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November 2013 issue

 

World mail  November 2013 issue

 

Write to us!  E-mail –>     This e-mail address is being protected from spambots. You need JavaScript enabled to view it

 

Letters are published first in the magazine, then here in our web archive. We cannot guarantee to answer all mail, but we do manage most!

 

Or  comment in the Comment section at the bottom of each page.

 

Your experts are -
NK 
Noel Keywood, publisher; PR Paul Rigby, reviewer; TB Tony Bolton, reviewer; RT Rafael Todes, reviewer (Allegri String Quartet);  DC Dave Cawley, Sound Hi-Fi, World Design, etc.

 

 

 

Gordon Hamilton's sadly departed Trio KD-650 Direct Drive. "It was

classy looking, very well made and had the best sound overall too",

he says.

 

 

DIRECT ISSUES

 

I was delighted to find Martin Pipe's Olde Worlde feature on the Kenwood KD-600 Direct Drive turntable in the September 2013 issue. This was totally unexpected and very welcome! 

I confess to being a bit of a turntable nut as well as a computer audio enthusiast. I have owned a fair number of players over the last 33 years. Despite being brainwashed in my youth (when HFW was still just a twinkle in Mr Keywood's eye) by British hi-fi magazines into believing that Direct Drive decks were sonically (and even technically) inferior to belt drive players with three-point suspended sub-chassis, I have come to love and respect the better Japanese Direct Drives of the mid 1970s to the mid-1980s. 

In the mid-noughties I had a Trio KD-650 (the armed version of the KD-600) and ran it alongside several other vintage Direct Drive decks including a Sansui SR-838, Technics SL-150 + SME 3009 Series IIIs, Technics SL-1500, Technics SL-1500 Mk2, Technics SL-7, JVC QL-Y5F, Sony PS-X600 Biotracer plus a Linn Sondek LP12 (mid-eighties, Valhalla, Akito), Linn Axis and Rega Planar 3. 

The KD-650 was the best of the lot. Not only was it classy looking, very well made and superbly engineered but it had the best sound overall too.The standard arm was a lovely object – it had an excellent standard of finish, looked fabulous and sounded far better than any other S-shaped arm from the 70s I have heard. 

I foolishly sold the KD-650 after having used it for less than a year, to fund the acquisition of a new Technics SL-1200 Mk2 which I intended to modify. I never regretted buying the SL-1200 Mk2 and subsequently modifying it (it is still my main deck to this day) but I did still miss the lovely Trio. So, when the opportunity arose in the spring of this year to purchase a Kenwood KD-600 (the armless KD-650), via a certain well known auction website I jumped at the chance. 

To my fortune, the seller of this rare vintage deck was also located in the North of England and little more than an hour’s drive away. This KD-600 is a Kenwood rather than a Trio, as the previous owner had purchased it new in 1979 in Singapore. It was in lovely condition and the only flaw that was apparent when I went to collect it was that the hinges could no longer hold up the (nicely made and heavy) lid in the open position. 

I would have preferred a KD-650 complete with its underrated arm but I would have probably had to wait years to find another unless I was willing to take the risk of having one shipped from North America. Anyway, I had a spare Rega RB250 with the Origin Live Structural Modification and I was curious to know how it would sound on the Kenwood. 

After getting the deck home I gave it a clean and a thorough check over and found that it only locked onto speed properly at 33 and a third, the quartz lock light flickering erratically on the 45 rpm setting. I roughly checked the speed at the 45 setting and found to my disappointment that it was only doing about 35 revolutions per minute! I could have complained to the seller but I did not want to send it back and I had paid a fair price anyway. 

I would now dearly love to bring this turntable back to full health and put it into service in my main system and I was wondering if Martin Pipe could recommend someone to do the necessary servicing at reasonable cost (alas funds are currently limited)? 

Martin, you really should try a better arm on your KD-600. I never thought much of the SME IIIs, having used one on a Technics SL-150 (admittedly not in the same league as the KD-600 although the SL-150MK2 is much better). In fact my SL-150 + SME IIIs (with Ortofon VMS 20E MK2) was sonically no better than my SL-1500 (with stock Technics arm and the same cartridge). I bet the Kenwood would be superb with something like a SME 309 or SME V, funds permitting. 

About the military version of the KD-600/KD-650 you refer to – my guess is that it would have been aimed at U.S. military personnel stationed overseas as they tended to get the opportunity to purchase hi-fi and other consumer electronics at discount prices (tax-free?) through the Army. The only difference would probably be a selectable voltage so it could be used anywhere in the world. I hope you like the two pictures attached of my long gone Trio KD-650 sniff, sniff!

Regards,

Gordon Hamilton 

 

 

 

The arm of the KD-650 was conventional enough, but well made.

 

Glad that you enjoyed the article; your U.S. army explanation for the ‘military version’ mentioned in the instruction manual is interesting! Note that the manual is freely-downloadable from www.hifiengine.com; good news if your KD-600 wasn’t supplied with one. Yes, the KD-600 – like many higher-end Japanese ‘tables of the period – is under-rated. But interest in them is growing. A mint specimen of the Trio L-07D, the ‘superdeck’ that replaced the KD-600/650, recently sold on eBay for nearly £4,000! I was lucky to acquire my deck (and other analogue gear) at a time when public interest in vinyl was at an all-time low, thanks to CD. 

 

I would agree with your assertion that my KD-600 would benefit from a newer arm and cartridge. It would certainly make for an interesting article in Hi-Fi World, especially if the result of such experimentation is compared with a contemporary ‘table! 

As regards repairs, the fault that is affecting your unit could be down to any number of issues – all of which require professional attention. If you’re lucky, a realignment might restore correct rotation at both speeds. A more likely cause is failing capacitors in the PLL speed-control circuit; if one of the chips has gone to Silicon Heaven then this, as mentioned in the article, need not be a disaster as NOS (‘new old stock’) supplies are still available. A full service would also be recommended. Thanks to the shamefully-disposable nature of modern consumer-electronics products, most of the service technicians that were at one time found in every British town have hung up their soldering irons for good. But a few are still around; one repairer that, in our long experience, should be able to help is Chatham-based David Tutt. He can be contacted on  07759105932 or via his website http://www.tutt-technology.co.uk. MP

 

BIG IN THE STATES

Being an American electronics consumer for the last 50 years I find it a welcome relief to see the article about the Spendor SP 100 R2 loudspeakers. As a reader of your magazine for the last several years I have been waiting to see bookshelf speakers with 12 inch drivers! 

Back in the late 1950s and 1960s and 1970s almost every American manufacturer of bookshelf speakers made it a point to begin their best model using a 12 inch woofer, or at least a 10 inch woofer. Bookshelf speakers weren’t small and back in the 70s most of the models such as Advent, Acoustic Research, KLH, JBL, and many, many more could be realistically placed on a bookshelf or on stands for several reasons. One of the main reasons is that many of the speakers were acoustic suspension. Actually, back when those 'speakers were manufactured, bass reflex designs were considered inferior. I realize that the Spendor speakers and most of the speakers manufactured today are of the bass reflex design. I understand the reasoning in trying to make the speakers more efficient and also trying to increase the bottom end of the bass the speakers will reproduce, however I find it very ironic that the speakers of the past will blow away the speakers of today which have these tiny four an five and six inch bass drivers.

It also amazes me how these speakers with their tiny woofers are so high priced. Back in the days of the large Advents designed by Henry Kloss, almost anyone could purchase a full-sized bookshelf speaker that would produce a full-sized sound without using a sub-woofer. 

I have owned almost every type of speaker imaginable. I’ve also owned many different brands of speakers such as Klipshorn, Altec Lansing, JBL, Electro Voice,Advent, KLH, Polk audio, AR, Bose 901s, and on and on. All of these speakers had different sounds and all of them were made by great companies of the past with the exception of a few that are still in existence. 

I find it very disheartening also that of those still manufacturing are having their products made in China. 

So what is my point here? Let’s start making our speakers back in Great Britain and America where we know that quality is going to be the norm. Let us all start making speakers that are reasonably priced and have great sound quality without using a sub-woofer. Don’t get me wrong I do like sub-woofers if they are used properly. In fact today if you have a speaker system that has been made in the last 10 years and you don’t use a sub-woofer you don’t get the lower end of the audio spectrum. 

My only gripe with the Spendor SP100 R2 is the price. I still own speakers that I purchased in the 1970s such as AR 11s that would blow the socks off the Spendor product! And they sure didn’t cost $6000!

Julian Hirsch of Stereo Review said it best. Give me good old 16 gauge lamp cord and that’s all you need boys to get great sound from any speaker from any amplifier. This cable thing and speaker wire thing you “high-end” people seem to be hung up on reminds me of the story of the ”King and his new clothes”. Wire is wire boys! In a real blind test you couldn’t tell the difference between 16 gauge lamp cord and $20,000 six-foot cords. So cut yourself some slack, get real and speaker manufacturers start producing real speakers that sound great like the Spendor that has a real 12 inch woofer! My congratulations to Spendor for at least having the guts in re-creating a real speaker with real sound!

Sincerely, 

Mr. Kim E. Kryder

 

 

"I have been waiting to see bookshelf speakers with 12 inch drivers" 

says American reader Kim Kryder of the Spendor SP100 R2. Bookshelves

must be a lot bigger in the States then!

 

 

Hi Kim. The big benefit of a 12in woofer was great bass, but the big drawback was a cabinet so wide it looked like a broom cupboard. Back in the 1970s this was acceptable and boy did we have loudspeakers – giants like the Goodmans Magnum K (12in bass unit) or Magister (15in bass unit) on this side of the pond. I ended up with Leak 2075s and they were delivered in a pantechnicon (I love that word). In the States you had even bigger loudspeakers, JBL knowing no limit. 

When one drive unit has half the diameter of another it has one quarter its area. So you need four 6in bass units to match one 12in bass unit when it comes to moving a volume of air. That shows just what a big difference exists between large and small bass units.

Our measurements also show that even at modest sound pressure levels of 90dB at 1m, a small 6in bass unit will produce around 5% distortion whilst a 12in will produce less than 1%. So whatever way you look at it, big bass units work well, it’s just that they don’t look nice. 

Spendor recommend the use of a quality loudspeaker cable, as we do. Bear in mind that modern loudspeakers use computer designed drive units and computer optimised cabinets. It was the development of the Thiele-Small equation, and the need for Thiele-Small parameters to solve it, that lead to successful reflex design. Before science tamed them, reflex loudspeakers worked poorly. Times have changed, audio engineering has moved ahead and the reflex made to do a good job. Now bass quality and control has improved a decent pair of loudspeaker cables should be used. No point in spoiling the ship for a ha’porth of tar, otherwise the Mayflower wouldn't have made it! NK

 

 

BRIGHT CABLE

My treasured system comprises a Trio KR9600, a 1978 150 Watt per channel receiver, an even earlier Pickering FA104 with the XV15/625e, a comparatively recent Arcam CD73T CD player and my beloved KEF Chorale loudspeakers, homemade in 1973.

With ears suffering and very slowly deteriorating I realised it wasn’t just me, the T27 tweeters also appeared to be declining. The woofers had been replaced around 15 years ago by Coles B2000s built, apparently, specifically to replace the KEF B200s. 

I contacted Wilmslow Audio (original KEF unit suppliers!) and asked their advice. They responded promptly with a very helpful e-mail suggesting Morel replacements and a rebuild of the crossovers to enable a higher power rating. Close to taking this option, my brother persuaded me to audition modern alternatives. Grudgingly, I agreed and we listened to the KEFQ300. This was very interesting! I could not believe how the family sound was still there, plus fantastic staging. Still some reservations as turning down the level lost a lot of treble, a la Chorales, and there was still a little cuppiness. 

Then cool Phil at Audio T Swindon persuaded us to listen to some Monitor Audio RX1s. I had heard MAs sometime before but found they were a bit clinical.

Well! This was what I was missing. Sorry KEF and Wilmslow. Thanks Phil at Audio T. Extra and impressive oomph just where I needed it. OK the imaging wasn’t quite as good and I’m not sure I’ll ever prefer ported over sealed box, but I forgave all that just to hear the nuances I had been missing.

Some may find the Monitor Audio RX1s a little too bright or even over-done. However, as is always being said, listening is subjective and I have selected what may not be the ultimate best on paper, but they are best for my ears. The acid test was passed as I am eager to run through the whole collection to catch what I’ve been missing. It shows the benefit of shortlisting from reviews but then talking to the hi-fi shop experts, then just listening as much as possible. We also auditioned the Wharfedale Dentons – nice, but too polite, and Acoustic Energy 301s. The latter were great speakers, but finding the sweet spot proved very difficult. Positioning was not easy.

Now, ears the question (sorry); I am running QED Anniversary XT cable. It sounds fine. However, Audio T auditioned them with Chord Rumour and that sounded a bit better. Should I buy this, or your favourite, the slightly cheaper Black Rhodium Twirl? My brother uses QED Revelation with his KEF Q4s and they produce incredible clarity. How about those? Ironically, Peter Comeau also replied to a letter in the same magazine saying that, early results indicate that different amplifiers suit different cables and explaining that there is a fully documented technical background to the subject. Always ahead of the game!

Auditioning cable is not really an option and Twirl is too new to find comparison tests on the net. My preference is for full (euphonic?), open and clear sound and music choice is very eclectic. 

Many thanks

Andy Entwistle 

Swindon

 

 

 

"Phil at Audio T Swindon persuaded us to listen to some Monitor

Audio RX1s" says Andy Entwhistle. "They were what I was missing".

 

 

There is no doubt that the Chord Rumours are excellent cables and you wouldn’t regret purchasing them, I’m sure. That said, if you are looking for ‘that bit extra’ then the Black Rhodium Twirl is highly recommended. Offering excellent low impedance figures (so long cable runs would be no problem) and low noise (so fine detail is never masked), I found the cable excelled in offering a well structured soundstage and in its ability to convey upper frequency detail over a wide variety of music types. This cable would be a fine addition to your system. PR

 

PURITY 

Whilst vinyl has always been my format of choice, for all the reasons shared by your team, I have reached a point where my physical storage space is fast approaching its capacity, and will soon be unable to accommodate further expansion of my record collection. This, combined with improving sound quality from digital has led me to believe that my future purchases are likely to be Hi-Res downloads. 

Your recent reviews of the Astell&Kern AK100 and AK120 has planted a seed that I would like to explore further with you. I currently use a Shanling MC30 music centre as a pre-amp to drive 8m long interconnects to my Martin Logan Purity speakers, which as you know are fully active. The combination is nice and works quite synergistically. 

The auxiliary input on the MC-30 is used by my vinyl front end. An advantage of the MC-30 is that it has an iPod type input suitable I believe to take the headphone output from the Astell&Kern products. Assuming this input is of sufficient quality then my foray into Hi-Res would be neat and minimalist! 

So, to the crux of my letter and hopefully your sage advice:  I think the pre-amp section of the MC-30 is actually pretty good, but would welcome your thoughts on this. I have searched the net and there are companies who offer quite expensive upgrades to the MC-30 through the use of selected replacement components, but they tend to be U.S. based. Is there anyone in the UK that you would recommend to undertake an upgrade to the MC-30? My goal here would be to maximise the transparency and neutrality of its pre-amp section. Budget would be circa £500. Would some tube rolling be the way to go?  

The long interconnects currently used are an inexpensive Wireworld product. Again I would like to improve the transparency of these, and would value your opinion on suitable alternatives. Budget would be in the order of £50/m. They would need to be relatively thin and flexible to weave their way around skirtings and furniture. I have considered the DNM Reson cable, but there may be others you have reviewed which may be more suitable?

Any advice you can provide would be gratefully received.

Best Wishes

Scobie Alvis 

London SE1

 

 

 

Black Rhodium Twirl loudspeaker cable is a fine choice, says Paul Rigby.

 

 

 

Martin Logan Purity loudspeaker can be driven direct from a portable

player like an iPod or Astell&Kern AK100.

 

 

Hi Scobie. Both the AK100 and AK120 have enough output to drive Martin Logan Purity loudspeakers direct, through their line level input. They have a maximum output, adjustable using the volume control, of 1.6V. The Purity needs 0.1V for 95dB so you have a lot of leeway here. Also, both players will drive long signal lines, but the AK120 is better at this. Ideally then, you should bypass the MC30. I know this means another set of cables, which you may or may not find acceptable, but when it comes to 24bit resolution you will need to optimise the signal chain and this means bypassing unnecessary amplifiers, in this case the MC30.

Alternatively, run the AK100 straight into the MC30 using a 3.5mm jack lead. I would not get too involved in tweaking the MC30 because it will place a lower limit on resolution due to small amounts of noise in the output stage whatever you do – not serious but you may notice it. The MC30 has a lovely sound as I recall, although in your system it feeds Class D amplifiers in the Puritys, meaning you have power amps driving power amps – not an ideal situation. Martin Logan told us the loudspeaker inputs are attenuated down to the low level input that then feeds a Class D amplifier connected to a passive crossover unit. So the purest signal path is via the ‘line level input’ because it eliminates the need for a preceding power amplifier. 

In place of the MC30 you may be able to use a passive pre-amp like the Creek OBH-22, and long interconnects, instead of loudspeaker cable. I say “may” because I do not know whether your phono stage has a low enough output impedance to drive the capacitance of a long line without suffering treble loss. It is easy enough to check this however, by jury rigging a long phono cable from the phono stage to the loudspeakers. How to play CD in this setup? Don’t! Rip them to digital files on a computer that you load onto your digital player. 

You have a lot of options here; I hope they are not confusing. By driving the Puritys direct via their line level input using phono cables up to 5m long or so will, I believe, give the best result. NK

 

WINE & VINYL

I was charmed by the story in the July Issue about Pie & Vinyl. It sounds an excellent mix and a fun place to visit. In this part of the world (New Zealand) where coffee is taken very seriously, it is increasingly common to have combined coffee–music  bookstores. These seem to be working well in the age of Internet shopping. Presumably because they draw customers into a nice atmosphere where they want to spend time. But I recently was lucky enough to visit what must be one of the nicest hi-fi shops in existence. A combined Hi-Fi-Wine shop! Located in Parma, Italy any hi-fi shop is likely to be good here as it is a city that takes its music (especially Opera) very seriously. Parma also takes its food seriously as the home of Parmesan and Parma Ham. So Hi-Fi News Musica da Tavola (Which Trans-googles to Table Music) gracefully combines the two with wine! UK manufacturers (Naim & Funk) are well represented, as are a number of interesting Italian brands tucked amongst the bottles. As the picture shows, this is definitely a place for relaxed listening!

Simon Brown

Design Build Listen Ltd 

Dunedin 

New Zealand

 

 

 

In Parma, Italy, you can buy hi-fi alongside wine.

 

A BUZZ IN OZ

I have a long standing issue with amplifier hum at my off-grid property in rural New South Wales, Australia. We use a number of power sources including solar, batteries and inverters, as well as generators of both the modified square and sine wave varieties. The issue is that when using a generator or inverter with a pure sine wave inverter, a horrible vibration and hum is produced from the transformers of my amplifiers. The sort of gear I’m using is as follows.

Power production is by solar panels going into deep cycle 12V batteries then to 240v via pure sine wave inverter. When it’s grey and raining for a few days I use a Honda 1kva generator with pure sine wave inverter built in, producing 240v of tested pure sine wave power. A higher power system for washing machine/vacuum cleaner etc is a Honda 4kva generator with modified square wave inverter built in.

There’s no internal circuits in the house, so the power just comes in via extension cord. I’ve tried earthing this system both at the power source end and the amp end but no improvement noticed. I’ve tried earthing one end, both ends or neither with no difference in hum.

Audio: I have a variety of turntables including Pro-ject, Lenco, heavily modified Sugden Connoisseur BD1 as well as various Luxman and Technics Direct Drives. These are fed into various pre/power amp combos by the likes of Amber, Vincent, Transcendent, Leak and Dynaco, then on to some ancient but fun speakers like the Leak Sandwich or Sonab omni-directionals

For the sake of brevity and simplicity, a sample system that produces the fault would be a CD player going into a Dynaco Pat-4 preamp then Dynaco Stereo 120 transistor power amp, Leak Sandwich speakers. If this set up is fed by either my pure sine wave generator or older style pure sine wave inverter from the batteries, I get the horrible hum. Both these inverters have been bench tested by electricians and deemed to be spot on.

Interestingly this hum emanates exclusively from the transformer end of the power amp (not the signal from the speakers) and is so pronounced it would visibly shake a piece of paper sitting on top to the point of it blurring.

I don’t get the hum when I use a much newer sine wave inverter or a much older style of modified square wave inverter either stand-alone or part of my big generator. Modified square wave does have its problems though and I do get a nasty pitch warble from my synchronous turntable motors.

Most people I’ve asked about this problem scratch their heads and mumble ground loop into their beards. They may be right but I’ve tested grounding various bits with no luck. I’m wondering if this is a switch-mode issue? Could it be that the older style of pure sine wave inverter might be fine for power tools but no good for audio? Any advice would be greatly appreciated.

Warm Regards, 

Adam Mann.

 

 

This Honda EM4500 generator will provide 4000 watts of power for 9.6

hours before requiring a re-fill. It is like the one used by Adam Mann in

Australia. It's low output impedance/ high current delivery best suits

amplifier power supplies.

 

 

 

Toroidal transformers are sensitive to DC in the mains. Try using an

isolating transformer to block DC if this is a problem.

 

 

 

Jeez Adam, that’s the strangest query we’ve ever received! Of all the hi-fi set ups I have come across yours vies with Michael’s (as I knew him), a logger in Borneo who used World Audio Design valve amplifiers to drive Tannoy Westminster Royals, “somewhere in the jungle” he told me at the Kuala Lumpur AV Show. 

Anyway, I strongly suspect that the sine wave from the “sine wave generator that causes buzz” is impure and the distortion harmonics are causing the windings and/or laminations to buzz. Transformers are impregnated to prevent this, but it happens all the same. 

I do not know why your square wave inverter does not cause buzz, because a square wave is a very dirty signal, but this may be down to its harmonic content not resulting in an excitation that is in tune with loose windings or laminations, because they are not synchronous. As you suspect, earthing has nothing to do with it.

Your synchronous turntables wow because their speed is determined by mains frequency that, in your case, is varying. 

You need a pure sine wave and this is not easy to guarantee. Connecting test equipment to the mains to asses purity is dangerous to the operator and the test equipment; a step-down transformer must be used. These are easy and cheap to get hold of though: 240V in/12V out is a common specification and will do. At least, the sine wave needs to be visually symmetrical on an oscilloscope (top bit same as bottom bit), with no sign of a sawtooth shape either. I am assuming of course you have a repair man with such equipment; most can manage a ‘scope and step down transformer.

You need a generator whose output is guaranteed pure and distortion free (less than a few percent). It should be tested when loaded I must add, because output impedance comes into this, due to the way amplifier power supplies consume current only over part of the mains duty cycle. A high output impedance generator (low power) will distort more than a low one when feeding the typical rectifier/capacitor power supply found inside most hi-fi amplifiers, suggesting your high power generator may be quieter than your low power one.

Alternatively, there are mains regenerators like the Pure Power 2000 and Isotek Evo 3 you could consider. These produce a very pure sine wave and will make you as happy as a Koala in a Eucalyptus. NK

 

Grant Armstrong, Amethyst Transformers, says – 

Distorted sine waves will generate buzz in the transformer but when the modified “square wave inverter” used the problem goes away??

The square wave inverter by definition produces a very distorted sine wave and I am not surprised the turntable motor squeaks. 

I assume that the mains transformer in the amplifier is a Toroid. Toroidal transformers are very prone to DC saturation caused by small amounts of incoming DC voltage.

  If incoming power supply is doubtful (earthing problems, DC bias, poor waveform etc) an additional mains isolation transformer always improves things. This transformer will definitely absorb any incoming DC. A filter on the output of the transformer will clean up the waveform.

  Position inverter and the additional isolation transformer in a separate room to isolate any physical hum.

A friend of mine has a very nice audio system but being a transformer man I can definitely hear his “noisy” mains conditioning transformer (not one of mine I hasten to add). As with all transformers, the bigger the better (unfortunately bigger transformers cost more)

Grant Armstrong, Design Engineer, Amethyst transformers / Morite.

 

VINTAGE VIRTUES

As a vintage hi-fi man – Garrard 301 (with Kokomo bearing) + SME Series IV + Northwest Analogue modified Goldring G800, EAR 824P (modified), Leak Stereo 60 + AudioLimtis passive preamp, B & W DM2a’s, Linn Karik + Musical Fidelity A3 DAC, I take a particular interest in the Olde Worlde articles you publish. One such article was the review of Haden Boardman’s Heathkit MA12’s published in the July 2012 edition of Hi-Fi World.

I was delighted hearing that another piece of vintage kit (of similar age to me) could hold its own against the more youthful and handsome amplifiers of today. Happy enough indeed, until I got to the second half of the penultimate paragraph. As a bit of a tweaker, I tried to figure out the modification Haden Boardman has been making to his Leak Stereo 20 and TL12+’s, and to the review subject Heathkit amplifier. 

To my distress, I read in the following sentence that Haden believes the Stereo 50 and 60 to be beyond serious audio salvage, and therefore not worthy of the modification. Haden’s views on the Stereo 50/60 seem to me to be a little at odds with the views I’ve previously read in the magazine, in particular recommendations made within the World Classics section of the magazine. I am quite content with my Stereo 60 running TJ Full Music ECC83’s and Electro Harmonix, CA7s, despite Haden’s comments.

To put things into perspective, I think it would be fascinating it you were to compare the relative merits of a number of commonly available vintage power amplifiers in one or two group tests based on EL84 type and EL34 type models. Perhaps, the use of alternative valves, capacitor replacements and simple modifications could be explored where these exhibit serious audio benefits.

Many thanks for a great magazine.

Mark Gaudet 

Maple Ridge, 

British Columbia

Canada

 

 

 

 

The Leak Stereo 60, famed for its lovely sound. "I am quite content with

my Stereo 60 running TJ Full Music ECC83’s and Electro Harmonix, CA7s,

" says Mark Gaudet.

 

As far as I am aware most Leak Stereo 60 owners are happy with their lot. Leak amplifiers in good condition sound simply gorgeous, a world apart from the hard, one-dimensional battering so many transistor amps mete out. Even by valve amp standards they are especially gentle and euphonic. Everyone has their own opinion of course but I think you are not alone and can be happy to know that your Stereo 60 isn’t easily surpassed. NK

 

PC SOUND CARDS

My current main system is centred on a Naim SuperUniti and Quad ESL57s with several sources, including Rega RP1 and Quad 77CD and several PCs. Have you heard a SuperUniti with ESLs? Try it: it has transformed the Quads! (PS my second system is the Quad 77 amp with Mordaunt-Short Aviano 2s: they have transformed the old Quad amp!) Most of my listening is classical/folk/blues/soft rock on LP, CD and HD FLAC files stored on a ReadyNAS network hard drive.

My reason for writing is: please, please, please,sit down with all your test gear and golden ears and listen to and test some computer sound cards through expensive hi-fi equipment. I have three PCs with three diiferent sound cards built over several years as I have spent hours working out the best way to rip LPs (and some tapes) in HD so I don’t have to keep wearing out my favourite LPs. I am so old I have been buying LPs since the late 1960s and some are not on CD. Some are on CD but my HD rips of the LPs are better than the CDs!

I attach an Apache Open Office file of a very thorough test report (off the web) of the Creative Sound Blaster X Fi Titanium HD internal PC sound card. This is one of the cards I use. I also use an M-Audio Audiophile 24/96 and an AsusXonar DX. I think all these cards are still available in PC World or Maplins. The attached test mentions that the Creative Titanium card uses a PCM 1794 DAC and a PCM 4220 ADC (Burr Brown) and has normal ‘phono plug’ connectors. I quote from the attached review:

‘The PCM 1794 Digital to Analog converter chip is easily one of the best converters available from any company. This chip boasts excellent measurements with a dynamic range of 127dB in this configuration and a THD+N of 0.0004% according to the available information. It should be noted that the PCM series of DACs are becoming more and more prevalent in modern soundcards.’ ‘We were amazed to see this quality of an ADC on a consumer level sound card. This ADC is usually seen in very high end external converters used for recording. Lets go over the specifications and you will see why, as this chip offers a dynamic range of 123dB (A-Weighted) and a channel separation of 132dB. This type of input quality is very impressive indeed for a consumer level card at this price point.’ Surely this is enough to tempt you to investigate and report? I look forward to reading a comparative test! 

One question: Is there any benefit in going up to 192/24 sampling for LP? Can experienced reviewers with tens of thousands of pounds of equipment hear the difference over 96/24? I am sure others, like me, rip using a PC and then listen on good quality ‘streamers’ like the Naim.

How do you rate these cards and by how much is the apparently hi-fi specification degraded when used inside a PC? How do internal sound cards compare to external sound cards such as the Terratec iVinyl usb phono pre-amp, which I also use but which has probably been overtaken by the chips in later internal PC cards?

My aim is to make the best HD FLAC files of my favourite LPs at an affordable price. Are there other ways of creating HD FLAC files from LP? If so please test and compare?

And finally – if you want another reference quality CD for your collection I suggest Jon Boyes Hacienda: a truly brilliant recording on CD. The guitar playing is also brilliant. He is based in the West Country and my wife bought the CD from him when he was busking in Sidmouth! (http://www.jonboyes.co.uk/index.html)

Yours sincerely, 

Mike Tartaglia-Kershaw

 

 

 

"Naim's SuperUniti has transformed my Quads" says Mike Tartaglia-Kershaw.

 

Hi Mike. You have an impressive system there and have obviously spent time on digital. The paper specs you quote sound impressive but they are derived by the manufacturer – Burr Brown in this case, part of Texas Instruments – and are the very best case result, so much so as to be barely believable – a dynamic range of 127dB we have never measured. With 24bit resolution 110dB – 115dB is common and 123dB the best we’ve measured to date, from a Teac UD-501 DAC with high quality on-board linear power supplies that are quiet. Computers are run from cheap, modular Switch-Mode Power Supplies (SMPS) that output a lot of noise on their many d.c. lines, not an ideal environment and one that would degrade these best-case figures. 

Also, we are not a PC magazine and not equipped with the latest PC hardware in vanilla form that could act as a valid test mule. Running Windows and loading drivers is another world – a fading one. 

To record LP get a Furutech Esprit preamp that has an excellent chip set, including Tenor USB chip, 24bit/192kHz WM8716 Wolfson DAC plus the 24bit/192kHz Cirrus Logic CS5361 ADC (Analogue-to-Digital Convertor) chip. It records at 24/96 resolution and outputs digital audio via USB. To date, I am not sure I have heard any clear benefit in 192kHz sample rate, but I may learn otherwise in future. NK

 

 

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