Inner Ear Report,
Volume 9, # 1 1996
85 Moorehouse Drive, Scarborough, Ontario
Canada M1V 2E2
Tel: (416) 297-7968
Fax: (416) 297-0311
| Source: Wyetech Labs
Price: click here
This amplifier represents the dedication and love for the better things in life from a man who has never dealt with the consumer electronics business. It's the result of Roger Hebert's efforts to build a no-holds-barred single ended vacuum tube amplifier which can drive all sophisticated loudspeakers with an efficiency rating of about 87dB or more. This newcomer to the high-end electronics industry isn't your regular high-end amplifier, nor can it be classed as a whimsical piece of equipment. Rather, the Topaz represents a masterpiece of classic vacuum tube design in circuitry and component selection, as well as appearance. The result of many years of research and countless hours of auditioning, the Topaz is a statement well made, as we shall see.
The amplifier is mounted on a solid steel chassis which has been finished in a purple colour. Its front isn't the conventional faceplate with the company logo, but rather, it's the place for the amplifier's inputs and speaker terminals. Two unusual LEDs on the unit's front allow users to quickly determine if the amplifier is in the standby, the operating or the off mode. The LEDs were imported from England and sport small, slightly protruding bubble lenses so that they can be seen from any angle. Though unusual, it's by no means the only "different looking" part. Two beautifully crafted, chrome and gold plated transformers literally force you to admire the unit. Mounted on the rear part of the chassis, in front of the perforated cage, these transformers appear indicative as to what to expect. The cage houses two large and one small transformers (EI types), a couple of heat sinks, two electrolytic (Sprague) capacitors and two Agastat industrial plug-in time delay relays.
It would be easy to tell you that this is a single-ended vacuum tube amplifier, and leave it at that. However, in the world of high-end audio, there are single-ended designs and there is the Topaz. It's single-ended all right, but let us have a closer look, beginning with the parts. This unit's fixed terminal circuit boards are hand crafted, labour-intensive and therefore quite expensive to assemble. Silver solder and stainless steel hardware are used throughout the design, complemented by Teflon insulated, silver-plated OHFC copper in critical areas. The output transformers are from Audio Note, the blank circuit boards are made by Vector Corp., the polypropylene capacitors are from Solen and the resistors come from RCD and Holco. WBT connectors are used as well. All high voltage DC lines boast double and triple insulation starting with two layers of Teflon and a PVC overall tubing to eliminate sporadic discharging or leaking into the audio circuitry.
The power supplies are the heart and soul of all single-ended amps and a special, rather beefy arrangement was chosen for the Topaz. Hebert opted for two power transformers to drive the single output 1200 volt supply. According to him, this method allowed for the mechanical noise floor (hum) to be lowered substantially, thereby increasing dynamic range. (It is said that lowering the noise floor increases dynamic range in the same manner as an increase of power output). The power transformers each feed a centre-tapped, full wave rectifier which in turn charges its own capacitor. The input / output voltage power supply uses a current surge limiter and a dual full-wave rectifier feeding a double filter network for regulation and ripple / noise rejection. Four large chokes and ten polypropylene capacitors are employed in the high voltage supplies. Further noise reduction is obtained by limiting the peak charging current allowed by these full-wave rectifiers.
The 211's single-ended, self biased output tubes drive Audio Note transformers. These transformers are known for superb sonic clarity and resolution along with lower distortion and improved low frequency response characteristics.
Hand-crafted Vector boards accommodate point to point wiring, clevery arranged to yield the shortest signal path circuit. To sum it up, a total of four power transformers are employed to power all DC supplies. One for the 211 tube filaments, one for the front end (first and second stage) and two for the 1200 volt power supply. There is a lot more to this than we can possibly document in this report, but we are obliged to tell you about the mechanical construction before we go on. Hebert used an extremely rugged (12 guage) welded steel chassis to battle any possible vibration-induced signal aberrations, while a baked-on pearl enamel finish complements the assembly. Let us now go on to the nitty gritty...
For the listening sessions, we used the Gershman GAP 520-X, reviewed in this issue, the Gershman Avant Garde speakers, Totem Tabus, the Orbital-Sterling IIs and our editor's own Ethera Vitaes. Why so many loudspeakers? Because we had them in house, we wanted to find out about the systems' synergy or compatibilty. In order to stay with vacuum tube, we used the Flemming Model One preamplifier, some Audio Alchemy components and an Elite Laserdisc transport. Various high-end and lower priced cables were used for the sessions.
What became apparent with all of the loudspeakers was that this single-ended amp has better resolving calibre than any other we had auditioned. Throughout our listening sessions, the Topaz exhibited no weakness of the character that is often described as tube-like bass. Although the certain blossoming touch of vacuum tube devices is maintained, the extreme bottom end - pedal-note bass information - remains clearly resolved all the way down to the last audible bass fundamental. Additionally, the Topaz manages full-bodied sound which finishes the ultra-high frequencies, not missing any harmonics - the stuff we can actually hear.
It is almost pointless to describe all the good things a sound stage can offer. The Topaz does this with ease and with realism which allows listening into the music. Focus and inner detail go hand-in-hand with precision, making it possible to count the rows of musicians and to listen to one or the other soloist without missing a note from all surrounding instruments (or voices). Indeed, the Topaz's outstanding feature is its revealing quality which allows listeners to pinpoint sources of music within the sound stage. Of course, highly resolving speakers are a prerequisite. We had the best results with the Gershman Acoustics Model GAP loudspeakers. With the Gershman Avant Garde loudspeakers, the overall sound remained clear and well resolved, if to a lesser degree. The Totems really perked up and sounded wonderfully transparent. The Ethera Vitae speakers never sounded better than when we connected them with the Topaz, introducing body and weight, air and definition, but most of all, musical bliss. Another great match was achieved with the Celestion Kingston speakers. However, many other loudspeakers may qualify as synergetic matches, but personal taste must prevail and it is best left up to the end-user's preference to choose. One thing is clear, the amplifier will do what we have described with all the loudspeakers listed above. One more thing: Hebert has written a white paper and supplies it along with a diagram in the elaborate owner's manual. For more information, contact him.
To say that this amplifier is excellent is a gross understatement. The Topaz is a state-of-the-art component which offers magical sonic attributes. While this is exactly what audiophiles and vacuum tube lovers want, the amplifier must be regarded as a statement component which recreates the art form - the music. It is a reproduction device of the first calibre which - while maintaining the classic design principles of vacuum tube technology - offers innovative, though expensive, modern implementation of circuitry and parts.
Let's not ignore the price; this is an expensive component. We feel, however, that the price is within reason - the reason being the Topaz's performance which is in line with more expensive high-profile amplifiers. Let us say that the amplifier is a cut above most others including some of the brands with which you may be familiar (a politically correct statement, since we didn't mention other brand names).
In conclusion, we must tell you that this is indeed a rare amplifier and most likely the best vacuum tube device of which we know. However, the Topaz mustn't be ranked as the best tube job, it must be ranked along with the best amplifiers we have heard, regardless of design philosophy or preference. Given that the backup components match the elevated performance level of the Topaz, it renders some of the best sound quality you'll run across.
TIER readers may have noticed that our reviews are kept as objective as we can manage. I do not favour one technology over another, simply because I believe in the art form, a unit's position in the audio market and its performance as it relates to music. This aligns me with no given technology and I am not caught up in the battle of tubes versus solid state. I have learned to appreciate both, frequently criticizing or praising either design. I agree with the reviewers of the Topaz, since it charmed the pants off me, but not necessarily for the same reasons an audiophile might have. I like it because it delivers the most important aspect, indeed the very essence of audio - it delivers entertainment, music, magic; and it does so ever so correctly. The rating in the heading of the review may be a bit confusing since we have three full musical notes and two half notes. The best rating (four full notes) will be reserved for equipment which we know to be the best without a hint of doubt. The two half notes in this rating indicates that we are almost sure that the Topaz is right up there with little room for improvement.
© 1996 The Inner Ear Report