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Readers' Corner - July 2001

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Hello Lucio,
Nice web site you guys have!! I refer to it often and have found it very interesting and helpful.

I have made a few of the TNT DIY cat 5 speaker cables (TNT Triple T) and had excellent results. A question occurred to me, but since it involves re-braiding the cables I thought I would ask you guys first. Since the number of twists in these cables (in addition to the individually insulated solid conductors, etc) determines their electrical characteristics, I was wondering about the arrangement of the left and right speaker cables as they wind their way from the amp to the speakers.
In my setup the cables run along the wall/floor parallel to each other for about two thirds of the distance, then divide and go to each speaker (a total distance of about 17 feet).
Would anything be gained by making a composite braid using all the left and right cables for the two thirds distance? How would this affect the channel separation? Perhaps the idea is rather twisted?
Mike Ellison - E-mail: roundabout@loop.com

Dear Mike,
the idea isn't all that "twisted". Actually, I know some audiophile already twists the right and left cables together. It is common practice, for example, to twist the two runs of cables when biwiring the speakers. So, you should - at least - try. I'm pretty sure this won't affect channel separation.
All the best (and let us know),
Lucio Cadeddu

3 tweaks 2 die 4 :-)
I often dip in to your site and have a look. I have not done anything myself yet, but thought I would bring this idea to your attention.

A while ago I bought a pair of Sony Brooklands floor standers. The first thing I did was put them on concrete blocks and change the wiring. They sound quite nice upside down too.
I notice that on your page you incorporate many ideas I have considered, but I notice on omission - when I re-built my speakers I applied a layer of silicone sealant behind the speaker cones and the crossover. I believe that this will assist with damping vibrations, and this stuff is available in clear, black, white and several shades of brown, so if any leaks out and is visible it is possible to quite closely match it against cabinet colour.

Another idea is to use a router to embed the tweeter unit into the cabinet where previously it stood proud - I don't have a router but a friend who does tells me that it improved the treble no end.

Next tweak - for your vinyl.
I have found that WD40 can make a dramatic improvement to the sound quality of a record. My theory is this: friction is bad right? if you drag something against something else it will skitter across the surface - the rougher either surface is, the worse the skitter is. If you add oil, the skittering is much reduced.

Further, WD40 contains a small amount of white spirit, which is an excellent cleaning fluid. Of course, there is potential for damage, but according to the tech guy at WD40 this will do its job then evaporate away before any damage is done. certainly I was surprised how much white fluff was removed from records that I thought were clean.

Anyway, after the white spirit has done its job, there should be some residual oil in the grooves of the record. The needle, tracking in the grooves, passes smoothly along and follows the track as it should, except that it does not skitter about as a result of friction. The result is a much smoother playback.

A couple of cautionary notes here. The oil will change the appearance of the label - it will not lift it off, but the colour will deepen as a result of the oil. If you use too much oil and keep your records in anti-static sleeves you will get ugly blotches on the surface of the vinyl.
These can be cleaned off later, but it involves much aggro and of course you remove the oil from the grooves in the process. I would recommend that you get hold of WD40 in a non-propellent bottle, apply to a cloth and then to the record surface - you will have a much more controlled application.

Why not try it on an old record you don't care much about and see. Re-visit it in a month or two to check it is still alright, if you are dubious about this idea.
Hope these ideas appeal to you, keep up the good work.
Andrew Gladwell - E-mail: andrew.gladwell@nextra.co.uk

Dear Andrew,
it's a pity only a small part of the tweaks published here on TNT-Audio has been translated into English. Otherwise, you'd have read here about tweaks 1 & 2 (more or less). As for tweak # 3....I would NOT suggest playing records with oil (or any other liquid stuff) into the grooves. Yes, friction may be lowered...but what about the reaction of the glue that holds the stylus attached to the cantilever???? I'm afraid this could cause serious damages.
Anyway, according to me, the best way to play those LPs is to keep 'em as clean as possible. Your idea, more or less a clone of the infamous and destructive LencoClean playback system so popular in the 70s, can be good for really damaged records and old carts. Otherwise, be extremely CAREFUL.
Lucio Cadeddu

UBYTE2 cables
Very informative website. Just wanted to let you know that you can now buy CT125 and CT167 satellite TV coax from RS components (just in case you didn't know already). The CT125 and 167 have 1.25mm and 1.67mm centre conductor diameters respectively. This is an increase from the CT100 1mm diameter and should (as I understand it) provide a slightly higher frequency response due to lower skin effect losses.
I have just purchased a reel (100m) of CT167 and plan to use both at home and in my car. Also on a side note do you have any info on testing for skin effect? I wasn't aware that it could be an issue at such low frequencies.
Russell Koehne - E-mail: Russell.Koehne@anu.edu.au

Dear Russell, thanks for the precious info. As for skin effect with respect to low frequencies, please contact Tommy Jenving of Supra cables, he has a good theory about the effects of this on audio cables.
Lucio Cadeddu

Rega arms mods
I notice you have the Expressimo mod on your rb-250. How do you feel it compares to the Origin Live approach? How do you feel the Origin mod compares to the Expressimo DIY mod (http://www.expressimoaudio.com/ and http://www.tnt-audio.com/accessories/heavyweight_e.html).
I'm considering the screw-in Expressimo rather than sending off to Origin but the left hand says the screw-in approach is bad (Origin Live) while the right hand says it is ok (Expressimo). Also, their Heavyweight counterweight gets great reviews but appears to just slide on the stub rather than affix tightly ala set screw. Again, left hand meet right hand. John W. Little - E-mail: jwlittle@bellsouth.net

Lets see if we can help. First, let me clearly state, I have not reviewed the Origin Live mods (other than in pictures and reviews) so I can only speak with authority regarding the Expressimo products.

First, a quick (visual and written) comparison of the two. The Heavyweight uses a solid stainless steel, screw in end stub that utilizes the existing internal end stub threading where the Origin appears (in writing anyway) to be of the same design. Origin states that the new end stub is "torqued onto the arm by a high tensile bolt" which leads me to believe that the Origin is threaded. On the surface they appear the same in this regard.

Next, the counterweight design. Origin has drilled the hole for mounting to the end stub dead center of the counterweight. The Heavyweight is drilled off center thus lowering the center of gravity of the arm. This is a biggy, a REAL biggy, read on.

On this point I can speak with authority. When I installed the Heavyweight, the first thing I noticed was when I picked up the arm to play the first record. I noticed that it felt different, completely different, strange as that sounds. I personally noticed the difference on the first grooves. The arm tracked so much better.
With the stock Rega counterweight (a center drilling similar to the Origin), the arm was subject to the slightest vibrations on my equipment rack. I do a lot of A/B comparisons between vinyl and CD's.
Before, I had to use the slightest touch to keep the arm from skating across the record when switching back and forth from phono to CD. Now it's rock solid. I can actually knock on my rack and the arm doesn't move, a bit.

Another improvement. I don't use a rumble filter on vinyl, it cuts off music contained in the lower frequencies. On marginal LP's you could see my woofers trusting back and forth caused by a poor cutting (old stamper or mother, cutting head out of adjustment, poor quality control, or whatever).
The Heavyweights greatly improved tracking ability has nearly eliminated this. Now, only on the worst of vinyl do you see these imperfections.

The listening test of the Heavyweight revealed TONS more detail. I can now point to the individual drum being hit rather than just hearing a drum kit in the background. The soundstage is so much more well defined I can almost point out 6 inch separations in the instruments. I won't even get into the improvements in the timbre that are now apparent.
As for the rigidity of the mounting for the Heavyweight, Sal does utilize a set screw to affix the Heavyweight to the end stub. The Heavyweight is isolated from the arm tube and end stub by means of a thin rubber isolator, slightly larger than the end stubs outer diameter. This provides the de-coupling of the counterweight from the arm tube. See the pictures in Nels' review, you'll see what I'm talking about with the rubber isolator.
From the pictures I've seen of the Origin, they do not utilize this additional counterweight isolation.
I haven't yet installed the VTA from Expressimo but from the looks of it, it should do it's job just fine. It's nothing more than a thin threaded sleeve that allows the vertical adjustment of the Rega arm, very simple actually.

Something I want to make you aware of, this is a paid advertisement for Expressimo. That's right, I paid FULL price for the Heavyweight, no reviewers discount at all. It was worth EVERY penny. First, you don't have to send your arm off for several weeks.
Second, the installation takes all of 15 minutes (re-balancing included). Third and lastly, you will be shocked at the improvement of the Heavyweight and End Stub combination.
Again, I haven't auditioned the Origin. It may well be as good, I don't know. I do know that the Heavyweight is well worth the money (it's not that expensive anyway). Hope I've helped.

Just a quick postscript to the note I had sent you before. I did some checking with Sal, the creator of the Heavyweight. He corrected one minor (major) word I used.

I stated that he used a thin rubber isolator. I was incorrect. Sal stated it was a material called "Delrin". It is a plastic material, rather than rubber as I had stated previously. Also, he mentioned that the set screw has a green locking tip that provides no metal to metal contact with the end stub. Together, the Delrin and the plastic tip provide sufficient de-coupling to reduce most of the unwanted vibrations that could be picked up from the counterweight.
To quote Sal, "This design squelches most of the sonics from going down the arm tube.. This why you can hear low level detail so detailed..."
Scott Faller

Re: Merlino vs Morgan la Fey
Thanks for the Merlino. It really rocks.
Robert Chatfield - E-mail: field@ains.net.au

Dear Robert,
thanks for the feedback. At least someone who can build a Merlino ;-) (cf. the letter-flame titled "Merlino vs Morgan la Fey" on our June volume.
Lucio Cadeddu

Tower speakers < $800
I enjoy your reviews. I was wondering what you would recommend in tower speakers < $800. I would be using them mainly for classical, jazz, and Dolby Prologic surround sound.
Chris Brown - E-mail: cbrown@visioncorrectionctr.com

Dear Chris,
depending on you tastes, you may try the walls-shaking Klipsch RF-3 or the smoother Aliante CNM Tower (see reviews here on TNT-Audio). Do not forget to throw an ear to the Polk Audio stuff also, they make pretty damn good towers for the money.
If you like an analytic though sometimes cold sound, the Monitor Audio towers may be worth listening to. The Silver series should be into your price tag, not sure they come with magnetically shielded drivers for HT use near a TV screen...
If you can, test listen to these speakers and then let me know.
Lucio Cadeddu

Sumiko Blue Point tweaking
Signore Direttore: I've read in a letter from a reader, that exists an upgrade or tweak for the Sumiko Blue Point cartridge ("Ferrarizzata" it reads).
I can't understand some words in italian, could you please send me a translation, or any link or something that could help. Tante Grazie,Caro. Daniel - E-mail: campos@w3ar.com.ar

Dear Daniel,
that tweak has been suggested on our Italian Readers' Corner by a colleague from the Italian print HiFi magazine known as Suono. The guy is Roberto Rocchi. Here's what he suggests: cut away the piece of transparent plastic at the top of the cartridge, then glue an ART cartridge Q-Damper (a small Q-Damper especially made for carts) et voila', the Sumiko BP is ready to rock.
I've never tried this tweak at home, as I've never owned a BP or BPS, since I find these carts too bright. When trying this tweak at home, be extremely careful!!!
Hope this helps,
Lucio Cadeddu

Subject: A tweak too far, part 2
Dear Sir,
Following your advice I gave the Audioprism Blacklight a better chance...just to come up with the same conclusion. I even tried some inconclusive blind tests with the help of my wife.

And by the way, try to convince a Doctor in Psychology of the benefits of a glowing-in-the-dark cd mat.
It took my wife about three minutes to come up with a very embarassing Freudian theory...
Anyway, this cd mat did not work out for me, in my system and with my ears (and some friend's).

Furthermore the mat does not glow longer than 15 minutes and frankly, i's a pain to use, glowing or not. I have better results with the Statmat!
I will try not to forget that old "audiophile" rule: if you do not hear it, do not try to listen for it, it's probably not there.
Thank you for your time and a great site.
Michel - E-mail: Belvest@Belvest.com

Dear Michel,
thanks for the precious feedback. I agree with you: if a difference can't be heard, stop searching for it against all odds...perhaps it isn't there.
Lucio Cadeddu

A letters to us...from one of us :-)
As people keep telling me I have the diplomatic skills of a hand grenade, I can state already in the first line that I do not agree at all with Mr.Rampino's explanation of upsampling.

Mr.Rampino puts all blame on the combination of conventional oversampling filters with analogue reconstruction filters that would incur severe phase rotations in the audible band.

Well then. Commercial oversampling filters are linear-phase high-order low-pass types that only require extra analogue filtering way above 20kHz, where such analogue filters can easily be made to have little phase shift at 20kHz and below (to wit, read my remarks on this in the MP-DAC and AN DAC1.1 reviews). Moreover, some oversampling filters contain a phase-warp that zeroes the net phase shift below 20kHz when combined with an analogue filter of a specified type.

Conclusion: conventional oversampling leads to very little, or zero, phase distortion in the audio band.
What then does upsampling do?
Nothing different, actually. Upsampling IS oversampling. Only now, under the aegis of DVD-Audio and under the impulse of clever marketing types, it got a new name, and new target frequencies. Where oversampling went to 88.2kHz, 176.4kHz, 352.8kHz or even more, upsampling now confines itself to multiples of 48kHz.
This looks better on the glossy product leaflets, but this is bound to be worse as it implies a non-integer conversion factor and numerous numerical distortions related.

Can such a new-fangled upsampling box sound different? Of course it can. As there are several strategies to oversampling, these strategies can sonically differ from each other. One method already mentioned is linear-phase brickwall filtering at 20kHz. Another possibility is linear-phase low-order filtering at 20kHz, which leaves some ultrasonic spuriae in the band between, say, 20kHz and 40kHz. Burr-Brown offer this as an option on the DF1704 oversampling chip. (We only have to wait 'til an audio company discovers this option and claims a "significant breakthrough" from a "revolutionary technology").
Yet another method is "time-domain" interpolation, for example using splines to join the dots. This also exists for well over a decade: take a look at Wadia and Pioneer. The method also leaves some ultrasonic garbage unfiltered.

So, upsampling is oversampling (though often combined with a less-than-ideal conversion factor), and there are two kinds of oversampling: brickwall and lower-slope. The latter kind may offer a lead to better (or better-perceived) sound.
One is that the presence of sound above 20kHz, ANY sound above 20kHz, may simply be better, or different, to some, or to most, people.
Another possible explanation is that the ultrasonic signal acts as dither of the lowest bits of a ladder-type (multibit, R2R, ...) DAC component, improving linearity. Note that this does not hold for bitstream types of DACs (Delta Sigma, ...).

Another thing that matters is numerical precision during the whole process. Digital filters multiply the signal with a bunch of coefficients, and these coefficients are only defined with a certain accuracy, dependent on the word-length of the filter's data path. Older oversampling filters likely were NOT of 48 bit or more accuracy.
Newer ones likely are. And those valiant enough to run their own algorithms on soft-programmable DSPs or FPGAs have the accuracy mostly in their own hands.
But again, this has been done before, and there's nothing new here (in fact the only significant recent breakthrough in conversion technology was dCS's RingDAC architecture, but nobody seems to make a buzz of that anymore).

I hope the above clarifies things a bit. I also hope that this makes readers listen more with their ears, and less with their marketing-jargon-saturated eyes.
Werner Ogiers - E-mail: werner@tnt-audio.com

Dear Werner,
when all's been said and done, only our ears can add something relevant to the discussion. And I can't help but remark the Northstar Model 192 is a FAR BETTER DAC than its ancestors, namely the Model 3 (with no upsampling) and Model 3 + 4 (with 24/96 upsampling).
I don't know if the difference is due to upsampling or not and, roughly speaking, I don't care much. All that we want are better sounding digital machines. That's it.
Also, I'm not sure everyone can understand complicated technical explainations, hence this could lead to even more confusion.
TNT-Audio readers know well that the ONLY truth one can find can be discovered by one's own ears. Numbers will never tell you how a device sounds like.
Otherwise, 0.00000001 % THD '70s Japanese amplifiers should be the best amps ever made on Earth ;-)
Thanks for the precious feedback.
Lucio Cadeddu

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