Power conditioning. Talk about a contentious topic. You'll find many views on the matter ranging from "It's pure snake oil!" to "It's absolutely essential!" and everything in between. It's hard to even know what someone means when they talk about audiophile power equipment because there are so many variations out there. Is it a simple power strip? Does it have some minor inline filtering or noise rejection? Does it actually even protect against surges? One can approach the topic from almost any angle and find a corresponding product or two or ten. The funny thing is - pricing is not necessarily in line with features. We can find all manner of very expensive minimalist power strips that offer extra outlets and maybe some surge protection but don't really "do" anything else from a technical perspective (for a good example of this, see the HB Cable Design products, where the entry level mode appears to be a $4,000 power strip and it goes up from there). We can also find somewhat reasonably priced units from non-audiophile specific brands like Belkin or Furman or Panamax that are packed full of engineering but often derided by audiophiles as "strangling" dynamics among other things. There is also a group of engineering-oriented power equipment that is in fact geared towards the audiophile - I'm thinking of PS Audio, BPT, and Equitech among others. You can visit their websites and read all sorts of information on the topic if you feel so inclined.
It's really easy to dismiss this whole category as being not necessary. Focus on your DAC, your amp, your headphones, and be happy. Yet I'd say that's a mistake for two reasons, with one being more important but the other also worthwhile.
Reason #1 is protection. Plugging stuff straight into the wall or into some $9.99 power strip or "surge protector" is fine when you've got a simple system. But when things start growing, soon you've got hundreds or maybe thousands of dollars worth of components, and you'd really hate to lose it to a power related mishap.
It's the kind of thing where you think "it will never happen to me" - until it's too late. I've personally had a transformer blow in my neighborhood and take out the entire living room (TV, DVD, AVR, etc) and kitchen (microwave, toaster, etc) in one shot. There was nothing I did wrong to cause this to happen: no overuse of really long, thin gauge extension cords, no massive loading of too many components into a single outlet. It just happened, and it was beyond my control - or that of any neighbors who also had their equipment fried. Thankfully I had a fairly decent UPS on my computer which had enough protection to keep that safe. This was long ago before I had a nice headphone system worth speaking of but I would have been rather upset if that had been the case. In my particular situation it was determined to have been caused by a power company trainee (poor guy!) messing up something while learning the job, so we all got reimbursed for our loss. However I suspect that to be a rare event and wouldn't normally count on any sort of compensation. And even if they do offer compensation, they might find it hard to believe that someone paid $1500 for a headphone.... without a receipt you'd surely be out of luck.
Reason #2 is sound quality. This is where things get murky. Some companies make fantastic claims about night and day SQ improvements, which I think tends to give the whole category a bad name. To make matters worse, it's the sort of thing where each user will experience different results. Why? Because each house or apartment or condo or whatever they live in will have a potentially different quality of power coming from the wall. Some people are fortunate enough to have no problems at all, while other folks are plagued by severe issues. Even from room to room one may find a power conditioner to make varying degrees of improvement. Factor in potential ground loop issues and differences in sensitivity between equipment (really sensitive tube amps, for example, will be more susceptible to hum and other noise) and it's no wonder everyone has a different opinion on the subject.
The focus of this review is the Yulong Sabre P18
($329), which matches with the A18 and D18 as part of Yulong's Sabre line of equipment. I'll cut right to the chase and say that the P18 satisfies both of my reasons above, and does so in a way very compatible with the needs of headphone listeners.
What do I mean by that? It's simple really. Units from Panamax to PS Audio to Monster, tend to be rather large and cumbersome. They usually have something like 8 or 10 or 12 outlets on the rear, which is many times more than an average headphone system would require. They also take up far more space than most headphone amps and DACs which means they become difficult to fit into many systems - especially now that folks regularly set up their headphone system around their computer desk.
The Yulong P18 on the other hand is the same size as Yulong's other desktop equipment - 10 inches wide, 7.5 inches deep, and about 2.5 inches high. That makes it easy to fit into most any headphone setup. At 5 pounds it won't be a burden to any small rack you might use - contrast that with the big 37 pound PS Audio P3 Power Plant as an example. You "only" get 4 outlets but that should be enough for most headphone systems. Connect a source, a DAC, and a headphone amp or two, and the P18 will have it all covered. At $329 shipped it is certainly one of the cheaper options out there - compare it to even the most basic models from other brands and the Yulong will usually be the more affordable option.
The front panel is mostly blank since the P18 doesn't use any type of LCD display. On the left side, near the Yulong logo and Sabre P18 text, we simply get two LED indicators - one for power, the other indicating a phase or ground problem. The power LED lights up whenever the unit is plugged in. The phase light apparently shows up to indicate some wiring issue in your outlet or possibly your AC cable. I'm not really sure because thankfully mine has never lit up. I feared the worst prior to receiving it, but I've since tried it on many outlets at my house and it never indicated an issue. If it does show a problem, I'd try another AC cable or two, and then either have an electrician out to take a look, or else just live with it for the time being. The P18 is simply pointing out an issue that already existed so it should necessarily bother you too much unless it gets accompanied by noise or other problems.
The rear panel has the IEC input plus four quality power receptacles divided into two blocks - two of them claim to be for digital use, the other two analog. It doesn't look like the two sections really have any major differences between them, so it's more about separation than anything else. There's no power switch or anything like that - just unplug the main AC cable if you want to disable everything.
Internally, this is among the more "full" boxes you'll find in this category. I'll start with Yulong's description of the parts involved:
P18 uses an enormous ferrite core, wound with 11 AWG Pirelli wire
Vishay 8uf X2 MKP as common-mode filter
Vishay Sprague Y2 as differential-mode filter
Vishay transient voltage suppressor is used to avoid sudden impulse noise signals
LITTLEFUSE varistor (VDR) is used for absorbing voltage surges
Double layer parallel wide traces on PCB with 20 ounce copper
11 AWG Pirelli wire is used for internal wiring.
Schurter IEC inlet socket
Cooper IG8300 receptacles
Specially designed aluminum enclosure provides great Electromagnetic shielding
Two groups of outputs, separating digital and analog equipment
Phase and grounding error LED indicators
Feel free to Google some of those things if you aren't familiar with them. The highlights are the various filters to remove different types of noise, the varistors (aka Voltage Dependent Resistor or VDR) to protect against surges, the transient voltage suppressor which protects in areas where the varistors will not... and most importantly is the massive ferrite core used as an electronic choke.
You've probably seen ferrite cores
somewhere before. Sometimes they show up as clamps on USB cables or HDMI cables or even AC cables. You'll also see them inside other power protection and conditioning products. What you probably won't see is a ferrite core anywhere near the size of the one inside Yulong's P18. This thing is simply huge. Some of the full size units from Panamax and others will often use multiple smaller cores to cover several different "banks" of plugs. Since the P18 just has the two sections (for digital and analog) it only uses the single large ferrite choke and doesn't need anything else. I'll show a few pictures of different units from other brands, just to give you an idea of what they tend to look like. An older but still interesting thread from HeadFi
is worth reading as well, though I would make sure to keep going until you've heard both sides of the argument.
A Belkin unit
PS Audio AV3000
My knowledge of this stuff is more limited as compared to some other areas. But you know who is an expert? Yulong, the man himself. He worked as an electronics engineer in the telecom industry for many years and regularly dealt with power related issues. That makes him immanently qualified to design a product like this. Contrast that with some audiophile designers who don't have any technical background and essentially design their power equipment "by ear". I know who I'd rather trust my system to.
As you can see, the P18 stacks perfectly with the other Sabre gear. This is something of a "standard size" and should stack with most components that are wider than they are deep. Some stuff though, like the Benchmark DAC-1 type which is deeper and more narrow, will not fit.
Now for the fun part - listening. But let's be clear here: you can't actually "listen" to a power conditioner. Any listening is really being done to the system surrounding the conditioner, which of course will vary from component to component. And remember how we talked about different houses and even different outlets having varying degrees of problems? Yep, it's hard to nail down.
I'll start by listing two extremes. The first is the system in my bedroom where the P18 essentially made no difference at all. Sure, it was great for helping organize my cables, but in terms of sonic advantages? Nope, nothing. And this is a fairly high resolution system consisting of a Firestone Audio Tobby DAC paired with the matching Firestone Bobby balanced amp, driving either the balanced LCD-2 or a single ended Thunderpants. I just could not hear any issues prior to inserting the P18 in the chain, nor did I hear any changes (drastic or otherwise) once the P18 was in play. This is something of a worst case scenario (or best case depending on how we look at it).
The other extreme is in my living room, across from where my main system lives. I've got a little end table close to the kitchen (I'll come back to that in a second) upon which I've stacked a great little setup - JF Digital HDM-03S music server, Matrix X-Sabre DAC, Icon Audio HP8 MkII single-ended triode amp, powering HD800 or T1. I've always had some trouble with this setup in terms of noise. I blame it partially on the Icon amp which seems more sensitive than most to ground loops and such, but I also think proximity to the kitchen plays a part. There's a refrigerator in there, a microwave, a dishwasher, and all the usual appliances which at any given moment could be cycling on or off. I know the outlet for this system is connected to the same breaker as the kitchen because I've played with the fuses while trying to learn more about my power situation. In any case, this setup just never sounded as clean as I knew it could based on the performance of each component in my main listening area. I added the P18 to the mix and bang! There was the magic I expected. Background was blacker, noise floor lower, details more apparent. Things seemed more rich and full, which improved dynamics and the general "impact" of the music. In short, this was a substantial upgrade on par with moving to a higher class DAC or amp.
Other systems in different rooms showed varying degrees of improvement when using the P18. Was it dependent on the system used, or the quality of power coming out of each particular outlet? I'd guess a combination of both but I really didn't have the patience to swap gear over and over to find an answer. But remember - even with no sonic advantage whatsoever, the P18 was protecting from surges and other nasties. So it was never useless no matter what the audible results.
Is the Yulong P18 the answer to all power related woes? Nope. It doesn't do voltage regulation which for some systems can be beneficial. I've got a certain amplifier that was theoretically built for universal voltage but in practice was only released in regions using 220V (so far). When I use it, I get random shut downs that at times can make it frustratingly unusable. The company tells me it is likely caused by voltage from my wall being slightly low and suggests a power conditioner with manual voltage adjustment to ensure it stays at 120V or above. In that case the P18 will not help at all - I'm considering trying the previously mentioned PS Audio P3 which does exactly what I need. Will its regenerated power offer any additional sonic benefits over the little P18? I don't know. But it costs many times what the P18 sells for so it's not really competition.
Ultimately, I can say that for some situations the Yulong Sabre P18 is a significant and worthwhile sonic upgrade. Just not consistently in all cases. But what is constant is the substantial protection from surges and other hazards, and the lack of any downside - even when it doesn't help the sound, I've never noticed a hindrance either. Which is actually kind of a big deal. When you consider the price and the size which seems ideal for headphone users, the Yulong P18 is very easy to recommend. If you have a decent system and have yet to invest in some type of power protection, you should look into it sooner rather than later, and the P18 could be just the thing.
Yulong also sells an optional cable to be used with or without the Sabre P18. There are actually two variations - the A230 for Analog and the D230 for Digital
. They have different colors in the jacket to help tell them apart. Both models sell for an even $100 shipped for a 4ft cable. Both feature quality construction - fine stranded pure copper cable sourced from Lapp Cable
in Germany , Marinco
male plugs, and Schurter
plugs on the female end.
I don't know the specific differences between them but Yulong mentions the A230 as best suited for headphone amps and describes it as sounding non-compressed and "possessing a wide, rich soundstage". The D230 is better for DACs and source components and offers "details and balanced tonality". Don't believe in AC cables making a difference? Then stick with the basic black cable bundled with the P18 and call it a day.
I used the D230 in a variety of scenarios, feeding Yulong's own D100 MkII and D18 DACs as well as his A100 and A18 amps, along with other gear from different brands. To be honest, I'm not a huge fan of expensive power cables - I normally use Cabledyne Reference AC cables in my main setup, with Charleston Cable Company Auric/Auric Ohno and CablePro Reverie cables in my other systems. They all top out at in the $300 range and I wouldn't spend much more than that - even in my reference system which can hit a 5 digit price tag depending on how it's configured that particular day. Some people would scoff at me for even bothering with something beyond a stock cable, and others would surely mock my "lowly" choices when I should be using some megabuck cable from Nordost or Shunyata or JPS. But I stick by my choices - a well done AC cable can help a system in my opinion, though there's a limit to the benefits obtained. I also feel like it takes a somewhat high quality piece of gear to justify the benefits - I probably wouldn't spend the money on an aftermarket cable for the A100 amp or even the D100 MkII DAC. You might hear a minimal improvement, but it will be rather small indeed and not worth it - better to save that money for an upgraded device instead. Once we reach the Sabre D18/A18 level though, I do think it's worth spending a little extra on something nice. Enter the D230/A230.
I won't go on an on about the sonic differences between all my cables. None of these are widely used cables so it's not like a lot of people will have them as a point of reference. And honestly, comparing minute differences in sound between cables is not one of my favorite things to do. I'm sure you'd rather read one of my upcoming reviews of a DAC or amp or something (I've got plenty on deck at the moment) so I'll just leave it at this - the Yulong D230, despite being more affordable than any of my other AC cables, does not stick out as sonically inferior to a major degree. Nor is it inferior in build. It won't replace my Cabledyne Reference cables in my main rig but it's also 3x less expensive. Check out my pictures to see some comparisons. It's not quite as flexible as the Charleston cables but it's more easy to deal with than the beefy CablePro options. Its plugs are small enough to be comfortable in a tightly spaced headphone rig. And it looks nice too. What more could you want?
In the end, only you can decide if you think aftermarket AC cables are worth paying extra for. If you find yourself on the fence, the Yulong A230 or D230 might be a good place to start.
Edited by project86 - 5/4/13 at 9:38am