hi,

i would like to use the CD4066 which is a quad bilateral switch as an audio source selector.

my question are the following:
1. is this device suitable for such an objective?
2. does this device degrade or introduce noise to the original signal?

your reply would be highly appreciated.

thanx :lol:

__________________
\"NONE BUT THE BRAVE DESERVES THE FAIR\" ~Shakespeare~

 

1. Yes, it is suitable for audio applications, provided the maximum signal voltage swing remains within the rail voltage.

2. No, It introduces no noise. You can even switch low level mic inputs with it.

 

also you should take in consideration that it has a resistance, and that the current allowed trough it is not very hight.
from what i know, it does not induce noise.

 

Yes, this resistance is usally in the range of 100 ohm's. If the input of the device you are trying to switch is low impedance (75 ohm for example) this can cause problems.

If it has a high impedance input then the few ohm's extra won't make a diffirence

 

With a supply rail of 7.5v the 'on' resistance of the switch is around 75ohms, and that is rarely found as the source or load in modern audio equipment. 75ohms is the normal impedance of coaxial-fed TV RF circuits, whereas the audio standard was (originally) 600ohms balanced line.

Nowadays, because of the influence of Japanese equipment designers, these stanards have been ignored and the source impedance of most audio equipment tends to be in the region of 10K to 50K. Under those conditions, the 4066 resistance can be ignored.

 

Pebe wrote:I think Pebe meant to say input impedance, not source impedance. Source impedance is generally much lower and irrelevant to this discussion.

 

thanx guys for the replies.

MERRY CHRISTMAS TO ALL OF YOU!!!!!!!!!

__________________
\"NONE BUT THE BRAVE DESERVES THE FAIR\" ~Shakespeare~

 

You're quite right, Ron. I must have misplaced my brain at the time!