Hi, i am new to here, i have a quite stupid question to ask, suppose i have a gainclone stereo amplifier with two LM3886, how i can split out and modify to install another mono LM3886 to sound up a subwoofer speaker. An easy way to say is, to make it 2.0 to 2.1.. can you guys show me any schmatics for me 🙂 thanks
regards
regards
Just add 10K resistors to each channels line level output, then connect their other pins together. And from this junction put another 10K to the gorund.. Means make a Y shape with 10K resistors.. One branch to left channel, one branch to right channel and one to ground..
Then from the center point, connect your subwoofer..
Then from the center point, connect your subwoofer..
An externally hosted image should be here but it was not working when we last tested it.
actually i not really understand.. ~.~
why no need to add another extra amp on it example a LM4651/52? ~.~
by the way, my bronze BR2 show it's weakness on movie, i need certain ooohmmm when playing movie.. 🙂
guide me out please .. 🙂
Hi,
use an inverting opamp as a summer amplifier.
Each channel is fed in through it's own resistor.
These meet at the opamp -IN input where the impedance is very low (virtual earth). Both signals add at this virtual earth and due to the very low impedance there is no crosstalk to the other channel.
If the opamp is configured as a CFB filter then the one opamp becomes the summer and low pass filter and sends it's combined signal on to the power amp.
If you are feeling very ambitious you can substitute the chipamp for the opamp and combine the whole shooting match into one chip.
ps,
DX has it all wrong.
use an inverting opamp as a summer amplifier.
Each channel is fed in through it's own resistor.
These meet at the opamp -IN input where the impedance is very low (virtual earth). Both signals add at this virtual earth and due to the very low impedance there is no crosstalk to the other channel.
If the opamp is configured as a CFB filter then the one opamp becomes the summer and low pass filter and sends it's combined signal on to the power amp.
If you are feeling very ambitious you can substitute the chipamp for the opamp and combine the whole shooting match into one chip.
ps,
DX has it all wrong.
Simple.
Buy a plate amp for your woofer and use the speaker level inputs. The amp has a high pass for your satellites and the woofer XO is variable to match. Sound quality degradation is negligible. Done it many times.
Buy a plate amp for your woofer and use the speaker level inputs. The amp has a high pass for your satellites and the woofer XO is variable to match. Sound quality degradation is negligible. Done it many times.
now this look interesting 🙂 Is it just simply connct parallel with my gainclone to the signal output source? By the way i will use one dualchannel opamp indeed of two mono channel op. But i still, don't get the meaning of R3, R5, and R7? why it need to be attenuater? For R3, is it tone control? and thanks, you have help me a lot 🙂
Dxvideo said:
Not wrong as such but wrong in this application. You want to feed only the lows
to the sub amp and woofer.
A summing amp is usually inverting. If you make it non-inverting, you get significant cross-talk.Dxvideo said:
Westerp said:
So, whats the difference between your circuit and mine? Except inverted and noninverted design, some gain and filter elements? In fact I was about to advice a LPF after that also..
May be, a better configuration adviced but nothing wrong I see..
Not in the sub. Crosstalk in the main channels. The signal coming from one channel not only goes to the summing op amp, but also to the second channel. AndrewT explained above, why this is less of a problem with an inverting op amp.Westerp said:
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