[sdiy] moog module survey

[Tim Daugard]

Hey Kevin,

Are you and I the only ones around lately? Most of the information I've
got, I've got from your site or the SOS site.

> Your second questions are rather subjective though.

This is exactly what I'm looking for! Subjective opnions can be useful.
As my wife keeps telling me, "I don't care what the critics say, I LIKE
Burt Reynolds."

> >garbage truck was coming down the street?
>
> I'd probably not cross the street for a 961, but that's me.

Okay, one vote against the 961.

> Building Moog modules from schematics isn't terribly easy.
> The schemos don't always include everything needed.

Exactly. This is why the other post on the LM308. The 923 uses two
LM308s in the filters,  with different compensation capacitors. This
means I have to find a LM308 and see what the different caps do to the
response.

I started with the 923 because the network to create the pink noise
intrigued me. I can't imagine trying to come up with that combination in
the early sixties. I'm not sure I would do it even now with my
spreadsheet that I use to design filters. There are five different
filters - and they all work by loading the signal that feeds the output
buffer. The circuit is just begging me to build it. And, I know I don't
have exact matches for the capacitor values in my bins. I stock 1, 2.2,
4.7 as my standard caps.

I'm temped to sort some resistors to find the exact values and order
some caps.

Another problem with the 923 is finding something to replace the SD10
noise diode. I'm probably going to go with a zener.

> >The descriptions of the 902 VCA makes it seem like I should build
that
> >next - the all transtitor version - if there are multiple versions.

> There are at least 5 versions of the 902 released.

I was going to start with the schematic from the moog modular service
manual on your web site. Do you have schematics for all 5 versions?

I suspect there are at least two different versions of the white noise
generator, before the pink noise was added to create the -A version. The
schematic drawing appears to have some changes to the power supply
filtering.

The SOS article on moog modulars states that the 902 has a punch useful
for bass that hasn't been equalied by anything else. And that statment
was the source for the idea of taking a survey to see what people think.
After all crtics aren't always right.

Tim Daugard
AG4GZ 30.4078N 86.6227W Alt: 3.7 M
http://home.sprintmail.com/~daugard/synth.htm