Logitek ULTRA-VU, Operation & Service Manual

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2-8 Connecting Analog Input Models
The Ultra-VU accepts balanced or unbalanced in-
puts via rear panel XLR connectors on analog input
only models or 3-circuit 1/4" phone plugs on dual in-
put models. The connectors are wired as follows:
Balanced Connection
Pin 1 or Sleeve Shield
Pin 2 or Tip
Pin 3 or Ring Signal -
Unbalanced Connection
Pin 1 or Sleeve Shield
Pin 2 or Tip Center Hot
Pin 3 or Ring Connect to pin 1
The Ultra-VU shield pins are bonded directly to the
chassis at the connector and do not share any ground
paths with the internal circuitry. This allows cable
shields to be connected at both ends without causing
hum problems.
The zero reference level for each input can be set
anywhere between -10 dBu and +20 dBu by adjusting
the multiturn gain control located adjacent to each in-
put connector. A small flat blade screwdriver is
needed to adjust the gain.
2-9 Rear Panel Programming Switches
A block of eight mode setting switches is located
on the rear panel of the meter to the right of the input
XLR connectors. The switches are numbered 1
through 8 and are set by pushing the white levers up
or down with a small screwdriver or pen point.
The bargraph zero reference marker and the refer-
ence level of the zoom display is set via switches 6, 7
and 8 as shown.
Zero Reference Setting
Sw6 Sw7 Sw8 dBs below full scale
Up
Up Up -10 dB
Up Up Dn -12 dB
Up Dn Up -14 dB
Up Dn Dn -16 dB
Dn Up Up -18 dB
Dn Up Dn -20 dB
Dn Dn Up -20 dB
Dn Dn Dn -20 dB
A second set of orange markers indicate the de-
sired peak operating level. Switches 3, 4 and 5 set
these markers a fixed number of dBs above the zero
reference level.
Peak Marker Setting
Sw3 Sw4 Sw5 Function
Up
Up Up +18 dB above reference
Up Up Dn +16 dB above reference
Up Dn Up +14 dB above reference
Up Dn Dn +12 dB above reference
Dn Up Up +10 dB above reference
Dn Up Dn +9
1
3
dB above reference
Dn Dn Up +8 dB above reference
Dn Dn Dn Off
Switch 1 turns the peak display on and off. This is a
single red dot with a fast attack time and a slow re-
lease time. Peak hold is controlled from the front
panel and is unaffected by switch 1. Switch 2 sets the
dynamics of the peak display. True peak shows the
largest single peak. This mode is useful for avoiding
digital clipping. PPM mode averages the peak read-
ing over a short period and is comparable to PPM me-
chanical meters. The green average display is
unaffected by switch 2 and is always VU response.
Bargraph Settings
Sw1 Sw2 Function
Up
Peak display OFF
Dn Peak display ON
Up True peak dynamics
Dn PPM dynamics
The programming switches are only checked oc-
casionally, so it may take up to two seconds for switch
changes to be reflected in the meter’s operation.
** Ultra-VU Operation & Service Manual ** Page 6