First try in making an active crossover. Not working.

[junesony]

Hey everyone,
It is my first try in making an active crossover circuit using two TL072 to drive a 4ohm woofer, first TL072 for the buffer and the low pass circuit, the second TL072 for the lowpass equalization. So no sound comes out through the 3rd stage, how come?
Circuit is Similar to this http://www.linkwitzlab.com/images/protos/w-xo-lp2.gif i checked everything out twice but nothing yet... could it be overdriven?

[wakibaki]

Originally Posted by junesony

using two TL072 to drive a 4ohm woofer

Woofer impedance is irrelevant.

What amplifiers are you driving with these crossovers?

w

[junesony]

Woofer amp by the way is LM3886 non-inverting.

[junesony]

For testing purposes:
mp3 player>headphone amp>the above mentioned crossovers>Linkwitzlab LM3886>4OHM speaker
here is the schematic of the amp:
http://www.linkwitzlab.com/images/graphics/3886pwr.gif

[junesony]

Also tried this one(woofer stage only):
Stealth2-Rev3.jpg (image)
But not working either

[wintermute]

Hi Junesony, I hope you are using that as a line level crossover (ie before the amplifiers) and not putting it between your amp and speakers a number of things in your post lead me to think that you might be though.

Tony.

[junesony]

Originally Posted by wintermute

Hi Junesony, I hope you are using that as a line level crossover (ie before the amplifiers) and not putting it between your amp and speakers a number of things in your post lead me to think that you might be though.

Tony.

Hello Wintermute, yes i hope it is correct placement of a line level crossover... this is how i did it:
source->FIIO5 headphone amplifier->active crossover->LM3886 amplifier->4ohm speaker
Do you think i should do away with the headphone amp?

[multisync]

the 3 stages of your crossover are dc coupled. It is possible that you driven the 3rd stage to the positive or negative rail?

[Frank Berry]

How are you powering the active crossover? I'm assuming that it's a bipolar power supply with something like +15 and -15 volts.
A little bit of d.c. offset on one of the stages shouldn't stop the entire crossover from working. Perhaps one of the chips is bad. Is there audio on the output of the first and second stages?

[Frank Berry]

Originally Posted by junesony

For testing purposes:
mp3 player>headphone amp>the above mentioned crossovers>Linkwitzlab LM3886>4OHM speaker
here is the schematic of the amp:
http://www.linkwitzlab.com/images/graphics/3886pwr.gif

The schematic is not an amplifier. It's a power supply.
I assume that this schematic was posted in error.