Highly Biased Output: The Taddeo Digital Antidote II, the Shakti On-Lines, and the E.A.R. 834P Phono Amp
Jennifer Crock

The Future: Getting Closer All The Time

Well, it was really the late 60’s, but what a film it was! Remember HAL 9000, the ship’s computer that decided it had to kill all the humans onboard because ‘he’ decided that they jeopardized the success of the mission? Dave, in the fight of his life, finally shut down HAL by extracting ‘his’ optical data cubes.

Back then it seemed so far fetched, but such a memory device may be operational by the actual year 2001. A Georgia Institute of Technology team have under development a light activated optical switch which they believe could be the basis of a new type of re-writeable data storage system. Special trigger molecules induce a phase transition in liquid crystal materials, allowing different forms of polarized light to read, write, and erase digital information. Notes Dr. Gary B. Schuster, Professor of Chemistry at the Georgia institution, "Using light for memory applications is only going to be useful if you can do it in three dimensions. If you could write three dimensional holograms optically and read them, then you would have something worthwhile."

Recall that magnetic tape, floppy and hard disks, and CD based optical memory are all two dimensional, and hence have severe limits on data density. Even the multi-layer CD technology is a disguised 2-D system. A new system using 3-D optical switches, scanned by multiple light beams, could simultaneously read and write huge amounts of data at very high speed. Think about it: Fully interactive sound and visual information with no moving parts!

Closer to production is a new memory cell being developed by Toshiba’s ULSI Research Labs. It features an innovative trench capacitor structure coupled to a transistor to produce dynamic random access memory chips, DRAM, in the neighborhood of 1 gigabit or more per chip. The size reduction to achieve this array density has proved difficult due the space required by the charge holding capacitor. Beyond a certain minimum dimension, the capacitor will not hold a sufficient charge. The Toshiba engineers reasoned that if the capacitor was treated as a three dimensional device and deepened in the vertical direction, its horizontal space requirements could be drastically reduced. The result of their efforts is a micro size capacitor with a bottle like cross section that can be fabricated with conventional chip processing technology. The commercial 1-gigabite chip is promised in about 3 years. I expect it sooner.

The implications are pretty amazing….A credit card size carrier could be loaded with many hours of high quality music, or compressed video and ‘regular’ audio. Once again, no moving parts! This is just around the corner. Do you really want to invest in motion picture DVD now to get a picture inferior to laserdisc, and then have it rendered obsolete by fast access solid digital media that you can even record on? The future is not too far away — it gets closer and closer, faster and faster every day.

For the time being it appears that we will have to be content with the 5 inch optical disc as the primary medium by which musical ‘data’ is stored and distributed. However, the audio compact disc as we know it is finally about to go through a much needed evolution. The "Delayed Variable Disc" as I usually call it — "DVD" to most of you — looks like it might soon be arriving in an audio format which addresses some of the concerns of audiophile music lovers.

The latest word from Japan is that one version of the DVD will use its high data storage capacity to hold stereo audio in a 24 bit voltage measurement taken at a rate of 96 thousand samples per second (the so-called "96/24" standard). Compare this to 16-bit which yields a useable dynamic range of somewhere about 80 to 85 dB,1 or HDCD™’’s 20-bit (which is a audibly better in this respect), and the sample rate of 44.1 thousand per second shared by both standard CD and HDCD™. If this format reaches commercial production, we should enjoy usable dynamic signal range about equal to the best analog systems, and lose nothing of the already low noise floor digital is known for and does so well. High frequency musicality and image depth should improve dramatically for two reasons.

The first is from the reduction by a little over one half of the arbitrary quantization phase realignment.2 This is a random effect of the low ratio of sampling rate to signal frequency most noticeable in the upper three octaves, and is uncorrectable due to its random nature. The second is that the steep filter needed to keep ultrasonic signals out of the analog to digital converter can be more than doubled in its functional frequency, from about 20 kHz to over 45 kHz. This will push the filter induced phase domain errors out of the audio pass band where they now clearly lie, in the upper octave between 10 kHz and the upper limit of 20 KHz. In the meantime, all past and currently produced CDs will continue to be made with this form of filter induced phase distortion.

This is all fine and grand and the stuff from which wishful thinking springs, but what about a fix for this problem in the "here and now"? Those of you fortunate enough to own really expensive DAC equipment, such as the top of the line Wadia, are already enjoying a correction of the high frequency filter induced phase domain errors. The correction of these group delay effects is vital to a sense of ease and "naturalness" in audio. The absence of this correction is a large contributor to the artificiality and sense of "harshness" in all but those very best digital decoders, which include built in correction networks or some form of DSP programmed to do the phase shifting.

So, wadda ya do if your disposable income is closer to that of "Average Joe In The Real World?" The solution is easily affordable, and in my opinion, indispensable. For about 400 dollars you can install the Taddeo Digital Antidote II.

The first version of this patented product was introduced about 4 to 5 years ago as a passive device placed in the audio path between the CD player or DAC, and the amp stage that normally follows. The design goal was to place a corrective phase domain filter in the audio path. The improvement in image structure and harmonic balance as heard by reviewers in both the Commercial and Underground press was nothing short of stunning. The main tradeoff was a slight roll off in the strength of upper octave signal, an exchange felt by many to be quite acceptable for the improvement in digital playback.

Mr. Tony Taddeo of Taddeo Loudspeakers has now developed his second generation device. Unlike the original Digital Antidote, the Antidote II is an active filter housed in a small rack style enclosure with power and bypass switches. A blue LED lets you know the power is on; your ears [and the function switch position with its own blue LED] lets you know the correction filter is engaged.

Opening the box reveals a build quality that is adequate. The printed circuit board is a good quality fiberglass fabrication, and contains both the power supply and audio circuits. The power supply starts with a small EI core transformer mounted right to the circuit board and is shared by both channels. The RCA jacks are inexpensive generic gold plated parts. The internal wire used to hook up the jacks and function switch to the PC board is also of generic quality.

An examination of the active electronics, the IC amps, are by Burr Brown and are of very good quality. They mount to the PC board by an excellent grade of IC socket and thus are easily upgraded if the owner should wish, though it’s not likely that you’d want to. Resistors are 50 PPM metal film types, and signal level caps are small poly film types, both are OK by me. The power cord is connected by an unfiltered IEC socket.

When one considers the exceptionally low price of this device, the use of this grade of wire and jacks is excusable. Building in even 50 bucks worth of higher cost parts can result in as much as a 250 dollar increase in retail price. Such is the law of marketing. This would push the cost of owning a Taddeo Digital Antidote II out of the reach of those most in need of it. At 400 bucks, buying one is a real no-brainer. Many skilled hobbyists will take a few hours to install really good jacks like those from Vampire, or my favorite from Cardas, and better wire of their own choice. Another obvious mod would be to substitute Black Gate filter caps and Shottky diodes into the power supply. Those with a more adventuresome spirit might even want to install a filtered IEC power cord socket, and certainly most of you will experiment with your favorite brand of audiophile power cord. Just remember, any time you mod ANY piece of gear, you void your warrantee, and assume all product liability and safety risk.

In spite of the ‘built to a price point’ nature of this device, it is of exceptional sonic merit. A pre-amp with this sort of build quality would not have chance of making it into any ‘strongly recommended’ list. However, the benefit derived from the function of the active filter dramatically overshadows the losses induced by the average quality parts. The sum is truly greater than the total of its bits. [Sorry for the digital humor. Sometimes I just can’t help myself….]

I have auditioned the stock Taddeo Digital Antidote in both my own system and in Positive Feedback Editor David Robinson’s primary system. Comments about an ‘Antidote’ with Cardas jacks, JENA LABS wire, filtered IEC power socket, and some other mods will follow at a later time, and will be accompanied with some ‘how to’ instructions for the Do-It-Yourself’ers out there.

David’s primary system leans strongly toward analytical sounding, and tends to be an intimate ‘up front and dynamic’ experience. (Ye Olde Editor notes for the record that it is set in a fully dedicated listening room: 10’ x 18’ x 9.5’; wall-within-a-wall construction; concrete floor with carpeting; non-parallel walls and ceiling/floor; and a fully dedicated power supply: 4 x 20 amp and 3 x 15 amp, cabled with 10 gauge solid core copper. Acoustical treatments at this point are by ASC.) With analog source material, open reel tape or LP, it is really quite a treat. Dynamic crest factor and fine edge resolving of details are superb. With digital source material, the resolving power of this system lays bare all the flaws found in the digital audio domain. The Vimak DT800 digital front end has a balance that I would describe as having an "etched resolution".

Don’t get me wrong on this. The Vimak seems be very much a "truth-teller." The very few really good-sounding CDs sound as they should: really good. The vast majority, however, are revealed for what they are, full of ‘bright’ artifacts. While this allows one to hear all the little edges of the music signal and is very exciting, even visceral, during a short listening session, I personally have found it to be lacking in long-term listening pleasure, especially in the reproduction of massed strings. I find myself remembering how much more real David’s Linn LP-12/Ekos/Troika/Lingo/Cirkus system sounds via the Coda O3P phono amp, and am distracted from the digital sound with thoughts of comparison......"Hmm, wonder what this would sound like in analog??"

Enter the Taddeo, and a transformation beyond belief happens. All the irritating edge is gone! The high frequency balance sounds right! It is strongly present, but not "in your face." The dimensionality is now stunning. Front to back is more than doubled, side to side improved, and coherency inside this larger stage is also improved. In natural acoustic hall recordings, the shape of the performing stage is now clearly a part of the illusionary sonic event, something hinted at before, but not quite in focus.

In this regard, stage recovery is now similar to David’s analog front end, very satisfying indeed. Cymbals ring with metallic harmonics, and are free of spittiness and glare. Close miked human voice floats out of space but maintains its strong presence without assault. Most importantly, the digital system now has an inviting character that lures you to stay and listen to that collection of favorite CDs. Even the ‘difficult to do digitally’ massed strings now sound rich! Fatigue factor...zero! Fun factor.... "Hey, let’s stay a little longer and play that other stack of CDs!"

Which is exactly what we did....

The system my husband Mike and I have is very different in its basic nature from David’s. First, we have a much larger room, so the basic sound is less intimate. Second, our home brew bi-amped electrostatic with dynamic transmission line sub speaker system has been designed from the ground up to provide a balance of transient detail, large, deep and specific sound stage, and a wide frequency range. It does not have the level of dynamic crest factor found at David’s listening room, and there are I times I wish it did.

Recognizing this main limitation, our mostly vacuum tube system has been fine tuned at every level to suit my personal taste. Our heavily modified Monarchy DAC now delivers a sound free of any fatigue, but still including loads of fine detail. I can sit down and listen to even loud CD music for hours without fatigue. This took a bit of tinkering with both the digital and (especially!) the analog sections of the DAC, and even includes an accessory to the interconnects. More on this a bit later.

Is the Taddeo a worthy addition to this kind of system, one that I already find digitally acceptable? Absolutely yes. Everything improves in the same way here as in David Robinson’s system. Rear wall sound stage is WAY back there. Liquidity and wrap-around-you comfort abound. The digital system now has a character much like our turntable. No, not equal — but similar. This is no small feat, as we have a pretty reasonable vinyl playback system, consisting of a Basis Ovation table, an ultra modified Dennesen air bearing arm, and the top-of-the-line Benz Ruby cartridge.

Mike and I have listened to all kinds of music on CD through the Taddeo, including new age spacey stuff, pop and rock, classical, and jazz, both from new digital masters and from old analog tapes. Our verdict is unanimous and without exception. The Taddeo is indispensable. It is also VERY affordable. Unless you already have the very best megabuck DAC, I believe that the Taddeo Digital Antidote II will bring much of the high dollar listening pleasure to your music listening room at a fraction of the usual admission cost. Got some soldering and fab skills? Your pleasure can be enhanced even further with a fun DIY mod project, resulting in even more musically satisfying results.

While we are on the subject of wider, deeper, and more resolved: Shakti has a new product out, the On-Lines. [Those interested in this new product from Shakti should also refer to Clark Johnsen’s column mentioning them, elsewhere in this issue.] Regular readers of this publication should be most familiar with the ‘stones’ by this company and the wonderful overall improvement they make when placed on audio equipment. The new product is a miniature version of the classic, about a half inch square by a few inches long.

This little puppy goes on interconnects and speaker wires. It is held in place by a pair of hook and loop straps. As claimed by the maker, the reduction in ultrasonic and radio frequency ringing brought on by the addition of the On-Lines produces a blacker, deeper background foundation and increases resolving power, dynamics, and imaging specificity.

I suppose that I could go on and on with the usual verbiage about how they "make everything better," but that would just take up space. Suffice to say, they work well, and they seem to work on any cable — even power cords. More importantly, the On-Lines do equal magic with both analog and digital source material.

As a cable manufacturer myself, I am VERY aware of the technical problems involved in interfacing audio components. After hearing the On-Lines I plunked down the cash and made them a permanent part of my system. I strongly recommend them to all my customers. Can you think of a stronger endorsement? They run about a hundred bucks a pair. For optimal results you will need a pair for every cable in your signal path. Even so, this is a very affordable ‘add on’.

At Positive Feedback we often talk about the importance of system synergy. The Taddeo Digital Antidote II and the Shakti On-Lines, when used together, demonstrate a strong and pleasant synergy. The On-Lines are an important part of what makes my digital system listenable to me. The Taddeo takes things several steps further. All in all, this is a combination that is worth looking into.

Manufacturers:
Taddeo Loudspeaker Co.
2604 Elmwood Ave. Suite 105
Rochester, NY 14618
716-473-9076

Shakti Audio Innovations
2405 Cloy Ave.
Venice, CA 90291
310-305-1857
310-827-8373 (FAX)

Nope, I’m not done yet! Every once in a while a real audio gem comes along that represents a really good sound value. Sometimes when I discover such a product I go beyond the usual expectation of purchasing one for my own system. Being in the audio manufacturing business, as opposed to the audio reviewing business, I have a number of my own dealers and a few retail customers with whom I share products of merit. This is only a small part of JENA LABS business, but because it does generate some profit, I want you, the gentle reader, to know about the whole situation and not come back later screaming that I used my position with Positive Feedback to blatantly sell goods. ‘Nuff said.

Last year I was introduced to a product through the PF review process that I liked so well that I became a dealer for it. Not only that, I introduced it to two of our cable dealers who have themselves now become authorized outlets for this product. Well, what, says you, is the product? The E.A.R. model 834P and 834P w/level RIAA phono stage preamp.

If you have a CD only system, are satisfied with the sound and the format, go ahead and turn the page. I’ll see you over in the Taddeo Digital Antidote II review. But if you have a vinyl front end, or are interested in adding one, you might want to read on.

The 834P is robustly built black box a little bigger than a brick. It provides gain and RIAA compensation for either low output MC type cartridges or higher output MM type. Three 12AX7A tubes do the voltage gain, and an honest to goodness real audio input transformer is used in the MC position to provide low noise matching for the low output associated with this family of cartridge. As implied above, a version of this device can be had which incorporated a built in volume control.

Now, to be honest, the unit without the volume control is a just a little bit better overall, due to expected potentiometer coloration, but the prospect of doing away with normal pre-amp altogether might raise an eyebrow or two. The audio circuits are the same in both versions, so no difference is found outside of the dual section stereo volume pot and its short internal hook up wires. Power enters by the usual IEC socket, and is converted to useable voltage in a low stray field toroidal power transformer. A high quality PC board holds the balance of the parts. RCA jacks are of the molded plastic frame variety that mount directly to the PC board. A small rotary switch on the front panel turns the unit on and off. On the version with volume control, an additional front panel knob is found. From turn on, it will begin operation in about 20 seconds, without any clicks or thumps, but if started from cold it should be left for a few minutes of warm up to fully stabilize before playing music. It really blooms after about an hour. I just leave mine running all the time.

The 834P, like other E.A.R. products is designed by Tim deParavicini. I have had the pleasure of meeting Tim and really enjoyed talking engineering with him. Audio is a field where almost anybody can throw a few parts together and be in business. This simple act does NOT, however, make them a qualified designer. Rest assured that Tim absolutely does NOT fall into this semi-amateur category. He combines an excellent solid traditional engineering comprehension and plenty of creativity with the good judgment needed to design high value and highly reliable products. This is a rare professional blend, indeed! In addition to home stereo electronics, Mr. deParavicini also designs and manufactures a complete range of recording electronics which have earned a reputation around the world as being just about the best there is. You may recall that the Water Lily Acoustics recordings which I have highly praised in the pages of this magazine were recorded on equipment built by E.A.R.

Well, so much for the small talk. You want to know, "how does it sound?" In a word, neutral. Very quiet. Very dynamic. Very dimensional. This is not a device that will shout out to you and say "tubes are in me". It has none of the classic soft tubby and over rich character typical of older, or less expensive modern tube designs. It is solid and firm in the lows and very fast in the top. The mids are liquid and emotional. The frequency spectrum and dynamic expression work in harmony, with no one aspect of the sound standing out as better than the other parts. Conversely, nothing is obviously lacking either. This is one sonically well balanced design!

The synth and cymbals on Lori Anderson’s Sharkey’s Day are hot and really tingly, but never to the point of fatigue. This indicates speed and bandwidth without transient ringing and overload. The hall space on Proprius Label’s famous Cantate Domino is well defined and large. Reverb seems to go on forever and those palpable voices.......they just appear from space and demand that you believe. Rough Trade, For Those who Think Young, is an interesting album in that on some otherwise pretty good systems it can sound almost flat and 2 dimensional. A really good phono pickup helps with this record, but if the phono stage is in the least bit lacking, you never hear the space and dynamics that are hidden. Note that the E.A.R. pulls almost as much space and rolling bass slam out of this disc as does my Vacuum State Research reference preamp — and one of those (custom built all the way, believe me!) would set you back about 30 grand! Vocals are smooth and well placed in space, if recorded well. It even works with both male and female voice, rendering either with a flair. K.D. Lang’s "Save Me" on Ingénue and Eddie Arnold’s "Cool Water" on Cattle Call bring tears to my eyes.

Lesser equipment just puts the tunes in the room. This one moves me.

I have seen the 834P shipped with two different brands of tubes. Direct sonic comparison of the two standard varieties reveals only trivial differences, so you need not worry about what brand of tube will arrive in your 834P.

One of the pleasures of owning tube gear is to enhance performance or fine tune the sonic signature by the process of installing specific tubes of known character. Changing the generic tubes to an expensive premium graded variety such as offered by Gold Aero, or installing a set of your favorite NOS brand offers you an easy method of both tuning the basically neutral character of the 834P and expanding on its already abundant sonic virtues.

In my own unit, I am using Gold Aero Platinum grade, Chinese origin tubes, about 1989 vintage., These are the ones with the large silvery colored getter on the side of each plate. These tubes are fast and detailed. They present an incisive soundstage with really excellent localization queues. Bass is rock solid and free of flab or tubb. Mids are precise, and topped by nimble highs. The extremely rare Siemens 12AX7A of the 1970s have a similar sound, and are my true favorite, but good luck finding enough of them to weed out the also-rans. One of my customers is using Telefunken diamond bottom tubes in his 834P. These tubes are legendary for their warm and comfortable treatment of the music. While not as precise in the localization of the soundstage, the music will seem to have a more ‘wrap around’ or enveloping character. Fatigue from this tube is zero, but there is no real tradeoff in lack of high frequency resolving power. Tubes of this sonic family are the ones to choose if your system has just a tad bit of bright, but you wish to loose nothing in the cure.

I’ve listened to 834P in direct comparison to several other commercially produced phono stages, some in its own price range of about a thousand dollars, and others up to about twice its price. While not an exhaustive survey of all available phono stages, the 834P easily bested every unit in this price range of those auditioned. These comparisons were not just done at my home, but at several locations in systems of widely varying basic nature. The 834P shined brightly in every application. This direct experience of hearing the 834P in systems with tube and transistor amps, and all types of speakers including electrostatic, planer magnetic, and dynamic cone, leads me conclude that it is basically right, and not dependent on the coloration of some other piece of the audio chain to correct an inherent error.

Is it as good as some of the really high buck gear from say Audio Research, or perhaps some of John Curl’s expensive phono stages? Well, not really. But it will stun you how close it comes! For the price of one of these really high end phono stages you can buy the 834P, put in some killer tubes, get yourself a Benz Glider and mount it up to any of the several really good arm/table combinations now on the market and hey, there you are! Great vinyl system for about three or three and a half grand!

Both of the versions of the 834P discussed here currently sell for $895.00. Just released is a version of the 834P that has a very thick polished chrome front panel that cosmetically matches some of the other E.A.R. equipment. The phono stage so equipped will carry a price of $1,195.00.

E.A.R. also has a line stage pre-amp. Though it has been out a few years, I have not yet heard it. I have made arrangements to audition one in the near future, and will let you know what I hear when I hear it. Based on my experience with the 834P and the great price/performance value it represents, I have high expectations for this line stage.

You can read both the lines and between the lines on this. It’s no secret, I believe the 834P to be the phono stage steal of the decade. Did I mention that its made in England? The importer, Dan Meinwald, will be glad to give you a dealer list, and to also tell you about the other E.A.R. products.

Specifications: EAR 834P and 834P w/level RIAA phono stage
Input sensitivity: for 1 volt out at 1Khz.: MM: 2.20mV, MC: 0.22mV
Noise: [unweighted]: -80dB IHF method
Max. output voltage: 30V
Tubes: Both models: 12AX7A [ ECC83 ] x 3
Silent turn on/off.: No thumps, clicks or pops!

Manufacturer
E.A.R./Yoshino Ltd.
Rectory Farm, Cambridge Road
Godmanchester, Huntingdon, Cambs. PE18 8BP
England

E.A.R. U.S.A
Dan Meinwald
1624 Sunset Ave.
Santa Monica, California, 90405
Phone/Fax 310-396-1919

FOOTNOTES

1 Digital technophiles might want to take me to task on the dynamic range of the 16-bit system as being closer to 90-some dB. This is true on paper and in the lab, but as anyone who has actually recorded live music knows, you must leave some room at the top to prevent any possibility of hitting digital clipping. Unlike an analog tape recorder which just gets more distorted — but does it pretty gracefully — during short duration peaks, digital signal level overload will produce an awful noise burst. Signal limiters can be used to prevent any possibility of the level going over a certain point, and allow use of more of the theoretically available digital dynamic range, but now you have more junk in the recording signal path.

This is just part of the reason why live recording of real musicians in actual live acoustic settings is so hard to do really well. One microsecond of overload and you blew the whole set! Just turning down the record level a little bit may lose you a few dB in real dynamic range, but it still sounds a lot better than any limiter I ever heard. An under-level digital master can be level boosted when processed to CD, but resolution once lost is forever gone.

Please also remember that dynamic range is the ratio of largest to smallest signal expressed in dB. Signal to noise ratio is the ratio of largest signal to the RMS of the backround noise voltage, also expressed in dB. These are very different measurements and should not be confused.

During the last few years several professional digital recorders have appeared that record in 20 bit voltage resolution at a 96 KHz sample rate. One of these is the Nagra D. Many recordings are being mastered in this format and are then converted to the lower resolution CD formats for today’s commercial releases. When a better system is finally in wide use, these recordings can then be re-released in the higher resolution mode.

2 Believe it or not, analog tape recorders have a similar problem, with the high frequency bias signal modulating with the upper octaves of musical signal in a manner very similar to the random quantization errors found in analog to digital converters. The bias excitation frequency has an effect very much like the sample rate of a digital system. The arbitrary relocation in time of the high frequency music signal is less severe in analog recorders, but it also has an amplitude error component missing in digital encoding. This is why modern professional analog tape recorders use bias frequencies approaching or even over 200 kHz. My Studer A-80-VU decks have a bias frequency just short of 300 kHz! Digital designers should take the lead from the experience of old school analog designers, and go for really high sample rates. This would reduce the random quantization errors to trivial amounts.

POSITIVE FEEDBACK ONLINE © 2002 - HOME