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Scott Dorsey Scott Dorsey is offline
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Default [OT] Adding volume control to electronic device

gray_wolf wrote:

Remember the old drive in movie theater speakers with the volume control?=


Those were 70V system. 70V constant power going down the cable, each tap
has a step-down transformer, then an L-pad (not a simple pot but a three
element pad so the transformer always sees an 8 ohm load) and a crappy
speaker. Because they were all parallel loads, if the main cable was shorted
by someone driving away without removing the speaker, it would take all of
them down.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."