Monday, May 30, 2011

Acrolink Power Cords - A relook into conductor purity

Quick Comparison Table

Model               Price     Gauge        Conductors       Shielding        EMI absorbing cord

7N-P4020III    $90/m    Medium     0.26mm x 37    Copper tape  Yes

6N-P4030        $160/m  Large        0.26mm x 100   None            Yes

7N-P4030II     $200/m   Large       0.26mm x 100   Copper tape  Yes

For purposes of a fair comparison, all cords mentioned were terminated with Oyaide P-004/C-004 connectors, which are the matching plugs for the Oyaide R-1 AC outlet used.


The smallest cable of the lot (by gauge), the 7N-P4020III is supremely flexible and a cinch to strip and terminate.

It is considerably more detailed than the 6N-P4030 with better “look-through” and high frequency extension. Both transient and ambience definition is improved.

In the lower frequencies, it appears to be less weighty than the 6N-P4030. Closer comparisons actually reveal that the 7N-P4020III has deeper and tighter bass. However, the 6N-P4030 has a fuller mid-bass. Overall, the 7N-P4020III sounds tight and grippy, but with little bass bloom. It low frequency reproduction reminds me of the a Class-D amplifier, as opposed to a tube amplifier.

This cable fares well on background “blackness”, dynamics and separation. I would consider it to be a worthy upgrade in most systems and given its affordable cost, it is excellent value compared to the rest of the cables here.

Well after this comparison was done, I swapped the AC plugs for the Oyaide P/C-046 which in my view is a much better match for this cable, with a slighter fuller and more forgiving balance.


The 6N-P4030 is moderately easy to strip but tricky to terminate due to the large gauge of its conductors. To prevent undue strain on the clamping terminals of the Oyaide plugs, it would be best to strip a bit more of the cables than recommended and divide the raw copper strands into two equal bundles, i.e. resembling a two prong fork.

Formerly, my favourite cable (for source equipment), the 6N-P4030 has always impressed me with its refined midrange and high frequencies and its delicate reproduction of ambience and air. It has several weaknesses though. One is that the sheer amount of high frequency information makes the cable sound subjectively bright. Secondly, the equal emphasis on both the transient of the note and the decay may make some systems sound a bit slow. Lastly, it sounds very natural and gentle, and sometimes the force and dynamics of a recording are somewhat diminished.

Comparisons to the 7N siblings illustrate these shortcomings. The 7N cables sound more dynamic with deep extended bass and seemingly faster transients. Lengthy comparisons show that the 6N cable has less control and separation under heavy mixes with a slight loss of refinement.


The 7N-P4030III handles exactly like the 6N-P4030 in terms of flexibility and ease of termination.

Sonically, it combines the best of the two preceding cables. It has the mid-bass bloom lacking in the 7N-4020III while retaining its dynamics, separation, detail and speed. Subjectively the 7N cables have more background “blackness”, perhaps due to the copper tape shield. Overall, this cable sounds focused, while maintaining composure and refinement.

In terms of music, notes on the 6N-P4030 are always soft, gentle and very natural. The 7N-P4030II could be said to be more hi-fi like with a more defined and projected leading edge. The difference in presentation is unlikely to polarize fans of Acrolink cables and the basic DNA and house sound is still there.

To use a food analogy, the 7N-P4030II is like Cantonese soup from a top restaurant, flavoursome, yet crisp, clear and clean. The 6N-P4030 is more like good consommé. Always refined, flavoursome and clear, but with slightly less contrast.

Moving up the pyramid

How do these cables compare with higher end models such as the 6N-PC6100, 7N-PC7100 Mexcel, or heaven forbid the 7N-PC7500 and 7N-PC9500 ? My separate review on the PC7500 and PC9500 may be worth a look.

The PC-6100 has a quieter background and more solid bass. Otherwise, I think the 7N-P4030II has an edge over it in terms of staging, high frequency extension and detail. The PC-7100 is a clear step above these cables, combining the strengths of both, and with added detail and refinement. However, unless you are getting a good price on the PC7100, it is well worth the extra cost to go for the latest PC7500 or PC9500.

Monday, May 23, 2011

Furutech FP-1363 UK AC Outlet

Singapore Audiophiles do not really have much choice in installing audio grade UK wall outlets. Most make do by buying special US outlet faceplates that fit on our existing UK back boxes. This is of course in violation of local electrical codes.

Furutech is one of the few manufacturers to offer a solution - at a price. They make a single or dual outlet UK receptacle, with a choice of gold or rhodium plating. The base metal of the contact points is pure copper and treated with Furutech's proprietary alpha process, which involves both cryogenic and demagnetization treatment.

Featured here is the gold plated duplex model, FP-1363-D(G)

Plain cardboard box (with a bit of sticker shock, according to Mrs. Audiophile)

The plate is rigid and far less resonant than the stock outlet commonly used
A close up of the terminals. No problem with the beefiest of cables

A few pointers when installing these outlets. The faceplate is slightly longer than a standard socket. Measure carefully if installing them in tight corners, or adjacent to other sockets. Secondly, each outlet has an independent terminal, so make sure you have extra cable to jumper both outlets together in case your existing receptacle only has one set of wires. Lastly, the screws supplied are a bit on the short side. Probably fine if your backbox is not deeply recessed, but woefully short for my house installation.

If you do not know how to switch off your mains supply, test your circuit for live current, or to do the installation, please pay a qualified electrician to do it for you. This is not really a situation where you should be cheap.

First impressions after a 24 hour run-in of the outlet were positive. They gripped my matching Furutech FI-UK-1363(G) mains plug tightly and firmly. Apart from a refined smoothness, micro-detail was a step up compared to the stock outlet (a two year old Legrand). High frequencies were a touch cleaner and more extended. It was a subtle improvement but not of the earth shattering nature.

After a week of run in (my source equipment are left powered up permanently), the Furutech opened up slightly. The positive initial impressions remained but the refined smoothness gave way to openness without any hint of harshness. I generally find gold plated connectors a bit soft sounding, so it was a pleasant surprise that the Furutech did not dull transients or obscure detail. There is a possibility that this boils down to the mating of similar metals between the outlet and the matching Furutech UK plug used in my system.

To put things in perspective, I found greater differences in replacing power cords, or receptacles on my power distributor. The improvement brought about by changing the wall socket probably counted for a subtle but noticeable improvement in the 5-10 % region. In a top notch setup, this little bit of difference is enough to bring the system to a higher level. I would tweak elsewhere first, but for the audiophile that has done the whole works except the wall socket, this is well worth the effort.

Monday, May 2, 2011

DIY your own balanced interconnect

DIY your own balanced interconnects with Mogami Neglex 2534 !

Neutrik XLR plugs, Mogami 2534 cable, paper cutter, Kester 44 solder and Teflon plumbers tape

The Mogami Neglex 2534 is a flexible shielded star quad cable, i.e. separate shield and four individually insulated conductors. I have used this cable in both single ended and balanced applications, and this cable really shines in balanced form. Singapore readers can get this cable from Team 108 in Macpherson. You can have a look at their website for contact details and opening hours,

Once you have cut your cable to length, slide the rear plug housings on to the cable. I have lost count of the number of times I have soldered cables happily only to realise that I forgot the backshell !

Strip the cable and conductors, and twist the same coloured conductors together, i.e. form two conductors by twisting the clear cables together, and repeat with the blue cables. Bundle the shield wires together too.

I would suggest tinning the cable ends once you are done.

For plugs, general convention is male on one end, and female on the other. Check your equipment to be sure - I've seen some funky equipment that do not follow this.

Solder the shield to pin 1. Then solder the two conductors to pin 2 and 3. It doesn't matter whether you solder the clear cable or blue cable to pin 2 or 3, just make sure you are consistent on both ends.

Once you are done, it would make sense to wrap the exposed parts with a bit of plumbers tape. Other good practices would be to clean all parts, including the stripped wire with a bit of isopropyl or denatured alcohol, before soldering.

The 2534 may just surprise you. To my ears, it sounds as good as  many other expensive balanced cables that shall remain nameless.

Sunday, May 1, 2011

12AX7 tube comparisons

Here is a quick comparison of new 12AX7 tubes tried recently. All new tubes had at least 20 hours of burn in time on them.

From left, RCA 5751, Sovtek LPS, Tungsol re-issue, Psvane, GE Triple Mica Black Plate 5751. My morning cup of coffee just happened to be there. 

Tungsol re-issue (steel pin)

Following from my review of Tungsol's 6SN7, a quick audition of its 12AX7 brother suggests that New Sensor is going for a particular house sound with Tungsol re-issues. Predictably, the 12AX7 sounds smoother, richer, with more bass emphasis compared to its EH cousins.

The Tungsol has a creamy smooth midrange with a weighty and slightly rounded bass. The trade-off is comparatively less open highs. Brass instruments and the shimmer from ride cymbals have noticeably less rasp and decay. This also affects the retrieval of fine acoustic space. The lower register weight helps Piano notes though which have impact and good timbre.Resolution and dynamics are mediocre.

BTW, like the Sovtek LPS, don't chuck them out if they "fail" to light up. The filaments are so deeply recessed that the tubes do not glow when switched on.

Sovtek LPS

If the Tungsol is "night", then the Sovtek LPS is certainly "day". Not to be confused with the standard Sovtek offerings, the LPS is a Long Plate Spiralled filament version.

The Sovtek has a very tight and focussed sound, against a deathly quiet background. This is far from being a dark sounding tube. Bass is tight although not particularly extended. The midrange is forward and almost solid state like, but grain free. Highs are clear and extended. Dynamics are first class. On the downside, the Sovtek tends to emphasize voice sibilance. When the mix gets really heavy, separation of instruments also tends to fall apart.

Put into perspective its low price, this is an excellent tube that is actually better than a lot of the ho-hum NOS tubes out there. It is not the best available, but could be just the ticket to opening up a dark and slow sounding system.


A premier offering from Shuguang, the Psvane (as well as Shuguang's power tubes sold under the Black Treasure series), is sold with eye-popping prices (for a Sino tube) and rather fanciful (but ultimately useless) foam lined cardboard box with individual test results and serial numbers.

Psvane signal tubes (I had a roll with its 12AU7 brother too) seem to have one thing in common - tonal density. These are not insipid or wispy sounding tubes. They have a strong and full flavour. Bass and midrange are full and smooth. Coupled with good high frequency extension and good separation, they are well balanced and good overall performers. They are also quiet and refined sounding. Top marks for composure - they never lose their cool, even under complex and messy mixes.

In terms of ultimate high frequency extension and speed, the Sovtek LPS have an edge over the Psvane. The Psvane also tends to deliver larger than life images - perfect for the SET / full range speaker crowd.

If its tonal balance suits you, this is a very nice tube. Objectively, it is head and shoulders above most current production tubes (and it should be - with a matching price tag). However, I could think of a few NOS tubes that could blow it out of the water, or at least give it a serious run for the money.

RCA 5751 double mica black plate / GE triple mica black plate

OK. The 5751 is not a 12AX7 tube. They have slightly lower gain, but other than that can generally be used as a substitute for 12AX7 tubes in buffer and line level applications. My tubes were bought NOS from a well known local dealer and have at least a few hundred hours on them. They are featured here as a comparison between new tubes and NOS. Price wise, the Psvanes are almost as expensive as the RCAs.

The RCA has a nice big and wet bass. It has a rich and creamy midrange which controls sibilants well. On the  downside, brass lacks bite and dynamically, this tube sounds a little bit slow. In comparison, the GE triple mica 5751 grey plate or the Sylvania triple mica gold pins are significantly faster and more open. Rather unfortunately, the tubes mentioned have become horrendously expensive as of late. For the money, I would pick the Psvane over the RCA.