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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September 2010

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Shaffner filter inside
Buongiorno, dear Lucio!
First I want to express my heartfelt thanks to you, and the whole team! TNT-audio - you are a great team! Most importantly - a very competent description of your improvements! Everyone was so tired already by the "militant audio-dilettantes"....
The second part of my letter - it is a complement to your development. I'm living a lot to do .. and rework for my need. really so turns out - just buy me bored :-) Not so long ago I read your article about use SHAFFNER filter for each audio component.
In fact - "intoxicated" advertising "clean electricity" audiophiles are spending real money and that within these expensive boxes - "firm power filters and cond'rs" - often too Schaffner filters with fuse.. o'eahh, and one blue LED. ( better to buy new CD's or vinil ...).
My idea - the development of your recommendations on the use of filter Schaffner. It occurred to me - do not put the filter in each of the audio components. For too many people, this is quite a serious operation - lost warranty etc :-)
I bought the power strip, removed cord, and inserted filter Schaffner inside. See please, photo in attachment. I use a separate item for low-power components (cd-player, tuner, preamp) and power-amp. In fact, think of something not so hard ..thoughts come themselves if necessary :-))
Make an important idea for easy copying anyone.
Sergey - E-mail: barh (at)

[Shaffner filter]
[Shaffner filter]

Dear Sergey,
thanks for your message, though I'm not 100% sure I completely understood what you wrote. Anyway, though not new, it is a good idea to place a Shaffner filter inside the mains distribution strip. You can easily improve it by star-connecting all the inlets to the filter (a piece of wire for each inlet).
Happy listening,
Lucio Cadeddu

Miniwatt/Virtue Audio Sensation
Hi Nick,
I am a little desolate of worring you by some questions but however I try. I like very much Your reviews in TNT so I have bought the Miniwatt that I like a lot. My fullrange speakers are 97db sensitive so the Miniwattt does the job at normal listening levels. Apart this amplifier I bought, few years ago, a Winsome Lab Mouse (the same chip as Virtue One and Two)which is very good too.
When I was younger I built some DIY amplifier like Hiraga 20W/8Wamplifier and I was pleased to see that the new generation of class D amplifiers were sounding better and with no comparison about weight and dimensions. However I think I prefer the Miniwatt /Winsome at normal listening level. Recently I bought a Paul Hynes regulator (not have received yet) to upgrade the Winsome and perhaps equal the Miniwatt in sound quality (+ more headroom). After having read your review about the Virtue Sensation I am wondering if it will be an upgrade over the Miniwatt (and over the Winsome).
After reading some very good reviews about the first watt F1 from Nelson Pass I was ready to build one to drive my fullrange speakers but?
Do you remember what kind of sensation you had between Miniwatt and Virtue sensation? I suppose you have heard the better amplifiers in the world so how could you describe a Virtue sensation in front of these animals. I have a mono sub and three inputs and now the Paul Hynes regulators so the Sensation would be a must for me but only if it would be an improvement over the Miniwatt.
I apologise once more for this waste of time but if I could have an answer I would be very glad.
Best regards,
JoŽl - E-mail: joel.perret (at)

Hi Joel,
Don't worry about asking questions. TNT was started to help people who can't get to hear a lot of equipment and we are always pleased to help if we can. The choice of amplifier (or should I say the choice of the type of amplifier) is quite a personal thing and will depend on how we like music to sound to us. It will of course, also depend on the synergy with the other equipment in our system, particularly the speakers.
So I think that the first decision, i.e. which type of amplifier really has to be one made by you rather than by a reviewer. That said, things are much more complicated these days with the class-D amplifiers sounding a bit like tube amplifiers, more so if you partner them with a tube buffer or preamp.
Then we have the issue of power requirements, speaker efficiency, and headroom, all of which you speak about. It sounds in your own case that you can get away with a power amplifier of minimal power output, as the Miniwatt successfully drives your speakers. In my own system with very efficient speakers, the Miniwatt also works very well, as do the 12 volt class-T amps. But I can hear a clear improvement when using the higher powered class-T amps such as the Virtue ONE/TWO, or the Virtue Sensation. I prefer to use those amplifiers with a valve buffer and get the sound that I like.
The Sensation is the best sounding of the Virtue amplifiers, has many more facilities, and looks fantastic as well. Of course you pay more for those extra qualities. As regards your Winsome Mouse, that also uses the higher voltages that the Virtue amplifiers do. I have not heard one but I would suspect that it sounds almost identical to a Virtue ONE or TWO. With a Paul Hynes regulated supply, you should be getting the best performance from the Mouse.
So it really comes down to the added facilities of the Sensation. It does have the sub output that you would need for your sub. It also has remote control.
So to answer your question, if you prefer the Mouse to the Miniwatt, you would prefer the Sensation as well. I hope that this helps answers your question.
Happy listening,
Nick Whetstone

Clock upgrade
Dear Mr. David Holgate,
I am sorry for disturb you and excuse me for my English, I read with great interest your articles on TNT-Audio about NETaudio clock generators. I have a Jolida JD100 CD tube player and I just want a little detail more and improve its already good quality. My idea is to put a clock generator better than that already present.
On the internet I found the following clock generators (list sorted by the more expensive price)

       NewClassD (D-Clock Audio) (D-Clock: 206 euro)
       Audiocom (superclock) (Superclock 4:  £170.00, Ultraclock mk2: £425)
       Bursonaudio (Low Jitter Clock) (Low Jitter Clock: $185)
       LC Audio (LClock XO 3) (LClock XO 3: 172 Euro)
       Tentlabs (XO2.2,  XO3.2) (XO 2.2: 116,81 Euro , XO 3.2: 150,42 Euro)
       Audioupgrades (C1 master clock) (C1 master clock: £75, C2 Premium
 clock: £175)
       Trichord (clock) (Clock 2: £73.40, Clock 4: £151.70)
       Net Audio  (MicroClock MK2: £38, MiniClock: £70.00, RockClock MK3:
       TCXO Clock (Ebay) (TCXO Clock Module: 31 Euro) [ 1ppm e < 6ps]
       Audio gd (Kingwa) (Kingwa JZ-1 Clock, 17 Euro) [ < 1.5 ps]
  1. The clock on my CD is certainly worse than any of these ? (On the list there is a clock that costs only 17 Euro)
  2. Because I have a limited budget and it has to be a inexpensive choice, there would be a noticeable difference with the clock inside my CD player ? Or the only way to appreciate the differences is to focus on a range of at least 100 Euro ?
I found one on Ebay (TCXO Clock) that actually costs only 31 Euro but I don't known if this is the best choice...
Hoping not to have disturbed, awaiting for your response.
Best Regards,
Marco - E-mai.: marcopanza (at)

Hi Marco,
Thanks for your letter and sorry about the delay in my reply. I'm sorry that I don't have the technical knowledge to say which clock would work best in your CDP. I think you need to find out more about the clock in your CD player and then contact the manufacturers of a few clocks to get their specs. Remember the highest price is not always the best. I liked the two clocks I tried, but I can't really remember the difference. You could also post your question on the TNT-Audio forum.
Do you plan to do the mod yourself? Why not try one of the cheaper clocks and see if you like it? There are other upgrade mods you can try as well, e.g. see this list of ideas by Underwood HiFi.
Good luck with your experiments. Please write and tell us what you learn.
Happy listening,
David Holgate

Scythe Kama Bay amp
Good evening,
First I wanna thank you for your detailed review of the scythe kama bay amp. In my search at the most environment-friendly amp I came across this review. On other reviews I have read that the power consumption of this amp is very low. I came to understand that was true for most of the amps of class D (or T). I'm planning to use this type of amp for a 5.1 surround setup. I recently bought the scythe kama bay amp 2000 as a starting point. All your requests (from your kama bay amp review) are there:

So, maybe they have listened to you? I had two questions:
  1. Is this still a good amp or would you recommend a different one (especially for this price or in this class)?
  2. Has biwiring the same effect as monobridging it or do you really have to modify the chipset pins? Concerning this: can I use one amp to drive both my subwoofer and center speaker? Or do I need two amps for this: one for my center speaker and one for my subwoofer (how to connect this)?
I have searched extensively for solutions on these questions but couldn't find them. I would be most thankful if you could help me with these.
Kind regards,
P.S. The kama bay amp 2000 is working great, great to have multiple inputs and using this little energy to listen to music with such clarity!
Boaz - E-mail: boaz (at)

Dear Boaz,
I'm not sure you can use such a low-powered amp for a 5.1 HT set-up, as this normally requires high power output to sound realistic. Anyway, you can try. I'd avoid connecting the Scythe to a subwoofer, as I'd prefer an active subwoofer for this purpose.
For its low price the Scythe is hard to beat: good sound, quite flexible might just ask for some extra watt of power output :-)
Happy listening,
Lucio Cadeddu

Janus Platter Mat
I'm writing from Vancouver, Canada. I recently came across your interesting article on a DIY platter mat and am wondering whether it is thin enough as described to go on my Thorens TD125 leaving enough spindle above it to accommodate a clamp. Can you please let me know the approximate thickness of the mat in mm.
When mating the cork with the tar sheet, I presume you would use the self-adhesive side of the tar sheet for the 'mating', but when, finally, both protective films have been removed would not the exposed side of this material - given its 'Tar' nature - be tacky and want to stick to records or platter, depending which side up? And would it not also attract dust and anything else that might come into contact with it?
Many thanks.
David - E-mail: davcub (at)

Dear David,
it all depends on the thickness of the cork sheet and of the damping (tar) sheet you'll use to build it. Mine is around 3-4 mm's but I don't know if this will work well on your TD125 (maybe yes, considering the thickness of old Thorens rubber mats). If you think it might be too thick start with a simple cork sheet, then add the damping sheet.
As for the tacky nature of the tar sheet, it is not a problem. The tar sheets I used weren't tacky at all! Check this out before purchasing the sheet.
Hope this helped,
Lucio Cadeddu

Loudspeaker bracing
Hi Mark,
Thanks for the loudspeaker bracing suggestion. Might have to give this a go as the speakers I was planning to get are no longer available due to the company (World Designs) going bust.
Maybe I can get the Tannoy R3's better balanced with extra bracing. They are great on bass light music like the Incredible String Band but not so good with albums like Get Happy or the last Kasabian cd.
Listenable, but a bit thick sounding in the low mid-bass. However they are good at low listening volumes, so I'm stuck with them for now.
Jas - jaswant4 (at)

Hi Jas,
The Incredible String Band, Kasabian and Elvis Costello in the same sentence! I must come round and explore your CD collection; mind you, I believe Get Happy was also the title of a classic swing LP like Ella Fitzgerald or Peggy Lee, in my Dad's collection.

Yes go for it! Add the bracing, and possible a hardwood outer shell. This is cheaper than you think, using thye currently fashionable hardwood sheet flooring. Use a hard dense 2-pack adhesive like aerolite 606 (I know the name implies the opposite) for best effect. It costs relatively little for much added rigidity, and more than doubled mass.

Furthermore, while you are at it, extend the hardwood down to floor level to make a tall, narrow floorstander. You can either mass fill the cavity with kiln dried sand, or include a tuned quarter wave pipe with the exit at floor level. This will extend the bass and reduce bass phase shift (called group delay in the audio comics) once you optimise the long fibre wool stuffing quantity and distribution.
Let me know how you get on.
Happy Listening,
Mark Wheeler

Tubes vs transistors
I read your article about tubes vs transistors and it made me smile. Thanks!
As a sometimes musician that also is a technician in various sorts of the fields, you'd be amazed by some of the ways things were recorded that are things where people think they can mystically re-create the performance with the right gear. My preference, in recording people, is to use AKG D-202s (I like them and know them) and a couple SM-57s, but there's been some horrible gear that recorded many a popular record. As far as mixing desks, you have stuff ALL OVER THE MAP, so the only way you ever are going to "capture" an actual performance is by being there in person to listen to it, although that is complicated by the fact that a lot of stuff is multi-tracked from all over the PLANET, literally, and so it's an electronic invention to begin with.
I have old tube stuff and spiffy new ALESIS digital stuff and a LOAD of stuff in between and at the end of the day, I have a NAIM NAIT, a Linn, some decent near field monitors I put together, and a couple decent sources of digital input and a large library of music...I play string instruments, and especially when I got into guitars I was trading guitars and building guitars and modifying guitars and trying to find perfect, and I realized there wasn't a "perfect" answer and I settled on things that I mostly liked, but the funny thing about some audiophiles is they THINK there is a perfect solution.
I live outside of Austin, TX and have worked with the big boys and I've laughed my ass off at people showing off their 50k stereo with surround to play something I saw recorded on stage with SM-58s and board-outs from shitty mackie mixing desks...They're lucky they used mid-range gear or else their "showing off of their superb stereo" would involve drunken musicians trying to conceal belching :-)
Thanks for the read. Good to know some people "get it".
Tom - E-mail: amish.tom (at)

Dear Tom,
thanks for your kind feedback!
Happy listening,
Lucio Cadeddu

UK Govt plans for digital radio switchover
Hi Mark,
I found out today that Ed Vaizey, the UK Government Minister responsible for broadcasting, will be making an announcement about the Government's plans for digital radio switchover in the House of Commons (UK parliament). As such, I would strongly urge people to send their views on this subject to Ed Vaizey. His email address is as follows:
vaizeye (at)

Judging by what they've said up to now, the new Government Ministers appear to be just as keen on digital radio switchover taking place as the last lot were, and it appears to me that they've fallen for the radio industry's lobbying about this hook, line and sinker.
As they only seem to have heard one side of the story here, I honestly don't think the new Government realises just how opposed to digital radio switchover the public is, so now would be an opportune time to let him know!

I plan to add new content to the Save FM website as well.
Steve - E-mail: newsletter (at)

Hi Steve
We will post this letter on the TNT-Audio website. We share your commitment to FM broadcasting and share your horror at the dumbing down of broadcast quality, sacrificed on the alter of more content at any price, including content diluted to make it go further. Do sign up to our Real Stereo campaign. You'll get the logo to put on your site and a link from ours that may attract other folk dedicated to good audio quality.
Happy FM listening,
Mark Wheeler

Mission 774 tonearm
I'm writing to you as I would like to ask you to write me back a few information about Mission 774 tonearm as I couldn't find to much in internet about this. In addition to this I've got a few specific questions e.g.:

  1. I'm considering to put this tonearm instead of my current SME 3009 s2 Imp. to my old Thorens TD 160 Super. Do you think it will be a good change?
  2. Generally, is it a good tonearm or it's too old and every new one (Rega, Origin Live) will be much "better" at all and much better for this old TT,
  3. Do you know any brand new cartridge MM or MC HO which will be a good match for this tonearm?
That's all for the moment.
Once again, I would be very thankful for your answer. Looking forward to hearing from you.
With best regards,
Cyryl - E-mail: kotyla (at)

Hy Cyryl,
If you mean the original one, which has a headshell "block", no finger lift and a sorbothane decoupled counterweight, then it is very good. The later ones are okay but nothing special. It would be fine on your Thorens, and worth trying in the place of your SME 3008 Imp, if they are of similar condition of course.
You don't mention your budget for a cartridge, so I can't comment. I think it could use a less compliant cartridge than your SME. You can get information (picture, manual, etc) on this arm at vinylengine.
David Holgate

KAB 1200
Hello Arvind,
I greatly enjoyed your review of the Technics/KAB 1200. I found it very informative and appreciated the objective as well as subjective assessment. I wonder if you could help me out with deciding between a stock 1200 and one from kab. Among many concerns, I am wondering if the reliability of the kab version is as good as the stock version. Since the review I read was updated 2007, what can you tell me about your experience with the kab since then that may help me with making a decision?
Thank you again Arvind for your review.
Best regards,
Paul - E-mail: kasnakian.paul (at)

Hello Paul,
Thanks for your kind feedback. The KAB version does not mess with the mechanics, and thus should not effect the reliability of the stock unit. I have not since compared with any other units, but it still serves me several times a week. I would strongly recommend the tonearm damper upgrade, if you were only to get one.
Hope this helped,
Arvind Kohli

Wood amp
Hi Mark,
I read your article about steel, aluminium, and wooden amp boxes. There was a mystery back in the day why NAD amps so cheap could sound that good. I have an old NAD amp and its made out of wood. I want to build a plate amp box out of aluminum but am not sure about the grounding and rf. This is a class D amp with Toroid, what do you think?
Rob - E-mail: RobeMcDona3 (at)

Hi Rob
Why, when you have read my article and clearly share my opinion, would you consider taking an amplifier from its superior wooden case and placing it among the slings and arrows of that outrageous band of Eddy Currants and the Torroidals?
If you want better screening because you are picking up RF interference, you would be far better served by using thin copper sheet to add shielding to the existing copper box around the offending high gain part of the circuit. Twisting power supply DC feeds tightly together with a drain wire earthed to the chassis star earth point might also help.
I cannot sanction anyone abanding a wooden amplifier case and replacing it with aluminium, it's just not cricket old boy. On the other hand I have no recollection of an all wood NAD amplifier. Which one is it?
Happy tweaking,
Mark Wheeler

JBL 10 studio speakers
Hello Lucio,
I have a loud speaker problem and so found this web site. My audio problem: I have a pair of JBL 10 studio speakers. I accidently knocked one off its stand. The speaker cabinets are built strong; however, there was some kind of damage. The 12" speaker is without sound. I hooked up the wires to a cheap car speaker and did get sound.
I need to know then, if I can presume that the speaker needs to be repaired or replaced. There are other "electronics" in the speaker cabinet, but since I got sound from the test speaker, I am presuming that all of that is OK.
Best wishes,
David - E-mail: davidz (at)

Dear David,
if another woofer, connected to the same wires, sounds OK there's nothing damaged inside the cabinet (there's a crossover network inside, with caps, coils and resistors). Perhaps the voice coil of the JBL woofer has been damaged by the crash. Send it to some professional drivers repairer, they can rebuild virtually anything! The first service that comes to my mind, located in St. Louis, Missouri and which also specializes in JBL drivers, is Winstonorgan but there are many others. Try Googling around for something closer to where you live.
Contact a repair/rebuild service describing what happened to your speakers and ask for a price quote. I don't think it will be an expensive repair.
Hope this helped,
Lucio Cadeddu

VTA article
Your VTA article is superbly written!!!! Have messed with the same stuff myself-Audioquest AQ7000-the orig fussy one-ACT2 arm and a seriously modified AR Legend. I can still hear to 19500-tested-so can hear harsh top end reasonably well and also use your bum down system (I call it the wormy dog technique for obvious reason-specially with the actual shape of the back end of the Act2 arm) because it gets rid of the AQ's slightly harsh top on sibilants without trashing the rest of the mix. The arm height adjustment on the Benesch arm is archaic to say the least for such an expensive arm so I mess with it as little as poss.
Also tried adding weight to the front "wings" of the Act 2 counterweight at the extreme front and rebalancing the arm/tracking weight. For some reason I seemed to get less rumble on warped lps and better tracking with the Aq cartridge, but on the odd occasion I fit my Koetsu Black and can hear no diff at all with no apparent tracking improvement either!!
Any ideas? Maybe something to do with distance of the weight from the pivot point being lessened so less inertia from the counterweight?Would love to hear your take on that.
Superb and informative website-keep up the great work!!
Best regards,
John - E-mail: masterpr (at)

Dear John,
Thanks for the mail and the kind words. The weight you add to the front of the ACT-2 counterweight wings will have several effects. First it increases the load on the bearings - this can be benificial or detrimental, but is most likely to be 'different'...
Second you'll increase the twisting moment of the arm - i.e. it will become more resistant to twisting - especially relevent to a false unipivot like the ACT-2, but will also alter the resonance of that motion - slowing the rocking frequency slightly.
Third the increased weight will mean the counterweight is closer to the pivot and so the Effective Mass of the arm will decrease. There will also be other effects - the resonances within the counterweight will alter - the extra weight may act as a vibration 'sink' (if they are lead or example) and so-on. Overall you will have made subtle changes to a whole host of arm parameters and these will effect some cartridges more than others as they too have different mass and resonances. It's why definitive tests on how good a tonearm is are so difficult as you can only test an arm as a cartridge/arm/turntable system, never in isolation, and what works with one cartridge may not with another even though the technical spec may be quite similar.
I guess it's what makes these things such a black art and why one reviewer might find an arm 'bright' and another 'dull'... Cheers,
Geoff Husband

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