TDA7293 AC noise

[santitrucco]

Hi , i finished one TDA7293 stereo amp.

I have Fostex Fe206en with 96db efficiency speakers.

One channel do some AC noise, i do not know if the 96db is the responsable, or if some is wrong in these channel.

I look at the circuit 100 times and I do not see anything wrong.

Can be the poor insulation between the transistor and the heatsink?

Santiago.

 

[santitrucco]

Could be some cable very close to another ?

 

[nigelwright7557]

Usually wiring layout problems.
Have you used star grounding ?
Do you use a single earth in your system ?
Transformers next to audio wires ?
Unscreened input wires ?

 

[santitrucco]

Usually wiring layout problems.
Have you used star grounding ?
Do you use a single earth in your system ?
Transformers next to audio wires ?
Unscreened input wires ?

tomorrow I will look at those details

 

[santitrucco]

There is 0.01v Ac in one chanel.

 

[santitrucco]

?

 

[santitrucco]

ac V

 

[santitrucco]

Please