Appendices; Battery Information; Setting Trim Pots - Lynx Hilo Preliminary User Manual

5 Appendices

5.1 Battery Information

Hilo can operate off of a portable DC Battery Pack for field recording or whenever AC power is not available. The
BATTERY IN connector is located directly above the AC connector on the Hilo back panel.
Battery Packs can be purchased from retailers of video cameras and other electronics equipment. Almost any lead acid
or lithium battery should work as long as it has the following characteristics:
•
9-18 Volts. Typical choices are either 12V or 14V.
•
A 4-pin XLR connector. The connection should have pin 4 hot, and pin 1 for ground. No other pins are
connected. This is a standard configuration.
•
Hilo consumes 22 Watts. Check with the battery's stated watt hours to determine operating time you can
expect with a fully charged battery. For instance, a 60 watt-hour battery would provide up to 2.72 hours of
operation.

5.2 Setting Trim Pots

As discussed in sections 3.4.5 and 3.4.6, Hilo's Line Inputs and Line Outputs can be set to Trim values of +18 dBu;
+20 dBu; +22 dBu; +24 dBu; +0 dBV; +2 dBV; +4 dBV and +6 dBV. These trim positions are factory calibrated to
these values within 1/100th of a dB. Trim levels can be selected from the Hilo Home Page. These set levels will satisfy
the overwhelming majority of Hilo users.
In some cases, these levels may need to be tweaked to match the reference level of gear that is not calibrated as
accurately. Also, in time and due to changes in temperature, it may be necessary to tweak trim levels to set them back
to their original reference.
For this purpose, Hilo has ultra accurate, 25-turn trim pots accessible from the bottom of the chassis that can be used to
adjust + or - .5dB from the established trim level. Here are the steps to calibrate via these trim pots:
3. It is best to use sine wave tones to adjust trims. If adjusting Input trim levels, send tones from an external
device and measure the results in either software or a scope with digital inputs. It is best to avoid analog input
routed to analog output paths for this kind of calibration. If adjusting Hilo Output Trims, send tones from a
software source via the USB connection, or tones from an external device connected to one of Hilo's digital
inputs routed to the Line Out. Make sure that the entire signal path is set to unity gain.
4. Adjust the trims clockwise to increase the gain on the inputs or outputs, or counter clockwise to decrease gain
until the desired reference level is achieved.
1. Remove the plate from the bottom of Hilo. There are four screws that
hold it in place. The front-right rubber foot will need to be removed to
allow access to one of the screws. Locate the input and output trim
pots on the underside of the Hilo main board.
2. Set the Line In and/or Line Out trim levels on the Hilo Home page to
the value closest to your desired level.
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