I have inherited from a friend a lot of car speakers, amplifiers and related equipements, 'cause his widow says i'm the only friend with some general interest in this field. Most of these stuffs are from the eighties, some are rusty, some were flooded a couple of years ago and recovered, anyway almost all are in an unknown state, so i want to test them all and decide what to keep, sell or discharge.

I tried one functional amp by using a PC power supply but it can't handle the power peaks.

I have a big 230V to 24Vac transformer, which could handle the required power, but i'd need to build a circuit to have the 12~14Vdc.

I'm not really an expert so i don't know how to take care of the required power, so my question is: what could be a cheap circuit to have 12Vdc and enough power to test that equipement, starting from 24Vac?

("test" means that i doubt i will try to go to full volume, and that i don't care if the circuit can generate some noise... all i want is to see what's working and what's not)



Buy yourself a cheap bench power supply.

Since you have no idea of the functionality of the units you are trying to power up you really need something that can limit, and display, the current the thing will try to draw when you plug it in.

Nothing does that better than a bench power supply.

You can probably find a cheap used one somewhere.

  • \$\begingroup\$ I agree that a bench supply is the way to go. Unfortunately something which can supply lots of current for car amplifiers and the like won't fall in the cheap category! \$\endgroup\$ – Colin Apr 28 '17 at 11:36
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    \$\begingroup\$ @Colin__s, True, but first he needs to see if the thing will even power up, especially the ones that were flooded. \$\endgroup\$ – Trevor_G Apr 28 '17 at 11:38
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    \$\begingroup\$ There are plenty of Chinese made supplies on Ebay that are rated for 0 to 30 volts at 10 amperes for about $60. These should be more than adequate. \$\endgroup\$ – Barry Apr 28 '17 at 12:33
  • \$\begingroup\$ Well, i generally agree on a bench supply. Fact is that i have to stay at minimum expenses. I'm a programmer working in an electronic lab, so i will spend nothing or near to nothing if i can build a circuit with common components, or by just buying something from the lab supply channels. So, while i apreciate your tips, i'll like to stay on the question and try to build something :) \$\endgroup\$ – Parduz Apr 28 '17 at 23:17

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