solitaire Posted June 17, 2011 Share Posted June 17, 2011 Is this true and if so: why is it so? Does that have to do with multiple amp circuits and multiple voice coils or what? Or is this merely a myth? Cheers, Jonas Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted June 17, 2011 Share Posted June 17, 2011 A myth. When you use a Y connector and both inputs, the amp sums the inputs. It's the same thing as sending a signal that's twice as strong. The amp does not become magicaly more powerfull. You can do the same thing by either turning the gain up on the sub or increasing the level of the sub output from your receiver. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted June 17, 2011 Share Posted June 17, 2011 Welcome to the forum! Quote Link to comment Share on other sites More sharing options...
solitaire Posted June 17, 2011 Author Share Posted June 17, 2011 Oh, thank you. I'm sure you're right about it being a myth. I think I read this about a JBL sub at some time way back. Might have applied to that one sub and not generally, but so many abiding to the Y-splitter rule I got the idea that at least subs of US design had separate amps or at least pre amps. I also read a review for a Klipsch sub (don't remember the model now) in which the reviewer said he used both inputs because "it increases the gain by 20". Can't speak for him obviously and not sure why there would be a difference if what you say is true. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted June 17, 2011 Share Posted June 17, 2011 There is an increase in gain. There's not an increase in overall output that the sub is capable of. Again, it has the same effect as turning up the gain on the sub amp. There is no extra amp on the other input. Quote Link to comment Share on other sites More sharing options...
solitaire Posted June 18, 2011 Author Share Posted June 18, 2011 Cheers, so by that you're technically saying the sub infact has separate pre-amps but a common poweramp, then. Quote Link to comment Share on other sites More sharing options...
DrWho Posted June 18, 2011 Share Posted June 18, 2011 Cheers, so by that you're technically saying the sub infact has separate pre-amps but a common poweramp, then. Ya...they need the separate pre-amps so they can sum the L and R signal into Mono. If I were designing for the lowest cost solution possible, then I would probably use a single summing opamp stage since the source will be low impedance. Not sure if that counts as two "separate" preamps, but their outputs will definitely sum. Btw, twice the voltage is +6dB of gain....not sure where that +20 comes from. Quote Link to comment Share on other sites More sharing options...
solitaire Posted June 18, 2011 Author Share Posted June 18, 2011 Thanx, yeah, I suppose he must have meant 20/ 100 on the gain knob or something. Yes twice the voltage should be 6 dB, but the same voltage driving two units I believe is only 3. Quote Link to comment Share on other sites More sharing options...
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