Is there anything I can put in line of a power to class D amp to stop the pop noise on power-up?
Hello all. I would really appreciate some help here being an DIY newbie builder. I have just put together a simple class D amplifier which is powered by a 24V DC power supply. All is good if you turn the amplifier on via its click rotary volume control. However, if you leave it turned up to where you want it and power it off via the mains and back on via the mains power switch it makes a 'not nice' pop to the speakers.
Being a 'electronics know very little' 🙂 Is there anything that I can put in line with the power to the class D board perhaps that will stop this pop happening? A gradual let the power through type of thing perhaps that may prevent it? (links to ebay or whatever would be much appreciated to a newbie builder). I'm assuming its from a surge in and a slower power up would perhaps prevent it doing it.
All I want is to leave it powered on or power on without using the rotary volume as its just going to be adjust and left at a set volume. I'll have a separate preamp to control volume.
Hello all. I would really appreciate some help here being an DIY newbie builder. I have just put together a simple class D amplifier which is powered by a 24V DC power supply. All is good if you turn the amplifier on via its click rotary volume control. However, if you leave it turned up to where you want it and power it off via the mains and back on via the mains power switch it makes a 'not nice' pop to the speakers.
Being a 'electronics know very little' 🙂 Is there anything that I can put in line with the power to the class D board perhaps that will stop this pop happening? A gradual let the power through type of thing perhaps that may prevent it? (links to ebay or whatever would be much appreciated to a newbie builder). I'm assuming its from a surge in and a slower power up would perhaps prevent it doing it.
All I want is to leave it powered on or power on without using the rotary volume as its just going to be adjust and left at a set volume. I'll have a separate preamp to control volume.
Usually D amplifiers have a mute function that gets activated at power on or when a fault like output DC voltage is detected. It is normally high(5V or more) when power is good. you can externally tie this pin to ground and switch the amp on by removing the ground with a simple switch.
It's unavoidable for the most part.
The issue is the way Class D amps are biased internally and not all board makers will implement soft mute, even when the chip actually has them.
Reducing voltage gradually is not recommended, you can use a relay to disconnect the speakers on power-off. This is a pretty simple circuit, just one transistor, a relay and a three discrete components. I use one such for the exact same functionality for LM1875. It needs a power source of some sort, and depends on the relay dropout voltage being higher than the turn-off threshold of the circuit to be disconnected if you share the amp's power rails.
The issue is the way Class D amps are biased internally and not all board makers will implement soft mute, even when the chip actually has them.
Reducing voltage gradually is not recommended, you can use a relay to disconnect the speakers on power-off. This is a pretty simple circuit, just one transistor, a relay and a three discrete components. I use one such for the exact same functionality for LM1875. It needs a power source of some sort, and depends on the relay dropout voltage being higher than the turn-off threshold of the circuit to be disconnected if you share the amp's power rails.
Interesting thanks, sounds a little more than I was expecting but I'm sure it could be implimented easy enough.
The "ALWAYS works" solution I add to my small PA amps used in places where absolutely NO pop is acceptable (churches, temples, yoga meditation centers, etc.) is to add a "standby switch" like many Tube amps have .
Actually a switch in series with speaker out.
Instructions:
On powering amp ON
* Both power and "standby" switches OFF
* turn power on.
* turn standby on
On powering amp OFF
* Both power and "standby" switches are ON
* turn standby off
* turn power off
Works like a charm.
If both switches are side by side, it´s even easier.
It becomes second nature doing it.
Actually a switch in series with speaker out.
Instructions:
On powering amp ON
* Both power and "standby" switches OFF
* turn power on.
* turn standby on
On powering amp OFF
* Both power and "standby" switches are ON
* turn standby off
* turn power off
Works like a charm.
If both switches are side by side, it´s even easier.
It becomes second nature doing it.
It's the SDZ pin 2 oif the IC. just switch to gnd there is a resistor to supply the high level, you can solder the line from the switch there. Switch to mute before removing the 24V, this is also mentioned in the data sheet. https://www.ti.com/product/TPA3116D2
https://www.ti.com/lit/gpn/tpa3116d2
https://www.ti.com/lit/gpn/tpa3116d2
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Thanks very much. I will see if my very small electronics brain can figure it out to do easily 🙂
Not today 🙁 but no need to.
You have a wire which goes from your board to the speaker (or two if your amp has balanced outputs).
You cut *one* wire going to speaker and connect it to a switch, which you call "Standby" , you could also call it "speaker mute" , and mount the switch at a convenient place.
This is "universal", works on ANY amplifier, no need for it to have a special "mute" function.
Of course, always talking SS amps, never disconnect speaker from Tube ones.
Since I make my own chassis, I can punch that hole anywhere, so I usually put it side by side with the power switch, also use same kind of switch for looks, but position is not critical.
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