500W PA amplifier with Limiter

[ElektronicarPG]

What is this last picture? Is it an amplifier? What kind it its?

 

[charlestpt]

What will happen when I change C5 from 470pf to 560pf in B500

 

[masood]

dear apex sir,
what are the wattage of amplifier used in big cinema theater ?can i look that type of system used in that.which type of transistors are used in that.thanks

 

[kamranyousaf]

Hi Nazirdigi
greetings did you manage to test your tef b500 heres the pcb
which schematic are you following
warm regards
andrew lebon

Great work sir...

 

[andrewlebon]

hi Nazirdigi
greetings something wrong with tef tried it today
warm regards
andrew lebon

 

[andrewlebon]

tef

Hi Nazirdigi
greetings please can you post which schematic you following
warm regards
andrew lebon

 

[wattaniya]

Hi Nazirdigi
greetings please can you post which schematic you following
warm regards
andrew lebon

hi andrew lebon,
i am following these schematic.

 

[wattaniya]

B500 TEF IN PROGRESS.

 

[wattaniya]

hi apex sir, pls help,
in b500 protection section can i connect 22k resistor to any one of the outputs of 1943 emitter.
in the image it connect to last output of 1943 emitter. is it possible?

can i use emitter resistor .22/5w instead .33/5w.?

 

[wattaniya]

hi apex sir,
can i test with two pairs of output with 50vdc in tef.

 

[wattaniya]

hi andrew lebon,
what kind of problem are u facing in b500 tef?
i also having problem with b500 tef.
1-when i adjust the 10k pot nothing will happen.
2-dc offset showing 50vdc (with 2 pair outs ,rail voltage 50vdc)
but no parts are burn.
when i switch on my primary 100w bulb is glows and slowly dimmed.

 

[44250]

i have reached to the 185 page and looked at all schematics before
but i haven´t seen anywhere 10k pot... Could you point me where to look or to put some schematics if you have time, please?

 

[andrewlebon]

Hi Nazirdigi
greetings where is the schematic with 10k preset 15k and 7.5k thats the schematic i want to see hoping you can post it
warm regards
andrew lebon

 

[wattaniya]

hi andrew lebon. and 44250,
check this,
http://www.diyaudio.com/forums/solid-state/162408-900w-h-class-pa-amp-limiter-206.html

 

[andrewlebon]

Hi Nazirdigi
greetings just take out BD681 and replace with MJE340 it will work tested it today
warm regards
andrew lebon

 

[andrewlebon]

Hi Apexaudio
greetings b500 TEF driver stage is working very good only problem when
volume control is fully closed hissing sound comes in speakers any way to make it less
on taking finger near NE5532 IC audio comes i think gain is to high otherwise audio quality is very good
warm regards
andrew lebon

 

[wattaniya]

Hi Nazirdigi
greetings just take out BD681 and replace with MJE340 it will work tested it today
warm regards
andrew lebon

hi andrew lebon,
good result.
1-i want to know what are the problem u faced before?
2-is my b500tef pcb layout correct?
3-which schematic u following?
4-how u adjust the bias? and bias voltage?
5-can u share pcb image of ur layout.

 

[wattaniya]

hi apex sir.
pls verify this,
so no need to bias,
so what is the bias voltage on the bias transistor?
is it any changes i have to make?
in the image, blue lines are between connections. u catch that.

 

[wattaniya]

hi apex sir pls help,
tef is working,
i adjust the 10k pot to 2vdc with 10r/10w resistor in rail.
below 2vdc cant adjust because 10k pot is minimum clockwise, if i turn to anticlockwise dc v is increasing, so how can i decrease dcv ? pls reply to this.

the bias transistor is bd681 not mje340.
in the image shows mje340.

 

[andrewlebon]

hi Nazidigi
greetings are you sure you are using BD681 on this pcb
warm regards
andrew lebon