From the photo on the first page of the thread, the unit has LEDs for the following marks: -30, -18, -12, -6, 4, 10, 22.
Why would one push the levels to the 4, 10, or 22 levels? Obviously not for our use, but surely for some - can someone shed some light for me?
I wondered this as well, basically the meter is 'with reference to the output'. Here is what is written in the manual:
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An eight segment LED bar-graph meter is fitted to each channel, calibrated in dBu as follows: -30, -18, -12, -6, +4, +10, +16, +22
With Refrence to the balanced output signal level.
The input level can be determined by reading the Meter indication, then subtracting the Gain settings of the Sensitivity swith and the Trim control. For Example, if the meter is reading +10 dBu, with the Trim control at, say, +2 and the main Gain switch is at 42, the level of the input signal is 10 - 42 - 2 = -34 dBu.
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I haven't got the hang of this yet, so I use them to make sure each channel is level, then use the AD500 and JB3 to detect clipping.