1000W Simple PA Amplifier

[wattaniya]

hi apex,
1-today i assembled ur ba1200, supply 50vdc, 2pair output.
i removed presets and put jumpers for bias and offset,
offset is 34mv.
soon i will post images,

2-in the protection board , i heated the 10k ntc and the relay goes off. (tik tik) sound coming . when i power off and again (on) the board same like tik tik sound coming, but when i power off and after 10 second i put (on) the relay is activate,
any reason for this?

 

[wattaniya]

1- i assembled ur ba1200, supply 50vdc, 2pair output.
i removed presets and put jumpers for bias and offset,
offset is 34mv.

tomorrow i will check with 110vdc .

2-in the protection board , i heated the 10k ntc and the relay goes off. (tik tik) sound coming . when i power off and again (on) the board same like tik tik sound coming, but when i power off and after 10 second i put (on) the relay is activate,
any reason for this?

 

[apexaudio]

1- i assembled ur ba1200, supply 50vdc, 2pair output.
i removed presets and put jumpers for bias and offset,
offset is 34mv.

tomorrow i will check with 110vdc .

2-in the protection board , i heated the 10k ntc and the relay goes off. (tik tik) sound coming . when i power off and again (on) the board same like tik tik sound coming, but when i power off and after 10 second i put (on) the relay is activate,
any reason for this?

Nice work,
Regards

 

[victoryz]

can i use njw0281g/njw0301g for d outputs with 0.47e emitter resisters?

 

[apexaudio]

can i use njw0281g/njw0301g for d outputs with 0.47e emitter resisters?

Yes

 

[wattaniya]

hi apex sir,
can u tell me how to bridge the ba1200?

 

[wattaniya]

can this amp bridge?

 

[wattaniya]

hi apex sir,
i supply 90 vdc, dc offset is 20mv.
both 10k resistors getting very hot,
my heatsink is getting very hot when the out in 35v ac.
i feed 100hz tone from my computer.

what is the output ac voltage for 8 ohm load when clips?

my 8 ohm dummy load.
1kohm x 125pcs x 5watt.

 

[apexaudio]

hi apex sir,
i supply 90 vdc, dc offset is 20mv.
both 10k resistors getting very hot,
my heatsink is getting very hot when the out in 35v ac.
i feed 100hz tone from my computer.

what is the output ac voltage for 8 ohm load when clips?

my 8 ohm dummy load.
1kohm x 125pcs x 5watt.

Output ac voltage at clip level is 5-10v under transformer voltage. With 2x35v ac transformer voltage output ac voltage when amp clip is about 28v ac.
Please share your PSU schematic.
Regards

 

[wattaniya]

my psu is smps 90vdc.

 

[wattaniya]

hi apex sir,
why the bias is so high?
because when i plug b500 with primary series bulp, the bulp is very little light,
but when i plug ba1200 with series bulp, the bulp glows brighter. amp is working, but heatsink is getting very hot when output ac 25v .

 

[apexaudio]

BD139 in bias circuit.

 

[apexaudio]

hi apex sir,
why the bias is so high?
because when i plug b500 with primary series bulp, the bulp is very little light,
but when i plug ba1200 with series bulp, the bulp glows brighter. amp is working, but heatsink is getting very hot when output ac 25v .

Replace 4k7 in bias circuit with 8k2...

 

[wattaniya]

which one is correct?
2k2 instead 3k3 and 1k instead 4k7?

now i have to disassemble whole board to replace bias resistor 8.2k.
lot of work.

 

[c08bm]

Both are correct, there are different transistors, first one is darlington, second is npn

 

[apexaudio]

BA2400

 

[wattaniya]

nice amp ba2400,
is it you manufacturing or custom built by you?
any other company providing the casing?

 

[wattaniya]

hi apex sir,
in my hand the 8.2k resistor not available, now i checked with 7.5k resistor, bias is ok,
92vdc power supply.
i feed 50hz sinewave and it clips 52v ac on output,
my 4ohm dummy load 250pcs x 1k x 5watts.

output transistors getting hot over 90degrees at 40v ac on out..

 

[DC sound]

BA2400

Hi Mr Miles, can you share the lay-out of the Amps inside?

 

[apexaudio]

Hi Mr Miles, can you share the lay-out of the Amps inside?

BA1200 X 2 with 2kW transformer are insaide.