TNT-Audio Readers' Corner
Monthly section devoted to your letters, positive and negative feedback about everything related to Audio and HiFi.

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May 2014

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Loudspeakers tweak
Dear Lucio,
Info on a diy experiment to improve speaker sound, with pic. A tweak with big results!
Idea from reading info on open baffles and the dipole nature of drive units. This indicates that having the mid/bass drive unit near to the edge of the cabinet is not good, also the edges of the cabinet front should not be sharp corners. As my Castle Chesters have both potential faults I made a pair of collars from card and finding some improvements went on to make the prototypes shown in pics with significant benefits.
The edge of the speakers are extended from 50mm to 250mm with collars, these are aligned with speaker front. My test subject is a friend who often listens to live music, uses a Gyro-deck, SME 4, and very expensive Koss electrostatic earphones, and is quite happy to point out any failure. He agrees that the sound is much more detailed, more musical, clearer, better bass, better stereo, and that the change is obvious. Pity about the looks. The collars just slide onto the speakers and so can be removed after a listening session (due to appearance).
This is an idea that can be tried in a few minutes with some thick cardboard, even made from 3 or 4mm ply and some 25 by 50mm softwood will only take a couple of hours. Well worth trying.
Mike - E-mail: mikejn (at)

[Speakers collar]

Dear Mike,
the pic isn't sufficiently detailed but I'm pretty sure to have understood what your tweak is all about. I suggest you to test this tweak for a couple of months, then go back to nude speakers. And listen.
I don't think dipoles come into play here. Actually, you're simply shielding (and adding a time delay to) the soundwaves bouncing back from the rear wall. This is strictly necessary with dipoles, otherwise the rear emission of the woofers cancels the front emission of the membrane, but this is not necessary with reflex (or acoustic suspension) cabinets. Indeed, you might try to get similar results by simply moving the speakers closer to the rear wall or experimenting with some kind of acoustical treatment on the rear wall.
Moreover, by widening the baffle area (that's what the cardboad does), you're simply adding sound diffractions generated by the cabinet. Generally, this is not a good idea, but it might add pleasant sound colourations in some cases.
Thanks for the feedback, keep us updated!
Lucio Cadeddu

DIY mains cables
I am contacting with respect to the article on a DIY mains cable. I am planning to change the stock cables for my audio system but some of these components have an connector with only two pins. For example:
What is your advice for replacing these stock power cables without the ground wire?
Thank you in advance for your support!
Best Regards,
Cristian - E-mail: c12121981 (at)

[Double insulation]
Dear Cristian,
if an electronic component has been designed and manufactured with just two-wires mains scheme (it means it has the so-called double insulation or Class II insulation) you can't add a ground wire to it. My advice is to use a variation of our DIY design, expressely meant for double insulation components, the Merlino CD. The article is in Italian but the design is nothing more than a four wires cable, where wires are connected in pairs like in the TNT Star loudspeaker cable design. Forget the shielding, as it is not necessary (and since the ground wire is missing there's no way to connect the shield somewhere).
Do not try to add a ground wire to a double insulation electronic component! If your HiFi component is of this kind it should display the double square logo (see pic).
Hope this helped somehow,
Lucio Cadeddu

Sonic Link Vermillion
Hi Mark,
You don't know me but I read the TNT reviews. I see that you once had some Sonic Link Vermillion titanium-core interconnectss. I just wondered what you thought of them? If you could bear to tell me. I have an option on a pair.
Many thanks for your thoughts and time.
Richard - E-mail: blyth.sutton (at)

Hi Richard,
It is always good to hear from a reader. It is the only way we know anyone is interested!
We don't do cable reviews on TNT-audio, because the effects of cables are too system dependent and far too many words are wasted on cables in other journals where they depend on advertising revenue.
I was not aware of the exact details of the the production Sonic Link (now Black Rhodium) Vermillion interconnects, whether mk I or mk II iteration. What I have are early prototypes with titanium 'positive' or 'hot' conductors and unspecified materials for shield/return (probably silver-plated copper, knowing the designer's preferences). These are only 0.5m length. I see flabby have some starting at 40 this week, which is a lot less than they were new, so a last few seconds sniped bid would give you a chance to try it and get your money back later if they don't suit your system.

If these wires are being offered locally, arrange to have an audition and buy them if you like them. Remember, wire is just there to connect components. It is the components that really matter. Money spent isolating components from vibration is usually better than money spent on wire. It is lavish to spend more than 10% of the cost of the less expensive component at either end of a cable. If a 200euro tuner is connected to a 10,000euro pre-amp, it only needs a 20euro cable. However, the 5,000euro CD player connected to the 10,000euro pre-amp will benefit from "up to" (and the phrase "up to" is crucial here) 500euro on wire. If the 10,000euro pre-amp is connected to a 10,000euro power-amp, it might be worth spending "up to 1000euro on wire. However, I would spend much less and buy more music to play.

Happy tweaking and listening,
Mark, the Old Scribe

Mutec MC3+ review
Hi Andy,
Would it be possible to connect this unit to a Marantz SA-7S1 which has a single BNC wordclock input?
I am not too technical, but looking at their website I couldn't tell.
John - E-mail: J46UAR (at)

Yes - I'm pretty sure that would be fine. It looks like the Marantz has a standard BNC type connection so it should be straightforward. It's the type of thing that clock input is for. You can always check with Mutec or a supplier to be sure.
Andy Norman

Merlin TSM-MMe
Hi Lucio,
yesterday I got the Merlin TSM MMe home for a demo with my Naim Nait 5i. The guy who owns the Merlins wanted to audiotion them with the Naim Nait 5i. So it worked both ways for us and especially so since the speaker carton is quite heavy and we made for quite a sight sliding the carton into / out of the evelator and into my 11th floor home :-))
The stands used were my Epos Stands and frankly I think we could have been better served with the conventional heavy frame stands. Regrettably the stands I had (earlier) had been sold to a friend of mine and they were too heavy to lug along or whatever !!
Merlin TSM has been on my mind since a long time - you know that. I simply do not have a chance to hear the Merlin's and when I got to know that one of my forum ( friends has it and that too at a 30 min driving distance from my home.. I decided to at least audition a Merlin - once in my life :-))
Music played:

Equipment: Room. This is a shared living room. Dimensions about 17 ft wide by 20 ft long and ceiling height about 10 ft. Largely unterated but we used a medium size carpet between the speakers. Listening position: The merlins were kept about 7.5 ft apart for best possible soundstage ( we eperimented a bit ) and about 3 feet from the rear wall and also about 2.7 ft from the side wall and toed in using the Merlin toe-in device.
I found the Merlin TSM quite sensitive to room placement and as was the PMC. One could play with the bass and the imaging to get the result you need. Initially we started without the RC network behind the merlins and then quickly realized the need for the RC n/w and put it on. The sound was not so good so we changed from the Supre cable ( don't know the model - but looked quite good and strong ) to the good old naim naca5 and i must say the Merlins showed up the change very well.
One of my friends said - WOW the naim Naca 5 cable is worth the money !! but i think its the transparency of the speaker that that came through. Note: The speakers were kept in their carton for nearly 5 months and yesterday - they played - so initially they did appear sluggish and we did play some low intensity music for about 10 min to let the speaker free itself a bit. But still the sound was sluggish - and a change to the naim naca % solved that to a large degree. ( I say large degree as the PMC DB1 is even faster than the Merlin ).
Yes - the Naca 5 is a good cable to match with the naim amp but the degree to which the merlin showed the difference in the speaker cable change was great ! I am reminded of TNT Audio review on the Merlin TSM MMe. My friends found the tweeter a bit on the aggressive side but strangely .. i did not.. maybe that what the audio business is all about. We all hear so differently !!
The U2 vinyl was a bad recording ( no mastering .. my friend thinks ) and the merlin TSM showed it for what it is.. there was no life in the recording.. and on some others like the Hindi vinyl - the sound came thru quite well. I also got acquainted with the "sealed design" bass and i think it was different from the normal bass refle bass but i think one can live with the Merlins ( understantement ). the bass while not being too forceful ( maybe the naim is only a 50 watter !! ) was adequate.
I am reminded of the Linn Majik 140 which i heard in a small demo room and the bass was so good with an all Linn 50W rig that my mind keeps going back to it. I suppose it is not possible to ask that kind of "presence" from a spaker half the size - physics does play a part you see.. The resolution on the Merlin TSM was quite satisfactory to me - i would have liked a bit more resolution and maybe a bit more fleet footed bass ( not like the heavy artilerry.. medium artillery but good scale and timing ).
The midrange was quite sweet and i think my friend would like to pair the Merlins with a tube amp. I have tried to put together a small detailed review but please revert to me if you find i have missed out anything. My friend felt - the naim merlin TSM MMe combo was not such a good one in terms of spatial imaging. They matched well but he felt maybe the imaging could have been better. Slowly, but surely, I am managing to listen to most of the speakers in my shortlist and am getting to the end of it. I would have loved to have some more time with the TSM MMe (2.5 hours is not enough esp when you have friends over) but i suppose I am happy I heard the Merlin TSM MMe.
Kind regards,
Mahesh - E-mail: mpwaran (at)

Dear makesh,
2 or even 3 hours are not sufficient to fully understand the Merlin TSM's, as these are quite complex speakers, with a strong character that requires careful listening and no-compromise system matching. They are magnifying lenses, so the rule garbage in - garbage out strongly applies here. Moreover, they are _not_ everyone's cup of tea. Audiophiles, sometimes, prefer to ignore what's going wrong with their HiFi systems :-)
Thanks for your report,
Lucio Cadeddu

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