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EQP501 Passive Equalizer / Re: Signal passes through unit, but no EQ

« on: February 25, 2021, 04:48:50 AM »

The problem was indeed the DOA.  I got a new kit and followed assembly meticulously.  EQ works now!  Cant wait for my next one...

Thanks so much.

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EQP501 Passive Equalizer / Re: Signal passes through unit, but no EQ

« on: February 19, 2021, 07:54:29 PM »

I was able to send about 1.9VAC to input and measuring across 0V and TP1 got something closer to 0.2VAC.

In double checking the Setup Guide on Step 4: "DOA Check" I realized when measuring between 0V and TP2 the voltage I get is -2.5VDC rather than 0.  When I take out the DOA the measurement is 0.  Does this mean the problem is in the Op-Amp?

I am also not sure where U1 is or its pins 4 & 8.

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EQP501 Passive Equalizer / Re: Signal passes through unit, but no EQ

« on: February 16, 2021, 10:53:21 PM »

I do hear a quiet click when the unit is powered on and powered off.  I have the DOA inserted and light turns on.

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EQP501 Passive Equalizer / Signal passes through unit, but no EQ

« on: February 09, 2021, 01:38:20 AM »

As the title says: signal passes through the eqp501.  When I turn the wide pot on top of the unit the LED turns green and the unit shows that it is on.  I've looked over all solder joints many times, reflowed, and checked component directionality...same problem.  I checked the DC voltage to eliminate the possibility of the DOA being the problem. When I tried to send a 100hz tone through the unit and measure between 0V and TP1 or 2 I get no voltage (no matter how high the volume or low).  I am not sure what this means or how I might be able to fix it.  I'm so close! Any help is greatly appreciated!

Dan