Simple amplifier needs simple bipolar PSU

C

Thread Starter

Callum

Hi,
I've made a simple amplifier circuit with an amplifier IC which takes +/- voltage (I'd like to use something in the region of 12v-18v). It should consume no more than 40W at those voltages, but higher power rating is better.

The issue I have is generating the 12v-18v without anything complex or with something pre-built. For now I've been testing it with two 9v batteries generating a +/- voltage but they drain very quickly.

Is there an easy way to do this? I thought about simply rectifying the +ve and -ve part of an AC wave but really at that kind of power the ripple's going to be pretty big.

Thanks in advance!
 
es this can all be done pretty easily. Your simplest option would be a transformer with a centre-tapped secondary. The centre tap connects to the 0V rail and the two ends connect to the AC input pins of a bridge rectifier. The positive and negative outputs from the bridge become the positive and negative rails, and must be individually smoothed with big electrolytics connected to the 0V rail.

If you're concerned about hum, or you want to maximise your output power, you can use regulators, as long as you increase the transformer voltage to allow for the voltage that must be dropped across the regulator.

I did an image search and found the following:

http://store.qkits.com/moreinfo.cfm/QK186
https://www.electronicspoint.com/threads/what-is-negative-voltage-power-supply.250018/#post-1478606 with a good explanation by davenn
http://orca.st.usm.edu/~jmneal/dual_psu/ with adjustable regulators and explanation
http://www.aaroncake.net/circuits/supply3.asp?showcomments=all

You could also use a pair of switching power supplies. These would be more compact, more efficient and therefore cooler running, and already regulated. The only disadvantage might be the switching noise getting into the signal path.
 
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