MOTM

From: "J. Larry Hendry" <jlarryh@...>
Date: Wed, 11 Apr 2001 18:33:32 -0500
Subject: Re: [motm] 830 dual mixer attenuation question

----- Original Message -----
From: Jeffrey Pontius <jpont@...>
Taking another look at the 830 in the News section, I'm
wondering about the levels numbering around the IN1 - IN3 pots.
IN1 has 0 to 10, and IN2, IN3 have -5 to 5.  Do these indicate
that IN2 and IN3 are full at 5 and that IN1 has twice the gain past
full?  Or is the numbering only relative, ie., full at 5 for IN2 and IN3
and full at 10 for IN1?
Jeff

Jeff, here is the last thing from Paul on the subjec of individual channel
gain:

Paul S wrote (to the list):
-----------------------
Something to be aware of........

When the Mixer is is dual 3:1 mode, each set of pots is set for full dynamic
range. That is to say,
if you have 3 full-scale inputs (-5V to +5V) the output with all pots on
11...err...10 is -5V to +5V.

So, the 'channel gain" is 0.333

But, what happens in 6:1 mode?

On the 'log pot' side, the output is summed into the second mixer with a 1/2
scale factor. So, for
the "audio" side, the channel gain is 1/6 (0.166666).

So: in 6:1 mode the 3 log pot channels are 'full range', 0-10 for their gain
ranges.
the 3 linear pots are at 1/3 channel gain, so they are more sensitive and
cranking all 6 pots to
max will cause the output to be +7.5V to -7.5V pk-pk.

Now, this is *not* going to "blow stuff up" or such. This is just the
MAXIMUM CV range for MOTM modules.
Look in the back of the manuals, I spec -7V to +7V control voltage range.

So, in this manner of compromise, we trade off knob 'sensitivity' in 3
channels to get max range in the other 3
AND still keep the overall output at the max spec limit.

Paul S.

> you might, come to think of it).
>
> If you read the MOTM-830 manual, there is extensive discussion on the gain calculations and how
> to modify them.
>
> Paul S.
>