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 2011

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Preamp choice
Dear mr. Cadeddu,
First let me thank you for all your efforts you put into TNT every week. I'm always looking forward reading it because I trust in in the reviews - they're certainly not shaded by "mild judgements" for sponsors' products.
I have to bother you with a question: what's your opinion on the sound quality of AM Audio pre amps? What would be your pick if you'd have to choose a solid state preamp of any make?
Thank you very much for your time.
Walter - E-mail: staehli (at)

Dear Walter,
we reviewed quite a few AM Audio preamps in the last years, you'll find our opinions reading those articles. The general consensus is that their power amps perform better than their preamps. Generally, I'd avoid partnering amps and preamps of different Companies, mainly because it is far easier to sell a well-matched preamp/power amp combo than selling the components separately. Then there are also reasons of electric compatibility (output impedance etc.). Purchasing a preamp/power amp combo from the same Company is safer, sonically and electrically (sensitivity/impedence mismatch are generally avoided this way).
There are many components in the market but I'd suggest you to have a look at the passive preamps which make use of transfomers (TVC), like the Django and the Music First Audio (reviews here on TNT-Audio).
Hope this helped,
Lucio Cadeddu

Hi Lucio,
You're having a laugh aren't you? I mean your comments regarding the sound quality of vinyl!
Come on now, it just doesn't measure up does it? For one thing they have to compress it so that the music can sit in the grooves and then they can't cut real bass into it. Then there's all the noise present even on the brand new black stuff. Then there's that wow & flutter and grotty cartridges that mistrack if the music starts to get going a bit. Then there's the cost of all the stuff that's involved. Ok if you're Carlos Teves I suppose.
In many ways it's vinyl that holds digital back. I mean would you stick a resistor across your low output moving coil at first opportunity? Well this is what you do to digital and it's called line level. My view is the exact opposite. Get rid of line level, it holds digital back. Please make amps for digital sources only so they are not held back by vinyl! Abolish passive speakers, replace with active and run Hi-Fi systems balanced, please confine single ended to expensive vinyl systems.
I was listening to my all digital system tonight. Bought some new classical (Telarc) on line and didn't pay more than 3.99 for any of it! Then I switched over to Freeview Radio via my 30 freeview box and enjoyed excellent sound from both sources through my active speakers. I always smile when I think of my days with expensive high end turntables and all the stuff that went with them. I just don't feel nostalgic!
Mike - E-mail: mikebooth (at)

Dear Mike,
I can't see how line level inputs are holding back digital. I agree that digital (especially liquid) can sound extremely well but high quality vinyl playback, though not easy to achieve, is something that makes you forget of all the problems you mentioned :-)
The shortcomings of digital are mainly caused by standards: 16/44, for example, is definitely a bottle neck. With liquid Music we can get rid of this (up to a certain point) but sooner or later you have to convert digital into analogue: either you use a D/A and then amplify its output traditionally or you design and manufacture an efficient power DAC, a device that converts into analogue _AND_ can directly drive speakers (even getting rid of passive crossovers, if you wish). Unfortunately this isn't an easy route: many attempts, few reasonable results.
As for Freeview radio...are you REALLY saying that you prefer compressed digital Music over vinyl? Really? You're having a laugh, aren't you? :-)
In any case...happy listening!
Lucio Cadeddu

Re: Real Stereo
Dear sir,
I would like to take some of your time and space, elaborating on the subject of Stereo (stable vs solid). My comment was for Mark's use of the, in English language translation, Greek word "stereo". As I wrote, in our language, means stable. Not solid, as Mark gratiously accepted that was misinformed about. That was that. No more, no less.
The further comment was on Blumlein's intentions, in seeking recording techniques, in order to capture performance on tape, as faithfully as possible. I didn't say that stereo or stereophonic means something else. Come to think about it Dave. A stable image recreates the illusion of an event in your listening room. A solid image is a frozen thing better captured by a camera. Imagine that you can follow, aurally, a performer moving on stage. If your audio setup allows the spatial info out, you have, a well defined, STABLE, performance (soundstage), and that's what we care about. Not a SOLID one. Try to grasp it. The event (performance) is the thing that defines the soundstage, not vice versa.
Best regards,
V.L. - E-mail: 7suenos (at)

Dear V.L.,
thanks for adding these insightful comments to our previous letters/replies on this topic.
Happy listening!
Lucio Cadeddu

Hi Mark,
I think my CD63 remote operating system has packed up.
I believe that I have proven that the handset is still ok (by looking at the tip light up via my cell phone camera), thus presumably there is something wrong with the machine IR receiver. I wondered if you could offer a suggestion as to how I might go about repairing/replacing this myself - assuming that it is something that I can do myself?
Then I found a web-forum where a guy had the same problem & somebody suggested going around the back of the box where a switch exists to turn the remote sensor from internal to external; what the hell, I thought, it's worth a look. Sure enough, this had inadvertently been set to external (accidentally, during cleaning presumably) and voila, it works fine now that it's been put back to internal.
Paul - E-mail: jpg132 (at)

Hi Paul,
Thankss for letting us know the solution, we can pass this tip onto our readers.
Firstly, faced with this type of problem, use a universal remote control to test the hypothesis that the problem does lie with the receiver. Then, check whether there are easy fixes like this, before dragging out the meter, the scope and the desolder pump.
I'm really pleased you sorted it out as I hate scrapping working gear that someone likes (there's nothing like the CD63SE on the market now, it wasn't a player I liked but others like you love it). This is why I recommend we upgrade our favourite classics with better power supplies and clocks. We keep the presentation we enjoy but get more information from the disc, now presented with better timing and coherence. To my ears, rhythm and timing were the CD63SE's achille's heel, and I've been told a reclocked CD63SE would blow away a lot of modern competition.
Happy listening again!
Mark Wheeler

FleXy rack
I would just like to thank you for providing the inspiration for my new AV rack. Your Flexy Rack design is both functional and beautiful, allowing me to express my love of good, simple engineering. Some photographs of the finished result can be seen here:
Thanks again,
Andrew - E-mail: aahendry (at)

Dear Andrew,
thanks for your precious feedback and appreciation. Also, congratulations on your DIYing skills!
All the best,
Lucio Cadeddu

Siri Svale's Band
Dear Lucio
in case other TNT readers would like to hear what your review of Siri Svale's Band was about, I've found the following link: SIRI SVALE BAND - NECESSARILY SO... [Normann Records]. "Sample" button under cover art.
Frank - Connecticut Audio Society - E-mail: FRANKZWAC (at)

Dear Frank,
thanks for the useful link! At the time I wrote that review I hadn't been able to find any free sound samples on the Web. I've updated that review accordingly.
Hope you enjoy this album as much as I do, after so many years.
May I suggest you to have a listen to this new musical gem from a band I recently reviewed here on TNT-Audio? It is that kind of song that remains buzzing in your head for days!

In case the video aboove doesn't load or gets removed, go to YouTube directly.
Happy listening!
Lucio Cadeddu

Little Dot transport & DAC
Hi there Lucio!
I've recently read your review of the above unit(s). I currently looking to add a DAC to my computer-based hi-fi system.
My system is: Mac Mini>AIFF files>Stello U2 USB converter>"DAC">Cambridge 840a amp>speakers.
Read your review with interest, but can you tell me what settings & inputs you used with the LD DAC in this review?
I'm looking out for a balanced-optioned DAC, as my amp has balanced inputs.
Do you think I could do better than a LD DAC at that similar price level?
Appreciate any advice!
Many thanks,
Mark - E-mail: Mark.Bradley (at)

Dear Mark,
I've tried ANY possible setting during the review but changes in sound were negligible. If you're looking for such a DAC with XLR's, USB input etc. you can also consider the Harmony Design DA-9 we've also recently reviewed. I can't comment on which one sounds better as I reviewed the old DA-9 more than 5 years ago (linked review is by Nick Whetstone)! I'm pretty sure you can't go wrong with one of these two options, especially if you're interested in very high VFM (value for money) HiFi components.
Hope this helped somehow,
Lucio Cadeddu

Garrard Zero 100: new owner and new to vinyl question
First off, I really enjoy your TNT website. Thank you.
I've recently acquired a Garrard Zero 100 from a local souce, paid US$25.00 for it. Some one was a little rough with the controls and the main cam follower on the underside of the table that runs all the automatic functions was "off track". I've thoroughly cleaned and re-lubed everything, but it is need of a new stylus. I'm on a shoestring budget and wanted to ask you if you have a cartridge and stylus combination that you can recommend? The stylus that came with it that is damaged is a Shure stylus and is has "RS 8T" on the front of it. Can you recommend a decent stylus replacement?
Thanks again for the wonderful website!
Dan - private E-mail

Dear Dan,
if I'm not wrong, your stylus is an equivalent for the N75ED Type 2, found on Shure M75 cartridges. My suggestion, considering the age of the turntable (and of the cart), is to replace the whole cartidge: consider that the 80% of the cost of a complete cartridge is the cost of the stylus. Since you're on a shoestring budget you can't go wrong choosing a Grado Black cart (50$) or, at a even lower cost, Ortofon OM3E / OM5E or a surprising Audiotechnica AT 95EB.
Enjoy your Garrard!
Lucio Cadeddu

Vifa tweeter on Polk Audio LSi7
Dear Lucio hi, I am Vassilios, a Greek in New York. I read your review on the Polk Audio LSi7 and I found it very informative. Its been a long time but I wanted to see if you think the Vifa XT 25 can be dropped into that speaker. From bad pictures seems to have the same 3 screw core as sold by in USA.
If this is an easy answer, mille gracie, if not no worries.
Love TNT audio
Vassilios - E-mail: vpipis (at)

Dear Vassilios,
yes, the LSi7, as I wrote in that article, uses a Vifa XT25 tweeter, so you can replace it if yours is damaged. If not, there's no reason to install it, as the original one is exactly a Vifa XT 25 :-)
If in doubt, contact the Polk Audio technical support.
Hope this helped somehow,
Lucio Cadeddu

Class D choice
I have been on the TNT-Audio website reading the reviews voraciously regarding Class T and D 2 channel amps. I have been educated by the reviews and had many of my questions answered. I enjoyed every single one of the reviews written by you and the others. I am currently stuck deciding which amp would be the right choice for me because I am not an audiophile or have any knowledge about HiFi systems. I have a pair of Bose 301 speakers and would like to power those with a simple low budget(under $150) amplifier. I have narrowed down my choices to the Scythe Kama Bay, Dayton Audio DTA-100a, Topping TP21 and the Dayton Audio APA150. I read in the DTA-100a article that you will review the APA150 soon and wanted to know what you feel about it and if you have any ideas about the Topping TP21.
I would appreciate your input on those choices and help me narrow down what will fit my need better.
Thank you,
Jay - E-mail: sarkissianj (at)

Dear Jay,
unfortunately I've never listened to the Topping TP21 amp so I can't comment on its value. For sure, you won't go wrong with the Dayton DTA-100a, as it has enough power to drive your Bose speakers without trouble. The APA150 (review will appear soon) is a different beast and is NO Class D design, as it is a standard Class AB amplifier, with much more power, that you might not need. If I were you, I'd choose the DTA-100a.
Hope this helped somehow,
Lucio Cadeddu

Re: Real Stereo
Further to V.L.'s letter to Mark Wheeler, I think it's generally accepted that the 'stereo' component of 'stereophonic' refers to the three-dimensional illusion created, rather than stability. I would have been willing to accept that this was perhaps an urban myth, but comparison with such words as stereoscope and stereochemistry suggests otherwise.
In some senses, mono sound is more stable than stereo, so that meaning seems increasingly unlikely IMHO.
Kind regards,
Dave - E-mail: mail (at)

Dear David,
thanks for the feedback and your enlightening comment. For sure stereo sound aims to create the illusion of a three dimensional musical experience. Nonetheless, there are many audiophiles, for example those of the Flat Earth kind, who use stereo systems not caring about 3D illusion. And with some reason, I may add, considering a lot of Music (esp. electrified) has nothing to do with 3D.
Lucio Cadeddu

2 amplifiers into a single pair of speakers
Dear Lucio,
I'd like to cover two subjects with this letter. First I've been reading the editor's corner archive and found one from 2006 ("Audio Lies") where you write about the common behavior of manufacturers to inflate their numbers in regards of equipment specs. Do you still believe that this is the norm among manufacturers or have you seen a change in the past 5 years?
Second, what are the dangers in connecting two amplifiers to a single pair of speakers? This might be a very dumb question and a very dumb idea, I can acknowledge that. But since I don't have the technical knowledge to be certain about this I would like to hear your thoughts. I browsed the internet looking for something related to this and found nothing. And as a reviewer and, most likely, someone who others call for help and advice you might have come across this.
The situation would be a solid state amplifier, a tube amplifier and one pair of speakers with twin binding posts (that allow for bi-amping or bi-wiring). Let's say I want to use the speakers with each amp depending on music content and so I'd have both amps connected to the speakers without removing the jumper that connects the two sets of binding posts. One amp/cable to the top post and another at the bottom post.
IF I make sure that at any given moment in time one and only one amplifier is on and feeding the speakers would that cause any harm to the other amp which is off? What if the amp is on stand by? Also can this cause any harm to the speakers?
I know that by using banana terminators one should be able to exchange cables and amps in a glimpse, and this situation would not exist. And the speakers at hand allow for that. But if for any reason this situation is desired, what are the risks involved?
Thanks a lot.
Marcello - E-mail: mpego (at)

Dear Marcello,
to answer to your first question, I'd say NO, the situation isn't any better nowadays. Many manufacturers, especially of small Class D amps, claim their products to have far more power than they really have. In particular, there's a bad common practice to list power output specs at 10% of THD, which is not into HiFi territory by any means.
To answer to your second question, I'd say NO again, you can't connect two amps to a single pair of speakers (unless you do some real bi-amping) without risking to make one of those amp explode. If you feel the need to connect two amps without swapping speakers cables each time, buy a multi-amp selector like this one. For 70$ perhaps it is not high-end stuff, but it does exactly what you need.
My advice would be to sell both amps and purchase a single, better, integrated amp. You won't need to switch between amps depending on the kind of Music you're listening to. That's crazy :-)
Hope this helped somehow,
Lucio Cadeddu

Temple Audio Bentam Gold or KingRex T20?
Dear N. Whetstone,
I read with interest the italian version of your recent Bentam Gold listening test. On TNT and over the net I found also enthusiastic listening tests of the KingRex T20: it seems to be so far the absolute Class T winner. It would be interesting to have a comparison of those two jewels.
In case you've had the chance to try the Kingrex, which one would you recommend?
Thank you in advance for your attention and reply.
Piero - private E-mail

Hi Piero,
I have not heard the KingRex T20 but it is based on the Tripath T2020 chipset, and I have heard a few amps based on that chip. The sound of the Bantam is different, more mature, more 'full-bodied' in my opinion, and I would pick the BG over all the T2020 amps that I have heard.
I hope that this is of some help although it is not a direct comparison.
Nick Whetstone

Hi Lucio,
I've bought a couple of recordings after they have been reviewed on TNT, Yucca Flats and Marlene Mortensen. Today i received the State Cows CD, and I am happy to welcome it to my collection. So keep up the good work. If i could recommend a band to you; Over the Rhine ( a well worth a listen and constantly evolving.
You also may remember I wrote about 18 months ago regarding Rothwell attenuators, you suggested I looked at improving my amplification first, I did, I now run an Astin Trew AT1000 plus pre amp and the AT 5000 power amp, again after reading a review of their CD player on TNT. Living where I live, there is nowhere to audition equipment so reviews are so important.
So thanks to TNT I have several holes in my bank balance, buy hey, I'm happy.
Mike - E-mail: mike (at)

Dear Mike,
thanks for the precious feedback and your musical suggestion. I feel sorry for the holes in your bank balance! I've choosen this sweet song from the band you suggested, I hope you enjoy it...
Happy listening,
Lucio Cadeddu

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