Which AC Power Filter?

[sanaka]

I'm planning a 'super-dooper' power center, on a super-tight budget, built around a Zero Surge (Brickwall) OEM style surge suppressor, which I've ordered. Basically just a box which provides surge protected, individually filtered outlets for all my HT components.

I stole most of the ideas from Glen B.'s and Thomas W.'s awesome balanced AC projects (yes, I want balanced AC, but that's out of budget right now. The current project could be reconfigured with balanced later on...).

The image below is of some 10 amp power filters available at Mouser. Since I'm not at all deeply knowledgeable about how these work, I'm not sure which would be the best one to use. The 'cheapskate' articles recommend the cheaper Schurters (2nd item down in the image), and I'm pretty sure GlenB is using the Corcom B series (top item in image). The more expensive Shurters (bottommost item) are out of my budget, since I need at least 6 filters, but I included it for comparison, as it's schematic is very similar to the Schaffner, which is the cheapest of the bunch. The Schaffner also claims good differential mode filtering, whereas the Corcom and Qualtek, for instance, only claim common mode filtering.

So which should I use? Is the Schaffner not the killer deal it seems like? Are the Qualtek units OK? Should I go for common-mode-only filtering if I plan to put caps across the outlets?

Your opinions and guidance are humbly appreciated.

Peace,
Sanaka

[ThomasW]

I think you're probably over analyzing this...... :wink:

Also buying from Mouser is expensive. After I paid their prices I found both local and online electronic surplus houses with filters for 1/2 Mouser's price.

For example...

https://www.brigarelectronics.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=BE&Category_Code=EF

http://www.cascadesurplus.com/catalog/product_info.php/cPath/105/products_id/924?osCsid=59692b3c761268b4bdd1790c2a2e5136

Just google 'surplus emi filters' or 'surplus rfi fliters' and you'll get tons of hits

[sanaka]

Thanks for replying, Thomas. Lurking around here has given me great respect for your abilities. Surplus is a good idea, I will certainly try to track down the best price on whatever I decide on.

I suppose over analysis is my style. It has always served me well Briefly purusing the Mouser and Allied catalogs reveals 5+ pages of power filters in each. It doesn't square that this would be because there are no meaningful differences between them.

How did you decide on the Schurter 5500.2042 for the 'Cheapskate' balanced AC project? They are actually $11.42 at Mouser now, whereas the seemingly almost identical Qualtek is $7.69.

Peace,
Sanaka

[ThomasW]

My choice was not based on research, I was aware of the Schuter brand and knew they made good stuff. And I bought from Mouser not realizing that there are so many surplus suppliers.

I was a bit embarrassed to find equal stuff (Schuter and Corcom) at a local surplus supplier for 1/2 the Mouser pricing. Unfortunately the local supplier is 35 miles away and doesn't have a website.

[ThomasW]

Here are some good deals.......

http://www.excess-solutions.com/filters.htm

[sanaka]

Thanks Thomas, those are indeed some excellent deals. And some selection to boot. :T

Peace,
Sanaka

[Glen B]

I agree with Thomas that you're over-analyzing things on the filter selection. No rocket science required. I use a single Corcom V series filter (Model 5VK1) to help isolate the digital section. BTW, I tried both Qualtek and Corcom filters of the same basic circuit design and amperage and found the Corcom to be sonically better.

[sanaka]

Thank you both so much for replying and helping out.

I just ordered 8 Corcom 10VR1's from Cascade Surplus. These have solder/quick tabs, which I wanted, and seem like nice two stage filters. They are $12.79 new at Mouser, so at $5 each, this turned out to be awesome :T

I realize I appear as a beginner here with only a few posts, and I'm not Mr. Advanced by any means, so I hope neither of you will take this as snotty impudence or anything, especially since I truly respect both of your work, but... I find it odd that you both discount the idea of putting much effort into choosing a EMI/RFI (or 'EMC') filter.

Obviously we've decided there's reason enough to consider using these. Given the huge variety of types and choices available, it only stands to reason that some are better than others for a given application. Comprehending that reason enough to choose one from amongst the many therefore seems reasonable enough

Both of your choices bely your agreement with this. Thomas, you chose Schurter based on brand reputation, not just the cheapest thing Mouser had. And Glen, you even tried two different brands and found one better. To me this seems kind of, well... analytical

Narrowing the field a bit seems like it could help the DIY community.

Peace,
Sanaka

[Glen B]

Thank you both so much for replying and helping out.

I just ordered 8 Corcom 10VR1's from Cascade Surplus. These have solder/quick tabs, which I wanted, and seem like nice two stage filters. They are $12.79 new at Mouser, so at $5 each, this turned out to be awesome :T

I realize I appear as a beginner here with only a few posts, and I'm not Mr. Advanced by any means, so I hope neither of you will take this as snotty impudence or anything, especially since I truly respect both of your work, but... I find it odd that you both discount the idea of putting much effort into choosing a EMI/RFI (or 'EMC') filter.

Obviously we've decided there's reason enough to consider using these. Given the huge variety of types and choices available, it only stands to reason that some are better than others for a given application. Comprehending that reason enough to choose one from amongst the many therefore seems reasonable enough

Both of your choices bely your agreement with this. Thomas, you chose Schurter based on brand reputation, not just the cheapest thing Mouser had. And Glen, you even tried two different brands and found one better. To me this seems kind of, well... analytical

Narrowing the field a bit seems like it could help the DIY community.

Peace,
Sanaka

Yes, there are many models from which to choose, but unless you have some highly specialized application that requires in-depth analysis of the specifications and circuitry, ANY of the more basic EMI filters will do a good job. In choosing a filter for my project, although I looked for a model with a reasonable combination of common and differential mode rejection and simplicity of circuit, I didn't spend a lot of time agonizing over the details.

[Hank]

My two cents from years of purchasing management in electronics manufacturing (telecom test equipment) is that two long-term brands are Corcom and Schurter, and can be relied on. Our EE's designed in some of those (I recall Schurter as being the dominate) into some very expensive electronic test equipment. Differences in models are basically two: stages of filtering and ampacity. I say why not buy multi-stage units at these dirt-cheap surplus prices?

-Not a Pooh-Bah, just a little commercial experience.

Smile and enjoy the music.