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Showing posts with label Tech Articles. Show all posts
Showing posts with label Tech Articles. Show all posts

Wednesday, October 11, 2017

My Thoughts on Surge Protection and UPS Battery Backups


Intro


This isn't going to be a long winded article, but a brief overview and tips on what I've found works for me so please give it a read and hopefully I can help improve your level of protection.

Any electronic equipment you may own such as televisions, network & computer gear, home theater equipment, modern washers and dryers, etc. is susceptible to damage caused by poor utility power. Often damage occurs in tiny increments unbeknownst to the user until a catastrophic failure occurs. This is why you should think about protecting your investment right from the start.


Surge Protection



Surge protection. This is the first line of defense. Its affordable and a must. If you're going to do only one thing tp protect your equipment, get a surge protector. Surges are caused by a variety of reasons such as lightning storms, generation snafus, maintenance of infrastructure and more. I typically use power strips with surge protection but also I use the type that sit right at an outlet. The thing to remember about these surge protectors is that they don't last forever. They contain a protection device known as a MOV - Metal Oxide Varistor. They absorb spikes of energy until they fail. Sometimes they just stop working and other times they burn up. For the latter reason I now try to buy only devices with metal cases, although this isn't always possible. When installing a new surge protector, get into the habit of writing the date on the surge protector with a permanent marker. After 5 years or so, consider replacing them. Its invisibly done its job for a great price and is most likely degraded significantly. You'll notice some have indicator lights to show the protection is working, but you can't rely on that indicator as foolproof. Energy absorption is rated in Joules so when shopping the more the better. Here's a few different surge protectors I personally use and like.



Tripp Lite Isobar - Brand name protection, noise filtering, metal housing, high quality. Choose your  outlet configuration.
Tripp Lite Basic Power Strip - Brand name, noise filtering, metal.
Belkin 10 Outlet - Nice large metal power strip with quality components.
Tripp Lite 3 Outlet - Small, fits on outlet. Value oriented.
Belkin 6 Outlet - Replaces outlet plate and screws into place. 6 outlets swivel. Value oriented.



* If your equipment that needs protecting is very expensive and you want to kick it up a notch, consider a surge protector which uses "series mode protection" instead of MOVs. This isn't a cheap option, but when only the best will do this is it. There are no sacrificial components that wear out. I use a Furman Pro-R in my home theater signal processing rack. Besides series mode protection you get advanced filtering capabilities, power factor correction with reserve current, and a slew of other features. There are other companies out there that also produce series mode protection surge suppressors such as ZeroSurge & Brickwall which are a little more affordable.

While treating surges at the outlet level is good, you should also consider a surge protection device right at your main breaker panel. This type of device has two main advantages. Its the first place a surge is seen and can act quickly to absorb energy before its distributed to various outlets. Second, they protects every device in your home including split phase 240v appliances! Modern clothes washers, dryers, dish washers and ovens are often found with advanced electronics inside and benefit from this type of surge protection. Also they are no longer expensive and can be found cheaply on Amazon or Home Depot. They aren't hard to install if you're comfortable working inside an electrical panel. If not, its very easy for an electrician to install and shouldn't cost very in labor. I use this Eaton Surge Protector for less than $100, but there are many others.


UPS - Uninterruptable Power Supplies, AKA Battery Backups



Battery backups not only provide you with extended uptime when the utility power completely fails, but provide a steady source power for times when you have power fail for half second or so. Many times during a blackout when the power is restored it can flicker back and forth for a second or so before its solid. This is also VERY bad for electronics. Battery backups can fill in this gap and prevent damage. They can also provide boost & trim functions which deal with sagging power during brownout conditions as well as over voltage conditions. As you can see they are the second layer of protection next to surge protectors in keeping your electronics safe. Many have built in surge protection as well, but keep in mind if they are MOV based they don't last forever, so I always encourage using separate surge protection in conjunction with battery backup systems.

My battery backup of choice is the APC-Smart UPS. I've tried others and always come back to these. APC is the leader in the field of UPS systems. What makes these better than the average lower priced battery backup you find in stores is the fact they output a real sine wave instead of a square wave or stepped square wave, so the output waveform looks identical (and in some cases better) than what the utility company provides. Sine wave output makes appliances with motors start easier, they have less harmonic content to be filtered by the appliance, and some computer power supplies simply refuse to run on a square wave input.




When shopping for an APC-Smart UPS, first you must size it correctly for your load. They are rated in volt-amps, which a a measure of power similar to watts. If you're interested in the details of these differences much is published on the internet and can easily be found with a simple search. To make it simple, I'll talk mostly about watts. A very common sized backup is an APC-Smart UPS model SUA1000 backup. Its rated for 1000va / 670 watts. Which means, you can't connect a 1000 watt load to it and expect it to sustain power. There are general rules of thumb I've read about, such as 60% upsizing the backup to the load, but there is wiggle room to be had. If you're battery backup is rated for twice the load you place on it, you'll get longer run time and less stress on the batteries, so that's what I aim for. If you don't know how many watts your load is going to be, grab yourself one of these handy little Kill A Watt electric usage meters to measure the power consumption of anything you plug into it.

Speaking of run time, this is an area most people don't think about. At full load 670 watts, our example SUA1000 is good for about 4 minutes of runtime before it shuts down. At half load 335 watts, its rated to run for 4-5 times as long, which takes it out to 18 minutes. See why I like to size them at 2x the load? You get 4-5x return on the runtime. You'll also find that "bigger" backups support heavier watt loads, but don't necessarily give you longer run times, even with smaller loads. However 5-20 minutes often gives you enough time to properly shut down a computer or unplug devices until utility power is restored. That said if your goal is to keep a device running as long as possible, such as a critical system like a boiler's controls, or a sump pump or even your cable modem/router then you need to pay close attention to runtimes and look for an APC-Smart XL backup. The XL means extended runtime. You pay slightly more for the XL models, but you get longer run times, better batteries, more watt capability, and heavy duty components with better cooling. You also get an Anderson connector on the back to plug in additional battery packs for even longer runtimes. In fact, the XLs are the only type I purchase anymore due to these features. An APC-Smart 1000XL for example will run for 10 minutes at full 800 watts and 33 minutes at half power 400 watts. If you have a 50 watt load, it will run for 5 hours! Compare that to the non-XL version which would run a 50 watt load for 3 hours. Models differ, so its very important to research the runtime charts. I find the APC-Smart 1000XL tower to be a really good bang for the buck UPS. It has a longer runtime than the much larger APC-Smart 1400XL, despite its capability to power a larger load. I use one on my DIY network rack and it keeps my router, modem, and main switch and access points running for hours on end.

Know that the batteries will typically last about 3-5 years. Expect to replace them at these intervals. The best prices can be found online. I tend to examine my batteries after a few years, because once they start to fail they can crack, bulge and leak. When you do replace batteries, find out how to perform a "reset" to let the UPS know you have new batteries and the runtime will be accurately displayed.

My next tip is while these APC models are pretty expensive, you can find them refurbished with new batteries for a great price. My favorite place to purchase them is Refurbups.com Full disclosure - My only affiliation with them is that I'm a happy customer. The prices are about the best I've found from all the online stores. I've bought several from them and I've been satisfied each time. Expect to pay a nominal shipping charge, because these are heavy items. I can tell you my last purchase from them was a 60 lbs rack mounted SMX750 that was double boxed and bubble wrapped and arrived in perfect shape.

In a future article, I plan to document playing around with connecting large external batteries on these XL backups to really push the runtime out for days at a time. There is more to it than just plugging them in!


Tuesday, November 15, 2016

Panel Bracing the Main Cabinets

Here you can see this loudspeaker cabinet has the internal bracing in place just prior to glue up. You'll notice I'm using pocket screws. Pocket screws are an easy way to firmly hold the bracing in place while glue is drying therefore no clamps are needed. I decided to use panel bracing along with a cross brace which anchors the baffle between the woofer and the waveguide cutout.



The "glue" I'm using is called PL Premium. Its a polyurethane construction adhesive commonly found in home improvement stores, or here on Amazon. It expands as it cures which helps fill in gaps, unlike your typical wood glue which shrinks. Its very messy to work with however, so wear nitrile gloves and be careful. It has the consistency of peanut butter and sticks to whatever it touches. Once you get it on a surface, its very hard to remove.

Panel bracing is a bracing scheme which increases the resonant frequency of a panel by physically subdividing it so acoustically it appears as several smaller panels. Panels tend to vibrate at a frequency determined by a formula which takes in consideration the dimensions of the panel as well as its density, bending stiffness and a few constants.

Our goal is to attenuate these resonances enough that they won't color the sound of the loudspeaker's output. We do this by first pushing the panel's resonance frequencies up and out of the band used by the woofer by altering the panels apparent dimensions via bracing.  Second we then attenuate those resonances with mass and stiffness. One could write a book on this topic alone. I've studied cabinet construction of JBL's 4xxx line of classic studio monitors and note they have done a great deal of research in this department. Not trying to reinvent the wheel, I've chosen this tried and true method to quiet these enclosures, plus a few other considerations not seen here to add a degree of overkill.

If you're interested in pocket screws, I started out with this kit Kreg K4MS Jig Master System with Pocket Hole Screw Joinery Kit. If you're a DIY type, you'll be amazed how many uses you'll find for pocket screws!






Thursday, July 3, 2014

Facebook Page


Join me for a social media experiment..

Please like my new FACEBOOK PAGE for more updates.

Thanks everyone!




Wednesday, April 9, 2014

Links of Interest #002


Why CDs sounds better than vinyl - Its all in the sample rate!

Roger Rusell's Speaker Wire - A History - Busting those wire myths. The bottom line is you want lots of copper. Everything else is marketing.

Rod Elliot's Article on Passive & Active Crossovers - Why a passive crossover will never be as good as an active one.

The High Life - An audiophile rants. While I agree with a few things and not others, its a short, fun read if you have a couple minutes.

Project Free TV - Find those TV shows you love. Online. Free.



And lastly I leave you with a music video. The is the Main Title from Star Wars, played by Jelani Eddington, on a majestic 50/80 Wurlitzer pipe organ at Sanfilippo Residence.


Wednesday, June 5, 2013

Links of Interest Series #001

The first installment of regularly posted links of interest that I stumble upon. I'll have a permanent link to show only these posts on the sidebar to the right. Enjoy!


The Best Turntable (Entry Level) $400

I need to try vinyl one of these days. Maybe this is a good starting point?

"After consulting experts in the field and reading countless reviews, the entry level turntable to buy today is the Pro-ject Debut Carbon. It comes with the best combination of tonearm and cartridge of the entry level models out there, and is built well enough that you can upgrade the cartridge or other components down the road without needing to replace the table first."


The Dynamic Range Database


Does that new album sound better on CD, Vinyl or HDTracks?  Find out here before you spend your hard earned money.


24/192 Music Downloads... and why they make no sense

A very good article on why you DONT want a high sampling rate. Open this in a tab and read it later if you don't have the time. Its worth it. I like articles that have solid science backing them up. This is one of them. I'll also link the video accompanying this article because it demonstrates how science backs up facts and dispels myths about DA/AD conversions. I hope Monty makes more videos like this.




Friday, May 31, 2013

Now Magneticmadness.com!

I finally worked out my issues between Google's blogspot service and my domain registrar. Something that is normally so easy turned out to be a huge hassle because I had two different Google accounts and didn't know it. The result now is you can reach this blog directly at www.magneticmadness.com

The next thing I want to announce is I am going to start making posts about electronics and technology projects in general, in addition to the audio/video. A lot of folks into audio and home theater tend to have interests in line with other things I'm doing and would love to write about, so why not broaden the bandwidth a hair and open it up to more visitors?

Also if you feel so inclined to donate to my blog or future endeavors with the audio system, please click the logo below to make a Paypal donation and you will receive my highest accolades!




Wednesday, May 15, 2013

Audiophool Cables



A humorous, yet serious rant about over priced audio cables. I didn't expect to laugh so hard. A worthy watch and a reminder of how gullible some people can be!





Monday, January 28, 2013

Acoupower Subwoofer Drivers

I compiled some videos about the subwoofer drivers in my audio system. It is an introduction and comprehensive look at the metal and soft parts which make up an Acoupower driver. You may have seen the introduction posted here before, but this includes videos of the inside of the drivers. A full 20 minutes worth. I'll soon publish a post showing the buildup of my cabinets and other data.

A quick summary of specs on these amazing 18" drivers :

- 6" copper 2 layer voice coil in an underhung configuration.
- Largest neodymium magnet used in any loudspeaker
- 97% of magnetic field lines in the gap
- Entrainment techniques used to eject hot air from the motor
- 5 sqft. of heatsink surrounding the motor
- 18mm of one way throw and still at 100% linearity on the BL curve.
- 39mm of one way peak throw
- 1% odd order distortion with 1KW input power




Thursday, December 13, 2012

Electronics Workbench Laboatory


I don't know what took so long. Maybe building cables on the concrete floor, taking laptops apart on the kitchen granite or building a Linkwitz Transform equalizer on the coffee table. What kind of electronics fanatic does not have a decent workbench? I set about to change this situation. Most of the materials I already had in stock and were recycled from other projects. Its a mix of warped 2x4s, 4x4s, Chinese Birch, Baltic Birch, screws and PL Premium adhesive. I don't have much equipment yet, but I have the basics. A good Weller soldering iron, Fluke Multimeter, 40v 5amp variable power supply, Tektronix 2465ACT Oscilliscope. A place to put my books, a computer, ect. The backbone of my home network sits on top. A pair of 8 port gigabit switches, a TP-Link router running DD-WRT, Linksys cable modem, Silicone Dust ATSC network tuner, and a Synology 211 NAS. To the immediate right of the bench is the back of my audio rack. There is even a Kenwood 599 Amateur Radio transmitter and receiver to play with. It is a work in progress, but I'm happy I finally have a start and a place to sit down and work on things.


Sunday, September 16, 2012

Acoustic Panel Project - Absorption



Here are some simple broadband acoustic panels I made, based on the GIK 242.

The frames are made of 1" thick by 3.5" wide poplar. Poplar is used because of its resistance to warping. Finished panel size is roughly 2' x 4'. The pieces are joined with pocket screws via a Kreg jig, which by the way is a great tool to have! I didn't use any glue with these and they are super strong. The corners are simply butted together because once covered in fabric, they won't be seen. As an added touch, I chamfered the outer edge with a router. This was initially just for looks, but it also helps prevent snags when stretching the fabric over the edges. The absorption material used is 2" thick Owens Corning 703 rigid fiberglass panels, which have well known and documented acoustic properties. I then covered the panels with Guilford of Maine FR701 fabric, which is acoustically transparent and meets fire codes. The fabric is neatly stapled on the back side of the frames. The completed panel gives you 2" of absorber material with a 1.5" air gap behind it, which increases the low frequency performance and gives you a place to hang the panel onto a nail or screw. Performance wise, they should be identical to the popular GIK 242 panel as they use the same materials and specifications. I currently use 4 of these at the first reflection points of the left, center and right front speakers. 








Monday, March 19, 2012

Subwoofer Ports

Subwoofer Ports

Great explanation of how speaker ports work, taken from the link above.

"The resonance of a vented box is caused by two factors. The first factor is that air in an enclosed space behaves like a spring. Anyone who has played with a beach ball, sat on an air mattress, or pressed on a balloon will realize that after pressing against an air-filled object, the object will spring back to its original shape. Ultimately, the air molecules want to remain a certain distance apart, and when you temporarily squeeze them together, or pull them apart, they will quickly return to their preferred spacing. The air inside a vented enclosure behaves similarly to you sitting on an air mattress; it acts as a spring pressing against the driver's cone, and also pressing against the air in the loudspeaker port.
 
The loudspeaker driver exerts force on one end of the spring, and the spring in turn exerts force on the air in the port, which brings us to our second factor that sets the resonance of a vented box. The port air is confined by the port walls and moves primarily as one big "slug" of air. This volume of air moves in and out of the port as it is pushed and pulled upon by the spring. The larger the volume of air in the port, the heavier it is. A heavy slug of air changes direction more slowly, from moving into the box to moving out of the box, when the spring pushes on it. A lighter slug of air can change direction more quickly.
 
Combining the two factors above sets the resonance of a vented enclosure to a specific frequency called the box resonance frequency, commonly abbreviated Fb. The box resonance frequency is defined by the combination of the volume of air in the port and the springiness of the air in the box. A large enclosure volume makes for a soft spring, and a small enclosure volume makes for a stiff spring. We use a large box (i.e. a soft spring) with a heavy (i.e. large volume) slug of port air to produce a low Fb. Virtually any box resonance frequency can be chosen by careful selection of port volume and enclosure volume."