MOTM

Working on the MOTM-101. Some things to report:

a) Upgrading the op amp in the white noise amps to make even *whiter* noise.
Also, the new amp
runs at a lower gain, so more noise gets through.

b) Switching the normalized S&H input from WHITE to PINK noise. There reason
is that there is such
more high-frequency content that the distribution of "random samples" was
too close to 0 volts (which is what
it's *supposed* to be!) But that makes for boring S&H noodlings. So
switching to PINK as the default
causes a much wider distribution of output voltages.

c) Not changing the internal clock range all that much. It is still on the
"slow" side. If you need exact clocking
in the 1Hz to 10Hz range, use a MOTM-320. The max rate is still about 15Hz,
same as the '100. With an EXT CLK,
you can sample up to about 4Khz for some "lo-fi" Mirage sampling effects.

All that is left to mess with is the SLEW. Since all I can use is 100K log
pots, I have to use larger cap and
the op amps don't like that. The max. SLEW may be about 0.5sec. Of course,
the MOTM-820 can slew *minutes*.

Paul S.

can't wait to get one...
peace,
doc

--- In motm@egroups.com, "Paul Schreiber" <synth1@a...> wrote:
> Working on the MOTM-101. Some things to report:
> 
> a) Upgrading the op amp in the white noise amps to make even 
*whiter* noise.
> Also, the new amp
> runs at a lower gain, so more noise gets through.
> 
> b) Switching the normalized S&H input from WHITE to PINK noise. 
There reason
> is that there is such
> more high-frequency content that the distribution of "random 
samples" was
> too close to 0 volts (which is what
> it's *supposed* to be!) But that makes for boring S&H noodlings. So
> switching to PINK as the default
> causes a much wider distribution of output voltages.
> 
> c) Not changing the internal clock range all that much. It is still 
on the
> "slow" side. If you need exact clocking
> in the 1Hz to 10Hz range, use a MOTM-320. The max rate is still 
about 15Hz,
> same as the '100. With an EXT CLK,
> you can sample up to about 4Khz for some "lo-fi" Mirage sampling 
effects.
> 
> All that is left to mess with is the SLEW. Since all I can use is 
100K log
> pots, I have to use larger cap and
> the op amps don't like that. The max. SLEW may be about 0.5sec. Of 
course,

> the MOTM-820 can slew *minutes*.
> 
> Paul S.

At 07:16 PM 12/25/00 -0600, you wrote:
>Working on the MOTM-101. Some things to report:
>
>a) Upgrading the op amp in the white noise amps to make even *whiter* noise.
>Also, the new amp
>runs at a lower gain, so more noise gets through.

paul, would you mind stating what the new opamp is, (is it the same pinout 
as the old-- is a straight swap possible?)

>b) Switching the normalized S&H input from WHITE to PINK noise. There 
>reason is that there is such more high-frequency content that the 
>distribution of "random samples" was too close to 0 volts (which is what 
>it's *supposed* to be!) But that makes for boring S&H noodlings. So 
>switching to PINK as the default causes a much wider distribution of 
>output voltages.

good idea.

-mark

> >
> >a) Upgrading the op amp in the white noise amps to make even *whiter*
noise.
> >Also, the new amp
> >runs at a lower gain, so more noise gets through.
>
> paul, would you mind stating what the new opamp is, (is it the same pinout
> as the old-- is a straight swap possible?)
>

It's an OP-275GP. You can't just "swap it out", as 4 other resistor/cap
values change as well.

Paul S.

To: <motm@egroups.com>
> It's an OP-275GP. You can't just "swap it out", as 4 other resistor/cap
> values change as well.

well, i'll ask first:
for the butchers among us, what would these value changes be..?

cheers
paulb

> I can probably only afford 2 more modules, so suggestions would help.
> 
This suggestion is not exactly filter related, but for using multiple
pieces of gear (and within motm) I have found the 700 DUAL switcher to be
very useful.  Examples: switching between 2 sequences in the A & B
channels of my SQ10 using the 320 lfo (or MS20 lfo)[cv], switching between
my Prophet 5 and MS20, both sequenced with the SQ10 [audio], switching
between 2 motm osc's both sequenced with the SQ10[audio], switching
between, say, sine & saw outputs from the 320 to filter cv input on the
P5[cv].  Your 800 could be used as the cv 'switcher' triggered by your 909
or 727.

I would guess that you could find the 700 useful for switching between
your 909 and 727 to generate some interesting and varied patterns. 

The 700 is more useful than I had originally anticipated.  I've
found that cv switching is more useful, in audio switching I still haven't
mastered always eliminating a sometimes switch 'click' (yes, 700 is set to
audio). I just need more practice.

If you are building motm kits, the 700 is straightforward (owing to Paul's
excellent instructions).  My 700 was the 3rd (I think) kit I had built,
and if *I* can build it and have it work then *anyone* can (Paul will back
me up on this).  [I am the novice of novices in building electronic stuff]

Hope this helps a bit , Jeff

I purchased a 420 filter and an 800 lfo about a year ago and love them. I 
have been wanting to expand, but haven't had the money until now.
Among the rest of my gear I have a sh101, pro one and a prophet 600 that I 
want to incorporate into the system I build.
Is there something I can send to the prophet's filter cv in? Anyone know if 
the filter cv reacts to a trigger from a 909 or 727?
I can probably only afford 2 more modules, so suggestions would help.

thanks,

chad phillips
http://cfiend.home.mindspring.com/
icq: 9033549 IM: ihatesushi

"Computer games don't affect kids, I mean, if Pacman affected us as kids, 
we'd all be running around in
darkened rooms, munching pills and listening to repetitive electronic music."

I purchased a 420 filter and an 800 lfo

I meant 800 eg.

chad phillips
http://cfiend.home.mindspring.com/
icq: 9033549 IM: ihatesushi

"Computer games don't affect kids, I mean, if Pacman affected us as kids, 
we'd all be running around in
darkened rooms, munching pills and listening to repetitive electronic music."