NHT SubOne makes hum when the standby mode is activating and when playing music there are pops when the volume gets loud.

Does the NHT sa-2 have it's own pre-amp? Because I'm wondering if the power off only works when it's own pre-amp is used? So when your receiver is connected it's shut off.

You could try something connected to it's own pre-amp (if it has one) and see if it goes off when there's no signal from that.

C7 and C15 capacitors bad, on main amp board, 470uf/25vdc, in +13vdc power supply circuit. BE SURE TO DISCHARGE MAIN LARGE CAPACITORS ON POWER SUPPLY BOARD AS THEY RUN AT + AND - 90VDC (180VDC TOTAL) AND STAY CHARGED LONG AFTER UNIT IS UNPLUGED!!! Shock hazard and may damage unit beyond repair if not discharged while desoldering components. Use around a 1000 ohm, 5 watt resistor across capacitor leads, if possible check voltage with meter to be sure they are discharged.

may be you have a ground wire loose

Well it sounds like your amplifier IC's are working correctly since you are hearing that pop. I have the same amplifier and every 10db increment it pops. Have you tried every input? Possibly try starting at a low volume, plug an RCA plug into CD or any other input, and touch the center prong of the other end of the cable. You should get a 60hz hum if your in the USA, otherwise it will be 50-55hz. Regardless it should make noise.

go to control panel
sound and audio devices
voice
under voice recording clk volume and mute the mic phone...........
or
some how your mic is conflicting with speakers. Keep your mic away from your speakers..

Do reply if this woks

Likely the power adapter has failed if it uses one. Try a new one first.

If half the rectifier blows out, a very impure DC voltage is applied which will be heard in the audio output.

Check your speakers one by one, maybe one of them are about to burn that´s the reason your device turn on protection state,good luck

It happens to me too. I tried a higher quality headphones and the hum happened, but when I used the ones that came with the player the hum can't be heard.

There is a standby indication that activates after 10-15 minutes without any input signal. I suspect that might be what the red light is telling you - no signal.

Loud hum from a loosened cable is normal as hum usually means there's an ungrounded connection somewhere acting as an antenna and the amp is doing its job to amplify what it thinks is a signal, in this case 60hz stray ac current is being sensed nearby. It's a good sign that you get hum from the sub because that means the amp is alive.

Avoid manipulating cable connections with the Sub or Receiver turned on as you could introduce a static spike that could harm any connected equipment.

Are you certain a bass signal is making it into the sub? The complexities of modern AV receivers vary in how you configure them to direct LFE to a sub. Bone up on that end of the chain.

Or, just hang a CD player on the Inputs of the sub and play something with a reassonable amount of Low Frequencies.

>>>> Be advised that this way of testing has NO VOLUME CONTROL because amps without volume controls always operate at maximum gain, relying on your external controls to attentuate it (hence, the loud hum from a loose cable); so choose a track that eases into the loud parts with some quiet parts up front and BE READY TO PAUSE THE PROGRAM AT ANY SIGNS OF STRESS. <<<<

A living sub will produce only muffled rumble in the absence of other speakers producing the higher frequencies which carry the intelligence of the signal. If that works, back to the receiver for settings. If not... sigh.

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For hum problems, even those you cause yourself:

Disconnect all inputs to see if that helps. If it goes away start with the signal cables and add in things until it comes back.

Sometimes the reversing the orientation of the AC plug can help with hum. Or it could be something like a loose or high resistance connection internal to the sub. Good luck.

Hi There, Please advise us what happens when you turn off the sub woofer is the hum still there....??

From YUBEUT.