Hy!
I've got problem with my TDA7294 amplifier.
When I built it there was no problem, but after few day there was problem.
When I turn it on everything is ok, but after 2 seconds there is a lot of distortion.
Where is the problem?
Here's schematics:
I've got problem with my TDA7294 amplifier.
When I built it there was no problem, but after few day there was problem.
When I turn it on everything is ok, but after 2 seconds there is a lot of distortion.
Where is the problem?
Here's schematics:
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
Well, for one, the schematic is quite unreadable.
Small text, grey on white, certainly does not help.
You show no Zobel network, it may be oscillating.
Small text, grey on white, certainly does not help.
You show no Zobel network, it may be oscillating.
An externally hosted image should be here but it was not working when we last tested it.
I found out that I solder -VS and GND together.
What can I do with -VS?
I use AC/DC adaptor as power supply.
Thanks, that's fine. 🙂
You need Symmetrical supplies, meaning if you are using, say, laptop powerpacks as an example, you need two of them.
Suppose they are both, say, 19V supplies.
Then you must connect one of them with negative to ground and positive to +Vs , and the other with positive to ground and negative to -Vs.
Be aware that in that case the amplifier will work properly , certainly loud enough for home use, but you won't have the 70 or 100W possible.
But that's not a big problem.
You need Symmetrical supplies, meaning if you are using, say, laptop powerpacks as an example, you need two of them.
Suppose they are both, say, 19V supplies.
Then you must connect one of them with negative to ground and positive to +Vs , and the other with positive to ground and negative to -Vs.
Be aware that in that case the amplifier will work properly , certainly loud enough for home use, but you won't have the 70 or 100W possible.
But that's not a big problem.
Thank you for reply.
I power it with 2 AC/DC adapters. One is ~+12V, other is ~-10V.
Only what I hear now is loud hum. There is no input.
Is this happening because of difference in power supply?
I power it with 2 AC/DC adapters. One is ~+12V, other is ~-10V.
Only what I hear now is loud hum. There is no input.
Is this happening because of difference in power supply?
Sorry but no.
1) first that you connected as suggested in post #4 , and check that proper voltages are present, meaning +12V at the + rail; -10V at the otyer.
This is most important, otherwise you can not proceed.
2) after that, check that you have 0V at the speaker output.
Measure this *without* speaker or you will kill it .
3) *if* you have +12V or -10V at the output, you have killed your amp 🙁
1) first that you connected as suggested in post #4 , and check that proper voltages are present, meaning +12V at the + rail; -10V at the otyer.
This is most important, otherwise you can not proceed.
2) after that, check that you have 0V at the speaker output.
Measure this *without* speaker or you will kill it .
3) *if* you have +12V or -10V at the output, you have killed your amp 🙁
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