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motor run caps in the output? good or bad idea?

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J

jarthel

Member
Joined 2002
#1
in the aikido circuit (specifically the headphone schematic), it uses an output capacitor.

I have search the forum about using motor run caps and all I've came across are references to using them in the power supply.

Has anyone used them in the output?

thank you for the replies.
 
#10
jamesjung21 said:
Oh, I see why... If GE makes 47uF, they will be awfully large and rare 🙄

Are you trying to stick with your local part sources...? (Jaycar at any chance? 🙂 )
Click to expand...


my local part sources are ebay, thlaudio, partsconnexion and percy.

farnell and rs non-audio quality stuff. dick smith for those things that are not really important such as heatshrink.

ps. I found a 40uF GE. I have a feeling it's not enough.
 
#11
RS actually does stock some good stuffs like siemens LL electrolytics, oscon, and the new emerging substitue for STD series Blackgates, the Rubycon ZA and ZL series...

Jaycar recently started selling ASC motor caps and I thought that's probably why you found ASC 🙂

Try Aerovox motor caps if you don't mind plastic film caps 🙂 More compact and readily available, at least when I looked up for one...

I bought a pair of 66uF at $15 before, and was available up to 150uF 🙂

Dick Smith is hopelessly expensive anyway...
 
#13
I know that GE makes (or at least has made) 45uf. Check your local air conditioning supply houses for old stock (most new will be from China). Many, many residential air conditioners use them for run caps on the compressors. Check Grainger and Johnstone Supply to name a couple. LOL, Jay
 
#15
try this place:

http://www.elecsupp.com/

elecsupp@verizon.net

They stock Sprague motor run caps in 50 and 45uf.

Here's an e-mail from the rep I dealt with:

>I have the following options in stock:
>
>100 mfd at 150VAC #325P107K15D31BCT. This is in an oval can with two screw
>terminals. The oval dimension s are 3.656" X 1.968" and 3.125" high. 1-2
pcs
>are $18.70 each
>
>47 mfd is not a standard capacitance rating for 325P capacitors. I can
offer
>45 mfd or 50 mfd and the tolerance is + or - 6%.
>
>45 mfd at 370 VAC #325P456H37N36A4X. This is in a round can with two 4
blade
>quick connect terminals on top. The size is 2.00" diameter and 3.75" high.
>1-2 pcs are $13.80 each.
>
>50 mfd at 370 VAC #325P506H37D30N4X. This is in an oval can with two 4
blade
>quick connect terminals. The oval dimensions are 3.656" X 1.968" and 3.00"
>high. 1-2 pieces are $13.80 each.
>
>Let me know if you have any questions.
>
>Regards,
>
>Peter
Click to expand...
 
#16
My understanding has been that Japanese made ASC polyprop in oil with brass contacts in round cans are the hot ticket. (386 series) Anyway that's what most of us around here use in lieu of the old CDE and other brand baddies with pcb oils in them that supposedly sound even better.. 😀

No question though that some of those old do caps perform quite well. (I have a heard a system that is full of them as well as WE types and it is definitely one of the best sounding systems I hear on a regular basis.)

IMO You might be even better off with the good old Solen which in my limited experience has much better high frequency performance than the motor runs I have used.
 
#17
ge caps

hi I cansecond the opinion that the ge oil caps do perform well
I have used them in cross overs and for coupling caps.
We use them at work with ballasts for gallium iodide h.i.d
lamps. true they are large and pricey, but they are nearly bulletproof.
I usually buy them from allied electronics or newark electronics
both will sell to anyone.
 
#18
Personally I wouldn't make too much out of the supposed difference between paper and polypropylene in oil. I've got a large stock of used and dented oil caps ranging from GE over aerovox and god knows what else there is. Although I never did any a/b testing I never noticed a big difference when going from one brand of cap to another. Siemens MKV (polypropylene) might be the emperor of 'em all; gave me a very detailed sound in a preamp. I've got those in two flavors: huge unpainted cans with big contacts (these are the older makes) and smaller cans painted black (although smaller these have higher voltage ratings for the same capacity --> another dielectric material??).FWIW I've only heard good things about ASC.

Simon
 
#19
If you go the big oil can route my only cautions are:

- Microphonics. I can't recall which circuit was under test but a tap on the can appeared on the output.
- In the same test I recall a floating case made a pretty good antenna.
- There's a non-trivial amount of capacitance between the case and terminals. Grounding the case shunts this capacitance between the Aikido's output and ground, floating the case in an exposed location puts users at risk of shocking surprises.

I also like and use the ASC kevink recommends (midorimeadows on Ebay) in power supplies.
 
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