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Mon newpg5.doc, Usage examples – Dangerous Music Monitor User Manual

Page 5

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Usage Examples

The ANALOG switches select from four sources to be listened to. The

selected source is sent to the “Functions” group and the “A-MTR” feed on

the back panel. The fourth analog selection is a built in D/A converter which

is fed by the selected “Digital” switch.

The “Functions” group allows channel phase reversal, speaker mutes, mono,

volume dim, alternate speaker selection, and a VU meter offset (to keep

from thrashing the meter movements when listening to high level program

material). The volume control is a 21 position stepped attenuator. It was

decided in the design process to use an attenuator for its accuracy and

repeatability. It was also found that attenuators provide consistent sound

quality at all volume settings whereas pots tend to change sonic

characteristics and balance depending on the setting. Pots also require DC

blocking to reduce scratching noises on adjustment. The gain of most power

amps today is set very high so the attenuator range is set for about 30 dB of

loss. Since it is desirable to occasionally listen to the noise floor, which

requires unity gain at the volume control, the last two steps are pretty big.

Please use caution near the top of the volume control.

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