500W PA amplifier with Limiter

[jalou1995]

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]

Originally Posted by 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.

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

[AndrewT]

Originally Posted by jalou1995

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]

Originally Posted by irvynejay

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]

Originally Posted by AndrewT

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]

Originally Posted by 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

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