MOTM

Revised numbers, taking my patchbay, mixer and some cables out of the
equation.

banana jack system:  -82.43 dB RMS (using shielded banana/1/4" cable to
mult)
banana jack system:  -82.08 dB RMS (using 3' banana/banana cable to patch
panel)
MOTM system:  -92.92 dB RMS

Interesting that the banana jack system improved more than MOTM, but my
computer audio setup is limited to around -93 dB so I believe we're just
seeing the limitation of my measurement setup.

This does not include the banana jack system recommended setup of connecting
the power supply ground directly to the interface ground, as my audio
breakout box does not have a ground lug.

I was using the MOTM-440 filter which uses TL072 op amps.  These are good
enough for CD quality audio, as indeed my results show.

John Loffink
microtonal@...

----- Original Message -----
From: "Paul Schreiber" <synth1@...>
To: "MOTM Mail List" <motm@yahoogroups.com>; "Microtonal"
<microtonal@...>
Sent: Sunday, July 08, 2001 9:11 AM
Subject: Re: [motm] Signal to Noise Ratio


> The mixer is the "noisy" thing in the loop. I read -91.5dB without a
mixer.
> Also, the filters use
> 'vintage' 4558 op amps which are adding some as well.
>
> Remember, 15dB is like a factor of 5 TIMES lower noise with the MOTM
> system!!!! I'm kickin' serious ass!
>
> Paul S.
>
> > Has anyone else had results like this?
> >
> > banana jack modular synthesizer, circa 1994-1995
> > Filter to vca to mixer, no signal input to filter, no other patches, all
> > appropriate levels set to max.  Used shielded banana to 1/4" cable to
> > multiple, then to patchbay, as results for a 3' banana/banana to patch
> panel
> > were atrocious, about -40 dB, some obvious signal leakage was seen -
> bursts
> > of signal.
> > -70.99 dB RMS (signal to noise ratio, unweighted)
> >
> > MOTM system, circa 2000-2001
> > Filter to vca to mixer, no signal input to filter, no other patches, all
> > appropriate levels set to max.
> > -85.49 db RMS (signal to noise ratio, unweighted)
> >
> > Other limitations in my setup (cables, patchbay, mixer, 24 bit audio
card)
> > may have given the -85 dB limitation, but the comparisons are
appropriate
> as
> > I used left and right channels simultaneously for the measurements.
> >
> > John Loffink
> > microtonal@...
> >
> >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>