Hey
Just a little question
My sansui au 222 is clipping a lot on positive half at powering of amplifier, during a few seconds
I guess it is normal as capacitor charge up, but I just wanted to double check!
Just a little question
My sansui au 222 is clipping a lot on positive half at powering of amplifier, during a few seconds
I guess it is normal as capacitor charge up, but I just wanted to double check!
That is not normal, either the positive supply has defective positive supply capacitors i.e. leaky and dont hold their charge. If there are no lengthy rude noises at turn off I think that is unlikely. If at any time the positive power supply has been seriously overloaded tne positive diodes in the bridge could have been compromised without total failure. If one positive diode is affected in this way the charging of the supply caps will be down on charge delivery and the opposie sides of supply would be out of balance with oneanother.
Hey !
Actually looking at the design, I find it rather normal at the end. There is no negative supply here ! Just one positive rail. So signal is around a positive fixed value, not zero. So I guess as the power supply build up, clipping is impossible at "negative" side because we ask the amp for voltages below the current supply. When we ask for positive side, the voltage we ask the amp for are probably above the current charger supply, so we clip. And it explains how the unclipping decrease as the charging shape of a cap (fastly at first then slow).
Also, I've just changed caps and supply diodes !
Actually looking at the design, I find it rather normal at the end. There is no negative supply here ! Just one positive rail. So signal is around a positive fixed value, not zero. So I guess as the power supply build up, clipping is impossible at "negative" side because we ask the amp for voltages below the current supply. When we ask for positive side, the voltage we ask the amp for are probably above the current charger supply, so we clip. And it explains how the unclipping decrease as the charging shape of a cap (fastly at first then slow).
Also, I've just changed caps and supply diodes !
Sorry I did not know the au 222 was a single rail power supply version which would also have an output coupling to the load. I presume you have also swapped that out?
Clipping can occur in any amplifier if it is driven hard into a low impedance load. You don't need to wind up the volume pot as the track resistance is logrythmic by design to be that way so there is a finer range of adjustment a low listening levels where this is needed..
Surprisingly one can get a reasonable listening experience at one watt rms. The maximum power rating is to handle music peaks if all music was at peak level any pets you have would leave the room.
Clipping can occur in any amplifier if it is driven hard into a low impedance load. You don't need to wind up the volume pot as the track resistance is logrythmic by design to be that way so there is a finer range of adjustment a low listening levels where this is needed..
Surprisingly one can get a reasonable listening experience at one watt rms. The maximum power rating is to handle music peaks if all music was at peak level any pets you have would leave the room.
That could be so. Another thought is the capacitor coupled to the speaker has not fully discharged at switch off causing annoyance at switch on. You could add a 2k2 resistor from the speaker output connection to earth to discharge that cap from the ac side at switch off. If there is some residual charge in the output cap there can be consecquences if is discharged by a short circuit.
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