Burnt out USB charger

Preamble

It’s one of those horrifically dangerous 2.5×2.5×2.5 cm mini-cube singe port 1 A USB chargers. There were scorch marks on the base of the case. The circuit was very simple, a simplified SMPS on two small PCBs… which held into the cube casing with white silicone/glue – scratch that away and it is easy to extract the pair of PCBs

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High power USB charging station

Preamble

Whilst looking into the XTAR battery chargers, I came across the XTAR EU4, which offers QC3.0, 2 x USB 2.4A and USB C (PD) ports… although the QC and PD capability is a bit limited (i.e. QC has no 20V capability, and PD current is limited to 20V 2.25A (45W)), but not by much…

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Synth Power Supplies

Preamble

Sort of following on from VCO madness, I was really looking for the Super Simple VCO (which seems to be actually a 555 timer as a VCO, see the GetLoFi LFO in Ha Ha Ha… 555 fun). However, I got distracted and ended up analysing PSUs and buses for synths.

For ease, in order to power my synth, I had been planning on using a couple of single rail 12V SMPS designed for LED lights, in order to make a dual rail supply, but I started to wonder about the noise implications – as all designs for synths appear to use the old fashioned transformer, rectifier, and linear regulator approach.

(As an aside, Julien Ilett also points this potential noise (as related to buck convertors and SMPS) issue out in Julian builds: a Split Voltage Power Supply (+/-12v and 5v) @5:20. See also, Julian’s Postbag: #85 – E.Ink, Spring Onion, Split PSU (@7:33-8:00), where he mentions that high frequency noise is not removed by the linear regulators in the Split Rail Power Supply Kit Build – SEPIC Cuk Topology).

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AC Supplies

Preamble

My mate Pavel had been having trouble finding an unusual power supply for his effects pedal, 9V a.c. There were a number avaiLable, specific to his device rather than general AC PSU, on eBay but these were a bit pricey.

Then he find this Instructables guide which makes the solution quite obvious: “root two times nine”

Featured image from flickr.

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