Dual supply SMPS - wrong purchase?

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Strgeo

Member
Joined 2022
#1
Hi,

I'm looking to upgrade the power supply for my DIY amp. I've currently hooked it upto a 24V wall wart supply. I've got a +/-40V SMPS supply with 3 output connections : V+, V- and GND.

My amp has 2 power input connections : V+ and GND. The amp manufacturer recommends a single supply SMPS.

The amp requires 24V to 51V. I have no electronics background, and reading how SMPS psu's work is hard going. But it looks to me as if I can't use the +/- SMPS supply.

Any ideas/suggestions, or do I bite the bullet and buy a single supply SMPS?

Thanks
 
#2
Hi, using dual supply smps is not proper choice. More power loss , also depending on topology of smps , you can't load only one output side, or put a load between plus and minus outputs, missing ground. Also depends on smps,it is unregulated or regulated ( output voltage not sags with load and sometimes even adjustable ). Also power utilisation suboptimal ,if only one side loaded.
 
#3
Some SMPS has the output floating around ground (box earthed) so you can wire it positive or negative ground. Check from manufacturer's data sheet if available, or use a led plus a 2.2K in series to see if the ground terminal is effectively floating (led dark) or if it is a split power supply (led brite). Check it between terminals marked as V+, V- and gnd as you said.
 
#7
This is the info I have :

Manufacturer/Distributor states specifications as follows:

- Model: HBP500W Power Supply Board for Audio Amplifier
  • Input voltage: AC 100-120V/200-240V
  • Output voltage:
Fixed main power supply (500W) voltage:
  • Auxiliary voltage: +/-15V, 1A (common ground with the main power supply),+12V, 0.5A (independent ground wire);
  • Auxiliary power supply, 7815/7915/7812 voltage regulator
  • Recommend 200-400W amplifier.
  • Size: 100*133*50mm
  • Transformer: 0.1mm*100 anaerobic enamel covered wire, efficiency 90%
  • Electrolytic capacitors with high frequency and low impedance, low ripple.
 
#11
Dual supply psu's required for class A / AB amplifiers , for direct speaker connection , without coupling capacitors. Class D chip amplifiers mostly use single rail psu , because they use bridged speaker connection, so no speaker connection to ground.
 
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