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,  http://www.team108.com/

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.

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.

Psvane

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.

Kingrex PSU Mk II - DIY DC Cable

Here is a nice project for a lazy Sunday afternoon. Frustrated with your stock DC cable that comes with your Kingrex PSU ? Come on guys, the cable is far too short !

Parts List

1x Neutrik Male XLR socket
2x 1m 18 AWG Neotech 7N Teflon insulated PCOCC copper cable or silver cable
1x Switchcraft 760 DC jack (fits my Squeezebox Touch just fine)

Instructions

Step by step instructions are probably unnecessary for this simple project.

I twisted the cables together lightly to provide a bit of RF rejection. It is worthwhile to also consider using shielded cable for this purpose.


Impressions

Initial impressions were that of a more detaled midrange and larger image size. Unfortunately, the high frequencies also sounded a bit hashy and the overall sound is quite grainy. In comparison, the stock cable is smooth, with a relatively laidback soundstage. The stock cable also sounds a little bit vague and the tonal contrast is lacking.

After 10 hours of burn in, things got better. The hash and grain are still there but are less prominent. The soundstage is a lot deeper and front to back layering is more distinct. Midrange is more forward which may not be to everyone's taste.

At the 30 hour mark, the cable is well settled and refined. Instruments are firm and transients are solid and distinct.   In guitar solos, you can clearly hear the pluck and reverbation of each string, together with the resonance of the guitar body. The midrange although more forward compared to the stock cable is both more full bodied and detailed.Soundstaging gets a boost too with good gains in stage width, height and depth.

With about 100 hours of burn in, the cable feels quite well settled. It is not a dramatic change compared to the 30 hour mark, but the improvements are nevertheless still significant. The cable still remains more forward compared to the stock cable, and although the treble is grain free, sibilance on female vocals is more noticeable. Piano notes in particular are solid, firm with a distinct separation between the strike of the hammer against the strings, and the resonance of the body of the piano.

In terms of sonic gains, this is at least the equivalent of an interconnect or power cable upgrade.All in all, this is an impressive upgrade for about S$ 30 in parts and less than 30 minutes of time.

If you are interested in a cost no object version, you could try using higher grade Neutrik XLR jacks (there are several different grades depending on the choice of plating of the metal pins), and Neotech's solid silver wire.

Solid Silver Wire Version

Over the last weekend, I decided to try out an improved version as suggested above. Utilising the same twisted wire construction, this cable is made out of 18 gauge Neotech solid silver cable. The cable was additionally cryo treated by the local distributor for a small premium.

Isn’t silver wire bright ? In my experience, silver is seldom bright. Silver plated copper can sound bright, but none of the solid silver cables I have handled or owned sound bright or edgy, which are common adjectives used to describe silver cables.

There were good sonic gains compared to my copper cable. The sound is similarly laidback, but imaging is more focused, and the level of fine detail is significantly better. Although the cable had only chalked up about 20 hours of burn in, it was able to outperform the copper cable by a comfortable margin.

Authority and extension on both frequency ends were enhanced, and the “atmospheric” feel of live records made it feel like you were almost there. The experience was just simply more holographic. You add about S$100 of cost, but this is money wisely spent. Given the overall low cost of making this cable, I would advise all readers to simply plump out for the silver cable version.