I was looking though the manual for an Elextrix Repeater and toward the
end it has a diagram for building a 12dB attenuation cable for plugging
it into a guitar amp. It's three resistors arranged like this:


tip-------------3.9k----------tip
| |
2.2k 2.2k
| |
sleeve------------------------sleeve


From my math, this gives about -8.9dB, not -12dB.
My math's not very good though. Could someone just confirm that I'm
wrong so I can go back and look for my mistake(s)?

Thanks