[rb67]

What is the technical cause for the thump some amps exhibit when turned on and off? Is there any risk of headphone damage?

 

[grndslm]

Uhh...movin' electrons?? That's the cause of all electricity, right?

 

[C/Ho]

As an electrical engineer, I can tell you that it's due to the reactance of your amp. When you turn your amp on and off, you create a transient or spike in the circuitry. Inductance will lag, and capacitance will lead when you drop the voltage by switching your amp off. Technically, this spike can damage components if it wasn't designed properly. Inductive spikes can reach several amps for a split second in some cases.

 

[TzeYang]

yes there's a risk to the headphones. It depends on the rail capacitance size of the power rails.

High dc offset can be a cause of the problem too.

 

[rb67]

Ohh, I see. Time to pull out the text books on the 'ol RLC circuits and try to understand transient circuit responses. Thanks alot!

 

[kramer5150]

*alert noob-reply below*

I think its basically OP amp instability and DC offset of the OP amp with supply voltage fluctuation.

someone correct me though

Drives me nuts though. Coming from car audio, an industry that practically requires soft-start and soft-stop circuitry for everything.