[SOLVED] Signal Reflection in audio amplifier

[Daydreamer86]

Hi,

I am thinking of designing an switching audio amplifier, however, I was confused with the reflection of signal. For audio application, do we need to cater to signal reflection?

The cable i used is definitely short (less than 1 meter). Personally, I only know that the as long as the wavelength is longer than the wire length, no signal will be reflected.

Do correct me if I am wrong.

Thanks.

 

[chuckey]

Unless you are running 100s of metres of cables you can ignore any " reflection" effect. With audio low level leads its the self capacitance of the cable, you have to look out for and for loudspeaker leads its the inductance of the leads.
Frank

 

[Daydreamer86]

Hi chuckey,

Thank you for your confirmation.

Just wondering, is there any standard or similar for this?

Thanks.

 

[chuckey]

The only standard I know is that all long audio leads are designed as a balanced 600 ohm impedance. With ultra long audio leads, such as overhead telephone leads, they are so touchy about any change of impedance that compensation is used for the core identification marks. So that pair one, might have a black marker every 100mm, pair two, two marks every 200mm, pair three, three marks every 300mm. So that in a kilometer every pair has the same number of markers. For long music leads, the balanced pair is enclosed in a screen and all the inputs are terminated in 600 ohms, though the outputs are normally low impedance.
Frank

 

[Daydreamer86]

Hey Frank,

Look like it should not be a worry as my cable is short.

Thanks.

Daydreamer

 

[crutschow]

If it's a switching amp to drive a speaker then the main concern is the wire resistance, which should be much less than the speaker impedance.