[mofonyx]

Hello there,

This is quite a newbie-ish question but I would like to know/learn about it anyway.

I have a cheap line filter Tacima - Pattrick Brothers Communications Ltd with a maximum current rating of 13A.

Other companies offer high current line filters at 16A.

Now I've read that power amps (or amps for that matter) are sometimes better plugged straight into the wall socket as they should be able to filter out noise or dirty power inside if it's well engineered.

I've also asked around and line filters/power conditoners shouldn't have a problem of "limited current" and it wouldn't be overloaded or limited even if you plug a few Krell amps onto your filter/audiophile mains extension.

Is 16A really enough? How does the maths work out to be 16A, and why 16A?

My limited knowledge in A-level physics allows me to recall P = IV (Power = Current x Voltage). Would Voltage be the Voltage coming in from the UK wall socket? 230V?

Does that mean that a 100W rated amp working in the UK would only require 0.43A? Hmm.

So my question is, if I get around to a power amp, should I still use my cheap 13A line filter without concern, get a power conditioner rated at 16A or plug it straight into the wall socket?

 

[mofonyx]

Humpdumpbump.

I've got my answer, a 100W rated amp into 2 channels requires 200W in total, making it require about only 1A or less when used in UK @ 230V. A 13A trailing socket would provide me with about 3kW of power in total, and definitely a headphone set up would be fine with that, even if I use Krell amps.

Having said that, it goes to greater lengths to doubt why people would *prefer* or *recommend* plugging it into the wall socket instead of going through a power conditioner. How is this beneficial compared to using a power conditioner.. or how is using a power conditioner bad?

 

[jamato8]

I have a preamp that sounds worse no matter what type of power supply, including one I built with a special power conditioner toroid, built for balanced power supplies, that weighs almost 50 pounds. My preamp has enough filtering from its power supply that anything except directly out of the wall messes up the sound. Why when my mono amps that draw much more current sound better with my toroid conditioner does the preamp not? It isn't the current supply that is lacking but something else. There could be an interaction of the power supply for my preamp and the power supply conditoner. A type of electromagnetic feedback may be occurring but whatever it is, my preamp with its separate power supply likes its current raw.

 

[LawnGnome]

Don't listen to the garbage people say about them.


People say a UPS that can put out amazingly clean sound makes their gear sound like crap.

But then they say an audiophile branded line filter is a "night and day" difference.

When they are often a basic line filter that is used everywhere, that have 5$ worth of components.

 

[mofonyx]

Thanks for the replies.

I did speak to my friend about this who is very much into E&E and he told me that the only thing that could possibly affect the sound with an extra component in the power supply pathway is harmonic reinjection.

Quote:

(10:17 PM) Empire23 - Yay!: the only thing i'd be worried about is harmonics reinjection (10:17 PM) . х е е м .: explain.. (10:17 PM) Empire23 - Yay!: and that just makes the amp sound a little worse if it's PSRR is low (10:18 PM) Empire23 - Yay!: devices have a tendency to reinject harmonics into the line (10:18 PM) Empire23 - Yay!: especially switching power supplies, switching wallwarts being the worst (10:18 PM) Empire23 - Yay!: harmonics can find their way into the amp or your audio circuit

Could this be the problem? I don't see how though, it seems like such a small issue!

 

[LawnGnome]

Quote:

Originally Posted by mofonyx /img/forum/go_quote.gif Thanks for the replies. I did speak to my friend about this who is very much into E&E and he told me that the only thing that could possibly affect the sound with an extra component in the power supply pathway is harmonic reinjection. Could this be the problem? I don't see how though, it seems like such a small issue!

It does not appear like he is talking about line filters or UPS.

Seems like he is talking about other devices on the same household circuit. And switching power supplies are bad for it. If they have PFC then they are much better however.

 

[mofonyx]

Mmm, okay. Fair enough.

So how is it that the wall socket can sound better, if it does?

What is the reasoning behind it, if any?

 

[infinitesymphony]

Power conditioners can limit current, especially if they incorporate surge protectors based on MOVs.

Not all UPSs output perfect sine waves, and some output waveforms that could be damaging to audio equipment (or so I've read). It's also important to note the wattage rating on UPS equipment as it's possible to overload them.

Solution: buy expensive power equipment or plug into the wall.

If you're just using a headphone setup, chances are good that these negative effects will be reduced, since the power requirements are not as high compared with a speaker setup.

The quality of power coming out of your wall may also affect the usefulness of a power conditioner. If you're living in an apartment complex or somewhere with older wiring that can't be replaced, the positives of using a power conditioner might outweigh the negatives.

 

[Arainach]

Quote:

Originally Posted by LawnGnome /img/forum/go_quote.gif Don't listen to the garbage people say about them. People say a UPS that can put out amazingly clean sound makes their gear sound like crap. But then they say an audiophile branded line filter is a "night and day" difference. When they are often a basic line filter that is used everywhere, that have 5$ worth of components.

Who's the one saying that higher-cost parts must sound better now?

 

[mofonyx]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif Power conditioners can limit current, especially if they incorporate surge protectors based on MOVs. Not all UPSs output perfect sine waves, and some output waveforms that could be damaging to audio equipment (or so I've read). It's also important to note the wattage rating on UPS equipment as it's possible to overload them. Solution: buy expensive power equipment or plug into the wall. If you're just using a headphone setup, chances are good that these negative effects will be reduced, since the power requirements are not as high compared with a speaker setup. The quality of power coming out of your wall may also affect the usefulness of a power conditioner. If you're living in an apartment complex or somewhere with older wiring that can't be replaced, the positives of using a power conditioner might outweigh the negatives.

I just explained how they can't possibly limit current. How can you total up to more than 3kW of power requirements from your headphone amplification?

So your statement on limited current requires explanation, otherwise it would not be sensible. I would really like to know how you can fully ultilise 3kW out of commercial headphone amplifiers (or power amps for that matter). The only amp that can probably max out the 3kW allowance is a Krell FBI.

Anyway, if you suffer from limited current, it means that your set up requires more than 3kW (13A, 230V), and with that, your fuse will go with it. So really, if your power strip is still working, there isn't an issue of limited current!

I would really like you to elaborate further on your post!

Thanks.

 

[infinitesymphony]

I'm no expert about power, but I do have personal experience with power-related tweaks, which is why I'm in your thread.

Equipment is rated for either 15A or 20A in the USA. However, I believe that this rating represents maximum RMS current, not maximum peak current. I've read that some power amplifiers can pull up to 45A of peak current; if this is limited to 15A by the power equipment, the dynamic range will suffer. At least, that's the idea.

Theoretically, the wall should also limit the power. I'm not sure if it's a recurring audio myth, but part of the saying goes that more current can be drawn from the wall than is specified by the rating.

 

[LawnGnome]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif I'm no expert about power, but I do have personal experience with power-related tweaks, which is why I'm in your thread. Equipment is rated for either 15A or 20A in the USA. However, I believe that this rating represents maximum RMS current, not maximum peak current. I've read that some power amplifiers can pull up to 45A of peak current; if this is limited to 15A by the power equipment, the dynamic range will suffer. At least, that's the idea. Theoretically, the wall should also limit the power. I'm not sure if it's a recurring audio myth, but part of the saying goes that more current can be drawn from the wall than is specified by the rating.

Household fuses and breakers are quick blow. As soon as you draw more than 15/20 amp, it blows.

Why amps can have peak outputs greater than what you think a wall could provide, is because they have large capacitor banks.

Remember, a lot of these sayings and myths are created by people who don't understand how these devices actually work.

 

[infinitesymphony]

Quote:

Originally Posted by LawnGnome /img/forum/go_quote.gif Remember, a lot of these sayings and myths are created by people who don't understand how these devices actually work.

Yep, I definitely agree with you there. Power is one of those areas that is still a little mystical to the general audio person (including me).

My experience with inexpensive power conditioners and strips, including a Furman PL-Plus power conditioner, Tripp-Lite IsoBar Ultra isolation strip, APC surge protector, and a handful of others was that they all noticeably degraded sound quality (though the effect was subtle). However, when I upgraded to a better amplifier, I noticed that it wasn't affected nearly as much by power-related tweaks. My guess is that part of the outcome of using a power conditioner is influenced by the quality of the power sections in the audio gear--higher quality, less influence on the sound.

If peak current isn't an issue, then the potential negative effects of power conditioners could be caused by the use of low quality parts or poor filtering methods. I'm only talking about conditioners at around $200 and below. I'd happily trade my non-surge strip for a balanced power conditioner any day.

 

[mofonyx]

infinitesymphony:

But then that doesn't make sense. Looking at the First Watt F1 manual for example, it only requires 3AG slow blow type, 4 Amp for 120VAC, 2Amp for 240 VAC.

The amp is fused at 2A, so how can it peak above that? The fuse would blow!

Can you point me to amplifiers that require 45A of *peak* current?

 

[mofonyx]

Just for reference, I took a look at Krell's FBI http://www.krellonline.com/new_pdfs/...14_037_MAN.pdf

and it operates at a maximal 1,800W which understandably requires at most 20A (ideally 17A should be enough, but nothing is in ideal operation). I can see why this would require to be plugged directly into the wall socket and require a special 20A power cord.

But hey, speaking of which, this brings up more issues. Your standard "audiophile" power cord is rated 13A or 16A only, so how is it different from the "limited current" on a line filter/power conditioner?