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post #1 of 65 Old 11-13-2019, 05:25 AM - Thread Starter
 
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Will power conditioner hurt pre pro

I have an onkyo pre pro and belles aria power amp and as I was looking into power conditioners like furman to use along with them, an online friend of mine is telling me that power conditioners limit performance, in the name of cleaning power, they limit the current being sent t and your equipment won't perform to the best of its ability. Is that true?
Do people on this forum recommend using power conditioners with pre pros, amps or avr's?
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post #2 of 65 Old 11-13-2019, 06:05 AM
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Quote:
Originally Posted by Menarini View Post
I have an onkyo pre pro and belles aria power amp and as I was looking into power conditioners like furman to use along with them, an online friend of mine is telling me that power conditioners limit performance, in the name of cleaning power, they limit the current being sent t and your equipment won't perform to the best of its ability. Is that true?

Do people on this forum recommend using power conditioners with pre pros, amps or avr's?
Why do you need a power conditioner? Do you live in an area where the AC power is unstable?

Power conditioners are the second snake oil products after power cables. They have zero affect on sound quality!

Audio components uses DC voltage to operate. The component manufacturers take the necessary actions to insure clean and regulated dc power.

The quality of the AC line has zero impact on the regulated dc supply.

If this wasn't the case, you'd see a recommendation to buy a power conditioner in the manual...

The only advantage of power conditioners is the included surge protection, but you can buy those seperatly for much cheaper.


As for the power demands, if the power conditioner is built right, that should not be a problem.

P.s, I happen to have a PhD degree in electrical engineering, and I work as a switching power supply designer for an Israeli company called Advice...


Better save your money for upgrading your equipment instead...

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post #3 of 65 Old 11-13-2019, 06:09 AM
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Quote:
Originally Posted by Menarini View Post
I have an onkyo pre pro and belles aria power amp and as I was looking into power conditioners like furman to use along with them, an online friend of mine is telling me that power conditioners limit performance, in the name of cleaning power, they limit the current being sent t and your equipment won't perform to the best of its ability. Is that true?
Do people on this forum recommend using power conditioners with pre pros, amps or avr's?
Yes, that can be true.

A pre-amp, probably not so much. A Power amplifier is a different circumstance. Many of the low end, less expensive power conditioners can/will limit current which can/will restrict the amplifiers output. Many amplifier companies recommend that you do not use a conditioner as a blanket statement as they can't control what people use.

My personal experience with Furman is that they are mostly junk. They can be ok for something like a pre-amp, CD/DVD player, etc. or something that does not present much of a load. A lot of the Furman units use cheap varistor circuits and circuit breakers for surge suppression and are little more than a pretty power strip.

However, conditioners from companies like Torus Power, properly sized, can work quite well. A good unit comes with a price and you get what you pay for.

https://www.toruspower.com/product-ranges/


FWIW, I don't use power conditioners.
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post #4 of 65 Old 11-13-2019, 09:50 AM - Thread Starter
 
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Thx for replies. I already have a surge protector, ill stop looking at furman units on amazon. dont want my expensive belles aria amp to be bogged down. Looks like this forum for the most part does not recommend power conditioners? But I must add, like cables, there is quite a divide over power conditioners if you do a web search. There is a subset of audiophiles that swear by them and their 'logic' hinges on a power conditioner making the power cleaner.
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post #5 of 65 Old 11-13-2019, 10:30 PM
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Originally Posted by b curry View Post
Yes, that can be true.

A pre-amp, probably not so much. A Power amplifier is a different circumstance. Many of the low end, less expensive power conditioners can/will limit current which can/will restrict the amplifiers output. Many amplifier companies recommend that you do not use a conditioner as a blanket statement as they can't control what people use.

(1) My personal experience with Furman is that they are mostly junk. They can be ok for something like a pre-amp, CD/DVD player, etc. or something that does not present much of a load. A lot of the Furman units use cheap varistor circuits and circuit breakers for surge suppression and are little more than a pretty power strip.

However, conditioners from companies like Torus Power, properly sized, can work quite well. A good unit comes with a price and you get what you pay for.

https://www.toruspower.com/product-ranges/

FWIW, I don't use power conditioners.

The Furman power conditioner in the link below has series mode surge protection, similar to SurgeX, but without the SurgeX circuits that are still under patent. It also has Furman's standard filter circuit that is used in all of its higher end products. Please analyze the surge mode protection and filtering of this Furman product and explain in detail why you consider it junk.

https://www.amazon.com/Furman-Aluminum-8-Outlet-Protection-Conditioning/dp/B000YYVLAK/ref=sr_1_1_sspa?crid=YLSD34T00MW1&keywords=furman+ pst-8&qid=1573711869&sprefix=furman+%2Caps%2C209&sr= 8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyVFVaU 0MwVVIxSjZRJmVuY3J5cHRlZElkPUEwNTE2MjA0M0NVVVJWQkh CUDJaRyZlbmNyeXB0ZWRBZElkPUE
wODYyNDUzM0ZJRUQ4RjhXT1pSMSZ3aWRnZXROYW1lPXNwX2F0Z iZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXR ydWU=

Please also explain why purchasing a Torus unit, for example the one in the link below, for $5,000 would be superior to adding a new 20A circuit wired with 10 gauge cable, and then using the Furman PST-8 in the above link. The sales tax on the Torus might pay for the new circuit and PST-8.

https://www.toruspower.com/product-r...former-review/

For reference here is a review with a measurements of an older Torus unit that doesn't appear to offer any amazing improvements:

https://hometheaterhifi.com/reviews/...oner-review75/
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post #6 of 65 Old 11-13-2019, 10:52 PM
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Originally Posted by Menarini View Post
Thx for replies. I already have a surge protector, ill stop looking at furman units on amazon. dont want my expensive belles aria amp to be bogged down. Looks like this forum for the most part does not recommend power conditioners? But I must add, like cables, there is quite a divide over power conditioners if you do a web search. There is a subset of audiophiles that swear by them and their 'logic' hinges on a power conditioner making the power cleaner.
Easy, audiophools are whales, and are keeping the overpriced snake oil vendors in business. And the others actually work for the companies in question, so are naturally going to be salespeople trying to sell you overpriced junk. Or they're going to sell you stuff you don't really need (e.g., amplifiers are a common extra people get sold they may not really need).

A salesperson day is made when someone comes to them and asks if they need something. To no ones surprise, of course they do. And usually the most expensive one.
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post #7 of 65 Old 11-14-2019, 06:04 AM
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This is not always so black and white. There is definitely noise in my system during peak hours, when everyone in the neighborhood is home. IMO, a definitive statement that power conditioners are never useful is not accurate. And yes, the cheaper power conditioners/surge protectors can limit power to powerful amps.

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post #8 of 65 Old 11-14-2019, 06:18 AM - Thread Starter
 
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Originally Posted by BillP View Post
This is not always so black and white. There is definitely noise in my system during peak hours, when everyone in the neighborhood is home. IMO, a definitive statement that power conditioners are never useful is not accurate. And yes, the cheaper power conditioners/surge protectors can limit power to powerful amps.
So you mean when your neighbors are home, the power coming out of your home's electrical sockets gets 'dirty'? How do you measure that noise?
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post #9 of 65 Old 11-14-2019, 06:32 AM
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Originally Posted by Menarini View Post
So you mean when your neighbors are home, the power coming out of your home's electrical sockets gets 'dirty'? How do you measure that noise?
With my ears. My AV system is very silent when used during the day Mon-Fri. At night and on weekends you can hear a definite hum coming from some of my AV equipment (fortunately not from the speakers). I have read that this is not an uncommon phenomenon.

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post #10 of 65 Old 11-14-2019, 06:41 AM
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Quote:
Originally Posted by Menarini View Post
I have an onkyo pre pro and belles aria power amp and as I was looking into power conditioners like furman to use along with them, an online friend of mine is telling me that power conditioners limit performance, in the name of cleaning power, they limit the current being sent t and your equipment won't perform to the best of its ability. Is that true?
Do people on this forum recommend using power conditioners with pre pros, amps or avr's?
This is just one of those subject's that tend to be lightning rods lol, not unlike expensive cables, or the vinyl vs cd arguments. You will find people who passionately think their side is right and the other it stupid lol Unless your AC power is really unstable, you probably would be wasting your money.
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post #11 of 65 Old 11-14-2019, 10:45 AM
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Originally Posted by Worf View Post
Easy, audiophools are whales, and are keeping the overpriced snake oil vendors in business. And the others actually work for the companies in question, so are naturally going to be salespeople trying to sell you overpriced junk. Or they're going to sell you stuff you don't really need (e.g., amplifiers are a common extra people get sold they may not really need).

A salesperson day is made when someone comes to them and asks if they need something. To no ones surprise, of course they do. And usually the most expensive one.
For fellow 20th century people, from the Urban Dictionary (slightly edited into more formal US English):

Whale: A person who spends incredible amounts of money in gacha type games which makes him/her ultra powerful and godlike.

Next level down:

Gacha (or Gachapon) is a monetization technique used in many successful Japanese free-to-play games. Originally a term used for Japanese Toy machines, this is used to describe games that pull a selection of data, people, heroes, etc. from a large pool at random.

Apparently "whale" has been broadened out of the gaming universe.


More personally, I have been using a Furman PST-8 for a couple of years, based on a recommendation from a forum member. I got it as a protection device; I don't get a lot of noise on my power line. (Single family house, neighbors apparently not running lots of power equipment.) It appears to do no harm. I never opened it up, but supposedly it has a lot more internals than your typical sacrificial surge protector. Maybe "b curry" knows better, but I'm skeptical of his skepticism.
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post #12 of 65 Old 11-14-2019, 11:58 AM
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There are actually different issues involved in this thread.
1. Hopefully everyone can agree that a good surge protector is important. Lightening struck outside my house a few years ago and traveled into my house, affecting several outlets. Fortunately all my AV equipment (plugged into a Monster power conditioner) escaped damage, but several other things (including 2 computers and my electric garage door openers) were fried. IMO, cheap surge protectors don't offer much protection. After the incident, I had an electrician install surge protectors at the electrical panel (the best way to protect your home), and also have my AV equipment and computer plugged directly into good surge protectors for extra protection.
2. Power conditioners can remove ground loops, and can also help versus noisy power lines. If you don't have those issues in your home or apartment, then you probably don't need a power conditioner.
3. Some power conditioners may limit the amount of power that some amps may need. Preamps and other AV equipment don't draw as much power and should be fine.
4. The most controversial issue is whether power conditioners can actually make AV equipment perform better. Some magazine reviewers and audiophiles claim they can hear benefits, and others believe they are just snake oil. I will leave this argument to others (I have no opinion on this matter, assuming you are not affected by ground loops or noisy power).

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post #13 of 65 Old 11-15-2019, 05:41 AM
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Quote:
Originally Posted by bobknavs View Post

...

More personally, I have been using a Furman PST-8 for a couple of years, based on a recommendation from a forum member. I got it as a protection device; I don't get a lot of noise on my power line. (Single family house, neighbors apparently not running lots of power equipment.) It appears to do no harm. I never opened it up, but supposedly it has a lot more internals than your typical sacrificial surge protector. Maybe "b curry" knows better, but I'm skeptical of his skepticism.
Most of the surge protectors from Furman in the $100-$300 range or anyone else for that matter use MOV devices for surge protection. They do offer some level of surge protection but they are not without downsides.

MOV's do not protect equipment from inrush current surges, from overcurrent situations, or brownouts. MOV's degrade with time and use and are disposable devices. Under normal utility voltage conditions, MOV surge protectors work great. But under normal conditions, you don't really need one do you?

MOV based devices cannot withstand sustained over-voltage situations and can result in the MOV device catching fire. I know this from practical experience using an APC branded surge protector. It melted down, caught fire, and burned a hole through the rooms carpet during a lighting strike on nearby power lines. I contacted APC to use the surge protectors APC warranty only to be told by APC that my circumstances were not covered. APC would not even replace the unit let alone pay for the damage. The internet is full of pictures of MOV based power strip fires with a simple search.

The Furman PST-8 is an MOV based device. Yes, I agree it probably appears to do no harm. MOV's work at a designed "clamping voltage". If that design limits current in anyway, you're potentially limiting the output capability of a power amplifier when higher volume demands are placed on the unit. Without test equipment, you can't really tell one way or the other.

Small surges are cumulative for MOV's and will cause there failure over time the same as one large voltage or current strike.

Furman states in the description of the PST-8 that it uses TVZ-MOV's. TVZ-MOV's are fancy MOV's that include a thermal protection fuse. I'm not really sure what Furman's SMP circuit is, some sort of AC voltage filter I guess, but if you look at the circuit board on their site, you can clearly see the MOV's.

From Furman's description of the PST-8:

"The PST-8 all feature Furman’s SMP circuit which incorporates Linear Filtering Technology (LiFT) and a high current TVZ-MOV to insure that …"
https://www.furmanpower.com/product/...ks-PST-8%20DIG

Functionally, most any $15-$20 MOV power strip will offer the same level of surge protection as the $150 PST-8 does.
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post #14 of 65 Old 11-15-2019, 06:02 AM
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Quote:
Originally Posted by bigguyca View Post
The Furman power conditioner in the link below has series mode surge protection, similar to SurgeX, but without the SurgeX circuits that are still under patent. It also has Furman's standard filter circuit that is used in all of its higher end products. Please analyze the surge mode protection and filtering of this Furman product and explain in detail why you consider it junk.

https://www.amazon.com/Furman-Aluminum-8-Outlet-Protection-Conditioning/dp/B000YYVLAK/ref=sr_1_1_sspa?crid=YLSD34T00MW1&keywords=furman+ pst-8&qid=1573711869&sprefix=furman+%2Caps%2C209&sr= 8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyVFVaU 0MwVVIxSjZRJmVuY3J5cHRlZElkPUEwNTE2MjA0M0NVVVJWQkh CUDJaRyZlbmNyeXB0ZWRBZElkPUE
wODYyNDUzM0ZJRUQ4RjhXT1pSMSZ3aWRnZXROYW1lPXNwX2F0Z iZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXR ydWU=

Please also explain why purchasing a Torus unit, for example the one in the link below, for $5,000 would be superior to adding a new 20A circuit wired with 10 gauge cable, and then using the Furman PST-8 in the above link. The sales tax on the Torus might pay for the new circuit and PST-8.

https://www.toruspower.com/product-r...former-review/

For reference here is a review with a measurements of an older Torus unit that doesn't appear to offer any amazing improvements:

https://hometheaterhifi.com/reviews/...oner-review75/
Well...

I'm not sure I understand the point of using 10AWG wire on a 20A circuit. The current is still limited by the 20A breaker and using 10AWG is kind of a PITA to make connections on 20A devices.

And then you want to hang a PST-8 MOV based surge protector that's rated at 15A on that 20A circuit? Again, I'm not sure I understand your point or the benefit here.

You're asking or expecting a surge protector designed to work at 15A's to preform with a 20A feed. The clamping voltage of the MOV's would be spec'd differently.

Further, based on your logic, I would be dollars ahead to use a $15-$20 MOV based power strip vs. the $150 PST-8. After all, with regards to surge protection, they are more or less the same device.

Torus makes many different unit's and yes they are/can be expensive. Just used them as an example and there are other suppliers that can be more reasonable. However, I should have been more precise and said that using a regulated power device after the mains or a UPS where the mains power charges a DC battery bank which in turn uses an inverter for supply of clean, sine wave, surge free AC is a much better alternative to MOV based power strips offered by Furman and others.

MOV based devices are disposable units, and often a fire hazard under certain conditions.
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post #15 of 65 Old 11-15-2019, 08:31 AM
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Originally Posted by Menarini View Post
Thx for replies. I already have a surge protector, ill stop looking at furman units on amazon. dont want my expensive belles aria amp to be bogged down. Looks like this forum for the most part does not recommend power conditioners? But I must add, like cables, there is quite a divide over power conditioners if you do a web search. There is a subset of audiophiles that swear by them and their 'logic' hinges on a power conditioner making the power cleaner.
Some kind of surge protection or voltage regulation for sure, especially in an unstable area. Where I live, power is pretty stable, so while I don't really need the Panamax unit that I have, it does serve as a protection device, great for power distribution, and also serves as a trigger for certain devices. On top of that, it fit the aesthetic I was after. Didn't hurt that I got it for a stupid, low price. (I would not have paid retail for it...). Minus my main amp and subs, everything is plugged into it, including the pre-pro, and no it does not hurt the pre-pro, nor the amp driving my Atmos speakers (super low demand), and I very much doubt it'd affect your other amp unless you were really pushing it. Others will disagree, but I've seen some pretty tremendous performances from amps connected to conditioners, detected no restraint in those situations. Maybe there was an effect, but it did not matter as the amps easily pushed the speakers to well beyond anything I would ever do as far as performance. YMMV as it will depend on the design of the unit.

CLEANER power? Not likely with other modern electronics, as has already been mentioned. STABLE power and protection, well, hopefully if the conditioner is any good. My Panamax advertises specifically "a clearer picture and cleaner sound" - maybe somewhere, but not in my system, does not matter one bit either way, but I didn't buy it for that.....

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post #16 of 65 Old 11-15-2019, 10:58 AM
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Originally Posted by b curry View Post
Most of the surge protectors from Furman in the $100-$300 range or anyone else for that matter use MOV devices for surge protection. They do offer some level of surge protection but they are not without downsides.

MOV's do not protect equipment from inrush current surges, from overcurrent situations, or brownouts. MOV's degrade with time and use and are disposable devices. Under normal utility voltage conditions, MOV surge protectors work great. But under normal conditions, you don't really need one do you?

MOV based devices cannot withstand sustained over-voltage situations and can result in the MOV device catching fire. I know this from practical experience using an APC branded surge protector. It melted down, caught fire, and burned a hole through the rooms carpet during a lighting strike on nearby power lines. I contacted APC to use the surge protectors APC warranty only to be told by APC that my circumstances were not covered. APC would not even replace the unit let alone pay for the damage. The internet is full of pictures of MOV based power strip fires with a simple search.

The Furman PST-8 is an MOV based device. Yes, I agree it probably appears to do no harm. MOV's work at a designed "clamping voltage". If that design limits current in anyway, you're potentially limiting the output capability of a power amplifier when higher volume demands are placed on the unit. Without test equipment, you can't really tell one way or the other.

Small surges are cumulative for MOV's and will cause there failure over time the same as one large voltage or current strike.

Furman states in the description of the PST-8 that it uses TVZ-MOV's. TVZ-MOV's are fancy MOV's that include a thermal protection fuse. I'm not really sure what Furman's SMP circuit is, some sort of AC voltage filter I guess, but if you look at the circuit board on their site, you can clearly see the MOV's.

From Furman's description of the PST-8:

"The PST-8 all feature Furman’s SMP circuit which incorporates Linear Filtering Technology (LiFT) and a high current TVZ-MOV to insure that …"
https://www.furmanpower.com/product/...ks-PST-8%20DIG

Functionally, most any $15-$20 MOV power strip will offer the same level of surge protection as the $150 PST-8 does.
I have the impression that a "TVZ-MOV" device has protections that make it less of a sacrificial device than an MOV in a $20 surge strip. True or false?
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post #17 of 65 Old 11-15-2019, 12:10 PM
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Quote:
Originally Posted by b curry View Post
- Omitted -

A pre-amp, probably not so much. A Power amplifier is a different circumstance. Many of the low end, less expensive power conditioners can/will limit current which can/will restrict the amplifiers output. Many amplifier companies recommend that you do not use a conditioner as a blanket statement as they can't control what people use.

My personal experience with Furman is that they are mostly junk. They can be ok for something like a pre-amp, CD/DVD player, etc. or something that does not present much of a load. A lot of the Furman units use cheap varistor circuits and circuit breakers for surge suppression and are little more than a pretty power strip.

- Omitted - to be addressed at another time

FWIW, I don't use power conditioners.
Quote:
Originally Posted by bigguyca View Post
The Furman power conditioner in the link below has series mode surge protection, similar to SurgeX, but without the SurgeX circuits that are still under patent. It also has Furman's standard filter circuit that is used in all of its higher end products. Please analyze the surge mode protection and filtering of this Furman product and explain in detail why you consider it junk.

https://www.amazon.com/Furman-Aluminum-8-Outlet-Protection-Conditioning/dp/B000YYVLAK/ref=sr_1_1_sspa?crid=YLSD34T00MW1&keywords=furman+ pst-8&qid=1573711869&sprefix=furman+%2Caps%2C209&sr= 8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyVFVaU 0MwVVIxSjZRJmVuY3J5cHRlZElkPUEwNTE2MjA0M0NVVVJWQkh CUDJaRyZlbmNyeXB0ZWRBZElkPUE
wODYyNDUzM0ZJRUQ4RjhXT1pSMSZ3aWRnZXROYW1lPXNwX2F0Z iZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXR ydWU=

- Omitted - to be addressed at another time
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Originally Posted by b curry View Post
Most of the surge protectors from Furman in the $100-$300 range or anyone else for that matter use MOV devices for surge protection. They do offer some level of surge protection but they are not without downsides.

MOV's do not protect equipment from inrush current surges, from overcurrent situations, or brownouts. MOV's degrade with time and use and are disposable devices. Under normal utility voltage conditions, MOV surge protectors work great. But under normal conditions, you don't really need one do you?

MOV based devices cannot withstand sustained over-voltage situations and can result in the MOV device catching fire. I know this from practical experience using an APC branded surge protector. It melted down, caught fire, and burned a hole through the rooms carpet during a lighting strike on nearby power lines. I contacted APC to use the surge protectors APC warranty only to be told by APC that my circumstances were not covered. APC would not even replace the unit let alone pay for the damage. The internet is full of pictures of MOV based power strip fires with a simple search.

The Furman PST-8 is an MOV based device. Yes, I agree it probably appears to do no harm. MOV's work at a designed "clamping voltage". If that design limits current in anyway, you're potentially limiting the output capability of a power amplifier when higher volume demands are placed on the unit. Without test equipment, you can't really tell one way or the other.

Small surges are cumulative for MOV's and will cause there failure over time the same as one large voltage or current strike.

Furman states in the description of the PST-8 that it uses TVZ-MOV's. TVZ-MOV's are fancy MOV's that include a thermal protection fuse. I'm not really sure what Furman's SMP circuit is, some sort of AC voltage filter I guess, but if you look at the circuit board on their site, you can clearly see the MOV's.

From Furman's description of the PST-8:

"The PST-8 all feature Furman’s SMP circuit which incorporates Linear Filtering Technology (LiFT) and a high current TVZ-MOV to insure that …"
https://www.furmanpower.com/product/...ks-PST-8%20DIG

Functionally, most any $15-$20 MOV power strip will offer the same level of surge protection as the $150 PST-8 does.

It's not clear why it is necessary to do this research when the information is readily available on the Internet, but based on the post above it is apparently necessary. Here is a link that explains Furman's SMP circuitry:

https://www.furmanpower.com/series-m...protection-smp

The module shown in the link above is use in Furman's upper level gear including the PST-8.

The circuitry described appears similar to part of the circuitry that SurgeX uses, the part of the circuitry that is off patent. This circuitry implements series mode protection and limits over voltages to very small values. In addition to protecting against large surges this type of protection eliminates the steady stream of small spikes from switching transients that mainly originate inside the home from sources such as leading edge dimmers, ECM motors, microwave ovens, etc.

As a note: SurgeX adds a specially wound transformer and some other circuitry in there products. Clearly SurgeX makes the best surge protectors, but their prices aren't for everyone. If you do some searching you can find the expired and current patents.

The MOV's in the PST-8 are very heavy duty units and are designed protect against very large surges. All MOV's aren't the same. Very low cost power strips may have marginal MOV's. A variation in quality and capability in consumer products is not limited to MOV'S or surge protectors. A consumer needs to understand what they are purchasing.

If you feel MOV's, that is quality, heavy duty units MOV's, represent an existential danger then you need to work to eliminate all MOV's from more than power strips and power conditioners.

Cutler-Hammer and SquareD both offer whole house surge protectors that use MOV's. Even worse for those who feel MOV's are unacceptable is the fact that the National Electric code, in the just adopted 2020 version, added a requirement that the service entrance panel in all houses have an integral, whole house surge protector. This means that all houses built starting the the early 2020's, will likely have MOV-based surge protectors in there service entrance panels. What did UL and the others who developed this new code miss about the inherent inadequacies of MOV's?
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post #18 of 65 Old 11-15-2019, 01:58 PM
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Originally Posted by bigguyca View Post

The MOV's in the PST-8 are very heavy duty units and are designed protect against very large surges. All MOV's aren't the same. Very low cost power strips may have marginal MOV's. A variation in quality and capability in consumer products is not limited to MOV'S or surge protectors. A consumer needs to understand what they are purchasing.

If you feel MOV's, that is quality, heavy duty units MOV's, represent an existential danger then you need to work to eliminate all MOV's from more than power strips and power conditioners.

Cutler-Hammer and SquareD both offer whole house surge protectors that use MOV's. Even worse for those who feel MOV's are unacceptable is the fact that the National Electric code, in the just adopted 2020 version, added a requirement that the service entrance panel in all houses have an integral, whole house surge protector. This means that all houses built starting the the early 2020's, will likely have MOV-based surge protectors in there service entrance panels. What did UL and the others who developed this new code miss about the inherent inadequacies of MOV's?
The MOV's on the PST-8 have a published clamping voltage of 188v. That's 60%+ over the expected line voltage. I think if you open it up and look at the MOV part number, you'll be able to find the part on ebay for $1-$2 each. I have. They're no more heavy duty than what any one else uses. They are sized based on the line voltage required and the clamping voltage.

NEC may well require it. That still doesn't change the fact that MOV's are sacrificial devices not unlike the fuses that circuit breakers replaced. If that's the building code requirement in 2020 and each state requires it, Home Depot/Lowes has a new revenue stream.

MOV's do not protect equipment from inrush current surges, overcurrent situations, or brownouts. Do a quick search for MOV power strip fire and you'll find 1000's of photos of just such events. Writing it into code does not change how they work.

A whole house unit is probably a better use of the expense vs. something like the PST-8. But it's still a disposable unit. It will fail because it's designed to fail. If the home owner does not check the unit on a regular basis, it will have failed and he won't know it. It does not interrupt or shut off the power. You'll simply have a service panel with a dead surge protector hanging on it. Most home owners will need to call an electrician to change it out if they want it to work again.

If you feel like spending the extra money for 30AWG wire and the trouble to connect it to a 20A breaker and outlet only to hang a $150, 15A MOV power strip off that circuit and call it protection, knock your socks off.

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post #19 of 65 Old 11-15-2019, 03:36 PM
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I have the impression that a "TVZ-MOV" device has protections that make it less of a sacrificial device than an MOV in a $20 surge strip. True or false?
The thermal fuse does give some added projection with regards to preventing a fire. The idea is that the fuse will pop based on temperature and shut off the current/voltage to the MOV.

The MOV engages or becomes active at the clamping voltage. At the clamping voltage, the MOV momentarily bleeds off or shunts excess voltage to ground. Simplistically, if the over voltage/current is sustained for more than a fraction of a second, the MOV heats up and begins to melt down or sometimes explodes. This can cause a fire.

The thermal fuse TVZ-MOV should sense the temperature rise and shut down the voltage before the MOV gets too hot. However the MOV has a duty cycle. As the MOV absorbs many small over voltage/current cycles over time it will fail. Or one big surge can kill it. MOV's (metal oxide varistor) will fail because they are designed to fail. Varistor is shorthand for variable resistor.

The PST-8 has a published clamping voltage of 188v. So it doesn't really start to work until it see's 188v.

EDIT: I would just add that once the MOV's fail, power is still supplied but you do not have the benefit of the MOV surge suppression. Some of the better units like the PST-8 do have an LED that let's one know if the MOV's are working. Don't get me wrong, it does offer some protection. But it's quite far from a coat and sweater protection most people think they have.

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Originally Posted by b curry View Post
The MOV's on the PST-8 have a published clamping voltage of 188v. That's 60%+ over the expected line voltage. I think if you open it up and look at the MOV part number, you'll be able to find the part on ebay for $1-$2 each. I have. They're no more heavy duty than what any one else uses.

NEC may well require it. That still doesn't change the fact that MOV's are sacrificial devices not unlike the fuses that circuit breakers replaced. If that's the building code requirement in 2020 and each state requires it, Home Depot/Lowes has a new revenue stream.

MOV's do not protect equipment from inrush current surges, overcurrent situations, or brownouts. Do a quick search for MOV power strip fire and you'll find 1000 of photos of just such events. Writing it into code does not change how they work.

If you feel like spending the extra money for 30AWG wire and the trouble to connect it to a 20A breaker and outlet only to hang a $150, 15A MOV power strip off that circuit and call it protection, knock your socks off.

More on surge protection:

Agreed, 188V is 60% over about 120V. That means you are using 120V as the peak voltage in your calculations since surge protectors reduce peak voltage. This implies a nominal voltage of about 86V. This compares with 100V in Japan. There is no where in the world where 86V RMS is the nominal voltage.

In the United States the nominal voltage is 120V RMS. The electrical power is supplied as a sine wave. Surge protectors work by limiting the peak voltage, not the nominal or RMS voltage. For 120V RMS the peak voltage is about 170V. 188V is about 10% over 170V and corresponds to 133V RMS. This is a tight limit. The Furman PST-8 is a Type 3 surge protection device. Type 3 protection devices have a standard for let through voltage of 330V maximum so the Furman unit has much closer control than the standard requires.

Concerning the wire size:

30AWG is very small wire. It isn't relevant to this discussion. As wire becomes smaller its current carrying capacity also becomes smaller. At the same time its AWG number becomes larger, in this range wires. The current capacity for 30AWG wire listed in the link below as .142A. Certainly it wouldn't cost very much.

https://www.powerstream.com/Wire_Size.htm

The proposal was to use 10AWG wire not 30AWG wire, which is a very different size wire. Why 10AWG wire may be a good idea is a subject for a future post.
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post #21 of 65 Old 11-15-2019, 05:45 PM
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Originally Posted by bigguyca View Post
More on surge protection:

Agreed, 188V is 60% over about 120V. That means you are using 120V as the peak voltage in your calculations since surge protectors reduce peak voltage. This implies a nominal voltage of about 86V. This compares with 100V in Japan. There is no where in the world where 86V RMS is the nominal voltage.

In the United States the nominal voltage is 120V RMS. The electrical power is supplied as a sine wave. Surge protectors work by limiting the peak voltage, not the nominal or RMS voltage. For 120V RMS the peak voltage is about 170V. 188V is about 10% over 170V and corresponds to 133V RMS. This is a tight limit. The Furman PST-8 is a Type 3 surge protection device. Type 3 protection devices have a standard for let through voltage of 330V maximum so the Furman unit has much closer control than the standard requires.
Not enough information. Assuming 120v nominal with 10% tolerance it would equal 132v RMS.

Furman says 133v RMS.

133v RMS/.707 = 187.9v PEAK that would seem to tick and tie with the Furman published clamping voltage of 188v for the PST-8.

Still doesn't change the fact that it's an MOV device.



Quote:
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Concerning the wire size:

30AWG is very small wire. It isn't relevant to this discussion. As wire becomes smaller its current carrying capacity also becomes smaller. At the same time its AWG number becomes larger, in this range wires. The current capacity for 30AWG wire listed in the link below as .142A. Certainly it wouldn't cost very much.

https://www.powerstream.com/Wire_Size.htm

The proposal was to use 10AWG wire not 30AWG wire, which is a very different size wire. Why 10AWG wire may be a good idea is a subject for a future post.
Yes, correct, 10AWG, not 30AWG. I was thinking 30A circuit as I was typing as 10AWG is used for a 30A circuit. The point is that there is no advantage to using 10AWG wire on a 20A breaker. The 20A breaker contacts aren't going see any advantage with a 10AWG wire attached to it.
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Originally Posted by b curry View Post
Most of the surge protectors from Furman in the $100-$300 range or anyone else for that matter use MOV devices for surge protection. They do offer some level of surge protection but they are not without downsides.

MOV's do not protect equipment from inrush current surges, from overcurrent situations, or brownouts. MOV's degrade with time and use and are disposable devices. Under normal utility voltage conditions, MOV surge protectors work great. But under normal conditions, you don't really need one do you?

MOV based devices cannot withstand sustained over-voltage situations and can result in the MOV device catching fire. I know this from practical experience using an APC branded surge protector. It melted down, caught fire, and burned a hole through the rooms carpet during a lighting strike on nearby power lines. I contacted APC to use the surge protectors APC warranty only to be told by APC that my circumstances were not covered. APC would not even replace the unit let alone pay for the damage. The internet is full of pictures of MOV based power strip fires with a simple search.

The Furman PST-8 is an MOV based device. Yes, I agree it probably appears to do no harm. MOV's work at a designed "clamping voltage". If that design limits current in anyway, you're potentially limiting the output capability of a power amplifier when higher volume demands are placed on the unit. Without test equipment, you can't really tell one way or the other.

Small surges are cumulative for MOV's and will cause there failure over time the same as one large voltage or current strike.

Furman states in the description of the PST-8 that it uses TVZ-MOV's. TVZ-MOV's are fancy MOV's that include a thermal protection fuse. I'm not really sure what Furman's SMP circuit is, some sort of AC voltage filter I guess, but if you look at the circuit board on their site, you can clearly see the MOV's.

From Furman's description of the PST-8:

"The PST-8 all feature Furman’s SMP circuit which incorporates Linear Filtering Technology (LiFT) and a high current TVZ-MOV to insure that …"
https://www.furmanpower.com/product/...ks-PST-8%20DIG

Functionally, most any $15-$20 MOV power strip will offer the same level of surge protection as the $150 PST-8 does.
I would love to get your thoughts on my thread below regarding this subject.

https://www.avsforum.com/forum/91-au...l#post58897040

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I would love to get your thoughts on my thread below regarding this subject.

https://www.avsforum.com/forum/91-au...l#post58897040

Like Ratman said in the other post - start simple, work up from there if you need to. Of course, nothing wrong with a nice power distribution/surge protector like what you're thinking (other than they can be pricey!). Don't worry to much about a problem that doesn't exist yet, and might never. And if a problem does crop up, there will be a solution.

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The MOV's on the PST-8 have a published clamping voltage of 188v. That's 60%+ over the expected line voltage. I think if you open it up and look at the MOV part number, you'll be able to find the part on ebay for $1-$2 each. I have. They're no more heavy duty than what any one else uses. They are sized based on the line voltage required and the clamping voltage.

NEC may well require it. That still doesn't change the fact that MOV's are sacrificial devices not unlike the fuses that circuit breakers replaced. If that's the building code requirement in 2020 and each state requires it, Home Depot/Lowes has a new revenue stream.

MOV's do not protect equipment from inrush current surges, overcurrent situations, or brownouts. Do a quick search for MOV power strip fire and you'll find 1000's of photos of just such events. Writing it into code does not change how they work.

A whole house unit is probably a better use of the expense vs. something like the PST-8. But it's still a disposable unit. It will fail because it's designed to fail. If the home owner does not check the unit on a regular basis, it will have failed and he won't know it. It does not interrupt or shut off the power. You'll simply have a service panel with a dead surge protector hanging on it. Most home owners will need to call an electrician to change it out if they want it to work again.

If you feel like spending the extra money for 30AWG wire and the trouble to connect it to a 20A breaker and outlet only to hang a $150, 15A MOV power strip off that circuit and call it protection, knock your socks off.
Not sure why you're so focused on the 2 MOVs in the Furman SMP board. And quoting MOV clamping specs is useless (and completely wrong as you'll see later), they're not the primary devices that deal with surge.

"Furman's SMP circuit employs a hybrid design utilizing a non-sacrificial, multiple-stage inductance circuit of low-loss series inductors, DC rectifiers, and high voltage shunt capacitors to absorb the vast majority of energy in caused by a surge or spike, as well as a high-current MOV and thermal-fused varistor to reduce the remaining energy to a non-damaging level"

The inductors, rectifiers, and capacitors are the "series mode" part that's based on the long expired ZeroSurge patent. The MOVs are there in the event the inductors and capacitors get saturated by a surge.

But don't take my word for it, here's a Wirecutter test showing the Furman SMP outperforming SurgeX and Zerosurge:


"Even though our test computer monitor survived the 400 V that our top picks output when subjected to a 5,000 V surge, the Furman Powerstation PST-8 goes much further in its protection. In our tests, it repeatedly allowed just 40 V of that surge to pass through to the outlets. Instead of relying on standard MOVs to absorb the entire surge, Furman adds additional protection. Once a surge goes over 137 V, the entire unit shuts down to protect itself and any connected equipment. (Toggling the unit off and on resets it.) Any surge that gets through before shutdown passes through a series of capacitors as well as a large inductor meant to filter the extra power. The large MOV, similar to those found in less expensive units, only sacrifices part of itself as a last resort after the filtering stage.

We recommend the Furman Powerstation PST-8 for most people looking for upgraded protection, because the added protection of its hybrid design—advanced filtering plus traditional, inexpensive MOVs—is commensurate with a price a bit above a standard surge protector. These true series mode models from SurgeX and ZeroSurge actually let through a little more voltage in our tests, despite costing much more. "

https://web.archive.org/web/20171202...rge-protector/


Furman's over voltage shutdown also makes it one of the best values. The other companies don't offer this feature in a 15A power strip format.

I use both a whole house and endpoint surge protectors.

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Not sure why you're so focused on the 2 MOVs in the Furman SMP board. ...


I use both a whole house and endpoint surge protectors.
Because I've personally had the experience where such a device failed. It was manufactured by a company that rhymes with Herman.

The sacrificial MOV's melted/exploded and caught fire. In turn, the carpeted flooring caught fire. Had I not been home and able to contain the fire, it's likely I would have lost the house. Nothing else in the home that was pugged in was damaged, only the power strip. The companies warranty was completely useless, they would not pay for the damage or even replace the damaged power strip.

Moving forward and researching MOV power strips, what happened is actually quite common. You only have to search MOV power strip fire to see thousands of examples. I don't care what Furman has in front oft them. MOV's are sacrificial devices and can be a ticking time bomb.
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Because I've personally had the experience where such a device failed. It was manufactured by a company that rhymes with Herman.

The sacrificial MOV's melted/exploded and caught fire. In turn, the carpeted flooring caught fire. Had I not been home and able to contain the fire, it's likely I would have lost the house. Nothing else in the home that was pugged in was damaged, only the power strip. The companies warranty was completely useless, they would not pay for the damage or even replace the damaged power strip.

Moving forward and researching MOV power strips, what happened is actually quite common. You only have to search MOV power strip fire to see thousands of examples. I don't care what Furman has in front oft them. MOV's are sacrificial devices and can be a ticking time bomb.
You literally didn't read anything. Your experience with some cheap MOV based surge protector has nothing to do with a completely different design that uses them as an additional protection mode. I once got really sick from eating beef at a restaurant, I guess I should never eat beef again.

So you think MOVs are the devil and should be banished from the universe? I have some shocking news for you. Open up your receiver, amplifiers, fridge, microwave, television, ac control board, computer power supply, AC adapters, garage door opener, etc etc etc.... and you will find those evil MOVs in the power section.

They are used everywhere because they work, and are perfectly safe in a properly designed circuit.

You might want to educate yourself before you go around applying your anecdotal experience (and random internet photos) as some sort of universal truth. Poorly designed products are bad, MOVs in those products are bad. But they are safely used in millions of properly designed products.

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You literally didn't read anything. Your experience with some cheap MOV based surge protector has nothing to do with a completely different design that uses them as an additional protection mode. I once got really sick from eating beef at a restaurant, I guess I should never eat beef again.
And you sir are the classic pot calling the kettle black. I'll repost it for you; "It was manufactured by a company that rhymes with Herman." In case you need it spelled out that would be Furman.


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So you think MOVs are the devil and should be banished from the universe? I have some shocking news for you. Open up your receiver, amplifiers, fridge, microwave, television, ac control board, computer power supply, AC adapters, garage door opener, etc etc etc.... and you will find those evil MOVs in the power section.

No, I did not say MOV's were the devil or that they should be banished from the universe. Are you having trouble reading?

They maybe in the receiver's, refrigerators, amplifiers, microwave, televisions, ad control boards, computer power supplies, garage door openers, etc., etc., that you buy but they are not present in any that I use.

An MOV is not designed to take any current for a sustained period of time and they are not nor were they ever designed with the capacity to conduct sustained energy under normal utility voltage conditions. Used as you suggest would result in frequent periodic failure of the unit. MOV's have a finite service life. Each time they bleed off a voltage spike, there service life is reduced.

Over voltage suppression in the type of equipment you're suggesting is typically done with circuits designed using diodes or zener diodes.

When was the last time you had the MOV's changed in your fridge, garage door opener, TV, etc., etc. I'll be happy to see any documented photo or a circuit schematic of an MOV failure with any of your listed examples. Sacrificial surge suppression, yep, they are used all the time and are as common as water in a lake.



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They are used everywhere because they work, and are perfectly safe in a properly designed circuit.

You might want to educate yourself before you go around applying your anecdotal experience (and random internet photos) as some sort of universal truth. Poorly designed products are bad, MOVs in those products are bad. But they are safely used in millions of properly designed products.
Perhaps you would like to run an experiment where "anecdotally" a piece of equipment starts a fire in your house. I'll be most interested in hearing you wax poetic about the experience.

I'm not saying that they are not used. They are widely used. An I didn't say that they don't "work". But they do pose a fire risk.

You certainly don't have to take my word. The internet photo's are hardly random, there are thousands of them.

Maybe contact NFPA as they have issued safety bulletins on the subject or any of the home owner insurance companies in the world as they also have statistics.

Yep, there are a lot of cheap power strips that use a single or up to three MOV's with one across each leg.

And then you have something like the PST-8 that uses a thermal fuse in front of the MOV with the design idea that the thermal fuse will shut down current before the MOV self destructs. It does add an additional level of protection but it's still an MOV and MOV's are designed to fail and they can start fires. To the best of my knowledge MOV's don't know if they are in a cheap or expensive power strip, nor do they care.

If everything on the front end of the PST-8 was a sure thing, why do they need the MOV?
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(snip)

If everything on the front end of the PST-8 was a sure thing, why do they need the MOV?
The fact that I use a PST-8 doesn't incline me to argue.

There are lots of positive reviews of it online, but I see none from any who tested it to destruction.

Fingers crossed that its steel shell will be sufficient to keep any flaming bits from its sacrificial components from burning down the house if iit ever fails.

Your anecdote about a near miss makes me wonder what the surge device was like. I'm surprised that anything catastrophic happened with a UL approved piece. (The PST-8 is UL approved.)

I think I'll probably continue to use the Furman, unless I replace it with something heftier someday. (It's rated at 15A, but plugged into a 20A circuit.)
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Originally Posted by bobknavs View Post
The fact that I use a PST-8 doesn't incline me to argue.

There are lots of positive reviews of it online, but I see none from any who tested it to destruction.

Fingers crossed that its steel shell will be sufficient to keep any flaming bits from its sacrificial components from burning down the house if iit ever fails.

Your anecdote about a near miss makes me wonder what the surge device was like. I'm surprised that anything catastrophic happened with a UL approved piece. (The PST-8 is UL approved.)

I think I'll probably continue to use the Furman, unless I replace it with something heftier someday. (It's rated at 15A, but plugged into a 20A circuit.)

I'm not saying that you should not use your PST-8. No question, it's substantially better than a simple power strip using only MOV's.

My point is that MOV's do present a fire risk. They are sized for an application based on clamping voltage. As long as the surge is inside the capacity of the MOV it works rather well. When/if the surge exceeds the MOV capacity, there is risk. And each time an MOV absorbs excess voltage it is weakened, cumulative degradation occurs, and its service life is decreased.

In my case, the surge was a double dip. A transformer was hit by lightning. The real irony in my situation was the only thing that was damaged in the house was the power strip and it caused a fire. The source of the ignition in the power strip was the meltdown and shorting of the MOV's in the unit.

Sure, the PST-8 gets good reviews as long as it works at or inside it's capacity. If it fails and your equipment is ok you're happy. Meeting UL requirements doesn't make it fool proof and the manufactures are second guessing what mother nature might do with regards to design capacity. Stuff happens. The levees in New Orleans weren't supposed fail either.

There are much better ways to protect equipment. Unfortunately, better solutions cost quite a bit more. For me, a $100 power strip like the PST-8 represents something of a false economy based on my "anecdotal experience". You get what you pay for.

YMMV and if you're happy, that's all that's important I guess.
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post #30 of 65 Old 03-10-2020, 07:48 AM
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Quote:
Originally Posted by b curry View Post
And you sir are the classic pot calling the kettle black. I'll repost it for you; "It was manufactured by a company that rhymes with Herman." In case you need it spelled out that would be Furman.
Meh... what does that have to do with my observation that you didn't actually read my post? A brief glance would've told you I was talking about Furman. And no I didn't need it to be spelled out.

You keep repeating that the cheap MOV surge protector that failed you was a Furman, like it's some sort of indictment on their completely different and more expensive SMP products. All the cheap surge MOV protectors are virtually the same, it just as easily could have a been a Belkin, APC, Tripp Lite...

Quote:
Originally Posted by b curry View Post
No, I did not say MOV's were the devil or that they should be banished from the universe. Are you having trouble reading?
Funny you should mention reading trouble, because I never claimed you said that they were the devil.

Quote:
Originally Posted by duckymomo View Post
So you think MOVs are the devil and should be banished from the universe?
Notice the "so you think" and also the question mark at the end. This is a rhetorical question implying that it's likely you believe MOVs "are the devil".


Quote:
Originally Posted by b curry View Post

They maybe in the receiver's, refrigerators, amplifiers, microwave, televisions, ad control boards, computer power supplies, garage door openers, etc., etc., that you buy but they are not present in any that I use.
Sure........... So you've opened every electronic device in your house, and in some cases destroyed them just to see if there's MOVs? Sounds plausible.


Quote:
Originally Posted by b curry View Post
Over voltage suppression in the type of equipment you're suggesting is typically done with circuits designed using diodes or zener diodes.
MOVs are just as common, especially in products with SMPS.

The whole point of that is MOVs are used in well-designed circuits all around us without issues. So stop lumping all uses and implementation of them together.

Quote:
Originally Posted by b curry View Post
When was the last time you had the MOV's changed in your fridge, garage door opener, TV, etc., etc. I'll be happy to see any documented photo or a circuit schematic of an MOV failure with any of your listed examples. Sacrificial surge suppression, yep, they are used all the time and are as common as water in a lake.
Cmon, that's not even close to an equivalent comparison. An appliance has tens or hundreds of components and failure modes. People don't typically tear them apart to find the failed component. A surge protector is a simple external device that only has one job.

Quote:
Originally Posted by b curry View Post
Perhaps you would like to run an experiment where "anecdotally" a piece of equipment starts a fire in your house. I'll be most interested in hearing you wax poetic about the experience.[IMG class=inlineimg]/forum/images/smilies/smile.gif[/IMG]
No need, I had a car that caught fire. It was a jarring experience, but you don't see me on car forums ranting about the dangers of gasoline engines.

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Last edited by duckymomo; 03-10-2020 at 08:23 AM.
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