Power Supply Debugging (for the Morgan Jones amp)
Apr 24, 2011 at 12:28 AM Thread Starter Post #1 of 2

keabler

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My friend and I are building the Morgan Jones headphone amplifier for a school project (the one with feedback which can be found here http://gilmore2.chem.northwestern.edu/projects/cmoy5_prj.htm).
 
The power supply I used is:
 

 
When we turn the circuit on we only see about 40V from the output of the power supply.  We have been checking every thing we can think of and we can't figure it out.  Does any one have any suggestions for what could be wrong?  Are there any common mistakes that are easily overlooked?  We have the correct voltage from the heater circuit so the rectifier should be in right.  The AC voltage we measure from the transformer leads is 253V.
 
Initially when we would turn the circuit on the voltage would ramp up to maybe 300V and then we would shut it off (300V is with in our capacitors operating range) so we didn't burn any thing out.  We decided to just rebuild the circuit on a different part of the turret board and now we aren't getting enough voltage (do you think we damaged something)?  
 
We are just really hoping some ideas because we are out of them.  It would be less of a big deal but out project is due on Tuesday.
 
Thanks
 
 
Apr 24, 2011 at 9:38 PM Post #2 of 2
you haven't inadvertently connected R1 to ground ? this would overload your circuit and pull the output voltage down. Maybe one of the caps with switched polarity? There is not much you can do wrong with a simple supply like this, it must be something so simple that you cannot see it staring at you..dB
 

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