[sdiy] op amp based filter

[cheater cheater]

Hi guys,
if I took an op amp with a very low GBW, and set the gain so that the
bandwidth becomes the cutoff frequency I need, could I make a low pass
filter out of that? I would need to make up for the gain before and
after that op amp (with op amps too, but ones that are much higher
bandwidth of course), and I would probably have to chain several such
modules (say 4-8) one after another to get a strong effect, but is the
basic idea correct?

The only 741 datasheets I could find mentioned a GBW of 4MHz, so
that's a bit too much - to have a cutoff of 4 Hz you'd need to have
gain of 92 dB, which could be a bit too much to ask of the system
without drowning in noise. I've noticed Digikey has a lot of op amps
with a very low GBW, even down to 2.7 kHz.

Any ideas are welcome!

Cheers,
D.