Yahoo Groups archive

MOTM

Index last updated: 2026-04-28 23:35 UTC

Message

Re: [motm] MOTM mixers-->passive or active?

2003-04-25 by media.nai@rcn.com

At 5:37 PM +0200 4/25/03, Aaron Day wrote:
>
>As I don't own one and can't tell from the site are the 2 MOTM mixers
>passive or active--i.e. when you turn them all the way up does that
>equal "0" attenuation or is there gain added at some point?

The term "passive mixer" has a couple of different definitions -- 
without pots or without power.  Both are powered mixers.

This is a quote of Larry quoting Paul S:


To: <motm@yahoogroups.com>
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.

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.