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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Fixing broken Dell Laptop power supplies

Preamble

Following on from Dell M6700 or M6800, there are a lot of laptops sold without power supplies or chargers. This made me wonder:

  • Is it because they blow often?
  • Why is that?
  • Are they plugged into power hungry docks
  • Are they underrated?

See M6600 Owner’s Review – Warning – Large pics – Personal Opinions for an interesting break down of the power supplies and current draw.

Anyway, I thought that instead of buying an expensive new, or second hand, supply (the 240 W or 330W can go for up to £100+), is it possible to to fix them? Is there a common failure mode? A recurring point of failure?

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Replace your RAMPS fuses

Preamble

Following on from Double the volts… double the fun! here is a nice little tip that I came across to avoid your 3D printer going up in flames…

Replace both polyfuses (PTC) (F1 and F2) in a RAMPS 1.4 board with car blade fuses 5A and 10 or 15 A respectively. The polyfuses, F1 (MF-R1100) is rated to 11 A 16 V, F2 (MF-R500) is rated to 5A 30 V

It should be noted that in subsequent versions of the RAMPS boards (1.5 and thereafter), the fuses are SMD (and may also require replacing).

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