TNT-Audio Readers' Corner
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May 2008

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NAD amps
I recently acquired a NAD 317 integrated amp at a steal, $140 in fact. It's a fantastically powerful amp, it sounds smooth and controlled, punchy, clear but forgiving. Great! I thought. But what should I do with my NAD 3020i? Use it as a pre-amp?
I currently got it hooked up like this: OPPO DV-980H -> Audioquest Silver Anniversary -> NAD 3020i's AUX input -> Lousy RCA from 3020i's Pre-Out -> NAD 317's Main In -> Another Lousy RCA from 317's Pre-Out -> NAD 3020i's Main In. (That's how the manual says to connect them. I've got the speaker cables connected to the 317, and yes there is sound, great sound).
However, is the 3020i a particularly good pre-amp? I like it's musicality which the 317 lacks, but I hate it's muddiness, it's dirty contacts and it's lack of a remote control. I can't use the 317's remote since both the volume and the tonal controls are bypassed. (is that a good thing?). At the moment I am unable to discern a difference between the setups mostly because I can't do an A/B check, and I'm using really crap ICs.
The main questions are: What does a pre-amp do? And should I use the 3020i as a preamp and invest in ICs or sell it away? It's a classic, I know, but I'm a student, so I need the cash. lol.
Eldrid - E-mail: baby_bass_breakinout (at)

Dear Eldrid,
the way the two amps are connected is quite fancy, to say the least. Trust me: forget the 3020 and use the 317 as standalone integrated amp. The 3020i is good but I guess the 317 is better. Moreover, all that lousy ICs won't do anything good to the sound of your system.
A preamp is needed _only_ if you have a pure power amp (which is not your case). With a good integrated amp like the 317 there's no need to use an outboard preamp. This way you will also be able to use tone controls and the remote of your 317.
Put the 3020i on Ebay, it'll get tons of bids (3020 lovers are going crazy these days).
Keep me updated,
Lucio Cadeddu

Vintage restauration or enhancements
Dear Lucio,
My current set-up is made of a Systemdek IIX, Quad FM4, preamp Quad 34 and Quad 303. This equipment was restored with respect to the original design (new electrolytic capacitors only). I would appreciate your comments on upgrade for vintage equipment that goes beyond replacing worn parts. (For examples: Fidele Audio or Net Audio). Some vendors will propose modern IC'S, better OPAMPS, alteration to the original design and so on. In which case, you may get the benefits of modern sound but a new hybrid Quad is born.
The same "ethical" question holds true for Marantz, Pioneer, Dynaco or MacIntosh vintage. I love the Quad design and features but before re-building a Quad preamp or any piece of vintage, where should one draw the line. Should one be looking at Celestion 44 (vintage classic) or Paradigm Studio 20 (modern classic)?
René - E-mail: rmarquis (at)

Dear René,
as you may know, I'm a vintage sports cars lover. The very same questions you ask arise in this field too: is it better to leave the car EXACTLY like it was (i.e. "restore" it to its original setting) or is it admissible to tune it (read: deeply modify) in order to improve its performance? There's no precise answer, it all depends on your personal taste. Generally, I prefer to leave things as they were intended to be. That said, I shipped a pair of vintage Naim amps for an upgrade to a guy who is famous for "upgrading" old Naims (shipped them 4 years ago, maybe, still waiting :-)). Of course, the final result will be a new, modern pre + power amp combo inside a vintage cabinet (more or less).
As for speakers may I suggest you to try a pair of Celestion Ditton 66, B&W DM-6 or Linn Isobarik, instead?
Happy listening and stay tuned!
Lucio Cadeddu

Hi Lucio,
Thanks for your comment on my NUFORCE questions! I have some new questions:

  1. Could a power supply solve the low-sensitivity problem of my speakers?
  2. I would need at least 2 inputs in the NUFORCE "ICON" and would therefore need a pre-amp. Which one would be a good match in relation to the price of the Icon?
  3. Something completely different: I would like to have those ALW super regulators but their site ( is dead. They're neither offered on ebay. My questions: do you happen to know what happened to this site and to the availability of those regulators? Do you by chance know which super regulators are comparible in price and quality?
Thanks again for your time and knowledge!
Herman - E-mail: herman.Marijke (at)

Dear Herman,
please find my answers below:

  1. A power supply won't add anything to a low powered amplifier. You can used a super-powerful PSU but the output power, for a given circuit, will remain the same.
  2. The Icon has three inputs: a standard RCA, a minijack stereo and a USB. The minijack one can be easily transformed into a standard RCA pair via a minijack/RCA adapter (cost: few euros).
  3. I don't know what happened to the ALW website (seems up but not running). You can try the Burson Audio SuperRegs we reviewed almost 2 years ago.
Hope this helped somehow,
Lucio Cadeddu

Hi Mark,
Hi, I came across an article from you on the Avondale AAA5 on the net. I have a modified NOS AA5. I currently have it on Sorbothane Feet. I was interested in your comments on the Little Rock. What was your verdict on this and where did you get it from? Let's face it, housebricks don't look that great!
Phil - E-mail: bishopfamily (at)

Hi Phil,
What do you mean, housebricks don't look that great?
Housebricks are beautiful examples of ceramic art... sometimes!

Staffordshire Blues are a fine high density high fired engineering brick with beautiful swathes of colour along their sides caused by heat gradients in the kiln. For those who prefer a red brick, New Old Stock (NOS) Waingrove B are the way to go.

I have quite a collection of bricks for audio, my favourite being the one you've seen in articles bearing the legend Baldwin Cables on its pitched top, and a cable channel cast into its apex. I got that from a demolition site of an old factory, close to the site of a former brick-works in Derbyshire (with the owner's permisssion) so I was very surprised to see an identical sample high on a Lake District Fell above Conniston, with a cable running through the hole. It looked like an interconnect but despite walking for miles that day I never found the rest of the system.

The bricks work well on BrightStar Isonodes, but BrightStar's own Little Rock did work well too. The Little Rock fits between components and the shelf above which cannot be said of the bricks. I got mine direct form BrightStar, whose president Barry Kohan strikes me as a friendly helpful chap in all my dealings with him so if you lack a local supplier I am sure he'll deal with you direct via the website's Factory Specials page.

I found the smallest Little Rock best on the Avondale modded Arcam as it sat in the middle of that horrible clangy top plate. You will also find the Isonodes are an improvement on Sorbothane under your cd player at very modest cost, so while you're paying for shipping, order a set of those too (and another set for your amplifier).

I can happily make these glib recommendations as cost-effective vibration control products like these (and there are some other cost effective brands too) will give you a far better bang for your buck than most audio purchases other than cds (or vinyl discs) themselves.
Happy listening
Mark Wheeler

NuForce Icon
Hi Lucio
In your comment on my questions about T-amps, you mentioned the new ICON from NUFORCE. My questions are:

  1. When will you review this amp?
  2. What type or brand loudspeaker cable concerning INDUCTANCE, CAPACITANCE and RESISTANCE matches best with this T-amp and my 2-way loudspeakers:
    • Brand: OPERA 1.5 (bookshelfs)
    • Sensitivity: 89 dB at 6 Ohm.
    • Cross-over type: 4th order
    • Bi-wiring is not possible: only one pair of sockets per speaker. Would it be worthwhile to have them modified for bi-wiring?
    • Drivers: SEAS woofer & SCANSPEAK tweeter
Thanks for your time! Cheers,
Herman - E-mail: herman.Marijke (at)

Dear Herman,
the Icon has just landed! It may take a couple of months before I can publish a listening test, though. The Icon uses custom-built CAT5-type cables, which are quite short (1 meter or so). You should build something on your own if you need longer lenghts as the Icon doesn't use standard speakers posts (it uses RJ45 connectors instead!). See all the specs and features on
That said, if I were you, I'd be much more concerned with the low sensitivity of your speakers! Cables are not a serious concern. And no, I wouldn't modify the Opera 1.5's for biwiring. If 12 watts are enough for you and if you can build your own cables then the Icon might be a worthwhile option.
Happy listening and stay tuned!
Lucio Cadeddu

Tube IMP Tube Tester Questions
Hi Mark,
Prior to possible purchase, I was wondering if you could please help answer a few questions I have in reference to using the Tube IMP tube tester for specifically testing E88CC/6922 tubes.

I understand that voltage gain is probably the most important characteristic to measure for matching dual triode E88CC/6922 tubes, to avoid any potential channel imbalance issues for pre-amplification use.
The Tube IMP tube tester uniquely offers this feature of measuring voltage gain values, compared to older Hickok vintage tube testers, but does not have the ability to provide high enough cathode currents beyond 10 mA. Receiving manuals for testing E88CC tubes typically quote an anode plate voltage of 90 V, resulting in a cathode current of 15 mA, using a grid voltage of -1.3 V for measuring mutual transconductance values below or above the acceptable limit of 12.5 mA/V.
I was wondering, would using a much lower anode plate voltage value for a resulting cathode current of say 5 mA on the Tube IMP tester still provide the necessary linear data for providing reliable and accurate voltage gain values for comparing both triodes on E88CC/6922 tubes?
Also, does the Tube IMP tube tester have the ability to display mutual transconductance values beyond 12.5 mA/V?
Your comments would be gratefully appreciated.
Many thanks in advance.
Kind Regards,
Paul - E-mail: xlr8or(at)

Hi Paul
Voltage gain is crucial for matching if you are trying to pair valves. Whether it is channel to channel match, or more importantly if it is for the positive & negative going halves of a balanced circuit. Sadly many NOS double triodes, the kind the Tube Imp is aimed at, have mismatched sections due to deterioration with age. My solution for home build projects is only to use half of a double triode at a time and have different bases in the circuit wired to use different halves so that the better side of any given tube gets used.

Voltage matching does not need to be undertaken at operating current, assuming the valves curves are roughly as they should be.

I did wish I could measure higher currents with the Tube Imp. Both your suggestions should work at indicating or predicting the higher voltage higher current behaviour well enough to be confident about inserting the valve into the circuit. The Tube Imp would need a MUCH BIGGER power supply (and higher spec'd innards) to meet the whole range of operating conditions of even the most common miniature double triodes so would cease to be such an appealing option for amateurs as its cost would more than double. I did keep hitting the Tube Imp's ceiling when testing but we just have to accept its limitations at this price and user friendliness.

The ECC88/6922 family are often 'juiced up' by audiophiles beyond their designed applications by using low anode voltages and high currents or vice versa so your scope for experimentation is immense. If they do make an octal Tube Imp some of the wilder applications I've seen for Red Base RCA tubes would need a psu borrowed from a welder!

Unless you already have a bench full of test gear the tube-imp is probably a safer recommendation than a portable 'scope as an early purchase.
Happy Tinkering,
Mark Wheeler

Toslink cables shootout
Hi Nick,
I would like to know about your testing environment, because I spend quite much time in thinking about digital connections, and without more info I would see some points of failure in the testing environment.
From my point of view, neither the (unmodded?) SB nor the (unmodded?) Behringer are known for good unjittery performance.
So the main question would be: are these pieces of equipment used out of the box or did you spend some effort in optimizing their clock jungle e.g.?
In the first case I would think you compared those connectors in one of the most suboptimal conditions.
Not an offend at all, I just would like to know about :-)
One conclusion could be, that (besides I like spdif connections more as long as one does not let in noise from the playing device to the dac) the spdif out of the sb is simply better than the toslink out (following the theory the optical element always adds noise to the digital signal, leading to problem extracting a low jitter clock).
Best regards,
Michael - E-mail: Michael.Rinus (at)

Hi Michael,
Thanks for your interest in this review and no offence taken.
The optical output of the SB3, and the DEQ2496 are indeed unmodified. The electrical output of the SB3 is modified, and comparing it to a standard SB3, it does make an improvement that may account for why I preferred electrical to optical by a small margin.
If only I had the time and money to be able to do these tests with a modified 'this or that', or different equipment! But as I'm sure you know, we are truly amateur at TNT and have to make do with what we have to hand. And then of course, the majority of readers will have unmodified equipment anyway.
Should I have the opportunity to try the optical cables in a more optimal set-up, I will update the article. In any case, I hope that most people will read the article for what it is, one man's experience in his own system. Perhaps we should preface every review with words to that effect! ;-)
Nick Whetstone

Consonance CD120 Linear
I want to thank you for your wonderful review of the Consonance CD120 linear CD player. As a result of your review and two other magazines reviews I became aware of it. After comparing it to the Arcam cd73t, Marantz cd7001, Cambridge Audio 640c v2, Creek Evo, Marantz cd6000ose, Marantz cd6002 I bought the Consonance cd 120 linear to replace my aging Marantz cd 63se. It has a so much more musical and open sound than the other machines. It seems to have a nice analogue type sound that I like - smooth, detailed natural sound. It did take a couple hundred hours to break in as well. I found it improved further with a good power lead and isolation devices such as vibrapods and cones as well.
Thanks again for helping me be aware of such a reasonably priced cd player that dosen't cost the earth.
Steve - E-mail: stephenn (at)

Dear Steve,
thanks for the feedback! Glad to know our review helped you choosing your new CD player.
Happy listening and stay tuned!
Lucio Cadeddu

Speakon, again
Hi Mark,
Do you have any thoughts about the use of speakon connectors in a DIY loudspeaker project?
There's not much about them online; their use seems to be limited to the pro-audio musicians where durability is an issue. I'm wondering if there is a genuine electro/sonic reason for not using them, or if its more a matter of habituation to the look and shine of gold on the back of the box - you know, a convention. speakons are plastic looking and utilitarian.
I guess if you were using commercially available cables speakons would limit your choices, but if the project is just DIY all the way that wouldn't be an issue. Speakons would be much cheaper and easier to install that the conventional posts and banana/spade setup. What do you think?
Chris - E-mail: chris (at)

Hi Chris,
this is your second TNT-audio reply as our editor Lucio Caddedu replied to you via our letters page last week. What great service you get from!

The story goes that Neutrik came into being in 1975 because their founder was so unhappy with the woeful quality of the available, and then ubiquitous, canon XLR connectors. I use ordinary Neutrik XLR connectors whenever I can. There are a few shiny gold plated XLR out there and I have tried them and they're no better, they cost more, and eventually the gold wears off. The full-price range of Neutrik XLR are the ones to beat at cost vs performance. And I have to pay full price for them despite being a reviewer. If I was not a reviewer I would build an all-balanced connection system with Neutrik connectors and never allow and RCA phono in my house again.

Neutrik say: "The Speakon cable connectors are the industry-standard connectors for amplifier / loudspeaker connections. The entire family of 2, 4 and 8 pole cable connectors has been designed to operate in high current, inductive load environment of loudspeakers. The cable connectors feature a robust plastic housing, the traditional Neutrik chuck type cable clamp, a unique locking principle and touch proof contacts. The 2 and 8 pole versions offer 30 Amp current rating while the new 4 pole SPX type features up to 50 Amp current carrying capacity for the operation of high power speakers and amplifiers carrying more than 1000 Watts."

The Speakons are robust and self wiping. They have the minimum number of interfaces between cable and load. All my projects have external crossovers; they sound better that way and you can easily switch from passive to active drive. I use Neutrik speakon connectors to prevent anyone inadvertently connecting full-range amp output to my tweeter. So the passive crossover gets binding posts on the input side so I can substitute whatever flavour cable is demanded by an amplifier manufacturer.

Between passive crossover and speaker I use 4-pole speakon connectors on flying leads to ensure that the high-pass wires are attached to the tweeter and low-pass wires to the woofer. They sound as good as direct solder connections to me. Wilson also use them between the Watts and Puppies on the captive lead, nuff said. I have tried a variety of other couture branded 5-way binding posts; EC approved connectors; 4mm banana plugs (aka Wanda plugs in some places); spade connectors and bare wire. The Rhodium plated Mitchell binding posts have given better service than any others and Rhodium plate is as good-as-gold and lasts much longer and needs no nickel substrate. I have tried VERY EXPENSIVE solid unobtanium or pure silver binding posts from well known manufacturers and they sounded no better and deformed under torque on my Sonic Link S900 cables.

The Mitchells are my binding posts of choice for universal compatibility but I'd happily use Neutrik Speakons all the time if I didn't have to keep changing amplifiers and speakers.

That's the definitive answer on Neutrik Speakon connectors from a man who can hear the difference between two different brands of blob under an amplifier on a stack of specialist audio isolation shelves. Speakon connectors are fine for audio.
Happy listening,
Mark Wheeler

Hi Lucio,
do you have any thoughts about the use of speakon connectors in a DIY loudspeaker project? I came upon your [negative] reference to them in TNT's review of the Diapason Prelude, but there's not much about them online; their use seems to be limited to the pro-audio musicians where durability is an issue. I'm wondering if there is a genuine electro/sonic reason for not using them, or if its simply a matter of convention, or habituation to the look and shine of gold on the back of the box - speakons are plastic looking and utilitarian.
I guess if you were using commercially available cables speakons would limit your choices, but if the project is just DIY all the way that wouldn't be an issue. Speakons would be much cheaper and easier to install that the conventional posts and banana/spade setup. what do you think?
Chris - E-mail: chris (at)

Dear Chris,
first of all is a matter of convention. Even RCA connections aren't the best around but almost everyone uses them (XLR's and DIN's are better, for example). That said, Speakon connectors might be better, safer and even easier to use but they do limit the type of speaker wires you can use. Oversized cables might be a problem, for example.
Hope this helped somehow,
Lucio Cadeddu

DIY speakers with Fostex
Ciao... long time, baizans...
Please take a secretive look at, pls scroll down and see some OB type panels with single Fostex fe 126e spkrs.
With that tube amp of ours and this wooden floor room, and the marantz cd 6000 ose... and straightwire cable amp, things are QUITE amazing.
I don't want to advertise our amp yet...this is just to show you how a simple 15mm thick plywood, 80 cm wide on floor and 60 cm high, with hole at 47cm, 23 cm, ( x, y ) can be SO amazing... despite such low tech and simplicity.
Do try it ...pls tell others about this OB freely.
Thank you,
Kishore - E-mail: mukashifriends (at)

Dear Kishore,
thanks for the DIY design. Unfortunately I don't have the time to build and test it (so many things, so little time, too many HiFi components waiting to be reviewed!!!) but I'm sure some reader might find the design attractive and stimulating.
Lucio Cadeddu

TNT-TTS DIY mains cable
Hi TNT-Audio,
I have some questions regarding the DIY TNT-TTS cable. The designer, Stefano Monteferri, is not available anymore. Can you help me, either answer some questions, or redirect these questions to someone who can? I hope it's OK with you :-)

  1. Is it important that it is 3 meter long? I need less than a meter.
  2. I found this cable available: it has only a single shield and with two conductors they can only offer a 0.75 mm2 version. With three conductors they can offer a 1.5 mm2 version. I only need two conductors, but should I choose the one with three conductors to assure large enough cross section?
  3. How large ferrites is needed for the cable? The company I buy cable stuff from offers the ferrites in various sizes.
  4. What is the cross section of the whole cable closest to the connectors?
Best regards,
Ketil - E-mail: ketil.oppedal (at)

Dear Ketil,
you don't need to make the TTS exactly 3 meters long. It works well even if made shorter :-)
Less than one meter might be too short, though.
As for cross section, it should be better to use the 1.5 mm2 wire. If you're concerned about having a "too fat" cable near the connectors, feel free to use the 0.75 mm2 one.
Finally, the size of the ferrites depends on the choice above. Once the cable is completed, you'll understand which kind of ferrites you need. You can even test the cable without ferrites first.
Hope this helped,
Lucio Cadeddu

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