Furman SMP is NOT real series mode surge technology!


If you have read erik_squires misinformation, please understand that he does not even know what a MOV looks like.

https://forum.audiogon.com/discussions/what-shunyata-and-furman-smp-have-in-common-inductance

Erik is merely trying to hawk his affiliate links for profit. If you are interested in the Furman PST-8 that he promotes, this is the only link to use AFTER clearing your internet browser of cookies:

https://www.amazon.com/Furman-Aluminum-8-Outlet-Protection-Conditioning/dp/B000YYVLAK


Here is a summary of the relevant information:

Furman does not license series mode surge technology. They were sued by Zero Surge - the originators and license owner of the series mode technology patent - and lost. Furman was forced to call their technology SMP (Series Multi-Stage Protection), which still uses MOVs.

https://www.furmanpower.com/furman-technologies/series-multi-stage-protection

SurgeX, Brick Wall, and Torus Power are the only licensees of series mode technology that I'm aware of. McIntosh - with the MPC1500 - appears to use series mode surge technology as a repackaged Torus. "Torus Power Technology under license from Plitron Manufacturing Inc."

https://www.mcintoshlabs.com/-/media/Files/mcintoshlabs/DocumentMaster/us/mpc1500om05L.ashx


"Zero Surge® was incorporated in March 1989 by J. Rudy Harford." He is the founder, and was the former owner and president. And yes, he’s the license owner.

https://zerosurge.com/about-us/

Look at the SMP circuit linked below. There are clearly MOVs. The same circuit board is used in all Furman products with SMP.

https://www.furmanpower.com/sites/furmanpower.com/files/_/Power-Report/smp-circuit.jpg

Still don’t believe me? "Furman’s Series Multi-Stage Protection Plus (SMP+) addresses some of the shortcomings of traditional MOV-based protectors by employing a variety of circuits to clamp, absorb, and dissipate transient voltages without having the device sacrifice itself. The company claims that MOVs used in a properly designed circuit will not fail.

Furman’s SMP+ circuitry takes pages from both shunt-and series- mode playbooks and adds its own twist. Along with a high-voltage MOV and a high-amperage thermo-fuse varistor, SMP+ uses a tuned circuit that includes series inductors, a bridge rectifier (which con- verts AC to DC power), and high-voltage capacitors."

https://zerosurge.com/wp-content/uploads/2016/10/Sound_and_Vision_July2007_Zero_Surge.pdf

"SMP allows Furman products to offer this protection without damaging any of their own internal components—that is, they are virtually non-sacrificial" Virtually, meaning not quite.

https://www.mixonline.com/technology/furman-sound-implement-smp-technology-381312

"• Zero Surge’s patented filter technology protects sensitive electronics from even worst case surges, repeatedly, without degradation or failure. MOV-free."

https://zerosurge.com/wp-content/uploads/2017/09/zero-surge-brochure.pdf

" • No sacrificial or wear components (no MOV’s)"

https://www.brickwall.com/pages/the-worlds-best-surge-protectors

The series mode surge technology patent states, "Provides an inductor system as the first means of protection."

"A branch circuit SPD (Surge Protection Device) using an MOV in front of, in back of or sideways of, a small ferrite core series inductor, labeled as ’series something’, is in my opinion, a marketing persuasion by our competitors intended to ride on our back and confuse you, and the only way to promote a product ’looking like ours’ without violating our patents. Are you a Switch or a Filter?

An MOV is a semiconductor switch. Switches will wear out and can suddenly fail when stressed. The monitoring of these switching devices over time as ’functional’ is tedious and a guessing game at best. A filter properly designed for its application will not wear out and will only fail if misapplied. Think about your passive LC subwoofer crossovers...when will it wear out?...perhaps when you wire it up to 440V just for fun?...or when you listen to too much music?" Michael McCook, SurgeX International

Furman purposely added MOVs to create a hybrid surge protection device that does not violate the patent. Due to the patent, Furman can not call the design series mode technology, and renamed it SMP+ in 2005. The whole point of series mode technology and the reason it was created is to avoid the use of MOVs. It’s fully ironic to use MOVs and call it series mode. It would be akin to saying you’re dying of thirst, and then eating the saltiest food you can, or calling a fat guy slim.

SurgeX does not have the same basic technology as other series mode designs. They have added ASM (Advanced Series Mode) technology. This adds an extra winding to the air-core inductor to further improve the surge protection and lower the let-through voltage.

https://www.ametekesp.com/-/media/ametekesp/downloads/white-papers/surgex-ametek_white-paper_advance...
sadono
Sadono, 
I politely in another thread tried to inform you that what you were stating is not really true, or at least not all true. You did not take that information to heart ... and called my search "half-hearted, incomplete, and mistaken".    In fact, you are mistaken.
- SurgeX sued for trademark infringement and false advertising, not patent infringement- A core piece of what Furman uses is almost exactly like the original SurgeX Series Mode technology

I am in no way trying to discredit the ZeroSurge products, just pointing out what you are saying about Furman is not really true.

 

There are current patents that protect new variations of a series surge protection circuit (as you noted above). The original patents, from the 80s, have long expired. You cannot create new patents to protect old material. Half the circuitry in the Furman is essentially what is in the 80s patent. Anyone can use that technology at this point which was the SurgeX Series Mode protection (you can't use the trademark nomenclature though).


SurgeX's series mode protection (original) is non sacrificial, but it is not perfect. It relies on an inductor as a filter element to block the high speed surge waveform before dumping what is left into a capacitor. As you know, in audiophile circles, adding inductance in front of a power-amp is often frowned upon. It of course also has a limit to how big a surge it can take before the inductor saturates, the diodes blow, or the capacitor is degraded.   Adding MOVs in front of this type of surge protector, especially big ones, can significantly increase how big a surge the combined device can handle. Using both, as Furman does, is a feature, not a design fault especially at a given cost point, and the Furman units are competitively priced.



SurgeX Suit Triggers Furman Response

By AVNetwork Staff (Systems Contractor News) January 28, 2005 Business 

  • Furman Sound has responded to a complaint filed by New Frontier Electronics d/b/a SurgeX, rejecting its claims in U.S. Federal Court and filing a counter claim against New Frontier. New Frontier's complaint is in part for promoting MOV-based power conditioning products as Series Mode products.
  • SurgeX, citing the false advertising and promotion prong of Section 43(a) of the Lanham Act, is claiming that the Furman Series II line of products use MOVs (Metal Oxide Varistors) as the main surge suppression technology and that the promotion and marketing of these products as Series Mode is false, deceptive and/or misleading.
  • Furman purports that the words in question, "series mode," refer to a common electrical configuration and are not owned by any individual or organization. Furman's Series II line of products does employ this technology, said the company, however the technology in Series II units goes above and beyond typical series mode protection with a total package called SMP Plus.
  • All SurgeX power conditioning products incorporate advanced technology, referred to as Series Mode, to mitigate surge and transient energy without the use of any diversionary or sacrificial components such as MOVs.
  • Furman Sound...www.furmansound.com
  • SurgeX...www.surgex.com

Sadano,

I think an apology is in order.  Everything that atDavid said is true.  Furman and ZeroSurge indeed use the same technology.  ZeroSurge's patents expired long ago.  Furman uses the same series mode technology and then subsequently uses MOV's for any remaining excess voltage.

Wirecutter did a test, comparing the Furman PST-8 vs high-priced series mode products and the Furman product actually performed BETTER than the high-priced series mode products.

And, atDavid's explanation of the lawsuit is correct.  It wasn't for patent infringement.  It was for FALSE ADVERTISING, filed by ZeroSurge.  ZeroSurge claimed that since Furman added the MOV, they can't call it series mode protection.  Isn't that petty?  Furman adds additional protection to the technology and ZeroSurge says you can't say it's series mode protection.  What a BS lawsuit.  If you go to ZeroSurge's website, it's full of misleading and deceptive information and articles.