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The TNT Janus: DIY double-sided turntable mat

[The TNT Janus]

[The Janus mat]
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[Italian version]

Any analogue-oriented audiophile knows pretty well how important is a good mat to get the most out of his beloved LP's.
There are many turntable mats in the market, some of them are very expen$ive, and during my never-ending search for the best mat I've tried many of these. Then I realized what I was looking for wasn't available yet so I decided to build it on my own.

The problem

A good turntable mat can make wonders to the sound of any analogue machine, since it is the first interface between vinyl and the outside world.
I'll try to briefly summarize what a good mat should do:
  1. It should dampen the noises and the resonancies coming out from the transport system (motor, pulley, platter, belt etc.) so that these can't reach the cartridge.
  2. It should work as a perfect damping interface between the turntable and the LP so that the microvibrations caused by the needle and the disc itself can't reach the platter, where they could be amplified and sent back to the needle.
  3. It should minimize the *pitch* errors, caused by the disc sliding a little on the platter while this is turning. Hence the contact between the disc and the platter should be as firm as possible (a disc clamp may help, too).
Many commercial mats, the 90% of the times being made out of felt, work pretty well for 2) and 3) but can't do almost nothing for 1). Then one can say that good turntables should be already noise and vibration free by design but we know this is impossible. Just take a sthetoscope and listen to your turntable while it's turning and you'll realize that it generates a bunch of wild...noises, hums, and vibrations that you can't even imagine.
Moreover, if your turntable isn't of the hi-zoot mega-$$$ kind or if it is rather old...well, you get the picture :-)
Other mats, made out of different materials like lead, for example, are pretty good at 1) and 2) but can't do nothing for 3), being pretty slippery.
Also, they are pretty heavy and if you use them coupled with a heavy disc clamp, in order to reduce the *slip*, you may easily overload the motor and the belt, with the consequence of a very long start-up time [YAWN!] (simply, we don't care about this, we're not DJ's after all), causing the belt to be overstressed and then deformated, changing its natural size (which is bad, as you can easily guess...).
Last but not least, a good turntable mat should be antistatic, easy to clean, dust-proof (not like those felt mats...), cheap and easy to build.

The TNT Janus solution

So my idea was to design and build a mat that could work well for 1), 2) and 3) being, at the same time, antistatic, dust-proof, easy to clean and cheap.
Mission impossible? Well, not exactly. What I needed was a double-sided dual-compound mat, with a strongly damping face to minimize the transport noises and with another face made out of a light, damping material that could help to minimize micro-vibrations, being at the same time not-slippery, antistatic and disc-friendly.
So here is the TNT Janus solution: a double-sided mat with even two different sonic properties, as we'll see later. Janus, you should know this pretty well, was a deity with two faces in one...here's why I choose this name for my DIY turntable mat.

Building the TNT Janus

All that you need is a sheet of tar damping material and a sheet of self-adhesive cork. Then you need a high-precision cutter (Stanley makes a solid aluminium cutter that is a pleasure to use...), a firm hand and a lot of patience.
How much will this cost? Much less than 10$, and you can even recycle the damping material that will be left over during the cutting process.
So the Janus isn't much more than this. Too trivial? Wait and read on.
Now, if the cork sheet seems too thin you can glue together two sheets of this, paying attention to avoid air bubbles during the glueing process...take all the time you need for this, don't fret.
Then you can glue the sheet of the tar damping material, remembering that an error during this delicate procedure will force you to start again with a new pair of sheets...so, relax, hold your breath and pay attention.
Now you should end up with a double-sided sheet, cork at one side, tar-like stuff on the other side. You may need to put the double-sided sheet below a pile of books, even better, below a pile of old HiFi magazines. The heaviest, the better ;-)
Now you're in the position to cut a disc out of this sheet. First of all you should try to cut a disc which is exactly the same size of our original turntable mat. Use the platter (for example) as a model.
The first cut should give you a slightly wider mat, so you can always cut away any excess after. Be sure that the hole is perfectly centered and not too wide: it is better this to be strict, so that it fits/clamps firmly over the spindle.
The key to build a good mat is micrometric precision: an error during the cutting process will make the mat unbalanced and hence useless.
Now, relax, take a deep breath, wipe away the sweat and be prepared for a new different experience :-)

Does it really work?

Well, this is one of my DIY projects I prefer. The fact that this mat has two different damping materials, with different absorption coefficients, makes the TNT Janus a perfect (OK, nothing's perfect) barrier against macro and micro-vibrations.
If you have a rather old and noisy turntable the Janus will make wonders, minimizing any noise and vibration coming out from the transport. But even if you have a new audiophile turntable, with a felt mat, you'll experience a new sound coming out from your LP's.
The reduced noise level and hence the improved signal/noise ratio will improve the overall dynamics and the level of micro-detail that was previously covered with a ...mat of noises. Even the soundstage widens a little bit, becoming firmer and better focused.
I haven't still told you in which way this mat should be used: well, it depends. I prefer the cork side to be facing the disc and the damping side on the platter but sometimes, depending on the turntable and on the rest of your system (its tonal balance etc.) it could be better to use the Janus conversely: the cork facing the platter and the tar facing the disc.
It's up to you to choose: just test listen and decide.
Roughly speaking, the cork facing the disc gives you a brigther and more refined sound in the highs, even a little bit light and dry in the mid-bass.
Conversely the tar side facing the disc gives you a more powerful, full bodied sound, with strong bass notes and well articulated mid-bass. This is why I called my mat - Janus: it does have a double personality, which is, in my opinion, a big plus since it allows you to choose the kind of tonal balance that fits best with your system and your ears. Don't get me wrong: I'm not telling that the differences are of the day/night - body/soul kind :-) (Joe, please forgive me), it is just the possibility to tune-up your system according to your needs.

Moreover the Janus, thanks to the properties of the cork side, is antistatic and very disc-friendly. It is easy to clean (just use a soft cloth...you can even wash it!!!), not slippery and it does have excellent damping properties: just tick with a metallic object the outer side of your platter with and without the Janus on and you'll understand what I mean.
For better results a disc clamp should be used but we'll talk about this sooner or later. Also, if your platter allows you to do it, you can glue the Janus directly on the platter for increased damping and *traction*.


Less than 10$, everything included. This mat is a bargain...no, no, wait, I'm not selling it, you should already know that EVERY DIY project here at TNT-Audio is for free, we're strictly non-commercial. 10$ is the amount of money required to buy the sheets you need to build your own Janus mat. Add a couple of hours of work (and sweat) and you're done.
Does it work? Yes, definitely. Is it the best mat around? Nope. You know you shouldn't ask: there's no such a thing as a perfect turntable mat. Each one of these is a compromise, you should choose the one you feel most comfortable with.
Happy cutting to everyone!

© Copyright 1998 Lucio Cadeddu

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