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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February 2009

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NAD 3020
Just read your review of the NAD 3020 (listening to my 24 year old example at the moment with some AC/DC). I agree that it is a great amp. Well worth the 85 all those years ago. As you say, themed range and bass is fantastic for price. It is currently powering the sound system in my kitchen. Source is a Compaq PC sound card and it drives two pairs of Bower and Wilkins ceiling mounted speakers fantastically.
Best piece of HI FI I ever bought. AR18 speakers and Dual 505 I bought at the same time have disintegrated into dust but the 3020 keeps on going.
Jason - E-mail: emmaraikes (at)

Dear Jason,
you're right, the 3020 is a very good piece of gear. Unfortunately, nowadays, it has become utterly overpriced and, in my opinion, more recent NAD (or Rotel) integrated amps sound better and can be found for much less. Not to mention the new breed of inexpensive (and damn good) Class D amps! I can understand one might wish to own a piece of HiFi history but spending nearly 200 € (as I've seen on Ebay) for a NAD 3020 is a complete nonsense. And yes, I admit that part of this crazy phenomenon is due in part to our review, considering this is the first result on Google when one types NAD 3020 :-|
Happy listening!
Lucio Cadeddu

Dear Nick
I read you review about the Trends Audio UD-10.1 Lite. You tested it with Ubuntu. Well, It seems to me this isn't the first time you specify you are a Linux User. I'm very happy about it, as I've been using exclusively Linux for at least six years. I have a question, as I want to start producing music with my computer (now I use Ubuntustudio) in a more professional way, so I decided to buy a new sound card. Can you suggest me something, something fully compatible? A usb or firewire connected device could be good. Now I have a soundblaster clone, a very cheap one they sell with 5+1 outputs and so on...
Thanx in advance for your help ;-)
Luca - E-mail: puppet.trash (at)

Hi Luca,
I can install Ubuntu and then get a USB DAC to plug into the PC and play music but I am no Ubuntu guru (nor expert on making music with a PC)! I suggest asking for help on the Ubuntu forums where you will almost certainly find somebody who can help you achieve what you want to do.
Nick Whetstone

Burson buffer
In 2006 Nick Whetstone reviewed the Burson buffer and mentioned its use with passive pre's. I am getting one of these to experiment in my main and secondary systems which both use passive pre's (TVC and stepped ladder attenuator respectively).
My question is whether the buffer is best placed between the DAC and passive pre' or between the passive pre' and amp. I'd be grateful for your opinion.
Best wishes,
Don - E-mail: def25 (at)

Hi Don,
I have no experience of TVC's so I can only make a couple of suggestions. One is to try the buffer before and after the TVC and see which position (if any) works best. I suspect that the 'best' position for the volume control will depend on the output impedance of the preceding stage, and the input impedance of the power amplifier. It really is a case of trying both positions and seeing what works best in your system.
The other is to contact Burson and ask their opinion.
Nick Whestone

Phono preamp
Hi Lucio,
Hope you don't mind me emailing you direct...I have just bought a Rega P3 with RB300 arm and Linn cartridge, and now I need to get a phono preamp to run into my Music Angel 845 amp. I can buy a used Project Phono Box quite cheaply, and after reading your review of it (2003), I am just a little unsure if it might not be "good" enough for the Rega table?
I know I can always upgrade later on anyway, but do you think that the Project would undermine the P3 performance and disappoint with the overall sound? Would a NAD PP2 or Cambridge 640P offer substantial improvement, or would I be better getting the Project and spending future funds on a counterweight upgrade or better cartridge for the P3?
Cheers if you have time to reply.
Mark - E-mail: McInerney.Mark (at)

Dear Mark,
yes, the Phonobox would act as a "bottle neck" for the performance of your analogue replay system. You should plan to consider better alternatives, possibly on the second hand market, such as the Rega Fono, Clearaudio Basic, Lehmann Black Cube and similar products. Even the Cambridge 640P would be a slightly better option.
The quality of the phono preamp plays a key role in getting the best out of any analogue set-up. Buy the best you can afford.
Hope this helped!
Lucio Cadeddu

I have written to you couple of times in past and thanks a lot for your suggestions. All of them work the way you say and that makes me to come to you everytime I venture into something new.
First, about my current setup. It is NAD C542 connected to C352 by Monster 400MKII and the speaker cable is Supra Ply 3.4S. The speakers are Tannoy Sensys DC2. The listening room size is 12' X 10'.
I like to go for a subwoofer now for which I need your advice.

Sorry for bothering you but going for any big purchase without consulting you is not possible for me.
Thanks a lot!
GopalJee - E-mail: GopalJee_Nigam (at) Countrywide.Com

Dear GopalJee,
thanks for your kind words. Subwoofers, when properly installed and adjusted, add more weight to the bass, more extension and, perhaps this might surprise you, they add extra depth to the 3D virtual stage. The general wisdom about subwoofers is that two is better than one. Two monos, of course!!! The problem is that most subwoofers are stereo, i.e. they use a dual voice coil.
Another problem is setting them correctly into the room. An excellent book where you can find some of the best advices on correctly placing and adjusting subwoofers is Get better sound by Jim Smith. Generally speaking you should avoid corners, for example. And then you should play with "phase" and "crossover frequency" to get the perfect match with speakers. A quick reference guide can be found on the Velodyne website where a quite useful product selection wizard can be used to browse among all Velodyne subs. You might start from there.
Keep me updated!
Lucio Cadeddu

Cartridge resonance frequency
Hello Lucio,
I hope either you or someone in tnt-audio could help me. It's about resonance frequency of an arm-cartridge combo.
To calculate the resonance frequency (rf) of an arm-cartridge combo one can use the following formula:
Rf=159 / sqrt ((effective arm mass + cartridge mass + mountings' mass) * compliance)
I believe the cartridge compliance used here should be dynamic but calculated at which frequency?

For example Audio Technica gives both static compliance and dynamic compliance at 100Hz for many of their cartridges. Cartridges I'm interested in: at440ml and at150mlx have the following compliance specifications: static = 40 and dynamic at 100Hz =10.
I'm guessing that in the above formula one should use some compliance value at lower than 100Hz but which one? Is there a way to calculate from the static compliance and dynamic compliance at 100Hz compliance at other frequency?
Or is there some other formula one could use to calculate rf using dynamic compliance value at 100Hz usually stated by manufacturers (or using static compliance)?
I'd really appreciate your answer and a few friends of mine as well.
Thank you,
Janusz - E-mail: Janusz.Pradzynski (at)

You say: "I believe the cartridge compliance used here should be dynamic but calculated at which frequency?".
At the frequency of resonance, which you don't know. Failing this, the 10Hz value should be used. Moreover: "a way to calculate from the static compliance and dynamic compliance at 100Hz compliance at other frequency?"
A reasonable estimate is the geometric mean of the static value and the 100Hz value. In the case of the AT that would be sqrt(40*10) = 20. Such estimate tends to be good enough as the formula for Fres is not very sensitive to variations in either of its parameters, be that mass or compliance.
By the way, the effective mass of a tonearm is also not a given, as it itself depends somewhat on the mass of the cartridge, the vertical tracking force, and the precise location of the cartridge relative to the arm's bearing.
Hope this helps,
Werner Ogiers

Re: Going active
Hello Mark,
thanks a lot for your response. I am now considering Marchand XM9 and Elliot Sound P09 project because people on several forums say that it is very flexible and top quality with the right selections of components.
I'll keep you updated.
Best Wishes
Pietro - E-mail: pcoretto (at)

Hello again Pietro,
The Elliott Sound SP9, to be found at looks like an uncannily similar filter configuration to the Behringer I mentioned. I did notice on the Pink Forum quite a few comments that the garden variety Ixo gets far more credit for its performance than Naim would imply in their comparisons with the HiCapped NAXOs.
Several posters comment that they were really surprised at the great results with very modest power amps, as I found using a simple emitter-follower 3rd order active with 2 chrome bumper Naim NAP110 (isn't it funny how MG classic car nomenclature has crept into audio? - I do know MGB & Midget owners who also have Linn/Naim set-ups).

Rod Elliot seems to have done all the work for you with that design, but leaves you to shop for your favoutite boutique component flavours. Phil Marchand goes further by offereing a kit with a case and power supply for the XM9 and has already worked out the appropriate compromises on componant choice. It all depends on your familiarity with particular component sounds in particular circuit positions and how much you wish to spend.

I really can assure you that whichever active choice you make you will not be dissappointed. In my experience, however much you would have spent on a power amplifier and a passive crosover, if you spend the same total figure on a suitable active crossover and two power amplifiers it will be so much obviously better that you will not need to try A-B testing to check you have spent your money wisely!
Even happier (active) listening
Mark Wheeler

Beaten again! Poly-speakers!
A few months ago, I was embarking on a Zigmahornet construction, but got stuck with the wood jointing (no tools!). Local woodworker quoted 120! Just for the jointing!
Remembering an old Wharfedale unit that used veneered polystyrene, I made the Ziggies from 1+1/2 inch polystyrene and was pleasantly surprised with the result from Dave Merrill's little 3 inch unit. I used PVA to seal the poly, plus lined the inside with gold "silver paper-lined" wrapping paper to channel the sound into the pipe a bit. I thought I'd invented a new concept in speakers; the semi-porous tuned pipe/almost OB - single unit speaker!
But, researching OB concepts and Hawthorne stuff, I came across your description of making.......polystyrene OBs!! So there goes my patent application? (-:) (Someone had advertised a Hawthorne based construction for sale).
I've been very interested in Ocellias for quite a while, PHY etc, and hope to go in that direction if I can sell my Avantgarde Duos. (Hope I don't miss the bass too much).
Anyway, thanks for the great review. It's very helpful to folks like me!
Chris - E-mail: cskelton (at)

Hi Chris,
I don't think that there is much new in the world of hi-fi!
I made some earlier polystyrene speakers, in fact two different designs, the second of which is described at
Anyway, I'm glad that you liked the review, and good luck with your future speaker projects.
Nick Whetstone

TNT Stubby stands
[TNT Stubby DIY stspeakers stands] Dear Scott,
I am sad to see that you do not write for TNT anymore (but I do not know when it happened... it could well have been years ago, for I started reading trough all of TNT only recently). This e-mail is just to send you a big "thank you" for your TNT Stubby project. I have found it simple and good looking, so I decided to build a pair of my own, and I believe the result is quite good, considering that I had never built anything out of wood and pvc before (ok, I had never built anything AT ALL, if I have to be completely honest :D).
My pair is made of fir instead of oak, and the pvc pipes are a little wider (3.2" approximately), but the soul is the same ^_^ And the sound is... well... awesome. Since I always had my speakers lying on the floor (was it a thunder that sound that I heard...?) I guess that any change would have improved their sound, so I cannot speak for the quality of the project itself (but I am sure it sounds better than many commercial stands), but I have been looking for some stands for my AR for quite some time and, beside the economic factor, I had never found what I was looking for.
They were always too tall, or too short, too wide or too narrow. Now they are perfect: they are exactly at the right height, and their base fits perfectly the speaker's cabinet. Even my cat seems to like them... she has refrained from making them fall (as she usually does with anything new that enters the house: at first she tries to eat it, and if that is impossible, she tries to kill it ^_^), so I guess it is a sign of appreciation :-)
I built them a couple of weeks ago and I tried the new sound for some days, then I took them away and put the speakers back on the floor while I was painting everything. Today I put them back in place (THEIR place, from now on ^_^) and the sound was so nice that I felt moved by their bright frequencies and lack of uncontrolled bass notes that I was used to hear wandering everywhere in my room when I had them on the floor. I raised the volume and let the AR sing for a while: wonderful. I hope the other people in my apartment building like music too, because today they have surely heard it :D
So, to make a long story short, I am really happy with the Stubbies. I send you a picture of one of them... and thank you again!
My best regards,
P.S.: Behind the speaker in the picture you can see a wonderful TNT Star cable ;)
Lucio - E-mail: kaptain (at)

Dear Lucio,
Scott (and now even Nels Ferré) writes for Enjoy the Music. Don't ask me why this happened...sincerely, I do not know. Perhaps it is a matter of feeling more related to an US-based mag, considering the guys are both from the US. Glad to know the Stubby worked so well for you!
Happy listening!
Lucio Cadeddu

Fresh air
Many many thanks for your online magazine. It's is a breath of fresh air in a turgid atmosphere. I have tried a couple of the diy cables, and lo! Even my clumsy hands were able to turn out something that substantailly bettered the sound of my system.
Please keep up your good work,
Roberto - E-mail: rpicciotto2004 (at)

Dear Roberto,
thanks for this so positive feedback (our only reward). Stay tuned for more "fresh" and cool ideas on how to improve your stereo set (without spending a fortune).
Happy listening!
Lucio Cadeddu

Going active
Dear Mark,
It was very interesting to read your articles about active crossovers. I wish to start a new project and this time it will be active.
Could you suggest a good active 2-ways 12db/oct crossover on the market with variable output level? I could also build one, so you could either point me to a good project.
Thanks for you valuable time.
Best regards
Pietro - E-mail: pcoretto (at)

Hi Pietro
Thank you for your kind words about the active crossover articles; it is probably time to follow them up with reviews of proprietry active crossovers, but my enquiries with manufacturers have not succeeded in obtaining samples to review. The least expensive active crossover I know on the market (other than those designs you build from kits or from plans) are two models made by Behringer (the German designed, Chinese made professional audio company). Their least expensive model, the Behringer CX2310 weighing in at under 75€ in most markets (YMMV) is a 2 channel (therefore suitable for domestic stereo) 2-way Linkwitz-Riley 4th order crossover. This would be suitable for your loudspeaker if your existing passive crossover is basically a frequency dividing network of two second order filters.

If a loudspeaker presently uses a 2 way second order (regardless of of type; Butterworth, Bessel, Constant Summed Amplitude) filter for both high-pass (tweeter) and low pass (bass-midrange) a fourth order corssover will do a similar job but better.
Why?, I hear you and hundreds of others chorus.
Better because even numbered filter orders work by shifting the phase of each passband by amounts that are simply related, hence a second order crossover, that roll response off at 12deciBels per octave (12dB/8ve) results in the high-pass section being neatly 180°r; out of phase with the low-pass section. This causes cancelletion between the drive units at the crossover frequency and a resultant notch. Common practice offers two solutions to this probelm, but only one of these is used in any application:
1. Reverse the phase of the tweeter (by connection - to the red terminal and + to the black)
2. Increase the overlap between the pass-band of each driver, on of the so-called constant summed amplitude approaches.

Whichever one of these solutions has been used is completely irrelevant if you repalce the second order crossover with a fourth order crossover. The only reason second order filters are used in passive crossovers is that fourth order crossovers would be very complicated (hence difficult to design and manufacture with medium tolerance high-power componants) and hence both more than twice as expensive and more than twice as lossy.

Odd-order (first and third) are often chosen for completely different reasons, particularly their vertical dispersion lobing characteristics, which are of no relevance to your situation.

I have recently bought the Behringer CX3400 (2-channel 3-way) crossover to play with and experiement, but I have not had enough experience with it yet to pas comment on its build quality and sound quality. I do know people who use their inexpensive PA equipment who do not report any disasters, which is good news at the budget end of the pro-sector. The next step up in audiophile terms might be one of Phil Marchand's products; I have not tested them yet but they are more expensive and designed with the audiophile in mind so I would expect superior sound quality. Go ahead and buy whichever you like the spec of, because any loudspeaker system driven properly by an amplifier channel per frequency band will sound better any any driven through a passive crossover using similarly priced equipment.
Even happier listening,
Mark Wheeler

Virtue Audio One
Dear Nick,
I've read your excellent review of the Audio Virtue One. I can imagine you must have received tons of emails re. this: did you have the chance to compare the Audio Virtue One to the Trends Audio Ta10.01 ? If yes, what are your impressions?
Also, you mentioned you have a modded SBIII+Dackit. What kind of mods have you performed?
Gustavo - E-mail: Gustavo.Salamone (at)

Hi Gustavo,
Sorry, I haven't heard the Trends amp so can't make a comparison with the V1. My mods to the SB3 are described at
As regards the DacKit mods, I am currently writing an article about them for TNT.
Nick Whetstone

Trends UD-10
thanks for your on target reviews! I own a Trends UD-10 and use it as my DAC. Which power supply would your recommend? I current run my Trends off the USB. I found the battery pack to veil the sound to my planars.
If it makes a difference, I live in the USA (115 Volts).
Thanks again.
Uri - E-mail: unuss (at)

Hi Uri,
I agree, when I have gone back to the battery pack, I haven't been too happy. I'm not sure what 5v supplies are available over your way. If it was me I would knock up one myself with a simple LM337 regulator circuit, but that's not much help if you do not DIY!
You could even try an SMPS type (also called switching power supply). None of these should be very expensive and it may help to try one or two and see if you can hear a difference.
I've had a look on Parts Express and found this but you should be able to find similar in quite a few outlets.
Hope this is of help.
Nick Whetstone

Active loudspeakers
Dear Editor,
I just read Mark Wheeler's two articles on active loudspeakers. I only wish he had written them 10-15 years ago. I have tried a number of "high-end" loudspeakers in my system and they all seemed to lack the life of music.
My first ear-opener came with a Fostex-based single driver system (Cain and Cain Abby's) driven by a low power tube integrated (Chameleon). Just like the now departed Ballentine Ale three rings, purity, body and flavor. I felt some power (bass) was missing and after some study decided to try Siegfried Linkwitz's Orion + system. One for each driver really makes a great difference. I could never go back to a system with passive crossover. The multidriver active crossover system is musical to the point where I can come home after a concert and recreate a significant amount of the original experience in terms of correct timbre of instruments, clarity and emotion.
Bruce - E-mail: schleinb (at)

Dear Bruce,
thanks for the positive feedback. Going active might be tricky, because the market doesn't offer many alternatives but it certainly is a very good route to follow. British "good old school" (Naim, Linn) suggested this route many, many years ago. And how it worked!
Happy listening!
Lucio Cadeddu

Building an entry level system
I'm trying to help my nephew to build an entry level system. Ffor some reasons, he can't go with the T-AMP (speakers sensibility 86db). He already has one turntable (a Rega P2 that he got with 30% in discount) for the cdp, useless to talk about it he's like me (a little bit my fault though). He's a vinyl lover. He's a teen that want to be responsible and he don't want me to neither give nor lend him money, so the main question is about the amplifier.
He has two choice: go with the Teac AH-500 (which he can have for 300$ in discount) and sounded very good (and has a damn good phono section) (I was very impressed by this little amp when my friend who works for an audio shop made me listen to it) or another option is to go with a Marantz classic marantz amplifier (that was an idea of my cousin) from the 70s. I had no experience with those Marantz amplifiers (in fact the only one I ever saw is dead since a while and when I heard it, it was suited with sears speaker so I couldn't really evaluated the sound) and my friend neither.
I know I could get a NAD or something but I found the little Teac more sonically involving (for the taste of me and my nephew). The other thing: I don't know if it's really safe to buy one of those 1970s amplifier. I don't want to see it burst in 3 month.
Could you give me an idea I know you already mention the little Marantz 1060 how did it sounded?
Mario - E-mail: master_veteam (at)

Dear Mario,
I own a Marantz 1060. It is a nice amp but it certainly is nowhere near a modern integrated amplifier. Let me say...forget it! Integrated amps from the '70s might be cool (I own some of them, even better than the 1060) but don't sound particularly well and, of course, they might need some heavy restoration (new PSU caps, for example).
I'm not familiar with the Teac amp you mention so I can't comment on it. My suggestion is to search for a good, powerful Rotel integrated amp from the 8xx or 9xx series. Many of these are equipped with very good phono stages. Also, a Naim Nait (1 or 2) or a small Rega amp could be an excellent partner for the Rega TT.
Hope this helped!
Lucio Cadeddu

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