G Evans Posted January 26, 2001 Share Posted January 26, 2001 Sorry to butt in chaps but following my comment in Three speaker stereo thread : as I mentioned there many vintage Scott amps provided a center channel derived from the 16 Ohm tap , but ment to feed a third amp with a Z in of 100K at least :-) . One version used two 8.2K from L/R and one 1.5k to earth. Another version used 82K from L/R and a 15K pot to earth for level adjustment. Advantages of this is that center channel level tracks L/R flanks automatically and does not interfere with L/R channels balance or introduce crosstalk (L/R coupling). Disadvantages are that the C Ch will be fed any noise ( like hum) and distotion generated in the stereo amp o/p satges and speaker back emf transients . Derived from the preamp volume control, some crosstalk will result always depending on resistor values and the output Z of the stage driving the volume control. Taking the output from the volume pot cursor will worsen this. The only way to prevent crosstalk with this scheme is to use an active mixer like an op-amp but all-tube rigg devotees will not buy this of course , I certainly wouldn't. George Three speaker stereo Quote Link to comment Share on other sites More sharing options...
MacKlipsch Posted February 1, 2001 Share Posted February 1, 2001 see post to Three Speaker Stereo::: I used to have to use the speaker outs from my integrated amp to the box and then on to the mono amp as described in figure B of the schematics from Klipsch...much better now that I have separates and can use the pre-amp outs...cuts out alot of noise and unnecessary paths.. Quote Link to comment Share on other sites More sharing options...
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