2. amps-preamps
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filter and tone toggles Audio Research SP-4 Preamp

I would like to know the funciton of the toggle switches: first one: up position = filter, down position = out, second one: up position = tone, down position = out.
tjaco325

Showing 1 response by rrog

rrog
1,958 posts
 
When the switch for tone is up the tone controls are active. When the switch is down the tone controls are not activate. The same is true of the filter. Up the filter is working and down it is not.

This is nothing new. Even Japanese receivers had these controls in the '70s.

Where did you get the SP-4 and what amplifier are you using with it?
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