Solid State Guitar Amp Forum | DIY Guitar Amplifiers
Solid State Amplifiers => Amplifier Discussion => Topic started by: lapsteelman on October 13, 2011, 09:22:30 AM
OK, so last night I am playing around with a chipamp (LM1875). I got the circuit done and needed to hook it up to a power supply. I had a power supply done up with a bridge rectifier and caps, but I couldn't find the center taped transformer in the garage. I wanted to test it so I hooked up an non center tapped transformer to the power supply board and it worked. ( Although the voltage were not equal, the negative was about 1.5 volts lower than the positive)
I tried it with the amp and the amp worked fine. Is there a downside to doing this? Could I just put some equal, high value resistors across the caps to equal out the voltage?
I'm not sure as I've never done it without a center tapped. Off the top of my head, I don't see why it couldn't work just fine.
If you put a resistor of say 100k in paralell with each filter cap in the PSU it will help even out the Voltage on the Positive and negitive rails and give you a more stable Ground .....
A downside will be that all of your return currents will be carried by the ground connection and not sinked by the centre tap of the transformer. The neutral is for safety, it's not suppose to carry currents. The ground is connected to the centre tap just to offset the windings. In a bipolar power supply the centre tap sinks return currents from the load.
If you need more info I think http://en.wikipedia.org/wiki/Ground_and_neutral (http://en.wikipedia.org/wiki/Ground_and_neutral) clarifies the situation.
Quote from: Evil_Food on October 23, 2011, 05:59:58 PM
A downside will be that all of your return currents will be carried by the ground connection and not sinked by the centre tap of the transformer. The neutral is for safety, it's not suppose to carry currents. The ground is connected to the centre tap just to offset the windings. In a bipolar power supply the centre tap sinks return currents from the load.
If you need more info I think http://en.wikipedia.org/wiki/Ground_and_neutral (http://en.wikipedia.org/wiki/Ground_and_neutral) clarifies the situation.
Excellent first post, Evil_Food. Welcome to the board!