Hello!
Good Day!
I have this problems in mono 850 Watts rms amplifier. This is China made amplifier.
Problems:
1. 14V DC out
2. When subwoofer is connected it produces whinning sound and popping but still has a clear music.
Symptoms:
When speaker is not connected:
1. DC out at 14VDC but not protect, rail voltages are normal.
When speaker is connected:
1. Positive rail voltage increases up to twice from its operating voltages
63VDC -> 115VDC.
2. Negative rail decreases from -63VDC to -55VDC.
3. Produces whinning sound and popping but still has clear music.
Thank you so much! Please help....
Good Day!
I have this problems in mono 850 Watts rms amplifier. This is China made amplifier.
Problems:
1. 14V DC out
2. When subwoofer is connected it produces whinning sound and popping but still has a clear music.
Symptoms:
When speaker is not connected:
1. DC out at 14VDC but not protect, rail voltages are normal.
When speaker is connected:
1. Positive rail voltage increases up to twice from its operating voltages
63VDC -> 115VDC.
2. Negative rail decreases from -63VDC to -55VDC.
3. Produces whinning sound and popping but still has clear music.
Thank you so much! Please help....
Attachments
With nothing connected to the amp, what's the resistance from the B+ terminal to the secondary center tap or to the negative speaker terminal?
No resistance between -speaker to B+. Sometimes DC out reaches >30Volts and goes down...
thank you.
Last edited:
By 'no resistance', do you mean infinite resistance or 0 ohms?
Hello Perry,
Resistance is above 75K ohms and still rising.
And DC out sometimes around >24VDC without speaker connected. If you connect speaker the one of the rail voltage increases from 63VDC -> 112VDC.
If you had the black probe on the primary ground, place it on the secondary center-tap.
Does the rail voltage shift up when using the secondary center tap as the reference?
Ill do this...
But I verified that primary GND and secondary GND along with GND terminal are connected with physical PCB connection.
Thanks.
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