ADA Depot - A Forum To Support Users of ADA Amplification Gear
Let's Get Technical => All PREAMP Tech Tips & Support => Topic started by: Dna^Yay on June 03, 2014, 02:00:03 AM
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So i just replaced a few opamps and the main EQ chip LF347 with a MC33079. Now im not sure if it is the chip or something else is shorting out on the amp but only the treble will work when eqing the sound, literally bass middle and presence do not work.
Can anyone help out ?
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Tried resoldering the pins of the IC again and it brought in the middle but still nothing on the bass or presence. Now though the whole thing is kaput and im getting signal on the front of the unit but nothing is coming out at all anymore, through the headphone socket i can hear the guitar really quietly. Uhh think its buggered
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My guess is something happend while soldering,maybe a short somewhere?
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My guess is something happend while soldering,maybe a short somewhere?
Thats what i am guessing but literally am having no luck in finding it. Would the amp still work if there was no opamps in it? Could the reason some of the eqs are not working is because some opamps are not soldered in properly?
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yes it should work but the EQ would not work.
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Ok so its got to be some of the dip sockets that are not soldered in correctly then which is not allowing me to change the eq on certain frequencies?
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Since you changed the quad opamp,yes.Another problem is one of the TC9176 chips,but i doubt that in your case.
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I left all of those opamps , just changed the ones near u4, what's weird is that I can hear the signal really quiet through the headphone jack but nothing comes out the output, literally hunted for any loose solder joints but nothing. Is it the main eq chip that would cause the unit to not output any sound anymore?
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No eve if the EQ chip is busted there should be output.Are all the voltages okay? (+-15V)
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I'm not too sure, it's weird because the last thing that happened was the eq light was flickering and the sounds was popping as I played guitar then once I tried to solder it again the output stopped and there's only a tiny bit of volume in the headphones. Il send you a photo of the opamps I changed.