500W PA amplifier with Limiter

[apexaudio]

Sir,do you have B500 layout in PDF??

Regards

B500 pdf

 

[QQ12e5k1]

B500 pdf

Thank you sir.

I want to make B500 with balance input but only use 3 pair of final transisitor.
How much bias and max voltage for it??

Regards

 

[viki_v2]

On the protect pcb where excatly does bd241c connect.

 

[jalou1995]

i would like to remove the LDR, i dont need the limiter. whats the value of the resistor that i will use in place for the LDR? im planning to bridge this.

 

[apexaudio]

i would like to remove the LDR, i dont need the limiter. whats the value of the resistor that i will use in place for the LDR? im planning to bridge this.

Use 33k

 

[QQ12e5k1]

Bias

I want to make B500 with balance input but only use 3 pair of final transisitor.
How much bias and max voltage for it??

Regards

 

[jalou1995]

Use 33k

thanks Apex

 

[apexaudio]

I want to make B500 with balance input but only use 3 pair of final transisitor.
How much bias and max voltage for it??

Regards

Set bias 25mA per outputs.
Regards

 

[mj777]

test voltage point?

Hello Sir Mile,

I have just finished to put components on my B500 board, right now I'm working with the protection circuit. i just want to ask about the key areas in the B500 schematic where I can test the voltage and the correct values that should be there?

I'm using a 10 Amperes, +/-50 volts AC and and in DC it's measuring on the multimeter around +/- 68 to 69 volts.

I'm using in R24 and R25: 2k2 2watts

Thank you in advance for the help that u can give.

regards,
mj777

 

[engel dela pena]

Use triple darlington topology and 8 pairs of outputs.

apex,
what would be the ideal bias for this 8 pair per output

 

[jalou1995]

power supply question

hey miles aka apexaudio, i want to use 40-0-40 transformer, how much ampere rating i should use for the transformer @ 2 ohms load and how much rms power it can deliver using this transfomer.

im expecting a rating 600w @ 2 ohms but not sure how much transformer amperes i should use. thanks

 

[viki_v2]

Hello,
I completed one channel of B500 Today,
Psu 37-0-37 3 Amperes.
Dc at out is 35mv.

The sound is very low, and very distorted.
I made connections as shown by mile.
Kindly Guide.

 

[irvynejay]

Hello,
I completed one channel of B500 Today,
Psu 37-0-37 3 Amperes.
Dc at out is 35mv.

The sound is very low, and very distorted.
I made connections as shown by mile.
Kindly Guide.

Did you connect input ground to psu? if not connect it

 

[AndrewT]

want to use 40-0-40 transformer, how much ampere rating i should use for the transformer @ 2 ohms load ................ expecting a rating 600w @ 2 ohms but not sure how much transformer amperes

The usual and best advice for selecting a transformer for an audio power amp is that the VA should be between one times the maximum power rating and two times the maximum power rating.
For 600W of maximum output power, you can use a 600VA to 1200VA transformer.
The amplifier will work if the transformer is smaller than 600VA and it will also work if the transformer is over 1200VA. Buy what you can afford and do ask what the regulation is. The lower the regulation, the "better" the transformer. The voltage sags less when the amp is asked to deliver current to the load.

 

[viki_v2]

Did you connect input ground to psu? if not connect it

Yes i did while testing.
Input gnd connected to psu gnd.
output gnd connected to psu gnd.

 

[jalou1995]

The usual and best advice for selecting a transformer for an audio power amp is that the VA should be between one times the maximum power rating and two times the maximum power rating.
For 600W of maximum output power, you can use a 600VA to 1200VA transformer.
The amplifier will work if the transformer is smaller than 600VA and it will also work if the transformer is over 1200VA. Buy what you can afford and do ask what the regulation is. The lower the regulation, the "better" the transformer. The voltage sags less when the amp is asked to deliver current to the load.

thanks andrew, do i need to add a few more trannies in this circuit so that it can handle loads @ 2 ohms?

theres a reason for me wanting to do this, i want to bridge this amp so that it can drive two subs rated 500w @ 8 ohms each using 40-0-40 VAC trasfo. In theory, if this amp can handle 600w @ 2ohms, bridging the amp could provide (fingers crossed) 1200w @ 4 ohms.

 

[bud17]

I have transformer 10A secondary voltage 45-0-45 (VAC) or 63-0-63 (VDC).
How many pair of output?

Thankyou.

 

[engel dela pena]

viki,
copper side must be clean,use acetone or laquer thinner and please make continuity check copper side mostly transistor pinning make shure nothing is shorted better remove all those flux.
and better find mylar caps instead of ceramic 100nf 47nf 100v

 

[viki_v2]

I am using low power transformer , could that be the reason.
I have checked the tracks continuity, Its fine.

 

[jalou1995]

viki,
copper side must be clean,use acetone or laquer thinner and please make continuity check copper side mostly transistor pinning make shure nothing is shorted better remove all those flux.
and better find mylar caps instead of ceramic 100nf 47nf 100v

to add pre: check for cold solders and transistor pins and shorts.