900W H-class PA Amp with Limiter

[andrewlebon]

hi apexaudio

greetings today powered amplifier on series bulb is glowing
` very weak audio voltage seem's to be collapsing both high and low can u please give some tips on how to find faults

thanking you
Andrew lebon

 

[engel dela pena]

hello friend
please post again picture in much better color, more light

 

[apexaudio]

hi apexaudio

greetings today powered amplifier on series bulb is glowing
` very weak audio voltage seem's to be collapsing both high and low can u please give some tips on how to find faults

thanking you
Andrew lebon

I can't see all conection from PSU, do you conect GND from PSU to input GND with separate wire? Do you have wire jumper on coper side pcb? Can you post lighter picture.
Regards

 

[Gitsa]

Hi, Your version of pcb available?

 

[apexaudio]

Hi, Your version of pcb available?

APEX H900 pcb is in post #297

 

[Gitsa]

Here are gathered on your PCB

 

[apexaudio]

Here are gathered on your PCB

Fan must be for 24V, TL084 can be used instead TL074, some transistors was replaced?

 

[eesbiboi]

apex,

apex,

sir, without the presence of NSL32 on board, replaced with a normal LED and LDR enclosed in a black pipe, can i add another LED in parallel as clip indicator???...that would be two LEDs, one as clip limiter and another is clip indicator...
tnx...

 

[Gitsa]

Fan must be for 24V, TL084 can be used instead TL074, some transistors was replaced?

Replaced some of the denominations;
2n5551-bc547
2n5401-bc557
bd139-2sd880
Control relay-2n5401-2sa1020

 

[apexaudio]

apex,

sir, without the presence of NSL32 on board, replaced with a normal LED and LDR enclosed in a black pipe, can i add another LED in parallel as clip indicator???...that would be two LEDs, one as clip limiter and another is clip indicator...
tnx...

Yes, but two LED in series not parallel.
Regards

 

[apexaudio]

Replaced some of the denominations;
2n5551-bc547
2n5401-bc557
bd139-2sd880
Control relay-2n5401-2sa1020

That's ok you know pins layout.
Regards

 

[apexaudio]

@andrewlebon

I can't see all conection from PSU, do you conect GND from PSU to input GND with separate wire? Do you have wire jumper on coper side pcb? Can you post lighter picture.
Regards

I can't see connection between HV GND and MV GND on PSU. Check PSU without connecting amp.

 

[eesbiboi]

apex,
sir will my psu rated 55vac 0 55vac @25amperes, 4 10,000uf/100v caps and 2 35amps diodes do the job for b500???...tnx...

 

[apexaudio]

apex,
sir will my psu rated 55vac 0 55vac @25amperes, 4 10,000uf/100v caps and 2 35amps diodes do the job for b500???...tnx...

Yes, but you need 4 35amps diodes or 35amps bridge recifer (gretz).

 

[engel dela pena]

apex,
sir will my psu rated 55vac 0 55vac @25amperes, 4 10,000uf/100v caps and 2 35amps diodes do the job for b500???...tnx...

maybe he means 35a bridge diode

 

[apexaudio]

maybe he means 35a bridge diode

Maybe for dual mono.

 

[eesbiboi]

apex,
engel,

what i mean was 2 35amps/400v bridge diodes...how much power would the amp give me???...tnx...

 

[apexaudio]

apex,
engel,

what i mean was 2 35amps/400v bridge diodes...how much power would the amp give me???...tnx...

400W on 4R load, 500W with 0,5% THD

 

[eesbiboi]

to achieve maximum 500w of power on 4r load, i must then raise my rail voltage up to +/-90vdc... or come up with a +/-70vac @ 25ampere transformer...

 

[apexaudio]

to achieve maximum 500w of power on 4r load, i must then raise my rail voltage up to +/-90vdc... or come up with a +/-70vac @ 25ampere transformer...

With 2X60vac you have 500W on 4R with 0,1% THD
+/-90VDC is for 650W on 4R, but I not recomended
2x70vac is out of safe operation