Output Limiters - PSC AlphaMix Operation Manual

cut corners and wind their transformers on standard single output size cores.
Ours were custom made to our specifications by a leading transformer
manufacturer. Transformers have been chosen over a transformerless design
because of their inherent ability to interface with virtually any other device,
especially RF based products. This is very important in this day and age in
consideration of the frequent use of multiple RF transmitters. These outputs are
available via the right hand panel mounted male XLR connectors. These outputs
are switchable between line or microphone levels. At the line level setting, the
mixer outputs deliver a nominal +0dBv signal into 10K Ohm loads. When set to
microphone level, the outputs supply –50dBv signal levels. Please note that 10K
Ohm loads are typical of the loads imposed on the mixer by most Betacams, and
other recording devices. Additionally, the AlphaMix's outputs are capable of
driving 600-Ohm loads.
B. MULTI-PIN (BETACAM) CONNECTOR
The AlphaMix is equipped with two multi-pin in/out connectors designed primarily
to interface with Betacams. These connectors provide left and right balanced
outputs as well as left and right tape returns used for confidence monitoring. The
two connectors are labeled Camera A and Camera B. The Camera A connector
is wired in parallel to the standard XLRs. These multi-pin connections provide a
convenient means of interfacing the AlphaMix to two Betacams. Professional
Sound Corporation manufacturers a complete line of Betasnake cables used as
umbilical cables between mixer and camera. These cables are offered in 15' (4.5
meters) and 25' (8 meters) lengths and with and without camera fan out
breakaways (quick disconnects).
C.

OUTPUT LIMITERS

The limit threshold (activation level) is factory set at +3 on the meter. The limiters
compress the signal at approximately 2.7 to 1 ratio. This is to say an increase of
2.7dB in input signal will result in only a 1dB increase in output signal. Output
channel limiting is displayed on the LCD meter.
The AlphaMix contains two separate limiters that are controlled by one front
panel mounted switch. This switch has three settings: Off, Separate (S), and
Ganged (G). In the off position, no limiting occurs.
In the separate position, the limiters act independently of each other. This is
especially useful when recording split tracks. I.E. interviewer and interviewee on
separate channels. Thus, if one person un-expectantly raises their voice, that
limiter will activate, but the other will not. In the ganged mode, both limiters are
tied together and can be triggered by either input. This is useful in recording
stereo, as independent limiting would alter the stereo image. PRACTICAL USE
NOTE: IT IS HIGHLY RECOMMENDED THAT THE LIMITERS BE USED AT
ALL TIMES WHEN RECORDING TO BETACAM TYPE CAMERAS. Most video
cameras have limited audio track headroom and can easily be overloaded
resulting in distortion of the recorded audio. Play it safe, use the limiters!
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