Log or Lin?
 

Finally got my LM4766T amp going.Now I need a pot.
Ready made stepped attenuators are too expensive and I can't seem to find enough info on how to build my own so I choose to use some sort of high accuracy stereo pot.
Do I use a 100k log or 100k lin pot for input?
Or can someone show me the way to some stepped att. diagrams?

It depends on the input impedance of the chip amp. If you want to use a 100k pot which is quite high impedance, I would try a linear pot.

I just checked the datasheet and it shows 10k pot on input.My mistake.
So,if I use 10k pot ,should it be log or lin?

Use a log.

Just found this on another post, enjoy!

http://www.penguinlovers.net/audio/Attenuator.html


Cheers
Sparks

Yes if 10k use logarithmic.

Hi,
you can use a lin with log faking resistor added.

The slight advantage of the lin track is better matching of resistance. This can affect balance between channels and becomes a bigger problem at high attenuation rates.

When mimicing a log pot with a lin pot+faking resistor it is usual to select a lin~=10times log value and then add a wiper to signal ground resistor ~10%to 15% of lin pot value.
eg 10klog or 100klin+12k resistor.

Hi guys!

I've noticed that some sources, usually (not always) headphone sources, may have a cap at the output that causes the bass to vanish if a 10k pot is used.

Unless tried, you wouldn't believe that Alpha's A20K ($1) plus ordinary 24 gauge solid conductor copper, could be a viable solution.

Whether that's true or not, it can give you a baseline from which to evaluate other options.

I just read profsparks link about building a ladder stepped att.
I might have a go at making one of those,however in his resistor calculator table,should position 1 read -80db not -8db,or am I mis-understanding something?

http://www.penguinlovers.net/audio/Attenuator.html

-80db or -infinitydb are the choices. The 8 is an attempt to write the symbol for infinity which is similar to an 8 on it's side with the right hand end open.
If Rg=0 then attenuation is theoretically infinity.
If Rg = 1r0 then attenuation is -80db.