Where did you buy the output from?
If you remove the single transistor you replaced, is the audio clean?
If you remove the single transistor you replaced, is the audio clean?
I buyed from a cheap supplyer. Rechecked some bad solder joints. Now it seems ok, but the other channel shows noisy on the oscilloscope. Maybe there are also some Transistors damaged??? I will take them out to check.
So, i checked the output transistors from the working channel. All Ok.
The good Sinewave is from the output i repaired. The noisy wave from the channel wich was working before. Checked all Values, also compared drivers from both sides, all the same.
Any suggestions?
I have a 4 Ohm load on each channel. 200Hz injected.
Ground always from Minus Speaker.
The good Sinewave is from the output i repaired. The noisy wave from the channel wich was working before. Checked all Values, also compared drivers from both sides, all the same.
Any suggestions?
I have a 4 Ohm load on each channel. 200Hz injected.
Ground always from Minus Speaker.
Attachments
Ok, very strange. Please see the notes on th picture.
If i measure on the rail from the outputs, the signal is clean. If i follow the iron bar to the next solder, it comes more noisy. On the terminal it is very noisy. Can this be the influence of the power supply?
If i measure on the rail from the outputs, the signal is clean. If i follow the iron bar to the next solder, it comes more noisy. On the terminal it is very noisy. Can this be the influence of the power supply?
Attachments
So, for Information, the amp is running well and sounds good. Even with this noise. For me it seems, that the noise is inducted from the Powersupply, because the iron bar, which is transporting the audio signal is directly beside the transformers. If somebody can confirm this, it will be good for my expirience.
If you touch along the flat bussbar starting at the round bussbar and moving towards the speaker terminal, does the signal start out clean and progressively get noisier, closer to the speaker terminal?
If the zobel network is near the output transistors, moving it to the speaker terminals may help. You may also be able to replace the flat bussbar with a piece of 12 or 14g wire to see if that will help.
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