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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July 2006

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I have just modified a 2amp two stage filter to a three stage filter supplying a Hydra plug (my preamp, universal player and dac). They all have switching power supplies. A worth while improvement I say.
Do you know how to get rid of the high frequency noise interference my TV antenna picks up? It's ok till I hook my universal player into the tv then I hear it through the tweeters.
Tony - E-mail: tsykes (at)

Dear Tony,
I'd istall an anti-RFI filter on EACH component, just to be sure. And I'll try to have the ground wire removed from any component EXCEPT the preamp. This will cure any "ground loop" that may occour. Finally, I'd use ferrite clamp rings around interconnects and mains cables.
Hope this helped somehow,
Lucio Cadeddu

Going active!
Greetings from Adelaide, Australia. Re: Active speaker articles - our 3 way system using active subs,12in and horn (with super tweeter) with integrated valve amps and active c/o, sounds dynamic and clear listening to Mellencamp, Xavier Rudd, INXS, Gypsy Kings in 8m x 5m room.
If music is part of your life, listen to more of it! The next step in equipment will be 12in. active coaxials in big horns with ribbon tweeter. Congratulations on a great site.
Tony - E-mail: cmhabich (at)

Dear Tony,
thanks for the feedback! Incidentally, how are the INXS going?
Lucio Cadeddu

Deadening a room
Hi Lucio, the website is brilliant, but I am just an old 62 year old who can just about get my head around a cassette recorder. I have converted my garage into a sort of mini studio: Yamaha AW16 G Recorder + Behringer monitors. My problem is: what's the best way to deaden the room? I'm aware of the Acoustic tiles remedy, but I haven't a clue where to put them. I also have 3 or 4 guitars on the walls on small wall hangers + a wood burning iron stove in one corner.
The garage is roughly 12ft by 10 ft. and 8 ft high. Thanks very much.
P.S. I'm away this morning to buy some pvc etc. for your brilliant looking speaker stands. Only thing is, I might cut off my hands using those tools! "Handless McCandless " is my wife's nickname for me and she is definely right this time. So I'm gonna use a different joining up method. Thanks very much.
Victor - E-mail: Vicflic (at)

Dear Victor,
it all depends on what you mean by "deadening the room". Do you want it to sound better "inside" or do you wish to avoid annoying your neighbourhoods with your Music? These are two different problems that require two different approaches. For the first one you can buy some Tube Trap (or build them yourself using some DIY recipe you can find on the Net, try Googling with "DIY tube traps") and place them strategically, mainly on corners. Then you can use thick carpets, both on floor and on the walls. If the room is mostly empty this will help.
For the second're in trouble. If you wish to lower the amount of sound transmitted "outside" your room you should plan to spend big money to modify the walls (double walls, for example) and the floor (with a suspended floor).
Hope this helped somehow,
Lucio Cadeddu

Anti-RFI filters
you answered a readers mail message regarding these filters. Just for information there is an austrian company selling such filters für 2,95 Euro: Information on the manufacturer of this filter (I had to search the net long for this!) can be found here.
I bought ten of them a year ago, as the price is not much higher than a standard IEC outlet (OK, at Neuhold it is cheaper than most stores here).
Thomas - E-mail: thomas (at)

Dear Tom,
thanks for the precious feedback and information!
Lucio Cadeddu

Tiring system
Hi Lucio,
I have a question regarding my mid-Fi system. I use CDP Cambridge Audio 540C, Rotel 971 amp and B&W DM603 S2 speakers. When I initially auditioned this set up - I was amazed. I could hear things I never did: sound was crystal clear, every instrument sounded live and I was immerged into music. I was thrilled and excited. But after a while I found that I can't listen for a long time. It's like if it's too crisp and clear, my ears would get tired after 15-20 minutes.
I took my CA cdp to several local dealers and compared it with others, like Rotel RCD1072 and used SONY 777ES and as much as they wanted to sell their stuff, they were amazed how 540c sounded. It was hard to tell the difference even on their HI-END equipment. May be Sony sounded little less forward then 540c on mid high range, but that was 5% difference and if you listen very carefully.
I listen mostly to jazz and instrumental music featuring soprano sax and clarinet (that's what I play), acoustic guitar, brass bands, accordion and some vocal groups.
My question is, should I try another amp like Marantz PM7200 that has reviews that make me believe would help. Or should I try different speakers, though I like B&W's. In any way, I don't want to make it expensive decision and would be fine even with getting used gear.
Thank you so much for your expert advise, and please save my ears!
Vitali - E-mail: vitali_k (at)

Dear Vitali,
the problem you refer is almost certainly caused by your speakers, provided they are set up well and your listening room isn't an acoustic nightmare. Modern B&W speakers tend to have a very detailed sound, with bright mid-high range. This tonal balance might be referred as "fatiguing" by some listener. I, for one, am not a big fan of modern B&W loudspeakers (especially the Nautilus series) though I often recommend them because they are very appreciated by a certain kind of audiophiles in search for the ultimate jota of detail.
My suggestion is to search for a new pair of loudspeakers. If you wish a more relaxed and warm atmosphere try audiotioning some Italian bookshelf loudspeaker, from Opera to Sonus Faber, from Aliante to Chario. I'm pretty sure you'll find something more enjoyable on the long run.
Before than that, though, try to analyze carefully your listening room acoustics and the way your speakers are placed into it. These two aspects alone might solve the trouble without buying new speakers. A carpet on the floor between you and your speakers might greatly help, for example. Trying even some "toe-in".
Hope this helped somehow,
Lucio Cadeddu

Isolation Transformer
Dear Sir,
I hear lots of praise for a good isolation transformer. My first question to you is: can you give us a DIY design to make a isolation transformer & a passive filter as well? Because you see all these staff is exorbitantly costly... My second question is if I use a simple 1:1 transformer for at least my cd player to see the result will it work like a isolation transformer?
Pls. throw some light on these so that we poor readers can make benifit out of it. You have published lots of other project as DIY but never did anything on this topic.
Sandip - E-mail: sandipb (at)

Dear Sandip,
1:1 transformers ARE isolation transformers. Add a mains noise filter like this one and you'll get an inexpensive mains conditioner you might evaluate within your system. My direct experience with isolaton transformers is a mixed one: the results haven't always been good, for this reason I haven't published a DIY project yet.
For some extra info on isolation transformers read our review of the ESE Labs Enlil unit.
Lucio Cadeddu

Re: Preamp match
Dear Lucio,
Thank you for your feedback on my recent "preamp to preamp" (or preamp to tape input) query. One thing I enjoy most, since getting into 'serious' hi-fi, are the many opinions I hear from many people who share the same hobby, yours included. Some are common sense while others truly out-of-this-world. For example, someone I know uses four Sonus Faber Electa Amators in his set-up, one pair placed upside down on top of another pair placed right side up! Ridiculous? Not according to people who have heard it — comments ranged from natural to realistic to sweet sounding.
Remember not too long ago, when Well Tempered Labs proved to all disbelievers that you could do without rigid, conventional bearings for platter and tonearm and still sound incredibly like nothing else on the planet? Yes, the accepted wisdom is to connect this equipment to that and to that, to angle speakers a certain direction, and to position oneself (the listener) in a particular spot. People seldom go against these tried and true rules.
Occasionally, however, we surprise ourselves by discovering something that pleases us even when technical measurements say it isn't possible! How is this so? Simple I think. The most important component in appreciating any and all sorts of sound are our ears, so even if a particular arrangement defies 'accepted wisdom', our ears tell us otherwise.
Audiophiles are, after all, the most unpredictable group of people ever!
For a review of my preamp, go here:
Many thanks again for the wonderful work in the website.
Raz - E-mail: razzwill (at)

Dear Raz,
thanks for your kind reply. As for "breaking the rules" I think we did that soooo many times, here on TNT-Audio. The T-Amp is just one of the most recent examples...
Happy listening!
Lucio Cadeddu

Active loudspeakers
Dear TNT,
Thanks for two great articles by Mark Wheeler on Active Loudspeakers. I have tried bi-wiring which I felt improved the performance of my Epos ES15 speakers. But I read on Rod Elliot's website, that bi-wiring is almost useless and that multi-amping is the way to go.
Incidentally I rate Rod's site along with yours as two of the best and most unbiased hi-fi web sites. Mark Wheeler's articles are full of very convincing arguments for multi-amping by means of active speakers. However, for the electronically uneducated such as me, all the technical details are hard to follow. I can fully understand that Mark can not or maybe will not give specific recommendations when us readers have an endless variety of different speakers but some general guidelines on how to go about selecting the right amp per speaker or even per driver would be greatly appreciated.
Perhaps even a short list of products or at least suppliers to start with. Keep up the great work with TNT and long live Pure Stereo!
Mike - E-mail: michael.shanahan (at)

Hello Mike,
It is good to know that we have readers in Sweden continuing to support Real Stereo. If you can hear the effect of bi-wiring in your system, then bi-wiring does have an effect in your system. I suspect the audibility of bi-wiring depends on many factors including the crossover design (and some with bi-wire terminals have a shared earth, or ground-plane, which rather defeats the object of bi-wiring) and cable impedance (LCR, not just resistance). In a perfect world bi-wiring should make no difference, but we do not live in a perfect world.
Use a simple multi-meter to check that the Epos has no connection between the minus terminals, and then it would be possible to bi-amp just by adding a second, matching, stereo power amplifier (easy if your pre-amp has two sets of outputs or just make up a splitter-box). This is the first step towards active Nirvana.
A number of pro-sector manufacturers make stand-alone active crossovers with variable filter frequencies, variable filter slopes & variable gain. I hope to persuade them to let me review some soon. I will then be able to offer suggestions specific to those under review.
Kind regards & enjoy listening,
Mark Wheeler

Dear Mark,
At last someone just spit it out. I do wonder how people can spend years of wages on gears and...............cables and forget about music. I have a Naim Audio set up and one of the main reasons i love it is the fact that, while others get mad about listening to cables and other woodoo stuff to improve gears that can't change their skills, I do sit and do what a stereo set is meant to do: play music. A lot of people just tell me to change my Nacas etc etc. The last time I needed an interconnect I mailed FlashBack Sales and they sent me an interconnect.
Just the price of an intercennect.
Job done.
Gianluigi - E-mail: monofonico (at)

Hi Gianluigi,
Sorry to be so long replying. Cables do change the sound. Cables do not make the sound.
Cables do not really matter that much, but I do have quite expensive cables in my system, I just do not change them. Naim NACA5 makes the best bass of any cable I have ever heard, but the midrange can be a bit shouty. Black Rhodium (ex Sonic Link) do a similar cable with a sweeter treble that worked OK with a Naim amp when I tried it, again that is not an expensive cable.
Kind regards,
Mark Wheeler

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