Motor run caps?

albireo13 · 4th March 2010, 11:17 AM

I ham looking at the SSE schematic and was wondering where folks use motor run caps? Are they necessary?
Which caps are the motor run caps?
I am a tube noob embarking on my first build ... exciting stuff!

Thx,
Rob

nightanole · 4th March 2010, 01:05 PM

80 uf 500 VAC Oil Filled Motor Run Capacitor Eyuda - eBay (item 310195976442 end time Feb-18-10 09:49:47 PST)

It goes in after the choke, its called "optional aux cap"

Motor run caps are the big metal ones that are normally oil filled. They handle alot more abuse and last alot longer under load then stock electrolytic. Other then ubber high voltage requirements im still not sure why everyone uses $15 motor run caps and not a 2nd $3 electrolytic cap.

AndrewT · 4th March 2010, 01:11 PM

motor start and motor run caps both come in either electrolytic or film type.

The electrolytic may not offer any benefit over normal high voltage electrolytics.

The film type are used because they allegedly improve the sound quality. They are bigger and more expensive.

urmoo · 4th March 2010, 01:35 PM

Quote:

Originally Posted by nightanole

80 uf 500 VAC Oil Filled Motor Run Capacitor Eyuda - eBay (item 310195976442 end time Feb-18-10 09:49:47 PST)
im still not sure why everyone uses $15 motor run caps and not a 2nd $3 electrolytic cap.

I am using 2 electrolytic caps (400WV 300uF) in row, signifficant improvement in sound... but have not tried motor run caps, so cant tell the difference...
Heh, 80 uf 500 VAC Oil Filled Motor Run Capacitor Eyuda 13$, transportation as follows:
US $19.64 Estonia USPS First Class Mail InternationalTM
And someone once was surprised how I managed to spend 900$ to my SSE

rknize · 4th March 2010, 01:36 PM

Film caps have really low ESR, which improves the dynamic response of the power supply. Surplus motor runs are a really cheap way to get a big film cap there, but the point is that it is a film cap and not another electrolytic.

urmoo · 4th March 2010, 02:09 PM

Sorry albireo13 for posting my question here, just wanted to ask if anyone know a good online shop in Europe to buy MRC? Have spend some time, but have not succeeded to find any...

nightanole · 03:12 PM

How can you tell if its film or electrolytic?

oil filled = film

rknize · 4th March 2010, 03:14 PM

Sometimes it's hard to tell, but here are some clues: If it says oil, then you know it is film in oil (some are just film, which is OK too). If it has polarity markings, it is electrolytic.

Zen Mod · 4th March 2010, 03:28 PM

search locally for Icar Italy motor run caps

neonthecat · 5th March 2010, 01:13 AM

Rob,

I'll second the recommendation for the Eyuda motor run caps. The people on ebay who sell them are great to deal with. These are big suckers, so make sure your chassis has the space. You can see what they look like by going to my post (Gratuitous shots of my new SSE). I think the motor run cap and Triad choke helped a great deal in making my SSE totally hum-free.

Regards,
"The Cat"

4th March 2010, 11:17 AM	#1
albireo13 diyAudio Member Join Date: Feb 2010	Motor run caps? I ham looking at the SSE schematic and was wondering where folks use motor run caps? Are they necessary? Which caps are the motor run caps? I am a tube noob embarking on my first build ... exciting stuff! Thx, Rob

4th March 2010, 01:36 PM	#5
rknize All the best stuff comes from Chian diyAudio Member Join Date: Feb 2009 Location: Chicagoland	Film caps have really low ESR, which improves the dynamic response of the power supply. Surplus motor runs are a really cheap way to get a big film cap there, but the point is that it is a film cap and not another electrolytic. __________________ Russ http://www.knizefamily.net/russ/cate...ics/tubeaudio/

4th March 2010, 02:50 PM	#7
nightanole diyAudio Member Join Date: Feb 2009	How can you tell if its film or electrolytic? oil filled = film Last edited by nightanole; 4th March 2010 at 03:12 PM.

4th March 2010, 03:14 PM	#8
rknize All the best stuff comes from Chian diyAudio Member Join Date: Feb 2009 Location: Chicagoland	Sometimes it's hard to tell, but here are some clues: If it says oil, then you know it is film in oil (some are just film, which is OK too). If it has polarity markings, it is electrolytic. __________________ Russ http://www.knizefamily.net/russ/cate...ics/tubeaudio/

4th March 2010, 03:28 PM	#9
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	search locally for Icar Italy motor run caps __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

4th March 2010, 01:05 PM	#2
nightanole diyAudio Member Join Date: Feb 2009	80 uf 500 VAC Oil Filled Motor Run Capacitor Eyuda - eBay (item 310195976442 end time Feb-18-10 09:49:47 PST) It goes in after the choke, its called "optional aux cap" Motor run caps are the big metal ones that are normally oil filled. They handle alot more abuse and last alot longer under load then stock electrolytic. Other then ubber high voltage requirements im still not sure why everyone uses $15 motor run caps and not a 2nd $3 electrolytic cap.

4th March 2010, 01:11 PM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	motor start and motor run caps both come in either electrolytic or film type. The electrolytic may not offer any benefit over normal high voltage electrolytics. The film type are used because they allegedly improve the sound quality. They are bigger and more expensive.

4th March 2010, 02:09 PM	#6
urmoo diyAudio Member Join Date: Sep 2009 Location: Estonia	Sorry albireo13 for posting my question here, just wanted to ask if anyone know a good online shop in Europe to buy MRC? Have spend some time, but have not succeeded to find any...

5th March 2010, 01:13 AM	#10
neonthecat diyAudio Member Join Date: Jan 2010 Location: Left Coast	Rob, I'll second the recommendation for the Eyuda motor run caps. The people on ebay who sell them are great to deal with. These are big suckers, so make sure your chassis has the space. You can see what they look like by going to my post (Gratuitous shots of my new SSE). I think the motor run cap and Triad choke helped a great deal in making my SSE totally hum-free. Regards, "The Cat"

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