Class D Stereo Amp in Mono?

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Hello,
I am new to this so please excuse my ignorance. I have a two channel Class D amplifier but only need to run one channel. Will it damage the amp to leave one channel unused? The amp is a Sure Electronics TDA7498 2x100 watt. Thank you in advance for any feedback.
Jeff
 
You should ground the input of the unused channel and check the filter components for geneated heat. If they get hot after some minutes i suppose to not leave the output open. (If the output filter components are getting hot, it might help to put a 4ohms resistor with a 33uh coil in series at the output)

There shouldnt be any problems, as this amp has an output filter. More care has to be taken when running in a filterless configuration.
 
Do you think, its a good idea to put output filters in parallel without changing their values?

Yes.

You should either parallel the outputs before the filter and change the values, or parallel after the filter and leave the values as they are.

In most cases there will be no negative effect of paralleling outputs after the filter on relatively low output amps such as is discussed here.

And in any case, leaving a channel unused will have far greater negative effects than tying the inputs and outputs together.
 
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What are you talking about? Space weather?


That's replying to this question.

Please also refer to this excellent guide that describes those output filter components that needs changing if you want anything resembling the promised performance.

Trevor Marshall - Class D Audio Amplifier Design - TDA7498 Output filters
Output
Are you trying to be funny?

The 7498E is, compared to the 7498, designed to be run in mono mode. Thats why you parallel the outputs before the filter. The 7498 is not.

There also shouldn't be a problem with shorting one input and leave the output open. With no signal the arithmetic middle belongs to zero.

Anyway, Trevor's essay don't belong to the things discussed here.
 
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Anyway, Trevor's essay don't belong to the things discussed here.

It does because as it mentions the output filter on the Sure amp is less than optimal so if you're going to do the trouble of tying the outputs together before the output filter, you change the values of that to the correct ones for your implementation. That is why I mentioned it at all.

If you just want it to run as a mono amp, you can tie both the input and the outputs together without changing anything. Simple.

I'm not sure why you mention the tda7498e at all. It's irrelevant to this discussion here.
 
I'm not sure if "bridging" is what Saturnus describes.

Paralleling is not bridging. Do not bridge this amp, it will fry instantly.

They are wrong though that there would be no problems running just one channel. In most cases it will fry the unused channel, and in some cases both channels. If you really want to use just one channel then do as suggested by the others above. Ground the input of the unused channel and load the output with a dummy load.

I suggested paralleling the inputs and outputs because it's easier, and it works.
 
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The problems come from an self-oscilating output when not loaded as the speaker is part of the filter. (Thats why Saturnus and me suggest a dummy load)

This behaviour depends on the internal circuit as well as the output filter, so there are ICs/amp which are not affected. As i mentioned earlier, the arithmetic middle of the output voltage is/should be zero with no/grounded input. Self-oscilations may occure with under-/overdamped output filters.

Amps/ICs with load-dumping-protection are save to run without a speaker connected as well as filterless configurations (mostly).

Its a rather complex topic.
 
If the amp used a post-filter (UCD-style) feedback, you'd be right, but as the Sure amp uses pre-filter feedback then leaving the output unloaded is perfectly ok, provided that you ground the audio input, so that the channel is not driving audio into an unloaded output filter.
 
If the amp used a post-filter (UCD-style) feedback, you'd be right, but as the Sure amp uses pre-filter feedback then leaving the output unloaded is perfectly ok, provided that you ground the audio input, so that the channel is not driving audio into an unloaded output filter.

In theory, yes. In real life though, I have seen amps of this kind fry one and both channels when input for one channel was grounded and output left open.
 
Saturnus can you draw simple picture how this parallel wiring goes ? I have mono boombox project with Sure 2x25w amp and my plans was to buy monacor stereo - mono converter and then put mono signal to only one channel and leave other channel open.
Im glad that i find this thread before i did that.
 
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