I never design for 'that should be OK' because there are always exceptions that will go beyond your assumptions. Always assume idiots are using the gear. You'll rarely be disappointed.
G²
I would like to know the possibility of using OPA549 in bridged mode but driving even 4 ohms speakers? Since this chip itself is capable of giving a continuous current output 8 ARms so instead of paralleling I would like to bridge it. What should be the Transformers secondary ratings for this configuration. Right now im using 18-0-18 as my sec output from the trafo. Any recommendation for Bridged mode... driving 4 ohms speakers as well...
Nope. Chips are not rated RMS. They are rated at maximum Voltage and current. A 4 Ohm resistive load on a bridged OPA549 with a split 25 Volt supply will draw 12 Amps at signal peaks. Your device is rated for 8 continuous, 10 peak. Bridged into 8 Ohms will make it with a resistive load but a reactive is more difficult. Find a different chip or go discrete.
G²
If your PSU is ~+-25Vdc then expect the maximum output from the chipamp to be ~20Vpk.
Into a 4r0 test load the current demand will be ~5Apk. And only 2.5Apk into 8r0.
With a 8ohms speaker, the maximum current demand can be around three times the equivalent resistor load. Expect the current demand to be 7 to 8Apk. This takes most chipamps to near their current limit.
Into 4ohms speakers, that same +-25Vdc supply will take all chipamp beyond their peak current demand. i.e. no chipamp I know of can meet a 15Apk current demand for a 4ohms speaker.
Into a 4r0 test load the current demand will be ~5Apk. And only 2.5Apk into 8r0.
With a 8ohms speaker, the maximum current demand can be around three times the equivalent resistor load. Expect the current demand to be 7 to 8Apk. This takes most chipamps to near their current limit.
Into 4ohms speakers, that same +-25Vdc supply will take all chipamp beyond their peak current demand. i.e. no chipamp I know of can meet a 15Apk current demand for a 4ohms speaker.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.