EMS filter construction

[Martin Czech]

:::This specifies 741 opamps, but knowing the conventional wisdom on
:::that part I thought I'd try to use something better. I did check the
:::archives, but I found a wide variety of opinions on what to use as a
:::replacement, so I thought I'd seek some feedback on this particular
:::application. If I read the schematic right, IC1 and IC2 are buffers,
:::and IC3 is in the signal path as part of the Resonance circuit (I
:::don't know enough to look at these things and exactly tell their
:::function; that's partly why I want to try building this). Also there
:::are these BC109C transistors, which from what I've read seem to be
:::obsolete as well.
:::

If you want a real clone, leave the 741 in the signal path.
BC109C: I've recently seen them in a Farnel or Conrad catalogue.
BC549C works also, this is a replacement. I got a 1000 box for free,
therefore.

m.c.