Saturday, November 20, 2010

Telos Audio Design RCA Caps

Telos Audio Design (http://www.telos-audio.com.tw/) was almost unknown in Singapore until recent distribution by local distributor, Audio Basic. Telos has beautiful and well made RCA caps. The interesting thing is the manufacturer's claim of sonic benefits from using these RCA caps to cover unused inputs and outputs. Bear in mind that their caps are of non-shorting design, i.e. there is no shunt of positive to ground.

Telos caps are made of copper and then plated in either gold or platinum. Fit and finish is excellent and is as good as jewelry grade. Insulation is teflon.


Photos from official website


I have had a set of both the gold and platinum caps for some time now but did not quite get around to writing a post on them. Part of the reason is my difficulty in rationalizing why these caps work so well. The manufacturer claims that they protect equipment from stray EMI and RFI. I think the reason is far more complex than suggested.

Both caps have a not so subtle effect. Putting on just a single pair of caps on an unused input lifted the haze that made the system sound homogeneous and blurred. Vocals in particular focussed tightly and instruments became more distinct and in sharper contrast to the background.

The platinum caps were the most dramatic of the two. Vocals actually became slightly more distant but with increased focus and texture. Micro-detail was excellent and the extension of high frequencies, especially hi-hats was particularly impressive. I noticed that the platinum caps tended to accentuate the sense of acoustic space in the recording.

The gold caps in comparison presented vocals in a more forward manner, but with a touch of warmth and smoothness. High frequencies also were more extended but to a lesser degree compared to the platinum caps. Bass notes gained both substance and extension, something which the platinum caps did not really do. Micro-detail was not as good as the platinum caps though.

How many to use ? And should you combine the platinum and gold together ? This is one situation in which you really need to experiment. Here are some observations I notice during my experimentation with these caps,

- The input being covered matters. If you have say three unused inputs, using just a pair of caps on each of those inputs will yield different results.

- Don't just try inputs but also outputs. You can even try covering the coaxial output of your CD player / DAC.

- You can combine them to get the strengths of both caps. But I preferred using the same type of cap throughout as I felt that the system sounded more coherent that way.

- More is not better. My best results were obtained using just a single pair in any one component. In fact using too many causes the sound to collapse and sound shut-in, sounding even worse than stock !

- Although the platinum caps are potent, they can make vocals too sharp and sibilant, especially if you use more than one pair per component.

At their low cost, Telos caps are a must have. I bought a box of the platinum and gold caps, and probably have enough caps to tune 3 or 4  systems.

Saturday, October 30, 2010

Almarro A-318B SET Tube Amplifier - Photo Essay and Mini Review

Photo Essay

Beautiful and classic workmanship. 18 watts of single ended power. Tube complement - 6SL7, 6SN7, 6C33C.
8 Ohm and 4 Ohm speaker taps, 3 inputs and an IEC inlet with user accessible fuse holder.

Russian 6C33C double triode. From Soviet era missile and Mig Foxbat service to consumer audio. How the world has changed !

Volume control.
 Carved logo on the front panel.
Input selector. There are 3 inputs. The first indent is mute.


RCA 6SN7 GTB and Sylvania JAN VT-229 tubes

Power transformer is inside the chassis. The exposed center "transformer" in the first photo is in fact a power supply choke.


Russian K42-Y2 coupling caps. A surprise, quite uncommon in commercial gear.

Mini-Review

The Almarro A-318B is quite an unusual beast. Single-ended triode and assembled by hand in Japan, the A-318B is affordable, beautiful and powerful - typically these words are not seen together in the same sentence.

Being an integrated amplifier, you save quite a bit of useful money. Total up the cost of a preamp, with an additional power cord, a pair of interconnects, footers, etc, and you realise that the savings are not insubstantial.

Despite its compact proportions, this is quite a heavy amplifier, tipping the scales at close to 20 kg. Much of this weight comes from its massive power and output transformers. The next thing that hits you is the sheer amount of heat produced, not just from the very hot running 6C33 power tubes, but from inside the chassis. An hour or two of operation even in an air-conditioned room will guarantee you a nice and toasty top plate and volume knob.

Operation is generally fuss-free and uneventful except for two things. First, the bias tabs (sitting underneath the tube socket base) may be accessed by itchy fingers - owners with children please take note ! The position of the two tabs are dangerously close to the top plate and accidental contact is not only possible but very likely, especially if you have a habit of biasing your amp in your dimly lit man-cave, after a beer ot two. It is far safer to take the bias from the two metal screws directly above the tabs on the ceramic tube scoket base. Secondly, I had intermittent contact with one of my power tubes. This traced back to a slightly loose tube socket. My amp is about 3 years old and was bought pre-owned. Anyway, I re-tightened the sockets with insulated needle nose pliers (you have to turn the amplifier over and take off the bottom plate to do this) and did not have any further incidents.

Right off the bat, it is obvious that the Almarro has more drive than its low power suggests (18 watts SET, but my set was delivering probably close to 15 watts at maximum due to my choice of a slightly lower bias point).

In the lower frequencies, the Almarro is no shrinking violet and has enough grunt and slam when driving my Focal Micro Utopia BE speakers (90db sensitivity, 8 Ohm load). The bass is not the most extended or deep (leave that to my Class D amps) but has sufficient heft and articulation. That being said, the Cary SLI-80 has deeper and more powerful bass.

Coming to the midrange, this is probably where the Almarro defines itself. Vocals have a beautiful glow and are open and realistic. Brass instruments and strings are equally well portrayed, with more emphasis on tone and acoustic space.

High frequencies are similarly open with cymbals shimmering in the right way with correct emphasis on both the transient and the decay.

The Almarro is a beautiful amp designed to appeal to the emotional side of things. From the logic side, the Almarro does not have the best of extension at both frequency extremes. It is easily bettered by the Cary SLI-80 in this respect. Resolution is good but not world class. Soundstaging, imaging and separation are acceptable to slightly above average. Despite all this, the listener is too busy listening to the beauty of the Almarro's tone to notice or care about such things. The feeling of holographically "being there" is a strength of this amp How the Almarro manages this without being a champ in imaging and soundstaging is baffling !

Asking my partner for a second opinion, she concluded that the Almarro was beautiful but somewhat emotionally draining, while the Cary was more balanced. I reckoned that this has more to the do with the high level of emotional engagement of the Almarro.

If you are the sort of listener that wants to be able to feel the emotion of a violin concerto instead of being able to discern the exact placement of all performers of the stage, bowing technique, what they had for lunch, etc, the Almarro is definitely for you. As long as used sensibly with speakers of suitable ease of drive, the Almarro is able to deliver a slice of high-end at real world prices.

Monday, October 18, 2010

Audio-Gd DAC19 DSP

Talk about quick shipping ! My order with Audio-Gd has been pending for quite some time now as I wanted some customised inputs done (gave up the USB input to convert to another coaxial input). It was shipped out on Saturday afternoon and arrived in Singapore at my doorstep on Monday evening.

The order process was hassle free and the unit was well packed and arrived in good shape.

The DAC19 is based on two Burr Brown PCM1704UK DAC chips paired with Audio-Gd's proprietary DSP filter. Audio-Gd's principal, Mr. He Qinghua has made an announcement that he is discontinuing his products based on the PCM1704UK due to difficulties in obtaining supply of the chip. That was enough reason for me to take the plunge.

You can refer to http://www.audio-gd.com/Pro/dac/DAC19/DAC19EN.htm for full technical details.

The DAC-19 in finished in a shoe-box sized case that is rather utilitarian. The case is decently finished and will not win any prizes for either fit or finish. Given its asking price and performance, this is acceptable to me. I can do without paying a lot more for a snazzier case that does nothing for performance. There is a little bit of free play on the front selector switch, but otherwise, the rest of the switches and jacks are functional and do the job.

It has been suggested elsewhere that the DAC-19 is not particularly sensitive to quality of transport, digital cables etc, or power cables, by reason of its powerful jitter reduction and power supply quality respectively. I believe that it is wrong to disregard those factors and use of the DAC-19 over the short time I have had it suggests that strong dividends may be reaped by paying careful attention.

Transport duties were handled by Slimdevices Squeezebox 3, linked with Oyaide's DB-510 digital cable. Out of the box, the DAC-19 sounds detailed and resolving in the midrange and high-frequencies, albeit sounding a bit bleached and light weight. Bass in particular is not deep or impactful and the overall balance is a bit dry. Things changes drastically after extended burn in, with vast differences heard past the 50 hour mark and 200 hour mark. New owners who suffer from buyer's remorse upon hearing the DAC-19 would be well served to persist in their burn-in duties and not give up !

Once well cooked, things become a bit interesting. Both the top and bottom end of the DAC-19 open up and you get tight tuneful bass, as well as extended and airy highs. What you do not get is any form of euphony or colour in its presentation.

Comparing the DAC-19 to my Lite DAC-50 was an academic lesson in extremes. First off, my Lite DAC-50 is quite extensively modded, with changes in the power supply as well as some circuit modifications in its tube output stage and coupling caps. Once modded, the Lite is rich, organic while sounding open and dynamic. It would be considered by most to be a musical sounding DAC. It also has a strong sonic signature and its richness of tone as well as its weighty and deep bass are obvious in all recordings.

The DAC-19 sounds neutral, rich or lean, depending on the recording. It seems truer to the recording than most, and as such will not help systems that are deficient in certain areas. As such, the DAC-19 would work best in systems that are already well-tuned for a neutral  source. Paired with the Acrolink 4020-7N power cord, the DAC-19 sounded a bit bright and thin. Changing the power cord to Acrolink's factory terminated 4030 power cord fixed this..

Similarly, a bit of tuning was needed in respect of the footers supporting the DAC-19. A trio of Finite Element's Ceraballs made the sound too forward. Replacing that with Golden Sound's DH cones struck the best balance between cleaning up the sound and adding some weight to the presentation of the DAC-19.

Describing the DAC-19's sound is more difficult than most equipment, because it does not seem to have any intrinsic sonic signature of its own.However, after extended listening, the one striking quality of the DAC-19 is its ability to resolve and present instruments and voices in the most complex of mixes in a coherent, well placed and separated manner. The Lite DAC has a tendency to spotlight the main vocals and principal accompanying instrument, with the other instruments relatively obscured. The DAC-19 resolves both well, with a surprising amount of low level detail that is not immediately apparent on other equipment.

For it's asking price, resolution of this nature is class leading. I am quite sure that a DAC of this quality with a Western manufacturer badge and snazzier case could easy cost 3 times as much as the Audio-Gd. If you are looking for a DAC that digs deep into your recordings and presents a true picture of what's there, you would be well advised to check out the DAC-19.






Pictures from Audio-Gd's official web-site

Postscript

My Audio-Gd recently started losing sound in one channel (December 2013) after 3 years of ownership. I loaned the unit to a friend and he was getting intermittent drop-outs that were almost impossible to recreate.

When I received the unit back, one channel was totally dead. I popped the hood and reseated the DSP board, and it works perfectly now. My guess is that despite being tightly screwed down, the pin connectors may develop contact issues over time. The movement during transport certainly didn't help. Worth a shot if you having problems with your unit.

Wednesday, September 8, 2010

Capacitor shoot out

Oh No ! Not another capacitor comparison test !

Actually, no one likes comparing capacitors. Do we really have nothing better to do in life but to swap capacitors in and out of circuit, burning in numerous capacitors just to find out how they sound ?

Right now, the stock Wima MKP10 output coupling caps in my Diva Audio M7 have been taken out and the wires soldered to alligator clips instead, to facilitate ease of swapping the caps in and out.

Unlike some testers than undergo thorough and scientific methodology, there was no blind testing, or gruelling 500 hours burn in test. Neither are all caps of identical value because many of these caps just happen to be lying around for trial. But according to my calculations, all of the capacitors tested are large enough in value to not cause any audible degradation to the bass response in my system.

I also happened to need to conduct some tests on the power supply, so some of these caps were used as a bypass cap in the last stage of the C-L-C power supply of my M7. The values used weren't consistent, and the listening notes there are included just for interest and completeness sake. I've included some of my personal experiences of these caps for crossover use too.

Please do not use any of these capacitors in AC mains filters - they are not properly rated for such applications !

The line-up (in no particular order) :-

1. Clarity Cap ESA
2. Solen Fast Cap
3. Auricap
4. Obbligato Gold Premium Cap
5. Jantzen Superior Z Cap
6. Mundorf M-Cap
7. Mundorf Supreme
8. Mundorf Supreme Silver in Oil
9. Mundorf Supreme Silver / Gold
10. Ampohm Paper-in-oil Tin Foil


(Top Row, Left - Right, Solen, Obbligato, Clarity Cap, Auricap, Mundorf M-Cap)
(Bottom Row - Left - Right, Jantzen, Wima, Mundorf Supreme, Mundorf Silver / Gold, Mundorf Silver in Oil)

For a value reference, here are the online prices of the above caps for 1.0 uF in USD arranged in order from the cheapest to the most expensive.

Solen                                               $1.76
Mundorf M-Cap                              $3.54
Wima MKP10                                 $4.00
Clarify Cap ESA                              $8.90
Obbligato Gold Premium                $10.50
Jantzen Superior Z Cap                  $12.00
Mundorf Supreme                          $20.00
Auricap                                          $21.50
Ampohm Paper-in-oil Tin Foil        $29.95
Mundorf Supreme Silver / Oil         $48.00
Mundorf Supreme Silver / Gold      $68.00

Stock Cap - Wima MKP10

Absolutely nothing wrong with the Wima. The MKP10 is a common sight in quite a lot of expensive equipment and instantly recognisable by its red rectangular box appearance. I know that T.S. Lim of Diva Audio favours this cap for its neutrality and dynamics.

It is a neutral cap and in the wrong systems can sound a bit lean. It is quite open and gives the impression of an overall lack of euphony or bloom. Although it has a relatively smooth midrange, when things get busy, the midrange can take on a bit of glare and hardness. In such situations, the treble becomes a bit tizzy and messy. This was made very obvious when going back to the Wima from the Mundorf Silver / Gold.

In terms of soundstage depth and presentation, the Wima is like sitting close to front row. Mundorf capacitors in comparison are more like sitting in the middle row.

Clarity Cap ESA


A very pretty cap and its metal foil body looks impressive. Initial impressions are that of a very dark capacitor with recessed midrange and not much treble extension. Thankfully, after a few hours of burn in, things improve  quite  lot.

This is an interesting capacitor. It has a weighty mid-bass that gives lower piano notes good solidity and feel. Vocals sound inviting and smooth, with almost no trace of sibilance on the usual problem tracks. Further listening reveals that the midrange is recessed and slightly less resolving as the Wima MKP10. Unlike the Wima MKP10 that has a dry and honest treble, the ESA has an airy treble and high frequency sparkle that highlights the decay of cymbals and high hats, and "enhances" the sense of acoustic space in recordings.

This could be an ideal cap to tame overly bright and lighweight sounding systems without making the overall presentation too dark. Given its relatively modest price by high end cap prices, this cap has plenty going for it.

Auricap

Auricaps come is a nice bright yellow wrapper and have insulated multi-stranded leads, one of which is black and the other red, presumably to differentiate the outer foil of the windings from the inner foil.

Audience, the manufacturer of Auricap, recommends that the signal enter through the black lead and exit through the red lead for signal coupling purposes, which is the way I installed them.

Moving from the Clarity Cap ESA to the Auricap restored my system back to the same tonal balance as the stock caps - neutral. Don't make hasty conclusions about this cap. For the first two hours, although it sounded neutral, high frequencies had a strange wobbly quality, a bit like tape speed variation. After about five hours, this more or less disappeared.

Compared to the Wima, the Auricap has a smoother midrange but a neutral balance through the whole audio frequency spectrum. The ESA has more air and high frequency sparkle than the Auricap. You can say that the Auricap does nothing wrong, but look elsewhere if you are looking for a cap to colour the tonal balance of your system.

Used in the power supply, this falls somewhat between the Solen and Mundorf Supreme. Definitely more open sounding that the Solen, but it doesn't quite have the musicality or openness of the Mundorf.

Mundorf Supreme

The Mundorf Supreme is the bottom of the Supreme range and is physically huge for its rated value. This is probably some part due to its induction free design which effectively uses two capacitors in series within the same casing. Do check the space available in your casing before you buy !

The Supreme ended up with a little more burn in than usual due to a strange phenomenon. The first few hours were fantastic ! Smooth, liquid and the most beautiful and lingering decay from notes. Things then took a turn for the worse, with the caps entering into a decisively unhappy state - the midrange in particular was hashy and grainy.

Way past the 10 hours mark, things began to settle down and serious listening could commence.

Coming from the Auricap, the Supreme was on the other side of the fence, highly musical, entertaining and perhaps not the most accurate sounding of capacitors. Although the tonal balance is quite neutral, the Supreme has a very polished and refined midrange with the right amount of meat throughout the frequency range. Musical notes are presented with texture and fine nuances, making the Auricap sound dry in comparison.

Easily the most pleasing of the caps tested this far, the Supreme combines the weight and treble extension of the Claritycap ESA with the speed of the Wima MKP10. Coupled to its highly resolving and musical nature and affordable price, do consider the Supreme for your next purchase. To nitpick, the only criticism against the Supreme against its competitors so far would be a slight loss of resolution in extreme high frequencies, and its artistic rather than honest approach towards music. The latter point is subjective anyway and you may personally have a preference for this.

This cap is also very good in power supplies. Apart from weight, it has speed and bloom.

This is also my favourite capacitor for crossover use.

Mundorf Silver/Gold


The Mundorf Silver/Gold sounds remarkably like the Supreme. What does spending 3 x more get you ? Highs are more extended with a better sense of air and resolution. Midrange has a warmer glow to it. Overall this cap sounds slightly more liquid, a bit like how the Supreme sounds initially (the subject cap here is very well run in since it is on loan from a friend who has put considerable hours on it) However, despite the subjective improvements, the value proposition is hard to argue. If funds are unlimited, this is a moot point. But if you have a choice between choosing the Supreme for 3 critical locations, compared to using the Silver/Gold for just one critical location, I would choose the former without hesitation.

Mundorf M-Cap

Compared to the Wima, the M-Cap sounds softer and more rounded. As a result, dynamics suffer a bit, with bass notes lacking in impact and extension. The Wima sounds a lot more open in comparison although the M-Cap does have a pleasingly smooth midrange. Unfortunately, the M-Cap sounds smooth yet has a sibilance problem in the midrange. In the upper frequencies, this cap sounds dry and restricted. The treble also has a tendency to get splashy when things get busy. The only conclusion I have is that this cap is probably more suited for some other application and is not suited for high voltage coupling use. This is the only cap so far in listening tests that make you want to reach for the power switch !

Mundorf Supreme Silver / Oil

What a breath of fresh air ! Coming from the M-Cap, the Mundorf Supreme Silver in Oil is a treat for the ears. The Mundorf Supreme family of capacitors have a distinct family sound. The Silver in Oil is much more liquid and open compared to the Supreme. I actually prefer this to the Silver / Gold. The Silver in Oil is very extended at both ends with excellent microdetails in the midrange and high frequencies. It is also exquisitely refined with an excellent balance struck between being analytical and musical. It lacks the midrange glow of the Silver / Gold but is more even throughout the entire frequency band. At all times, it sounds effortless and natural. Strongly recommended !

Obbligato Gold Premium Cap

Initial impressions during burn in time were quite promising. A very even handed performer with a neutral balance and good detail throughout. Balance wise, this reminds me of the Auricap the most except that the Obbligato has more extended and wetter highs. Midrange is pleasingly smooth without being muffled and there is plenty of information being conveyed in a tidy and controlled fashion. The Achilles' heel of this cap is its bass which is slightly rounded and not particularly deep, especially compared to the Mundorf Supreme series. This results in a somewhat lighweight sounding presentation. That being said, this is a very good cap, especially considering its competitive price. Subjectively, I feel that except for the bass issue, the Obbligato is more pleasing than the Auricap at a much cheaper price.

Jantzen Superior Z-Cap

The Jantzen Superior Z-Cap struck me as being remarkably similar to the Obbligato except for two material differences. Firstly, the Jantzen has a more extended and prominent bass, and high frequencies are fractionally more open and extended. With outstanding neutrality from top to bottom at a modest price, this is a very good cap with excellent price to performance ratio. From a subjective point of view, I prefer this slightly over the Obbligato. If the Obbligato could be said to be a wee bit off neutral towards the warm side, the Jantzen is a wee bit off neutral towards the cool side. My usual comment on neutrality applies, the Jantzen communicates the signal with an even hand - look elsewhere if you are looking for added “spice”.

Solen Fast Cap

According to common Audiophile wisdom, using a cap like Solen in signal carrying duties earns you a one way ticket to the Audiophile Hall-of-Shame. Well, surprise, surprise. Maybe using Solen caps is not the Audiophile faux-pas it is made out to be. The Solen can best be described as inoffensive but not particularly inspiring. On the plus side, it is smooth and pleasant. You can listen to it and fall asleep. Comparisons to the other caps  show that the Solen looses some low level information, with high frequency air and information being most obviously affected. The overall outcome is not life threatening and Solen would probably do fine for limited budget projects. In the test set-up, it fared better than the Mundorf M-Cap. Sonically, its second from the bottom of all the caps here on test. To put things in perspective, given its almost giveaway cost, you could do a lot worse.

This is quite decent in power supply use, with a big and chunky sound.

Ampohm Paper-in-Oil Tin Foil


Words cannot describe how big this capacitor is. I was filled with pride when my package arrived from the distributor of Ampohm, www.audiocap.co.uk (great buying experience - try them !). I excitedly  showed my partner the oil filled capacitors that looked more like a smoke grenade. Don't even think of using them in tight spaces.


 Ampohm capacitor with a Solen cap of the same value for comparison.
You didn't think I was joking about the size did you ?

The Ampohm sounds quite good. Good enough to fall nearly at the top of the heap. Taking into account its relatively affordable price, this is quite an achievement. Unlike vintage paper-in-oil caps or some other current production brands, the Ampohm manages to sound rich, liquid and extended at the same time. Its tonal balance is similar to the Mundorf Silver / Oil or Mundorf Silver / Gold. If compared side-by-side, the Ampohm sounds "blacker" with very silent quiet passages. Initially, there is an impression that instruments like cymbals and high-hats have less detail and decay. However, after extended evaluation comes the realisation that such instruments are equally detailed and extended but put in less stark contrast compared to the Mundorf Silver / Oil. Value for money wise, the Ampohm definitely beats the Mundorf hands down. Although I still prefer the Silver / Oil, I can imagine that the Ampohm could suit other systems better. Highly recommended !

This capacitor also works quite well in speaker crossovers, especially in the tweeter circuit.

Conclusions

Despite having personal preferences, it is worth stating that most of these capacitors would do perfectly well in all but the most critical applications. My favourites at the end of this test are :-

Cost-no-object - Mundorf Supreme Silver / Oil. Close runner-up, Ampohm Paper-in-oil Tin Foil.
Best of the rest - Jantzen Superior Z-Cap, Mundorf Supreme, Obbligato Premium Gold

For the selection of the best of the rest, it is a bit like baby bear's porridge - the choice of "just right" depends on your system. Jantzen if your system needs a wee bit opening up. Obbligato if your system is just right. Between these 3 caps, the Mundorf is for the heart (emotionally expressive) while the Obbligato and Jantzen are for the mind (neutral and truer to source).

Tuesday, August 24, 2010

Virtue Audio M5001 Monoblock amplifier

Virtue Audio is the new kid on the block in terms of manufacturers offering ICEpower based products.

ICEpower is by now quite established and there are many companies out there offering amplifiers based on their modules such as Bel Canto Design, Wyred4sound etc.

I normally do not write detailed reviews but was suitably motivated by the M5001 which avoids being a “me too” product by virtue (no pun intended) of its tube buffer supplied by Dodd Audio.

The M5001 is based on the ICEpower ASP500 module, which delivers 250 watts per channel into 8 Ohms and double the power into a 4 Ohm load. The ASP500 module includes a built in switching power supply and accordingly runs cool and efficiently.

The stock module input impedance is raised from 8 kohm to 100 kohm due to the tube buffer. This presents a much easier load for preamplifiers to drive, in particular tube based designs.

Appearance wise, the M5001 is quite handsome with a well finished case and lovely real wood veneer top. A variety of finishing options are available to customize the look of your amplifier. Round the back, an IEC power socket accepts detachable power cords, and input is via either an RCA or XLR balanced socket. A subwoofer output is provided.

The speaker binding posts deserve a special mention. The propeller posts make finger tightening a breeze. Both the binding posts and RCA socket are said to be made from gold plated Terrilium copper.

It is not quite the epitome of hi-fi bling-bling, but is certainly well finished enough to be proudly displayed on your equipment rack.


(Pictures from Virtue Audio's official web-site)
Dimensions are not quite shoe box like, with the width of the amplifiers being about 10 inches across. This makes placing each monoblock side by side a bit tricky for most equipment racks as you will find that the support columns will either block the AC inlet on the left of the unit or the input jacks on the right. The supplied feet are metal discs that screw into the chassis. As they project out of the chassis footprint, this makes each monoblock occupy a fair amount of real estate. The feet are easily removed though if you so wish.

Let us re-visit my impressions of ICEpower over the years :- extremely tight and powerful bass, high resolution and detailed midrange and treble, effortless presentation. The downside ? Dry midrange, lack of treble air and 2D like image.

After about 15 hours of burn in, and with the stock JJ 12AX7/ECC83 tube installed, serious listening sessions were conducted.

Preamplifier duties were handled by Diva Audio’s tube based M7. My M7 utilises a tube rectified and choke loaded power supply and has been upgraded to the latest specification by T.S. Lim with additional voltage regulators on the power supply and star ground wiring. The M7 can be best described as a linear and fast sounding pre-amp with both speed, dynamics and good bass authority.

After some trial with the speakers available at hand, the M5001 was matched with my main speakers, a Focal Micro Utopia BE.

The first impression was that of absolute control over both frequency extremes. Bass was tight and controlled.

Midrange is neutral with just the slightest hint of fullness.

High frequencies are extended with absolutely no loss of detail.

Resolution, in particular micro-detail is excellent with individual instruments in a mix being discernible even under the heaviest of mixes. One would be even tempted to flog the oft-used and abused audiophile claim of hearing detail in familliar recordings that went previously unnoticed.

The tube buffer would appear to mitigate much of the criticism I had against ICEpower. Images are fleshed out with proper depth while treble air and the sense of acoustic space are delicately conveyed. I did not see any downside from the installed tube buffer since all the things I liked about the stock module remained – no slowness in transients, or loosening of bass grip.

All that being said, this is by no means a tube-like amp. If you want tube liquidity, get a tube amp – this is not going to float your boat. The tube buffer does not honey coat the sound, it imparts a subtle warmth and organic flow to the dry sound of the stock module. Tonal balance wise, it still remains on the right side of neutral.

Choice of tube used in the buffer as well as pre-amp used could go a long way to tuning the sound the way you want. As far as I am aware, the M5001 can be used with most of the 12A*7 family tubes, enabling fairly cheap and flexible tube rolling, since you can avoid the insane pricing in the 12AX7 family and go for cheaper equivalents in less popular families like the 12AT7 for example.

Hyper-detailed and analytical with the subtle touch of liquidity and warmth – coupled with loads of power to control almost any speaker out there on the market. Take into account its relatively modest price, and I think Virtue Audio has an absolute winner on its hands.

Saturday, August 21, 2010

Acrolink 6N S-1400II speaker cable

The Acrolink 6N S-1400II sits about mid-way up in Acrolink's 6N speaker cable range and is a large gauge version of the S-1000II.

Full specifications of the S-1400II can be found at

 http://www.acrolink.jp/english/products/6n_s1400_2.html

(Picture from Acrolink web-site)

The S-1400II is a heavy but flexible cable and termination into your plug of choice is not difficult. There isn't much buzz about Acrolink speaker cables compared to their power cords (the 4030 being the most prominent of their line-up) and interconnects to a lesser degree.

If you have a look at my previous forays into the Acrolink family, I have come to a personal conclusion that Acrolink has a house sound - a delicate midrange and a high frequency extension and air that is not sonically neutral but artistically beautiful.

The S-1400II has the same delicate and refined midrange but a harmonically rich and heavy mid-bass and bass. In a complete Acrolink set-up, the combination works very well to add weight to the bottom end of the spectrum (which is not an Acrolink strength) as well as to keep the highs under control. Substituting out the S-1400II for a pair of Clear Day Audio Double Shotgun or a Goertz AG-1 (both cables are co-incidentally pure solid core silver cables) tipped my main system (Focal Micro Utopia BE) into excessive high frequency energy and harshness.

However, using the S-1400II in another darker system was far too much and the overall result was a shut-in sound that had the speed of molasses.

I suppose the difficulty in matching the S-1400II accounts for the number of used pairs up for sale (at steep discounts mind you) on local hi-fi forums. It's laidback and rich presentation mandates careful deployment. Unlike some other harmonically rich cables like the Canare 2S16 and 4S8 though, the Acrolink is far more transparent and resolving.

I have noticed that when using Acrolink cabling in pre / power set-ups, better results were obtained in my system by using a single Acrolink (A-2070II) between source and preamp, and an Acoustic Zen Silver Ref-II between the preamp and poweramp. This was better compared to using an Acrolink 2400II in place of the Acoustic Zen.

If you are interested in Acrolink speaker cables, have a look at my short write-ups on the 7N S-1000III and 7N S-1400III.

Conclusion - Very nice cable at current low second hand prices, but probably suitable only for full Acrolink setups or in overly forward and bright systems.

Saturday, July 31, 2010

Marantz CD6003 modification

I managed to acquire an almost mint condition pre-owned Marantz CD6003 recently. Brand new, this CD player is priced at a modest SGD 388 in Singapore, pricing it in the mid-entry level category.


Once upon a time, long long ago, a CD player of this build and sonic quality would cost at least two to three times the retail price of the CD6003. It's nice to see that the price of quality kit like this has come down over the years.


The CD6003 is quite a handsome player and has good build and heft (slightly over 5 kg). The chassis is fairly rigid with a double layered bottom plate and compared to the SA8003, the immediate giveaway in cost cutting is an extremely flimsy CD tray.


Based on the Cirrus Logic CS4398 DAC and Marantz's proprietary HDAM SA2 analog output stage, the CD6003 packs fairly advanced technology for a player of its modest price.


An IEC socket permits you to play around with after market AC cords if you wish.

Popping the hood yields no surprises, with three circuit boards connected by ribbon connectors. The left board is the power supply section with two separate power supplies. one linear and the other switched mode.


The center board controls the transport and the right board contains the DAC (hidden on the underside of the board) and analog output stage. The analog output stage is Marantz's HDAM SA2 circuit and is basically a discrete transistor circuit. 



There is a lot of information out there on modding Marantz CD players, the most famous being the infamous CD63/67 modification thread on DIYaudio. Limited this time by lack of a service manual, I decided to just do a few tweaks that were easy and bang for the buck. The CD6003 is intended for use in my office and I did not wish to spend too much time or expense in this project. Besides, if I wanted a reference class CD player, I would have bought a better one to begin with.


Over the years in modifying Marantz CD players, the most dramatic difference in my humble opinion comes from upgrading the DC blocking capacitors. So far, the Marantz players I have handled (63, 17MkIII and now the 6003) use a pair of Elna electrolytic caps back to back to make them non polarised. Usually I bypass them completely after determining that there is no DC offset. Unfortunately this time around, DC offset was quite high at 150mv. I don't usually try film capacitors in this location due to space limitations and the high value needed to avoid bass roll off. So, a pair of 6.3V 22 uF Rubycon Blackgate HQ NX non polarised caps were used to replace the existing 4 Elna Silmic caps used. I also usually remove the muting transistors, but decided to leave them alone this time.


Next, came the digital power supply to the CS4398 DAC. The local decoupling cap was changed from a 100 uF Koshin cap to a Sanyo Oscon cap of the same value. The stock circuit bypasses this cap with a small ceramic cap which I left in circuit. I have very good experience with the Oscon in digital power supply decoupling and cathode resistor bypass applications.


I also added some blu tack on the oscillator crystal, the CD transport bridge and the transport frame (not visible in my pictures).







  
Total cost of the modifications is less than SGD 20.


Extended listening was done to the modded and unmodded player on my main system which consists of  Focal Micro Utopia BE speakers driven by the Cary SLI-80 Signature Special Edition. Comparisons were also made with my usual CD player, the CEC TL-51XR.


In stock form, the 6003 is a competent player that punches well above its price class. It's sins are one more of omission. It is a smooth sounding player with decent bass and high frequency sparkle. Its failings in comparison to more accomplished machines are a lack of solidity, and somewhat homogeneous presentation of detail. 


Observations made using my regular test tracks :-


1. Eva Cassidy - Fields of Gold : Compared to the CEC, Eva's voice was somewhat vague in imaging. Her accompanying guitar was somewhat lacking in bite and body and blended into the background. There was an obvious lack of retrieval of ambience from the recording - the acoustic space from this track which was recorded live at The Blues Alley was not well conveyed.


2. Patricia Barber - Summer Samba. The percussion work about a minute into the track did not have the shimmer and air of the CEC. The fine detail in the high hats etc were not well separated and sounded somewhat lost in the mix. Piano notes were not realistic as they sounded a bit plasticky and lightweight.


3. Rebecca Pidgeon - Spanish Harlem. The sound of the shakers was quite similar. On the CEC, each shake was distinct and varying in image height and volume.


After modification and about 20 hours of burn in.


1. Eva Cassidy - Fields of Gold : The center vocal image is dead center. There is an overall increase in resolution with each pluck of the guitar being more distinct. Vocals are more distinct and Eva's voice has distinct varying shares of texture.


2. Patricia Barber - Summer Samba. The fine details in the high hats were better separated and the shimmer and air improved. Piano notes become a little more solid and more stable in pitch.


3. Rebecca Pidgeon - Spanish Harlem. The differences in each movement of the shaker was more easily discernible.


In summary, the modifications improved midrange transparency and  ambience retrieval. Vocals seemed to benefit the most, with the homogeneous nature of the stock player being significantly improved. Although there was increase in weight and solidity of the upper mid bass, the low bass notes did not seem to be improved by the modifications.


The subjective quality of the player was significantly improved but still quite far from the CEC. In separate listening sessions, the differences were quite liveable, but instant A/B comparisons showed that even modded, the 6003 was no CEC slayer.


Lastly, I tried a trio of Finite Element's Ceraball footers under the 6003. The improvement in quality was shockingly good and at least equal to the cap modifications. If we consider the 6003 in stock form to be about 40 % of the quality of the CEC (not bad if you consider that the CEC is more than 4x the cost of the 6003), the cap mods and Ceraball would bring the 6003 to around 60 % of the quality of the CEC.



Wednesday, July 14, 2010

Cary Audio SLI-80 Signature Special Edition

Cary Audio's SLI-80 Signature Special Edition amp is now in the house !

Jaguar blue finish.

Output tubes - KT88, 6550/KT88, EL34, 6CA7. Choose your favourite poison.
Rear socket and trim pots are for bias adjustment


WBT Binding Posts
Also functions as a headamp. The headamp runs through the tube circuit and is not the usual separate opamp circuit

Initial impressions were that of a very powerful sounding amp with good grip on the bass (not always a given with tube amps), but a slightly coarse midrange and moderate resolution. Thankfully, the sound opened up and the coarseness disappeared after a few hours of play time.

It runs even hotter than my Cayin A-88T which tells you something !  Don't even think of placing this in an enclosed cabinet.

Like the Cayin, the SLI-80 is based on a pair of KT-88 power tubes per channel in push pull configuration, with 6DJ8/6922 (the Cayin uses 6SL7 tubes here) input tubes and a 6SN7 phase splitter. The SLI-80 may also use KT-66, 6550 and EL-34 power tubes. Power output using KT-88 tubes is 80 watts per channel in ultralinear mode and 40 watts in triode mode.

The power supply is choke loaded and tube rectified by a pair of 5U4 rectifier tubes. 

Noteworthy features include basic remote control, switchable triode / ultralinear mode and a headphone output (run from the tubes and not opamp based).

Stock tubes supplied were EH KT-88 power tubes, EH 5U4GB rectifier tubes and EH 6922 input tubes. The 6SN7 tubes supplied were labelled Cary but internally look exactly like Chinese Shuguang 6SN7 tubes.

The Cary labelled 6SN7 tubes were soft, warm and not particularly open, so they were quickly substituted with EH 6SN7 tubes, which resulted in a fairly bright and fatiguing presentation. The EH 6922 tubes were substituted with NOS Mullard tubes, and the EH KT-88 tubes were replaced by Genalex Gold Lion re-issues. This resulted in a fuller and more liquid presentation.After some experimentation, the EH 6SN7 tubes were replaced with GE 6SN7 GTA vintage tubes.

Driving my Focal Micro Utopia BE speakers, the Cary sounded best in triode mode. Ultralinear had more slam and authority but sounded a bit rough and bright in comparison. Strangely, my Cayin A-88T sounded better with the same speakers in ultralinear mode.

The Cary seems quite hard on the rectifiers, and I experienced arcing more than once when switching the amp on. Some audio forum posts suggests that this is due to excessive capacitance being used immediately after the tube rectifiers, but I won't comment on this since I did not open the amp to check the power supply layout.

I also do not like the stock equipment feet which feel and look like sorbothane feet. In tropical weather, they turn greasy and sticky rapidly, leaving unsightly marks all over your rack.

Sound wise, these problems are rapidly forgotten. This amp sounds wonderful. It is certainly not the most transparent amp around, but it did have just a smidgin more resolving power than the Cayin A-88T it replaced. What is gains over the Cayin is a much bigger presentation in the form of a very expansive soundstage and excellent bass authority (for a tube amp). The Cayin projects a flatter soundstage, with image sizes comparatively smaller. 

Compared to my Almarro A-318B, the Cary has a warmer and thicker midrange and more extension and air in the high frequencies.

Tone is also more forgiving, with a more liquid and easy going presentation, without sounding dark or shut-in. In comparison, Cayin amps have a more solid state like sound, and may even be argued to be more neutral. If you prefer a slight rose-tinted glow to the midrange and the "wet"type of highs, look at the Cary first !









Wednesday, June 23, 2010

Acoustic Treatment

The listening environment is one of the most important "components" in the hi-fi chain that is often overlooked. How a speaker interacts with the room it is placed in will have a dramatic effect on how it sounds to the listener.

In space scarce Singapore, most of us (except for the really lucky / well-heeled ones amongst us) have to make do with placing our audio setup in either the living room or a fairly small spare bedroom.

The typical public housing flat bedroom in Singapore measures about 3 x 4 meters. This necessitates keeping the system small, choosing speakers that do not acoustically overload the room, or resorting to room treatment methods, or a combination of all of the foregoing.

Why does the typical audiophile neglect room treatment ? Laziness ? Cosmetic issues ? Possible irate spousal response ?

Anyway, I have just revamped my listening room and taken the opportunity to acoustically treat my listening room. Unlike American homes, walls in Singapore are almost always built from brick, concrete and plaster. This results in hard reflections and a bit of bass boom.

Room treatment options in Singapore are quite scarce. Professional products are expensive due to the economic inefficiency of shipping large heavy items from American and European audio manufacturers.

DIY is an option, but lack of a garage makes construction a bit tricky. Materials such as wood and rockwool are available but require a bit of effort to track down and transport.

In consultation with Joamonte (resident acoustic treatment expert - you will find him on Singapore hi-fi forums like Echoloft (gone with the wind) and Xtremeplace, treatment was only done on one side of the room, directly behind the system. The treatment consisted of a combination of diffusor and absorption panels.



According to Joamonte, treatment of all the early reflection points could result in the system sounding too dead.

Acoustically, my listening room is not particularly troublesome. It is modest sized (about 3 x 3.5 meters), and has a fairly high ceiling. It is a regular rectangle shaped room, but is acoustically not fully closed on one end, as the wall is made out of plasterboard.

Nevertheless, the room is a little live sounding, and imaging and staging is not as sharp as it should be.

A total of 8 diffusor panels and 2 absorption panels were deployed. The two absorption panels were placed in the corner of the room, at ear level. The diffusor panels consisted of both an early model sold by Joamonte and his current production, which utilises plastic wells placed in a frame. Not much low bass treatment was required as my system does not go very low, probably no lower than 40 Hz.





























































Verdict :- Great stuff. Soundstaging and imaging are much improved. The tonal balance of the system was not affected much. Some of the obvious improvements were,

Midrange, especially female vocals – female voices were less sibilant and the level of grain was reduced.

Background – much quieter, with very low level detail retrieval becoming much more obvious. Most importantly, the lowering of background noise did not affect the “air” of the system.

Air / Ambience – The sense of air around instruments, and the fade / decay from the initial transient note of percussion and brass instruments were more prominent and longer. This seemed odd as I would have thought that acoustic treatment could have the unwanted effect of reducing this.

The panels were made by a carpenter to Joamonte’s specifications. He has also made some measurements of the room to demonstrate the difference between the treated and untreated room.

It is amazing how spending a relatively modest amount (S$1,600) could change and improve the system tremendously. Instead of spending money on expensive cables and footers, perhaps some attention should be paid to acoustic treatment.

Here are the measurements of the room with and without treatment.

Monday, June 21, 2010

An update much overdue

Rather unfortunately, it has been ages since I have last updated this blog. There have been lots of changes to my system and lots of new accessories to be covered. Stay tuned for updates on acoustic treatment, the Acoustic Zen Silver Reference II interconnect, Telos RCA caps and speaker post plugs, and much more !