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Readers' Corner - January 2001

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The Twisted Twins
I am writing from Montreal, Quebec, Canada.
I did the TNT Triple T cables. A lot of cable skinning (I was really tired to skin 384 cables) BUT oh MY GOD..., what a surprise when I put the power on the amp.
Compared with the cable I had before!!! it is incredible. I immediatly heard the difference. The extension in the low end is unbelievable. I first listen to it at very low level (my daugther was sleeping) I never thought that my speakers could give me so much at low level. I don't have a 25,000 dollars system. My main speakers are Audio Monitors Silver series (5i), powered by an Adcom 200 watts/ch and a Rotel (RCD 975) and let me tell you that I will keep those cables for a long time.
The "TRIPLE T", I am now earing music and feel it.
Thanks a lot for your well described article on How to do it.
Gilles Gallant - E-mail: ggallant@rds.ca

Gilles from Canada? Have you ever driven a RED Ferrari??? :-)
Jokes aside, I'm very pleased to hear that you really enjoy the TNT Triple T cable. Having a "stable" power amplifier (the TTT can give some trouble with some amps...) and a well balanced HiFi system, this cable could be a very good choice with an incredible sound considering the price.
Enjoy your music, ciao!
Stefano Monteferri

On biamping
Thank you for an Excellent site!
I have some questions regarding biamping, could not find any questions in readers corner about this subject.
Maybe I missed it, but I try. Is it worth the extra money? (New Power Amp). The amp needs careful matching, like sensitivity, best with same brand? Regards
Roger Andersson - E-mail: roger.i.andersson@se.abb.com

Dear Roger,
biamping requires, normally, a second power amp, better if identical to the existing one. Otherwise you can mismatch the low frequencies with the highs. Is it worth the extra money? In my opinion, that depends. I still prefer active biamping (with external active crossover, your speakers need to be designed for that use like Linn and Naim) because with passive biamping (the one you suggest) the two power amps still amplify the whole audio spectrum, instead of the low and the mid-high range separately.
In my opinion, it is better to sell the amp you have and, with the extra money, buy a better power amp.
Hope this helps,
Lucio Cadeddu

Still on Mains secrets and flames!!! 1
just a comment about the now famous 'Mains secrets and...flames'... I saw the (excellent ;) reply from Geoff Husband to Nic Wong, and I have to agree: mains sucks.
At one point, Geoff wrote: "So, on a personal level.... Why do amplifier transformers buzz (very loudly in some cases) at certain times of the day? Why does my turntable motor vibrate (you can feel it) and become noisy at certain times of the day - now cured with a QC?"
I experienced the same problem here, in Switzerland, and as far as I know, this problem is generated by control currents, sent over the power lines to remote control industrial appliances.
This is mostly 100hz AC burst sequences, (at least aorund here) because they have to pass through the coils of the counters (sorry, don't know the term in English, you know, the box that counts the amount of current you use, to bill you).
It becomes pretty obvious if you check at what time that occurs, it's almost always at plain or half hours. Hope this helps, sorry for my english, and thank you for this great site !!!
Y. Bommeli - E-mail: Yves.Bommeli@swisscom.com

Still on Mains secrets and flames!!! 2
I just read the letters about mains electricity and although I also believe mains to awful, I'd just like to comment...

  1. The 50Hz of mains is definitely not set... Being an Electronic Engineering student I can personally vouch for this. When the load on the benerator increases (Like after a TV program the entire country has watched, people all switch on their kettles to make tea or whatever) the Frequency drops. Quite dramatically.
    We once experimented on mains in a university Lab... We tested the frequency in the middle of the day when all the restaurants and kitchens in the country were cooking and doing their thing. We got a staggering 46.43 Hz!!!
    But it was at 230 V. When we tested the mains at 11.30Pm (Yes we were still in that $0££ing lab) it was a reasonable 52.13 Hz. But still 230 V. So, the only time that the voltage should drop is when their's either a power cut or if your talking about noise on the mains which is in the area of less than 1/2 a volt... Compared to the rest of the 230 V.
    This isn't enough to warrant calling it a "severe amplitude variation".
  2. Your web-site is amazing! I just ordered the CAT5 cable from Maplin to make the FFRC for my Tannoy M15s'. But I can't find this "Winding Wire" from which I can make the X-15 interconnect.
    Are there any online sources I can order from? If so where are they? The only stuff I can find is laminated copper which is not insulated with teflon or anything lovely, Just varnished.
    I might try making interconnects from this as a reel is only £3. Has anyone else tried this weird stuff?
Again, cheers for such a great site.
Phil.B. - E-mail: BigBadPhi1@aol.com

Dear readers,
thanks a lot for your precious input!
I have a digital voltmeter permanently connected to the mains, so I can check the variations of the voltage anytime. I can see variations sometimes bigger than the claimed 10% range the Italian Electric Co. promises us :-(

As for "winding wire", any electronic parts store should have it in stock!
And it is probably available at RS or Maplin but I can't remember the code. To anyone who reads this and has more info, please contact Phil directly.
Also, let me remind you that for this kind of questions (where to find parts, wires etc for our DIY projects) there's our lively forum where hundreds of audiophiles from almost every Country in the World are ready to lend you a hand!
Ah, let me also announce you that we're about to publish a new DIY interconnects cable based on IBM Type 6 TokenRing cable. This one is easy & very good sounding, so stay tuned!
Lucio Cadeddu

Still on Mains secrets and flames!!! 3
I am a physics student with audiophile aspirations and I feel that I would like to comment on the letter that Nic Wong sent you and Geoff Husband answered to. You are both rigth.

  1. The Mains power suck, you have noise, distortion and severe amplitude variations, especially if you live in the countryside, near large factories and/or user low energy lightbulbs and thyristor controled dimmers. All of this shows up as vow and flutter on a turntable.
  2. The period of the mains power (50 Hz) is very exact. The variations that are being discussed (.5-4 %) are maximums over long periods of time. The human ear is very sensitive to changes in pitch and you would undoubtebly hear a pitch shift of 0.5% if you compare it to an undistorted signal but you will most likely not hear if the mains frequency is changed 2% over a period of several hours.
    That effect is masked by all the other ugliness that comes out of the plug anyway. Let me take an example. I happen to own both the PAL and the NTSC version of the movie Matrix. Its exactly the same film but it was filmed in 24 Hz, Pal is 25Hz and NTSC is 30 Hz. therefore the length of the film in the different formats differs with several minutes. If you compare the movies side by side you can hear this but if you listen to one of them you can't tell which one it is (but the picture will tell).

This was just my two cents, I hope I havent offended anyone with either my opinions or my spelling (English is not my native language).
Best regards etc.
Rikard Gothäll - E-mail: rikard@nada.kth.se

Dear Rikard,
thanks a lot for the input!
Lucio Cadeddu

Tar sheets Cheap...
I have found in car audio a cheep alternative to the Dynamat type dampening sheets is a material used in the roofing of a house. These sheets seem to be the same type of material as Dynamat, with a dense, rubber composition and self adhesive side. This material conforms best to contours when a heat gun is used.
Here in in the states you and buy the sheets at any DIY warehouse. Just ask the clerk in roofing materials for the ice shield material. The down side is that is usually comes in 70 ft by 4 foot sections. However, if more than one person shares the cost of the large size, it is quite economical. and you can dampen everything in sight.
Another tweak that I have yet to see on your page is the use of museum wax to stop things on shelves from vibrating under heavy bass sections of music. This wax comes in a bar about the size of soap.
Just scrape a bit off and roll it to the size of a small pea. Place the pea sized balls of wax under anything that vibrates, and the bass in your system will sound much tighter and controlled.

I hope that you will pass these ideas on to your readers,
Sean Connors - E-mail: seanchrisa@home.com

Dear Sean,
thanks for the precious tips! They help making TNT-Audio helpware instead of freeware :-)
Lucio Cadeddu

TNT StoneBlocks
I just wanted to drop you a tip regarding the stuff the TNT StonBlocks are made of. I was in a local $1 store today and found big blocks of the stuff in a pleasant black/charcoal color packaged as "Barbecue Grill Cleaning Bricks".
The price for a brick-sized brick was less than I'd paid previously for the tiny Dr. Sholl's "Beauty Stones" made from the same faux-pumice material. Cheers,
Bill McGair - E-mail: bill@mcgair.com

Hi Bill,
and thanks for the tip. I'm currently evaluating another fancy (and very strange) material that may work better than the TNT StoneBlocks. Its main drawback is its poor availability :-(
Also, let me remind all the readers of this section that we have a lively discussion forum where audiophiles share their experiences on various tweaks (various TNT StoneBlocks included :-)). Let me invite you to join the crew!
Lucio Cadeddu

Mains secrets and...flames
Hi Geoff:
Read with interest your article regarding the power supplies for turntables.
I was curious about your comment regarding "However we all know that the mains is a mass of nasties and only holds to 50 Hz on a good day. In it's favour it is an almost limitless supply for the demands of a turntable." This statement is simply wrong and misleading.

  1. The national grid and the various power generators feeding the grid are all at the same frequency and are synchronised to each other by the fact that if one generating station's frequency shifts the remaing generators in synch will pull it back.
    If this didn't happen then we would have a major catastrophe on our hands. Think about what happens when you put two car batteries back to back,... short-circuit!
  2. The nominal frequency of generation is 50Hz, and is heavily regulated to be better than +/-0.5%. This is done will precision regulators on the generating machines at large power plants. And is required as a national standard. Since so many mains powered clocks required around the country need this accuracy.
    Also your average colour television requires this accuracy to give correct frame synchronisation for the incoming video signal from the BBC or whoever. The nature of the gearing in most turntables means this error is very very small!
  3. Since the UK conforms to CE standards, any harmonic distortion on the power line must be less than 10%. This is pretty good. And means that the sum total of all noise must be less than 10%.
  4. No significant power exists in the distortion you think may interfere with the synchronous operation of your deck. If you don't believe me capture a mains cycle or ten with a storage oscilloscope, do a Fourier Transform on it, and you'll find the most dominant power by far is right on 50Hz!
    The other harmonics present simply cause a bit of local heating in the windings of the motor, bear in mind this heating effect is very very small compared to the inherent copper losses of the motor itself.
    If your unlucky to get a 5th harmonic of 50Hz present, 250Hz, of any significant power this will cause a slight opposing torque to occur in the motor. But bear in mind to have any effect what so ever it has to be significant, say at least 20% of the fundamental 50Hz energy!
    And even then it only effects the torque, and has almost no noticeable effect on the motor's slip speed compared to the synchronous speed of the mains.
So, I would suggest that in future before you make any sweeping statements or generalisations make dame sure you know what your on about.
Nic Wong - E-mail: nicwong@xtra.co.nz

Hi Nic,
A few points here. First I've never made any secret that my technical knowledge is very thin (at best) and I'm in no position to argue technical points with you.
However because of this I tend to be careful and read about a subject widely prior to a review and certainly there is no doubt that the comments I made are shared by hi-fi users and designers around the world (and incidentally computor users). They boil down to sweeping generalizations because of the limits of a short review.
I suggest you do searches on the subject on the web, the articles and scientific papers by Ben Duncan (of Hi-Fi News and Record Review) are particularly well done but there are many others.
Just a couple of examples -your comments are in quotes...

"The nominal frequency of generation is 50Hz, and is heavily regulated to be better than +/-0.5%. "

According to Duncan in Britain the long term frequency is accurate to +/- 2% (legal requirement). You may be happy with a turntable with a 4% variation in speed, I am not. The 50hz is an average over 24 hours which is why clocks run OK. - these comments apply even if one accepts your 0.5% figure.


"The nature of the gearing in most turntables means this error is very very small!"

Oh dear... Good at electronics but not mechanics eh? a +/- error of 2% in the frequency will produce a 4% speed variation in a synchronous turntable - the "gearing system" is immaterial.
You may not think that a tone drifting back and forth by 4% is important, but I do as do most of TNT's readership I suspect. (The average "untrained" human ear can detact 0.3% variations in pitch which is why quality turntables are made to be pitch stable).

But things are worse than this...To quote Duncan.

"The nub of the problem is that whilst mains frequency variations are small, some can be quite large, and all are apt to be relatively abruptly occurring (as descrete steps); and the pattern of pitch change so caused is random from the viewpoint of the musical performance you are listening to....
Frequency variations, either in small steps or large one's occur in the first instance when fresh alternators are brought up to speed and put on line before they have settled; when strong load variations effect alternator speed; and when complex synchronising interactions occur.
Others are introduced (sic) in order to counteract the running deviation, in order to maintain the statutory 50 Hz at the end of the 24 hour period. Musically this amounts to a conductor speeding up the orchestra slightly but suddenly because he's realised he's 'n' minutes behind."

So I hold to my comments on mains frequency.

You then go on to explain how perfect the mains is. Here I could re-write a few thousand words by Duncan and others but to be honest I'd simply be repeating other's research.

So, on a personal level.... Why do amplifier transformers buzz (very loudly in some cases) at certain times of the day? Why does my turntable motor vibrate (you can feel it) and become noisy at certain times of the day - now cured with a QC?
Why do my lights dim when next door turns on their milking machine, why do the lights in the house flicker sometimes, why does the voltage in my house vary by 10% over a typical day with peaks up to 360 volts?
Why has the hi-fi community spent millions on making power supplies for turntable motors. Why do battery powered pre-amps exist. Why do all these effect the way my hi-fi sounds?

You may have perfect electricity, I don't. What comes from the power station may be good, what reaches my home after many miles is not. The effects of other users equipment, airborn RFI, mains spikes, impulsive noise, arc hash, thyristor hash, motor hash, line whistle and a million crappy connectors take their toll. What works for an electric drill or a TV doesn't necessarily work for audio.

Contact the Hi-Fi News and Record Review accessories club and get a copy of "Audio Quality Mains Supplies" by Ben Duncan. Read it, learn and then I will accept your apologies and publish them on TNT.

"So, I would suggest that in future before you make any sweeping statements or generalisations make damn sure you know what your on about."

And lastly for your information and future correspondants, I find this kind of comment offensive. I know that it is currently fashionable to be rude whilst hiding behind a keyboard, but I for one will in future delete all such mails without answering.
I might add that the rudeness seems to be inversely proportional to the writers strength of argument.
Geoff Husband

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