I recently completed a 3-channel amp using the UCD400ST modules. During power down, the DC on the output of all modules goes from a few mV to a few V and then comes back down slowly. This causes audible noises on the woofer and there is even some HF on the tweeter as the amp powers down.
I am guessing that because it is common to all the modules, it is coming from the supply. So, let me describe the supply. The supply uses a large toroid and a common array of ten 6,800uF caps. There are 56k bleeder resistors across the caps. There is a CL60 on the negative leg after the AC inlet to resist inrush current. There is absolutely no noise during power up.
Signal connections are through RCA. On/Off pin is connected to signal ground together with the shield. Chassis is grounded and there is no hum.
The modules work perfectly, it's just that powering down is an uncomfortable process. Any help or insight is appreciated.
I am guessing that because it is common to all the modules, it is coming from the supply. So, let me describe the supply. The supply uses a large toroid and a common array of ten 6,800uF caps. There are 56k bleeder resistors across the caps. There is a CL60 on the negative leg after the AC inlet to resist inrush current. There is absolutely no noise during power up.
Signal connections are through RCA. On/Off pin is connected to signal ground together with the shield. Chassis is grounded and there is no hum.
The modules work perfectly, it's just that powering down is an uncomfortable process. Any help or insight is appreciated.
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