To People with OPA549 amps

[D_GR8_1]

I was thinking of doing a sub module with these chips because of their high voltage/high current ability.

Has anyone implemented this already?

The main question is what type of PSU will I need?

I have a 15-0-15/625VA toroid in a PSU that I am using to power car audio equipment. If I use this toroid, would this be sufficient?

The PSU will have +-21V/15A out of each rail!

[theChris]

note that car audio amps use SMPS which operate closer to 30,000 to 60,000 Hz, as opposed to the 50 to 120hz available from the wall outlets (120 is 60 on a full bridge rectifier). a benefit of high speed is that the size can be smaller, much smaller. the downside is hysteresis and switching loss.

however if you can use the car amp PSU properly and get the 15A 42V, then you are probably fine. you may want to use a regulator, though such is not needed.

[D_GR8_1]

sorry Chris, but I think you have misunderstood what I was trying to say. I said I have a 625VA TOROID in a PSU. Since when do SMPS come with TOROIDS?

The PSU I have is not SMPS, it is an analog PSU, good old TOROIDS!

however if you can use the car amp PSU properly and get the 15A 42V, then you are probably fine.

In Australia our cars run on 12V batteries and so do the Car Amps.

Why would I need 42V @15A?!?

Basically after rectification I will have 21V/15A per rail.

Is this good enough to power coupld of OPA549?

[theChris]

every real car amp i've seen uses a torroid in the psu, granted it is much much smaller due to high frequency usage (1-3" in diameter). still the defining shape of a toroid is present.

when you said it was to power car equipment i assumed it was run off a similar 12V SMPS. a 600+ VA toroid for use on mains will be fairly large, while a SMPS 600VA torroid will be smaller then a CD in diameter in almost every case.

42 is the two rails, 15A is the secondary current listed.

It should be just fine for powering the amp you list. My concern was that you might be thinking of using a very small toroid from a 12V car amp and using it from your main (220V, 50hz?) lines. such would be very bad. if the toroid was in a mains to 12VDC AC-DC converter then it should be fine.

[Kermit]

Im powering a opa549 amp with 25volt rails, so yes it wil do just fine for low output power. For a sub amp I would consider higher voltage.

[markp]

You will be looking at less than 40 watts into 8 ohms with that supply. I would try to get closer to 28 volts if you can.