existing bias, you should not be modifying any project.
Copy an existing working and proved project or learn how a circuit works.
Click to expand...

Its simple, a resistor from C to B about 1k and a 1k pot in series with a 220-500 ohm resistor between B and E. and a cap between C and E.
Adjust pot for around 50-75mA per output pair.
Says tekko ....?!
Cheers
 
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ostripper

ostripper

Member
Joined 2008
Regardless of what some may say , single pair MJE15032/33 should not drive more than 3 pair of BJT outputs. So , this is a bad design .. period. Besides that , no basestoppers , layout is not conducive to anything hi-fi. Slow down ... learn a bit more !!

For 500w/4R , you really need 6-8 pair depending on the SOA of the devices. At this power , a triple output stage is desirable , if not mandatory. Also , you would want your drivers to be outputs as well .... check out Rod Elliot's project 117 , this is the way !! LINK - Project 117
An externally hosted image should be here but it was not working when we last tested it.

PS - only use older slow devices with this circuit , for new fast ones - I am working on that now :D .

OS
 
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