Audio capacitors from PC powersupplies?

[Lisandro_P]

So, a friend of mine left a bag full of dead PSUs at my house a couple of days ago. I proceed to scavange parts from them, and promptly noticed every single one of them has a rather bigh 1uF non-polarized capacitor for filtering purposes, near the 220VAC side. I'm pretty positive they're polypropylene film caps (they look like this - not that brand though).

Are these any good as audio parts? I know some people here might faint at the mere thought of second-hand parts from a PSU in the audio path, but they seem to be quality capacitors. And the price is right

[singa]

Hi lisandro,
If they're polyprops then it's suitable for audio except the tolerance may not be close i.e. like +/- 20 %.10% is o.k.
At the least they are polyester.Most PP's have MKP markings and MKT for polyester.Even the electrolytics are 105 degrees rated which have lower ESR than standard 85 degrees types.It does'nt have to branded types.

[pinkmouse]

Free stuff is good stuff!

Give 'em a go, you can always swap them out later if you don't like them. As singa said though, you might want to check tthe capacitance first if you are using them somewhere critical.

[Sch3mat1c]

I use 'em all the time. The blocky ones are good too.

All kinds of goodies on those - medium voltage diodes, inductors, highspeed transistors and diodes, etc.

Tim

[Lisandro_P]

Yes, you can get all kinds of neat stuff from those - power resistors, small sinks, fans, capacitors, inductors of all kinds, connectors, switches, diodes, transistors...

As for the caps themselves, my first thought was to use them for coupling in the inputs of the audio gear in my chain (preamp / poweramp / headphone amp). All of them are pretty consistent in value, ranging from .98 to 1.02uF. Most of them are marked "MKP" (yay!) but a few are labeled as "MEF", any idea what those are?

[Shoog]

The electrolytics in PC power supplies are about the best you can get, They have to be for this demanding role. Prity much anything you will do with them will be like a retirement in an old peoples home to them. Also the 200-250V ones can be used in tubes power supplies, if stacked.

Shoog

[Sch3mat1c]

http://www.google.com/search?q=MEF+capacitor

Appears to be metallized (self-healing) polyester (mylar) film, noninductive construction.

Tim

[wintermute]

If you have access to an ESR meter might be a good idea to test them before using.

Only say this because my VCR has a SMPS which died. turned out to be a 1uF 450V electro that had died, replaced it and all was well again So I'm guessing that it could be a common part to die, and since these PS's are dead..........

Tony.

[sivan_and]

I used to buy New PC SMPS just for components..
I fully agree with Shoog,Lisandro_P,Sch3mat1c.....

Even Ferrite torroid cores/ Inductors can be found in old PC motherboards, Which can used for Buck type SMPS/Swiching battery chargers..uses are infinite....

[Leolabs]

Lots of quality stuff are available in an old PC SMPS.Low ESR caps,Schottky diodes, toroidal inductor,etc. I used to have lots these junk,before i cleaned 'em up after graduated from high school.Some are really good for audio,but some only just "looks good" for audio. For example,the much debated fast recovery rectifier for 50Hz app. issue.Anyway, u get many componenets for a much cheaper price.So,PC SMPS is still "audio friendly",if u agree with me!

Note:the 1 uF capacitor is for primary side snubber network.In my country,lots of them are polyester type.