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Subject: Re: How to connect balanced signals to the MOTM

From: "coyoteous" <antithesist@...>
Date: 2006-03-30

--- In motm@yahoogroups.com, "Paul Schreiber" <synth1@...> wrote:
>
> MOTM uses very large signals on the outputs: 10V pk-pk which is something like
> +24dBu

22.22 dBu reference: 0.775 V
20.00 dBV reference: 1 V
22.22 dBm reference: 1 mW at 600 ohms

(u = unloaded/m = 1 mW)

> Most "studio" gear uses +4 dBu which I think is like 1.5V pk-pk.

3.47 volts (p-p)
1.23 volts (RMS)

- but that is the operating level. Good gear will have 10 to 20 dB (or more) of headroom
above that. So, the better your equipment is, the less you will probably need to pad your
modular output, if at all. For example, this baby will take +30 dBu [that's almost 70 volts
(p-p)]:

http://www.spl-usa.com/dmc/2490_specs.html

> Mics need balanced cables because their outputs are in ∗microvolts∗ to say 5mv
> (that's 0.005V).

Right, 5mV = -43.8 dBu or about half of half of half of half of half of half of half of half of
a +4 dBu signal (1/256th? - you get the idea, my math may be off).

Barry S.

> Since the 'driving' signal is so small, any hum or noise is ∗relatively
> significant∗.
>
> Paul S.