As intrigued as I was by our editor's review of Audio Zone's AMP-1 integrated amplifier earlier in 2003, I was doubly so upon discovering that this up-and-coming Canadian manufacturer was located less than a 10 minute drive from my real job. Talk about small world. Suffice to say, it wasn't long before Audio Zone's George Tordai suggested that I audition his new AMP-2 monoblock amplifiers and the PRE-T1; a unique transformer-attenuated passive preamp. Audio Zone has taken the minimalist design aesthetic of the AMP-1 and further upped the performance ante with this trio of separates.


The AMP-2 monoblocks are roughly the size of a hardback novel but far heavier. They retail for US$2,295/pr. Each amp is constructed of machined aluminum panels that are assembled in such a way as to allow for airflow into the chassis. The cheeks on my samples were a smoky black translucent plastic but other materials and colors are available upon request. According to George and designer Peter Daniel, the sides serve no actual functional purpose other than cosmetics. Trannies are custom 400VAs by Plitron and power rating is 50w per unit. Build quality and attention to the minutest of details is absolutely mind-bending. Peter has tweaked this design and handpicked each part to maximize sonic benefits and reduce the negative effects of resonance. Everything from the massive central copper block with its own footer to the little pads of vibration-absorbent material scattered about on the inside were deliberately chosen after countless trial and error tests.

Initially, I was somewhat befuddled by the opposite-end positions of the signal and AC connections, thus making it rather difficult to figure out how to set these amps up. Why weren't they situated on the same side as is done with 99% of audio equipment? Placing the power inlet on the amp's same side as its input/outputs would have routed current in close proximity with the signal path, thus potentially affecting sonics. In the AMP-2, these sections are mechanically and electrically completely isolated by an enormous solid copper block/heatsink. The output devices are not transistors but opamp chips as used in 47Lab's GainCard, Jeff Rowland's older Concentra and the nOrh Le Amp/IRD MB-100 monos.


After poking around the amps' insides, I asked Peter to comment on the design of the amps:


"The LM 3875 chip is used in non-inverting mode. Resistors are from Vishay, Caddock and Riken and the actual choice was made after extensive listening tests. The caps are from Black Gate and transformers are 400VA Plitrons. You'll notice a chunk of copper bar (2" x 1") in the center of the amp. It creates the core of the amp and is supported by only one cone (mounted directly to the bar, with the hole in the bottom panel slightly larger to let the cone protrude). In this way all vibrations picked by the amp's chassis are quickly released. I wanted to create the shortest path from transformer to the chip (as we noticed earlier, that umbilical cord affects the sound of the stereo amp). However, doing this requires some heavy-duty shielding and the copper bar comes very handy here: Besides creating the base to which the chip is mounted, it also separates the active circuitry from the transformer. Copper, although more expensive, has some characteristics which are superior to aluminum - better heat transfer, preferable sonic signature and higher mass.
To make the circuit very compact, the chip is mounted right between the rectifiers and filter caps. Those rectifiers are connected directly to the caps via their lead-outs. Because of proximity of the rectifying diodes to the chip, a small copper bar is used to shield the chip, which additionally im-proves heat transfer. The caps are stripped of their plastic sleeves (denuded) and attached to the bar with a rubber O-ring, then isolated from the main bar by pieces of special dried rubber to prevent vibration and thermal transfer. All the connecting wires from the transformer are extremely short, all parts wired in 3-dimensional plane to transcend the limitations of PCB. Special slots between the metal panels improve ventilation in the active circuitry section. All screws are non-magnetic. With this series of amps, the side panels can be made in a variety of colors (black, tinted, frosted or clear acrylic) and materials (wood, cork, metal, slate).


The square brass bar for the rear support was also chosen for its specific influence in the amp's overall voicing. If you add rubber or neoprene pads under that bar, the sound becomes less bright but also less airy, with more emphasis on the midrange, which may actually be beneficial in some systems".
The PRE-T1 preamp is a down-right cute component built around a solid block of clear acrylic which according to Peter has excellent resonance control properties. Three inputs and one pair of output jacks make up connectivity. At the top rear of the PRE-T1 are three switches. One adds 6dB of gain and the other two control input selection for three sources. One toggle is labeled 'main/aux' and the other '1/2'. To access the 'main' input, the middle switch is set to 'main'. To access the other two sources, the 'main/aux' toggle is flipped to the 'aux' position and the '1/2' toggle is now activated.


Confused? It's really rather simple and you will catch on quick. The two circular metal enclosures on the top of the preamp house a Stevens and Billington TX102 transformer each, said to be sonically superior to passive switched attenuation and active stages with their power supplies and more complex circuitry. Indeed, scuttlebutt on the Web suggests that these trannies are fast becoming popular among audiophiles. A quartet of brass feet and Cardas I/O terminals and machined aluminum volume control complete this attractive package. The PRE-T1 (the pre-tee one?) retails for US$1,395.



I placed the monoblocks on the top shelf of my rack with the power inlets facing forward for strictly logistical reasons. I think the best permanent location would be on the floor behind the loudspeakers. Sources were my trusty Rotel RCD-971 and Sony SCD-XE670 SACD player. Scott Nixon's TubeDac+ with upgraded power supply also saw duty connected to my Rotel. Speakers were my reference Meadowlark Kestrel 2s and all signal connections were provided by DH Labs.