So I have these Philips (FW-V355) speakers, and I want to connect them to my PC via AUX or Bluetooth, ofc I separated them from their original old system/amplifier. In order to realise that, I bought an audio amplifier to power up the two 40+40ohms, 6 ohm speakers. It's (SANWU® 50W+50W TDA7492 CSR8635) from Banggood (http:// bit.ly/2Ab3XM3 ) it's relatively cheap and delivers big power (50w+50w) with positive reviews. Yes it's a little bit over powered but I heard it's better to have overpowered speaker than underpowered, and I also want high volume speakers, with minimal distortion. Now the third component to my setup would be ofc, the power supply to power the amplifier. And here starts my confusion, so I'm willing to buy this one from AliExpress (http:// bit.ly/2BfvdWQ), and they have 12V, 10A power supply, as well as a 24V, 5A version. Both deliver 120W of power. I know I'm getting more than the needed 100W of the amplifier, but again overpowered>underpowered. So my question is which one should I buy, the 24V 5A one, or the 10A 12V One?.

I tried to look online for the answer but didn't find a clear conclusion for my specific case, thus I'm writing this post :). If you need any further informations abt the speakers ,the amplifier or the power adapter I'm using, you have all the names u need, so feel free to look em all up online (I don't wanna get the 'it depends' answers :D), also I listen mostly to pop/hip hop music, so I'm all abt that bass x). I've heard on a forum that bass woofers would do better on a high-current power supply, and tweeters would sound better on a high-voltage one, but I'm not sure how accurate is that.

Thanks in advance for anyone who's willing to share his knowledge and help me out of this situation.


closed as off-topic by brhans, Wesley Lee, Trevor_G, winny, R Drast Nov 28 '17 at 10:59

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – brhans, Trevor_G, winny, R Drast
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  • 1
    \$\begingroup\$ electronics.stackexchange.com/questions/34745/… \$\endgroup\$ – brhans Nov 28 '17 at 2:21
  • \$\begingroup\$ looking at the photo in the link, it appears they have an onboard DC-DC smps anyway, so it doesn't matter. \$\endgroup\$ – dandavis Nov 28 '17 at 2:32
  • \$\begingroup\$ From the Q&A section banggood.com/… \$\endgroup\$ – Trevor_G Nov 28 '17 at 2:34
  • \$\begingroup\$ Why not use the Philips unit to power and contain everything and just have a BT dongle input to AUX. It is only rated for 40W rms into 6 ohms at 10% THD at 1kHz, so dont push it or you will blow the speakers on bass. get a sub-woofer \$\endgroup\$ – Sunnyskyguy EE75 Nov 28 '17 at 2:37
  • \$\begingroup\$ @dandavis the SMPS is probably for the Bluetooth though. The amp itself may use the raw DC \$\endgroup\$ – Trevor_G Nov 28 '17 at 2:44

A class D amplifier is basically a fancy bipolar buck converter, which means it can output any voltage into the speakers up to the power supply voltage.

The amplifier is rated for an input from 8v to 24v. It will function down to 8v, and provide maximum power at 24v.

The absolute maximum power you will get into a 6ohm load, assuming bridged speakers and neglecting all losses, is V^2/R, or 24 watts at 12v, and 96 watts at 24v. Clearly you will need the 24v supply to get 40 or 50 watts.

As a class D is a buck converter, it will draw less current on its input than it delivers to the loudspeakers (not magic, just conservation of energy, and the reason class D is popular), so the lower current 24v supply will be fine.

  • \$\begingroup\$ Thanks Neil, very helpful and you very well know your stuff. \$\endgroup\$ – cosmicmind Nov 29 '17 at 0:29
  • \$\begingroup\$ the usual etiquette on here is to accept an answer if you feel it answers your question. \$\endgroup\$ – Neil_UK Nov 29 '17 at 6:21

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