Saturday, April 30, 2005

CD vs. vinyl comparison, Tact Audio news

Source: Hi-Fi World June 2005

Hi-Fi World is vinyl and DIY oriented British hifi-magazine. It used the be printed in true DIY fashion as well ;), although quality of both format and articles has gone up a notch lately (my humble opinion). The magazine has been labelled as "digital-sceptic", though they prefer more relevant classification "digital-realist". What can be said in all fairness is that the magazine has kept vinyl focus alive in the UK during the last 15 years - which is good. Some idiosyncracies still prevail (e.g. David Price's fixation to mention superiority of his Yamaha NS1000M speakers in everything he writes). But as said, since they have been in publishing business more than 15 years they must provide something worthwhile for your readers.

The "The Digital Issue" has some worthy articles. The overall theme was "digital is finally showing real promise" - and personally I fully agree with this assessment. The first article of interest compared full Clearaudio system (Champion Level 1 turnrable, Unify arm, Symphone MC cartridge, Basic Symmetry phonestage) with French Metronome Technologies' CD3 Signature cd-player. As both companies make pretty striking HE-products (witness Metnonome's Kalista transport), for Clearaudio chosen combination can be said to be representation of entry++ level and in Metronome's case CD3 is merely an entry-level product (some entry at €6.000).

As expected, both products had their own charasterictics and were recommendable for their ability. However, review picked out cd-player as a winner. "To my ears, the Metronome digital player wins because it communicated the music more emotionally..." and continued "utterly wonderful as it was, the Clearaudio did not appreciate all the recordings' identity... I ultimately preferred it (Metronome) because it didn't lessen a recording's individuality. This is very important to me."

Viewpoint: Nice to agree with a reviewer once. "It didn't lessen a recording's individuality" equals in my books proper transparency and resolution of the unit/system. So often people mix-up what I call "artifical transparency" (enhanced digital resolution, top hot cd-player or speakers) with true, honest resolution - which I interpret as capability to illuminate even smallest nuances, ambiance noises, resonances and decays of instruments etc. In short, all those subtle, delicate sounds, which make every record distinctive and overall makes listener to connect emotionally with recording. However, having followed up vinyl gear lately with great interest, my opinion is that for a chosen budget some other analogue combination might have sounded more involving. Like what? Try Mitchell Gyro SE with Techno Arm or Thorens 850, Lyra Dorian, Sumiko Blackbird or Benz Micro cartridges, and GSP Audio Era Gold mk.V combinations.

The second point of interest in June issue was review of Tact SDA 2175 semi digital amplifier. SNA2175 has 200wpc 8ohm, SE/balanced in, analogue input stage and digital output stage. The price within the EU hovers around €1.100. Hi-Fi World said: "...superbly smooth, well proportioned, and insightful ... tremendous detailing... its treble is silky (like Japanese high-end) and spacious, its mid-band refines the concept of "class clear", bass is strong and tuneful....At the price, I have heard nothing - but nothing - that approaches this blend of competencies." German Stereoplay gave to its integrated variant SDAi 2175 in December 2004 respectable Spitzenklasse (49 points) classification.

Viewpoint: Having owned for 6 months Tact RCS 2.2x digital pre-amp/room correction system I need be persuaded that Tact Audio product are worth considering. For the money Tact asks for its products my experience is that they use second-rate componenets, especially power unit in RCS 2.2x was deplorable. Need proof? French distributor of TACT, DIRAC, has long recognise that Tact units needs tuning, and they offer modifications to various Tact products, for example to integrated S2150 (Black Gates caps, external clock input, modifications to analogue-in...). My opinion, all needed mods, but they also double the retail price to €3.600.

However, to be objective I have to note that DIRAC modified S2150 managed pretty well in Prestige Audio Video March 2005 issue where they tested 5 digital amplifiers. Shared top reviews with Audio Research 300.2 and 3D-Lab S300.

BTW, Tact Audio's April press release stated as follows: "All future products from TacT Denmark will be renamed to Lyngdorf Audio. Lyngdorf Audio will continue to develop groundbreaking audio products with outstanding performance. Lyngdorf Audio will be sold worldwide through the finest specialized retailers." Interesntgly, at the same time Tact Audio USA Web site has information of new company called Boz Audio. The Boz products seem to be re-branded Tact products, and geared towards multi-zone, home-theather installations. Confusing? The way I read it, founders have split the company, but both continue to sell (how long?) products under Tact brand. Since the key feature of all Tact products is software updates, it'll interesting to see who provides updates on various markets. No wonder prices for Tact products vary recently so much (French distributor advertise full loaded RCS 2.2x for €1.990, it used to be over €8.000!).

Friday, April 29, 2005

Moscode 401HR hybrid amplifier

Intersting looking product from Moscode, in particular for tube rollers as this hybrid can use a wide range of front-end driver tubes (see picture below). The auto-biasing circuit accepts 6H30Pi, 6GU7, 6DJ8, 6922, 6FQ7, 5814, 7730, or 12AU7 tubes!

Saturday, April 23, 2005

Denon DVD-A1XV universal player and jitter

Source: Hi-Fi News May 2005

For the readers of this blog it should be evident that I'm not a big fan of new, multimedia formats and universal players.

Hi-Fi News has, at least to my knowledge, performed the industry's first measurements of various digital links. Subject to review was praised Denon DVD-A1XV universal player connected to Denon AVC-A1XV AV-receiver - a combination of which multi-channel advocates have wet dreams. Check this out: Denon-to-Denon via HDMI incurs jitter at 4560psec; Firewire connection a whopping 275,600psec (!) and Denon-link delivers 1260psec of jitter.

Viewpoint: First, please, show me from any product category a universal, "convergence" product, which performs better than dedicated units. And second, cold shower for all those who claimed that HDMI connection will ridicule audiophiles by making investment in cables unnecessary.

UPDATE: In June 2005 issue Hi-Fi News returned to this issue. They tested Pioneer DV-868Ai universal player with Pioneer VSA-AX10Ai multichannel amplifier. Although CD and DVD-A jitter measurement were OK with both i.LINK and HDMI connections (some 250psec), transmitting audio from DVD video was another matter. They measured jitter of 25.000psec. Evidently the reason is that with video DVDs the sync-lock Pioneer is using is defeated. What to do? Transmit digital video by HDMI/DVI or FireWire but stick to S/PDIF for the bitstream audio.

For more information, visit Miller Audio Research Web site.

Wednesday, April 20, 2005

Response Audio offers 220V modified amps

Response Audio is well-known by Antique Sound Labs modifications. As of early 2005 the company is offering 220v version of both ASL Monsoon and Hurricanes. The specs look intriguing: V-Cap capacitors, Riken and Dale/Vishay resistors, Bybee Quantum Purifiers, etc. Plus, both ASL units have both SE and balanced inputs. You can even get custom color finish for USD 250. Prices seem to be reasonable (around USD 5000 for a pair of Monsoons), however the EU import add some 20% on top of the bill. Fabulous gear, only downside is that fully modified Response Audio "system will cause you to wet your pants." ;)

ASL Monsoon Extreme

Ming-Da preamps owners or anybody participating in "self-import from China" phenomenon. Check the extent of modifications available from Response Audio for this inexpensive pre-amp.

Wednesday, April 13, 2005

Aesthetix Calypso - what is going on?

Source: Absolute Sound. Robert Harley nominated this tube pre-amp as "linestage preamplifier of the year" (for 2003) in TAS 146, and furthermore in full review in TAS 151 concluded: "In an era in which many lesser-quality components cost considerably more money, the Calypso and Rhea (dedicated phonostage) establish new value benchmarks in their product categories" and within the actual text "a remarkable achievement for a $4500 product. Frankly, had the Calypso cost $10k, I still would have recommended it. Moreover, the unit’s build-quality and feature set would have justified a much higher price. The Calypso is not only a world-class performer, but a stone-cold bargain." Read full review here.

Viewpoint: Very high appraise indeed for this "classic" tube pre-amp (6922s, 12AX7WBs etc.), actually almost made me purchase Calypso when I was evaluating new tube pre-amp for my system. The only thing keeping me not buying Calypso was its lack of adjustable gain, the feature I perceive must-have for system matching. For the record, I purchased Audio Research LS25 mkII.

Enter users' comment in AudioAsylum. Evidently this post is not an hoax, and the guy seems to own serious HE-rig. According to him, Calypso with stock Sovtek tubes is quite noisy. His experience was that Calypso really needs to be upgraded with pretty rare and expensive NOS tubes, in this case Mullard 10M Gold Pin tubes.

In the same post, Jim White from Aesthetix stated as a response "For about the first 6-8 months of production, we had almost no tube problems with the Calypso. Then, they started cropping up, as noise like you encountered. This was our worst nightmare, because we thoroughly evaluated the units before they shipped. They were going noisy after leaving our facility. We immediately started burning the tubes in longer and testing more thoroughly and stringently, but with little success. I looked into alternatives, but no tubes of current manufacture worked properly or to my satisfaction, so we stayed with the Sovteks and continued trying to find ways of culling tubes that would go noisy. Near the end of last year, we finally found a 12AX7 of current manufacture that sounded good and would remain noise free. We have since switched to that tube (Teslov E83CCS), and our tube noise issues have been drastically reduced."

If you read follow-ups, you see that quite many other users claimed that Calypso indeed requires NOS tube rolling in order to sound best (decent?) , in particular rolling the 12AX7 tubes. In fairness, majority of the Calypso owners absolutely love the sound , but as said, subject to NOS tubes.

Tuesday, April 12, 2005

MoFi 24 Karat Gold CD-R

Source: MoFi Web site


Anyone who has ever damaged a CD-R through abrasion or excessive exposure to heat or light knows that CD-Rs are an imperfect technology and it’s all too facile and common to lose priceless data. For ocassions when you can’t afford to endanger your data, Mobile Fidelity Sound Lab is proud to introduce the Ultradisc CD-R. Our 24KT Gold ULTRADISC CD-R is designed for professional, data critical, music and graphic archival applications, and all other data storage where there is no margin for loss or error. These specially-gold-plated ULTRADISC CD-Rs ensure excellent reflectivity, are non corrosive, and have dramatically enhanced resistance to light and heat. Additional features include instantaneous pit burning (burst burning) for superior pit formation and extremely low to no error rate; and an added, patented, scratch resistant, protective surface. Due to these features, little if any error correction is required upon retrieval of information, producing precise reproduction of stored data.Where as the average CD-R has a projected lifespan of only 20 years—if stored in ideal conditions, our accelerated aging tests predict that the 24KT Gold ULTRADISC CD-R will retain its specifications for more than 300 years.

Thursday, April 07, 2005

Isotek Tital power filter

IsoTek Systems is a British specialist of power filtering. Apparently they do know something about filtering as Nordost's latest offering, Thor distribution unit, was joint-developed with them and incorporates IsoTek's proprietary filtering technology.

The Gil Titan power filter was tested in April 2005 issue of Hi-Fi News: "During the time spend with the Titan it never failed to improve a component's sound. It is, quite simply, the most impressive mains filter we've ever heard." Reviewer hooked it up with some serious amplifiers (Musical Fidelity A5 pre/power, Bryston 14B-SST, Krell KRC-3 preamp etc.), and did not experience any dynamic compression. His colleague tried it with Naim gear (with Flarcap 2), and confirmed the benefits: soundstage opened up, lower noise room, improved clarity and better timing.

Viewpoint: I can say having a bit of experience using power filters. I own PS-Audio P300, 2 x PS-Audio Ultimate Outlets (high-current version), Einstein "the Octopus" power distributor/filter and Trichord Research Powerblock 500 filter. And none of them is anymore in use in my HE-rig. Reason is simple: although "black is blacker" applies with all of them, I always sense loss of dynamics and reduced attack. But that's just me. Maybe Isotek has finally managed to produce a filter, which is ONLY beneficial.

Thiel CS2.4 speakers

Source: Prestige Audio Video April 2005, TAS issue 144, Haute Fidelite January 2005, 6moons January 2004, Soundstage November 2003.

See those reviews. Every one of them concludes that the CS2.4 is one awesome speaker. Furthermore, in German audio magazines' (Stereoplay and Audio) review list the CS2.4 has scored the highest points than any other speaker at €5.500 price range.

And yet, I have always wondered why Thiel speakers, in particular the smaller models, have not received greater success in Europe - or at least none the audiophiles I know use them. I have personally listened to model CS 2.4 and if I were seeking 5.500 Euros speakers these would be on top of my short-list (it's an insult for us Europeans that they cost less than 4.000 USD in the States!). These time and phase coherent, 1st order cross-over speakers resample me of Dunlavy IVA - uncanny sense of scale and acouctic space, "rightness" of re-production of music, and well defined and taut bass. However, 2.4s are more airy than Dunlavys, and in clarity terms close to electrostats and planars.

Sure, it's a bitch to drive (87dB sensitive, a 4-ohm nominal impedance hovering around 4ohm from 100Hz to 20kHz (yep, impedance curve indeed is linear between that audioband!), Thiel's minimum recommended listening distance should be adhered in order drivers to integrate (that 1st order cross-over) and so forth, but still for me the most underrated speaker out there. Compared with similarly priced B&Ws I would opt for Thiel everytime. Ah, power of marketing... Warning, be prepared to make an effort with the latest Thiel speakers, system matching is a key, avoid bright sounding components. Both CS2.4 and CS1.6 speakers have extended treble, which some listeners find a tad too bright with some components.

Viewpoint: As an owner of Revel Studio speakers I agree entirely with Marc Mickelson from Soudstage: "In strict sonic terms, the speaker that the CS2.4 reminds me of more than any other is the Revel Ultima Studio. The CS2.4 shares neutrality and precision with the Studio, along with deep bass, and thinking back, I suspect that both are similarly challenging for an amplifier to drive -- SETs need not apply. Of course, the Studios cost almost $11,000 per pair, considerably more than the CS2.4s. If you are considering purchasing the Revel Studios, or another speaker in their price range, do hear (and see) the Thiel CS2.4s as well. You may save yourself a wad of cash."

BTW, in the panel discussion during the CES 2005 Thiel's CEO commented that over 50% of companies sales comes from home-theather installations of their in- and on-wall speakers. I find that amazing.

Monday, April 04, 2005

The Mightier They Are, The Mightier They Fall - Wadia 302

Source: Haute Fidelite April 2005, Audio Video Prestige May 2004

Wadia is one of the engineering driven companies which legitimated digital sound. I, for example, got an HE-bug when I heard very first time Wadia 861x CD-player driving directly Electrocompanient Nemo mono blocks and Martin Logan Prodigy speakers. Consequently I went to become Wadia 801 owner. For me Wadias have always been musical players par exelence.

Against that background it was frustrating to read HE's review on Wadia. Although Haute Fidelite were impressed by typical audiophile idiosyncrasies (precision, dynamics, imaging), they were frustrated by non-musicality of the 302. According to review the competitors have move forward and for €6.000 the 302 doesn't anymore represent a good buy. And I agree, on that price level one should get a non-compromised player. But then, lets remember that this is an opinion of one reviewer, and as always, subjective. If 2-3 other reviews raise the same issues, then maybe there is a trend. In this context another French review of the 302 is illustrating. The Audio Prestige Video's reviewer found the 302 to be "a real Wadia", terrific sound staging and imaging, magnificient reproduction of voices etc.

Viewpoint: Nothing new here. Always trust your own earns, and take different reviews with grain of salt. Timing is also an issue, especially in digital domain. In this case a year difference can explain to large extent different outcomes: in 2004 and 2005 there has been a number of CD-player product launches which have re-defined what preformance you get for different price points between €3.000 - 6.000.

Sunday, April 03, 2005

MiniMax tube rolling

Since I own this little monster, this post is pretty much for my own record keeping purposes.

: extract from AudioAsylum Amp/preamp section Review by Hin H. on December 31, 2004

Minimax Preamp Performance Review

Results of Tube Rolling

The Minimax preamp was designed by audiophile Alex Yeung in Hong Kong and manufactured in China. Since its introduction in 2002, the preamp has already received a number of rave reviews in the U.S. This write up is concerned with the results of tube rolling that I have done recently.

The design philosophy of this line stage preamp follows a purist’s approach that calls for a minimization of the length of signal paths and the use of point-to-point wiring to enhance signal integrity. Secondary functions that may affect the signal quality, such as remote control, gain attenuation, etc., are eliminated. The design layout achieved a small size that measures only 12.5” wide, 4” deep, and 2.5” tall and the unit weigh approximately 9 lbs. The face plate is made of solid aluminum with variable thickness so as to make it less susceptible to resonant excitation by acoustics and vibrations in the surrounding environment. The chassis and internal hardware are very well built. The dark gray glossy color scheme together with the silver face plate creates a simple yet elegant appearance.

Power supply of the unit is done by means of choke filtered voltage rectification scheme using a 6X4 type valve (tube). The same kind of approach can be found on high end preamps. One 12AU7/ECC82 triode tube is used for the buffer stage and another 12AU7 for the amplification stage. Since only three tubes are used on the preamp, it is particularly cost effective for tube rolling in comparison with other preamps such as BAT and Audio Research in my possession.

Audio Setup:

The components of the audio system are listed below for reference. The listening room features a 18 ft ceiling and 760 square ft of carpeted floor space. The rear wall is not parallel to the front wall, and because of this geometry, stationary waves are more difficult to build up in this room than in a rectangular shaped room. Considering the Martin Logan speakers that are operated in a dipole mode, they emit signals in both forward and backward directions. Some reflection is needed from the front wall to make the music alive. Accordingly, the front wall is lightly treated to control the amount of wall reflection. No echo has been found in a sound sweep test and reverberation in the room is moderate.

The source and amplification equipment are placed in a room adjacent to the listening room separated by a wall. This arrangement would provide isolation of the equipment from the sound field and vibrations transmission from the speakers.

A few tweaks were used to enhance the performance of the audio system. These include the use of: Bybee quantum purifiers and Auri Caps installed at the output terminals of the power conditioner, Bybee purifiers installed at the drivers of the speakers, the use of risers to raise the speaker cables and the power cables for the speakers from the floor, and to allow the spikes at the bottom of the speakers to penetrate the carpet cut-through and land onto the concrete floor (note: don’t do this tweak at home unless you have the consent of your spouse). Furthermore, the Minimax’s ground wire was lifted.

The system has been tweaked to a point that the back ground hiss and noises emitting from the speakers have been virtually eliminated.

The Music:

To test the fidelity of an audio system, I like to use the distinct sonic characteristics of a violin, a piano, a soprano, an ensemble of multiple instruments, and a symphony orchestra. Five pieces of music are selected for the review, they are described as follows:

1. Paganini, Caprice No. 24 for violin, by J. Ehnes, Telac 80398.

Paganini’s music has been regarded as the most challenging for the violinists. This caprice demands both lyrics and skill presentation. In the musical passage, the theme changes pace with great transient variations. A century later, Rachmaniov’s famous rhapsody based on this theme had captured many music lovers’ imagination.

This playback allows the listener to examine the timbre of the violin sound and the musicality of the lyrics. In my opinion, the violin presentation should be natural and have an inherent inner strength and texture such that it can reveal the finesse of the instrument as well as the feeling or passion of the performer. A hint of sweetness would be nice, but excessive coloration may lead to an unnatural euphoric sound. As the audition turned out, this song proves to be a difficult piece for several tubes to achieve a full score.

2. Chopin, Prelude No. 20 for Piano, Reference Gold/Inter Sound RDW 3622.

The stunning effect of this master piece was demonstrated in the first few bars of the prelude. With 10 key strokes being played simultaneously, the richness and complexity of the sound are impressive.

This playback allows the listener to focus on the harmonics from the resonant chamber of the piano and examine the superb inner details, transparency, and richness. The crisp wave front due to each key stroke and its subsequence decay would provide a good example to check the performance of the equipment being used in the playback.

3. Verdi, Rigoletto Act 1, By Sumi Jo, Erato 450 97239-2.

This is perhaps one of the highest frequency songs a human can sing and the skill to sing this song is beyond imagination. Yet the presentation was so beautiful and graceful that the listener may have a temptation to repeat it for enjoyment.

For the listener, this is a nice song for testing the reproduction of frequency extreme of the equipment. For tube gears, excessive coloration would lead to an un-natural sound. For SS gears, the lack of second harmonic may render the vocal music lean and analytical. The tonal accurately, transparency, lean vs. full body voice, inner texture of the soprano voice, articulation of singing skill, and the overall musicality and liveliness, all come into play in this playback.

4. Inca Son, Vol. 1, El Condor Pasa, VMMT21, DID017042, 1993.

This popular South American song was performed by street musicians from Peru. It is an exceptional performance with four pieces of instruments, namely, a panpipe, a flute, a guitar, and an Indian drum. Using the Condor as a metaphor, the musicians express their deep feeling toward freedom and their home land. Especially in the second passage of the song, the flute brings out the emotion of the music with plenty of air. The drum beats were punchy and with a rhythm that made the music full of energy.

This song allows the equipment to demonstrate the three dimensional sound stage and pin point images separation. For this song, I would give up a little bit for the tonal accuracy in favor of the emotion and liveliness of the music.

5. St.Saens, Symphony No.3, “Organ”, Track 4, Boston symphony, RCA Victor,092026-61500-2.

This song offers a ground shaking effect due to the low frequency sound generated by the organ. This historical symphonic performance under the baton of Munce was perhaps the best among all recordings. However, the re-mastering process for the CD was less than perfect.

With over 60 pieces of instruments and a grand organ, the grandeur of a symphony orchestra is demonstrated in this song. The resolution of the audio system in general, and the performance of the preamp in particular, would be the focal point in the audition. The musicality of the playback would be demonstrated through the coherence of the whole musical passage, the foreground vs. background music, the micro vs. macro dynamics, and the very rich and powerful bass reproduction of the organ.

The Pre-Screening Process:

Of the vintage tubes that are in my possession, six are rectifier tubes (Genalex Gold Lion U707, Marconi EZ90/U78, GEC CV4005-1982 version, Tungsol 6X4W, Tungsol 6X4WA, and Haltron CV 493), one Westinghouse branded E80CC tube, and ten ECC82/12AU7 tubes (Mullard 10 M, Tungsram UK, Tungsol dark glass, Mullard 12AU7WA/CV 4003 ribbed plate, Mullard 8136 CV 4003 box plate, Siemens silver plate, TEN- from Japan, ITT Lorenz-CV491, TFK ribbed plate, Raytheon JAN 5814A red label, and Sylvania USN 5963 gold label).

Due to the large number of permutations for combining these tubes for the rectifier (Left), Buffer (Center), and Amplification (Right) positions, a pre-screening process was done in order to sort out the combinations that provide better performance before serious listening was carried out. This pre-screening process was done through casual listening.

As a result of the prescreening process, the tube combinations chosen for review are the ones that have better performance, despite the rankings between them are to be revealed later in a direct comparison. Technical measures such as acoustic imaging and sound stage are satisfactory for the tube combinations being used in the final comparison, and therefore these features will not be mentioned regularly in the following write up.

Some of the tubes were new, i.e. the Gold Lion U707, the Haltron CV493, the E80CC, and the TEN, their burn-in process was time consuming. I assumed the U707 had gone through some burn-in time during the factory selection process; it was burned only approximately 30 hrs in my system before the evaluation started. On the other hand, the other new tubes have gone through up to 100 hrs of burn-in time.

Of the six rectifier tubes, the performance of the Gold Lion U707, Marconi U78, and Tungsol 6X4W clearly stood out in comparison with the rest. To limit the scope of the write up, my review is focused on these three rectifying tubes.

Evaluation of three Rectifying Tubes:

Three pairs of ECC82 (namely, Mullard CV4003 box plate, Tungsram UK 12AU7, and Raytheon 5814A) were chosen to match with each of the three rectifying tubes (i.e. Gold Lion U707, Marconi U78, and Tungsol 6X4W). Hence there was a 3X3 matrix for evaluation.

The winning combinations were the Marconi U78 and the Tungsram 12AU7 pair, and the Marconi U78 and the Raytheon 5814A pair. The second best of the rectifier tubes were the Tungsol 6X4W and the Gold Lion U707, both of them tied for the second place; and their best matches remain the Tungsram and Raytheon. I believe the Gold Lion U707 can be improved in due course after a couple hundred hours of further burn-in. Regardless the rectifier tube was used, the combinations with the box plate Mullard CV4003 pair had less impressive performance. The following is a summary of the test matrix:

Marconi U78 and pair of Tungsram UK 12AU7:

Pros: Best overall, extended high, sweet mid, and accurate bass. Excellent inner rersoulation. Articulate and very musical presentation. More neutral presentation than others. Cons: None.

Marconi U78 and pair of Raytheon 5814A:

Pros: Very rich, articulate, realistic texture, excel in harmonics, and full of life. Magnificent in symphony orchestra music reproduction. Cons: None.

Marconi U78 and pair of Mullard CV 4003 Box Plate:

Pros: Play back was slightly better than with the U707, but overall in the same style. Cons: a little lean on violin sound.

Gold Lion U707 and pair of Tungsram UK 12AU7:

Pros: Exquisite sound, well balance for the high, mid range, and bass. Cons: Somewhat less relax probably due to insufficient burn-in.

Gold Lion U707 and pair of Raytheon 5814A:

Pros: Rich and full body sound, musical and articulate, vibrant at the bottom end. Cons: same as with Tungsram.

Gold Lion U707 and pair of Mullard CV4003 Box Plate:

Pros: Very good for reproduction of piano, soprano, ensemble, and symphony orchestra. Cons: slight coloration on violin sound.

Tungsol 6X4W and pair of Tungsram UK 12AU7:

Pros: Good tonal accuracy, rich in harmonics, relax, good resolution, articulate and very musical. Cons: None.

Tungsol 6X4W and pair of Raytheon 5814A:

Pros: Energetic, lots of guts, rich in harmonics, good resolution, full body. Achieved theatrical effect for the Organ music. Cons: none.

Tungsol 6X4W and pair of Mullard CV4003 Box Plate:

Pros: More musical than the combo with the U707. Cons: lack of emotion.

Entering the E80CC:

The E80CC is a sub ECC82 which draws a stronger current in operation. Based on the comments of many audiophiles, an E80CC is an excellent substitute for the ECC82 tube. For the buffer stage, it provides a linear response over a range exceeding that of an ECC82. By using this tube at the buffer stage, both the micro and macro dynamics are better reproduced while a full body sound can be maintained.

The E80CC tube being used in this reviewed is a Westinghouse branded tube with tinned pins. Its manufacturer is unknown. It seems to me the E80CC tubes made by Phillips and Valvo were featured with gold pins.

After a comparison with the performance with other ECC82s for the buffer stage, I reached the conclusion that the E80CC was the proper choice for this position. This choice led to a great simplification of the tube rolling because the only variable left was the tube for the amplification stage.

To evaluate the tubes for the amplification stage, I used the best tubes found earlier for the rectification and buffer stage to match, i.e. the Marconi U78 and the Westinghouse E80CC were chosen for this purpose. The ECC82/12AU7 tubes were inserted one at a time to the amplification stage to reproduce the five test songs. The scoring of each tube does not have absolute meaning; it is merely a way to show the relative overall average scale of performance. The results are summarized as follows:

A Comparison of the Amplification Tubes (ECC82/12AU7):

1. Mullard 10M: This tube is by far the most impressive among the 10 tubes being evaluated, with the combination of the U78 and the E80CC. The music reproduced by the Minimax was exquisite, articulate, full body, transparent, energetic, and have plenty of life. Regardless it was a reproduction of solo or ensemble, vocal or instrument, this tube performed well over the entire bandwidth of the sound spectrum with very good inner details and fine texture.

2. Tungsram UK: The construction of this tube is identical to the Mullard 10M and its sonic characteristics are also similar. In my mind, this tube could be a Mullard with a Tungsram brand. If a score for the previous combination is 10, I would give a relative scale of 9.9 for this combination.

3. Mullard CV4003 ribbed plate: This is a Mullard ECC82 with military spec. For military application, an amplification tube should be low in noise and less pronounced on second harmonic in the output. The sonic characteristics of this tube are similar to the Mullard 10M, with the exception that its output has less inner details and the violin sound has noticeable coloration. Overall, it offers the familiar Mullard sound. I would give a 9.8 for this combination.

4. TEN- Japan: The construction of this tube is identical to the Mullard CV4003 ribbed plate. The sonic characteristics of this tube are the same as the Mullard, but the coloration of the violin sound is less pronounced. It is a very good tube with all around performance. I suspect this tube was made in Japan using the same manufacturing tools from Mullard. It deserves a 9.8 for this review.

5. Raytheon 5814A: The sound of this tube is the richest among the 10 tubes being evaluated. I would use the words: vibrant, exciting, energetic, and full body to describe the output. Yet the music preserved the details and fineness. This is my tube of choice to reproduce the magnificent orchestra music. In terms of scoring, it deserves a relative scale of 9.9.

6. Tungsol 12AU7 black glass: This is another great tube in the line up. It is smooth, graceful, transparent, and articulate. Its treble is as good as the Mullard 10M but presented in a different style. Instead of using the word “exquisite” to describe the mid and high frequency sound, I would use the words: relax, open, and excellent tonal accuracy, for description. The bass is deep and very well defined. Overall speaking, this is a tube of great musicality and the fidelity of timbre is among the best. A solid 9.9 was marked on my notes.

7. Siemens ECC82 silver plate: This tube is very special due to its unique sonic characteristics. The second harmonic was not so pronounced in the output. However, the music can be described as bright, accurate, very good in clarity, and energetic. If the sonic characteristic of your audio system is on the dark side, this tube can surely cure the problem. Its overall performance is 9.8.

8. ITT Lorenz C491: The sonic characteristic of this tube is somewhat close to the Raytheon 5814A, but not as musical. It produced a heavy sound in a forward and full body style. In my opinion, this tube can perform much better at the buffer position than at the amplification position. Its overall performance is 9.7.

9. TFK ECC82: This tube is very good for the mid range and bass reproduction. Especially for the song No. 2, it produced a vibrant piano sound which is unheard of from the other 9 tubes. Apparently, this tube “generates” a bloom sound at the lower mid and upper bass frequencies. In many occasions, this extra energy made the music stunning in presentation. It has good transient characteristic as well as a full body sound reproduction. For the treble, however, it is inferior to most of the tubes being evaluated due to the early roll-off at the frequency extreme. The relative score is 9.7.

10. Sylvania USN 5963: This mil spec tube produces a clean output as expected. I would use the word “accurate” to describe the tone. However, if you are looking for a rich and emotional presentation, this tube is not your choice. The relative score is 9.6.

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