What causes AVR's to make clicking noises?

[Cygnus]

I'm just curious as to what causes AVR's to make clicking noises when:
1. They turn on
2. A few seconds after they turn on, and then sound and video are output.
3. Sometimes changing sound modes from Surround to Stereo for example.
4. Muting and un-muting.

Why do they do this, and what physically inside the units creates the 'click'? There's obviously a physical movement inside them that creates the noise, correct?

 

[PENG]

I'm just curious as to what causes AVR's to make clicking noises when:
1. They turn on
2. A few seconds after they turn on, and then sound and video are output.
3. Sometimes changing sound modes from Surround to Stereo for example.
4. Muting and un-muting.

Why do they do this, and what physically inside the units creates the 'click'? There's obviously a physical movement inside them that creates the noise, correct?

Electro-mechanical relays, so yes physical movements are involved.

 

[D Bone]

Harman Kardon AVR 2700 here that is dead quiet when powering on/off, muting or changing inputs......It actually took a while to get used to.

 

[RichB]

Relays bother many folks but I think they are found in good designs to completely remove the connections.
I can hear all 5 of my channels relays disconnect when powering on and off. I find that comforting

- Rich

 

[Cygnus]

Relays bother many folks but I think they are found in good designs to completely remove the connections.
I can hear all 5 of my channels relays disconnect when powering on and off. I find that comforting

- Rich

Ah . Are they removing connections from the...amps to the speaker outputs?

 

[RichB]

Ah . Are they removing connections from the...amps to the speaker outputs?

It seems that way. When you disconnect the power or power off there are 5 clicks and the sound is stopped.
The Outlaw/ATI amps keep on playing using their power reserves. I am not saying that is bad

Many products wait for the power supply to stabilize.

Clicks are good

- Rich

 

[M Code]

Electro-mechanical relays, so yes physical movements are involved.

Also...
There are electronic relays as used in the HK 2700.. Used for bypassing the video processor, totally silent...

Just my $0.02...

 

[RichB]

Bypassing the video processor.
Excellent. I wish more had relay based bypassing.

- Rich

 

[Cygnus]

This is some really neat information! Thanks guys

 

[Pyrrho]

Ah . Are they removing connections from the...amps to the speaker outputs?

Certainly in at least some cases. It can eliminate a power on and power off "thump" that sometimes occurs in ąmplifiers that don't use relays. Usually, such thumps are not harmful, but they are far more noticeable than a little click.

 

[M Code]

Certainly in at least some cases. It can eliminate a power on and power off "thump" that sometimes occurs in ąmplifiers that don't use relays. Usually, such thumps are not harmful, but they are far more noticeable than a little click.

The Power ON/OFF thumps can also be generated by a Pre-Amp controller. Thats why a time-delay circuit is inserted to make sure each of the internal components and voltages before going live..

Just my $0.02...

 

[TLS Guy]

The Power ON/OFF thumps can also be generated by a Pre-Amp controller. Thats why a time-delay circuit is inserted to make sure each of the internal components and voltages before going live..

Just my $0.02...

If a unit has a turn on thump while stabilizing then it need to be disconnected from the load for a while. This can be done by a relay or gated MOSFET switch, the latter is silent, and the better way.

 

[M Code]

Most quality audio components have some type of Power ON/OFF delay..
However in these days of mixing/matching old & new components once in a while a problem can arise..

Just my $0.02..