Power strips with EMI/RFI filtering

[Xan]

Seeing a comment in some other thread about those reminded me that I always wondered about their effects. I do use some power strips from the APC Surge Protector series for my gear, can that filtering have any positive effects on longevity/whatever of components compared to using a standard power strip?

[austin532]

Not sure if they help with longevity as I'm guessing some minor interference noise is not harmful to equipment but obviously they can help protect your equipment during a power surge. That's definitely a big positive.

[Xan]

Regarding surge protection, I stumbled across this article a while ago: http://www.gson.org/stepdown/ so it's not always a positive, apparently...

I've read claims from audiophiles that the filtering in these power strips can help audio quality a bit with certain equipment, but I'm not sure what to make of these claims. Perhaps it won't make any difference unless the local power source is really bad.

[blizzz]

Interesting article, but I think the author just bought junk. Even the cheaper step-down converters here in Europe have a galvanic isolation.

[speedlolita]

Interesting article, but I think the author just bought junk. Even the cheaper step-down converters here in Europe have a galvanic isolation.

Seconding this. That stepdown he has looks proper naff, not like Airlink.

http://www.airlinktransformers.com/

[Ed Oscuro]

Interesting article. Considering that I was interested in a 115 -> 100V stepdown, it may well have the same problem as that in the article.

That Airlink site looks interesting, though I'd like to see some actual schematics. Too bad they don't make US -> Japanese step-downs.

Speaking of junk, many devices called "power conditioners" (especially those marketed to audiophiles, apparently) are apparently not worth getting. Ideally you want the device to have more than simple noise suppression (EMI/RFI filtering suggests that to me), but also you probably want a proper voltage regulator. I'd also avoid buying multiple devices in the hopes of "building" those filtering steps, because you never know if one cheap device is undoing the work of another.

Cheap UPS devices are probably the worst to get because most put out that sawtooth ("sine-like" at best) power waveform.

[Xan]

Kind of related to this whole power noise subject, I was just testing out different aftermarket PSUs on my SFC, both of them being 9V/1A. Interestingly enough the bigger and slightly heavier one of the two causes crawling noise on the image, while the smaller one doesn't. The bigger one is even specified as being regulated which I thought was desirable; I'm not sure whether the smaller one is actually regulated. This makes me wonder what the deal here is, does the "bad" PSU lack some kind of specific filtering?

I'd go with the OEM PSU but I don't think feeding it 115V from a stepdown isn't going to go so well, doubtful if it has 15% tolerance...

Edit: Just ran it off a Roland PSU, image is noise-free... that adapter is linear rather than switched I believe, guess the more efficient switched-mode design of that one "bad" PSU is the culprit for the noise.

[Ed Oscuro]

You have to pay special attention to terminology in these cases. Here it seems "regulated" means that it's just the same type of AC-DC power supply used in most consumer applications. The other PSU is certainly regulated too.

There are some great small IC-based PSUs out there, at least for some applications (reportedly the flextronics ones are quite good) but probably to get the kind of features you're looking for requires a substantially larger and more expensive type of unit that won't be mistaken for a simple wall wart.

It's very interesting to read about how much impact different PSUs (and internal components, for that matter) can make to the quality of console output. A simple, uncomplicated "good enough" design from the late '80s or early '90s might still do well enough for reliability but in other respects we can probably get better with more modern components. From what I can tell, though, the best choices will likely be high quality (possibly medical, but be careful when buying these) power conditioners coupled with the best PSU you can find.

[Xan]

Yeah I'm really not too well versed in terminology, but I did gather some warnings about unregulated PSUs, as they supposedly pump out more volts when the PSU isn't fully loaded. Here as an example. Did you want to say that all of these consumer AC adapters are regulated? It seems that for appliances where a clean power source is required (i.e. devices with no built-in filtering in that regard) a linear type PSU is crucial.

[Ed Oscuro]

Regulated just means that you're going from your local AC source to a specific voltage or current level. That doesn't specify how tight the tolerances on that voltage are, or whether specific loading conditions will change the current. That seems more down to the quality of your converting circuit.

Linear supplies sound effective if your only concern is upfront cost, though I'm not sure that just buying something labeled a "linear regulator" is going to do everything you need, because it still has to filter out particular power wavelengths and still has to operate within the right tolerances. I would look at whatever the price-conscious audiophiles are doing - when I looked at this topic a while ago, some medical grade power regulators seemed to be a favorite choice for some audio applications (but again, as I noted there are some potentially dangerous configurations to watch out for). Can't guarantee this is going to tame all the wavelengths we will care about (which seemingly includes different wavelengths than just an audio application) but it is a place to start. I couldn't really see using a special bench power supply just for retro gaming, but maybe somebody does it.

[Xan]

The bit about tolerances is interesting - I just took a look at my PAL SNES AC adapter and it specifies an output voltage of 9-9.4V. Of course it doesn't explicitly say anywhere that this thing outputs AC, so anyone thinking they could power their imported NTSC consoles with this would have been in for a bad surprise...

[cools]

Airlink will build you any sort of stepdown you want, and their custom pricing isn't far off the standard models