"Thump" sound on Unity Atom power on

Not with my Nova - no thump, no hum, just music 

Pev posted:

Not with my Nova - no thump, no hum, just music 

What is the model of your speakers? I think power on "thump" mainly depends on the sensitivity of the speakers. If the sensitivity is low - we cannot hear the "thump". Mine speakers are Focal Aria 926 with pretty high sensitivity - 91.5.

Mine does it too, fairly normal I think so I wouldn’t worry

When power on, my Star do not make such thump sound. But when switch off and immediately off the outlet also, it will have the thump sound go according to the volume. It is suggested that you wait a while and lower down the volume before off the outlet.

Provided it's not loud it's noting to worry about, the capacitors in a linear power supply are bound to charge at slightly different rates, and that's what you are hearing.  As it's due to component tolerances, some units will do it, some units will be completely quiet, and it's completely random as to whether you get a 'thumper' or a quiet one.

Even my 300DR produces a low level, quite subtle 'thump'.

tony123 posted:

What is the model of your speakers? I think power on "thump" mainly depends on the sensitivity of the speakers. If the sensitivity is low - we cannot hear the "thump". Mine speakers are Focal Aria 926 with pretty high sensitivity - 91.5.

I have N-Sats with a Velodyne sub - not sure if these are "sensitive" but they do go loud!

Thanks

Huge posted:

Provided it's not loud it's noting to worry about, the capacitors in a linear power supply are bound to charge at slightly different rates, and that's what you are hearing.  As it's due to component tolerances, some units will do it, some units will be completely quiet, and it's completely random as to whether you get a 'thumper' or a quiet one.

Even my 300DR produces a low level, quite subtle 'thump'.

I'm not sure, but I think Unity Atom has a delay relay (or soft start). Because the Unity has delayed "click" sound on powering on. The sequence is:
- I press power on button
- then there is a pause about ~2seconds.
- then "click" sound from unity and "thump" from speakers. This is the moment the speakers are activated.

So hasn't this delay relay to eliminate all the DC irregularities and any "thumps" from speakers?

Why I still hear the "thumps" even with soft start?

tony123 posted:

Huge posted:

Provided it's not loud it's noting to worry about, the capacitors in a linear power supply are bound to charge at slightly different rates, and that's what you are hearing.  As it's due to component tolerances, some units will do it, some units will be completely quiet, and it's completely random as to whether you get a 'thumper' or a quiet one.

Even my 300DR produces a low level, quite subtle 'thump'.

I'm not sure, but I think Unity Atom has a delay relay (or soft start). Because the Unity has delayed "click" sound on powering on. The sequence is:
- I press power on button
- then there is a pause about ~2seconds.
- then "click" sound from unity and "thump" from speakers. This is the moment the speakers are activated.

So hasn't this delay relay to eliminate all the DC irregularities and any "thumps" from speakers?

Why I still hear the "thumps" even with soft start?

I believe the new streamers have a small SMPS which runs in standby mode, to keep power consumption low and comply with energy consumption regulations. When you turn it on, the main PSU powers up, and the SMPS shuts down, and that is what causes the click you hear.