bigugly
Well-known member
I know this is electronics 101 stuff but the formula I was shown only seems to work for max gain. Here's what I've been using:
[Rf * (Rs1+Rs2)]/[Rf + (Rs1+Rs2)] = X, then 20*Log10(X) = gain in db
When I run the numbers for max gain I get a sensible answer but when I use the numbers for min gain I get nonsense.
example:
Rf = 20000 (feedback resitor)
Rs1 = 200 (shunt resitor)
Rs2 = 20000 (rev log pot)
so at max gain Rs2 is shorted so my math is this:
[20000 * 200]/(20000 + 200) = 4000000/20200 = 198
20*Log10(198) = 45.9db of gain
min gain is:
[20000 * (20000+200)]/[20000 + (20000=200)] = 404000000/40200 = 10049
20*Log10(10049) = 80db of gain!
so i guess it's fairly obvious that I'm doing something wrong here.
Please help me. Of all the reading material I have, nothing covers this
Thanks
James Lee
Big Ugly Van Audio
[Rf * (Rs1+Rs2)]/[Rf + (Rs1+Rs2)] = X, then 20*Log10(X) = gain in db
When I run the numbers for max gain I get a sensible answer but when I use the numbers for min gain I get nonsense.
example:
Rf = 20000 (feedback resitor)
Rs1 = 200 (shunt resitor)
Rs2 = 20000 (rev log pot)
so at max gain Rs2 is shorted so my math is this:
[20000 * 200]/(20000 + 200) = 4000000/20200 = 198
20*Log10(198) = 45.9db of gain
min gain is:
[20000 * (20000+200)]/[20000 + (20000=200)] = 404000000/40200 = 10049
20*Log10(10049) = 80db of gain!
so i guess it's fairly obvious that I'm doing something wrong here.
Please help me. Of all the reading material I have, nothing covers this
Thanks
James Lee
Big Ugly Van Audio