My son and I are making an amplifier from a board from Amazon that requires 9-26 V DC input. I have an old laptop charger and am wondering if I can connect more ancillary boards such as input selection or tone control boards using the one power supply. If so, what would the wiring look like for this? If not, can I connect multiple power supplies to the same AC input into the case we will build? What will the wiring look like for this, would it just be as simple as looping wires from the incoming AC cable to the different power supplies? Would they then be wired in parallel?

We're both just learning. My son is autistic and has shown a keen interest in all things HiFi and electronic so we are going to learn as we go on together.

  • \$\begingroup\$ Welcome! Please post a block diagram or schematic. \$\endgroup\$
    – winny
    Sep 6, 2023 at 12:05
  • \$\begingroup\$ Well I was hoping someone would show me or explain to me what the wiring diagram should look like \$\endgroup\$
    – jamesccart
    Sep 7, 2023 at 16:24
  • \$\begingroup\$ Can you draw a block diagram of what you have, inputs and outputs? \$\endgroup\$
    – winny
    Sep 7, 2023 at 18:26

1 Answer 1


A single power supply can be shared with multiple "loads" provided that

  • All loads are tolerant of the voltage.

  • Total load current is less than that able to be provided by the power supply.


You do not say what voltage the laptop charger provides.
The most common is 19VDC. They can also be 16V, 12V and "other".

In this case it is likely that most other loads would use a lower supply voltage - typically 12 VDC. 5VDC is also common.
If so, using two or three supplies may be better.

The supplies should have their negative outputs joined.

Sourcing power supplies:

Used power supplies for various items of consumer equipment are extremely commonly available - often at no cost. Output plugs can be used, or they can be cut off and the wires terminated in some other manner.

Choose supplies with electonic regulators - these are now almost the only ones sold, but older ones often used transformers. Transformer based supplies are usually far heavier per size and have lower power ratings per size. The reason not to use them is that most have poor voltage regulation. A 12 VDC rated supply may output 14 or 16 or more volts under light or no load. This can be catastrophic for some equipment.

AC commoning.

You could "loop wires from the AC input.
As you are new to this area I suggest that it would be safer to use existing mains cables and a "power distribution board", with each supply either plugging into the distribution board directly, or via a premade power cable. This may look a little "Heath Robinson" inside the case - but would not be discernible from outside the case.

  • \$\begingroup\$ thanks I'd like to have it a bit tidier than that but I understand you comment re experience .I wondered if there was a standard way of wiring this ie connector block or something like that if the cables had to be heat shrunk etc \$\endgroup\$
    – jamesccart
    Sep 7, 2023 at 16:21
  • \$\begingroup\$ @James Connections are tidy if they are inside a closed case :-). || There are various somewhat standard ways of connection using push on crimped terminal, or soldering or connector blocks or ... BUT they are more something more easily found by looking at web tutorials and images than an answer here. That is not meant to fob you off but to note that the nature of this site is aimed toward singl well defind questions with quality answers that help others. That said, a connections "tutorial" WOULD have its place on this site. Not from me just now alas a too much else calls. Sometime maybe. BUT.. \$\endgroup\$
    – Russell McMahon
    Sep 8, 2023 at 1:18
  • \$\begingroup\$ Answers from me and others Here are liable to be useful. || Also here. || This is right on target. || This is immensely important . || Useful and useful and maybe \$\endgroup\$
    – Russell McMahon
    Sep 8, 2023 at 1:29

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