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Old 23rd June 2015, 08:03 AM   #1
TroelsM is offline TroelsM  Denmark
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Default TDA7498 ebay strange output levels

Hi

I've been building an active speaker with a TDA7498 amp from ebay:

El-cheapo active LOUDspeaker

The amp-module is the cheapest one from ebay:
100W High Power 100W Class D Amplifier Board DC20V to DC36V TDA7498 | eBay

The amp works, but measuring the output levels of the bridges I got some odd results.

PSU was approx 32V (lab psu, stable). One half of each bridge did approx 25Vpp into 8Ohm without visible distortion on a scope, but the other half does only approx 15Vpp at the same time.

This goes for both channels on the board and for two boards purchased 6weeks apart.

Is this normal operation for a TDA7498?
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Old 4th July 2015, 02:55 PM   #2
Dinithm is offline Dinithm  Sri Lanka
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Quote:
Originally Posted by TroelsM View Post
Hi

I've been building an active speaker with a TDA7498 amp from ebay:

El-cheapo active LOUDspeaker

The amp-module is the cheapest one from ebay:
100W High Power 100W Class D Amplifier Board DC20V to DC36V TDA7498 | eBay

The amp works, but measuring the output levels of the bridges I got some odd results.

PSU was approx 32V (lab psu, stable). One half of each bridge did approx 25Vpp into 8Ohm without visible distortion on a scope, but the other half does only approx 15Vpp at the same time.

This goes for both channels on the board and for two boards purchased 6weeks apart.

Is this normal operation for a TDA7498?
yes it is,,,,
just google full bridge configuration(full bridge amplifier,H bridge)
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Old 4th July 2015, 03:10 PM   #3
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A lot of Bridged class D amplifiers use virtual ground. That will confuse most readings!
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