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B a s i c  D e s i g n  P r i n c i p l e s

Use of non-magnetic materials

This extends from the choice of a cast-alloy aluminum chassis to the high quality components used. Many manufacturers used steel to form the chassis for their audio equipment. This material is widely used because it is cheap. Some audio designers recognize that the type of materials used in the chassis of an amplifier has a bearing on its sound. For instance this designer considers steel to be the least desirable because its magnetic properties seems to act as a drag on music signals causing a sense of lost of flow and drying out the sound. The mechanical resonance of steel is also imprinted onto the music and this metallic resonance is highly disturbing musically. Copper is highly desirable as a metal of choice for audio equipment but it is rather costly. Zenn components thus used a chassis that is cast from an alloy of aluminum and lead. Two metal that is non- magnetic and having a resonance that is pleasing to the ear. Even the special coat of paint used to give them a unique and attractive rockstone finish acts as an external skin that contribute to the Zenn sound.

Isolated power supplies

All Zenn components have this unique triad appearance. A single chassis constructed from three separate boxes. The center box contains the sensitive circuitry that does the important work of amplifying the music signals. This is isolated from the power supply that is located in the side boxes. Even the different sections of the power supply are isolated from each other. One box contains the "iron"- the mains transformer, the power supply choke and tube rectifier. Even this designer cannot do away with these two strongly magnetic components. Thus it is a good idea to keep these away from the other components. The other side box contains the rest of the power supply- the filter caps and resistors used to set the correct working voltages for the circuit. This approach allows the circuit to do its work of amplifying the sensitive music signals in an environment that is electrically quiet. The only electricity flowing in here are the music and DC voltages that are required to power the circuit. These are heavily filtered to remove any noise from them. Even then the wires used to carry these electrons are carefully kept away from wires carrying the music signals. Most other manufacturers design their audio equipment into a single box which contains all the circuitry and the noisy power supply components. With clever layouts the designer can minimize power supply noise such as hum from being audible. This designer feels that one can get away with such an approach in terms of audible and measurable noise but there is an audible effect on the sound, which cannot be measured but heard. For example, an amplifier has no measurable or audible noise but somehow when you listen to it producing music, it does so with an apparent background of noise. One test for this is to play it loud-it becomes extremely unpleasant to listen to. When you listen to a Zenn component, the music comes forth from an extremely dark background. Turn up the volume even to the point of clipping your amplifier or speaker-the music just gets loud but not noisy. This is a result of the total electrical isolation of the music amplifying circuitry. Other designers achieved this isolation by using a separate power supply box attached to the circuit-containing box with an umbilical cord. This approach works somewhat but is unsightly especially if there are going to be two power supply boxes. Form follows function.

Control of resonance

Notice that it says control not suppression. To suppress resonance is not only difficult (if not downright impossible) it may not be desirable to attempt to do so. A better approach is to use it to advantage, that is to tune it to a point where it serves to make your equipment sound more musical. Most audio equipment is built into large rectangular boxes. This creates large surfaces that create large resonance peaks that plays havoc with the effort to amplify sensitive music signals. This is especially worse for tube based equipment due to their microphonic nature. Zenn components are built from three smaller boxes to form a single unit. These smaller boxes result in smaller resonance peaks, which are also set at higher frequencies. This is less likely to mess up the critical mid-range. The sensitive center box that contains the main circuitry is also mechanically isolated from its environment by having the feet located on the side boxes. Form follows function.

Short signal path

This follows from the above. If a piece of audio equipment is built into a large, rectangular box then it usually follows that the signal comes in from the back, goes to the front (where the volume and selector controls are usually located) and then back again to the rear where the outputs are usually located. In the worst case the music signal can go through two meters of often-cheap cable before it sees daylight. This means that in such a case, an audiophile is wasting his money on expensive audio cables working into such equipment. Some designers overcome this by having the inputs/outputs located at the side or some cases at the front. You can imagine how unsightly this can get if your system is " fully loaded". Zenn components avoid this by containing the audio circuitry in a small box. This allows input coming in from the rear and the audio carrying cables are not more than six inches going to the front. Even though the internal cabling is already short, it was found that it still had an effect on the sound. The audio carrying cables used are specially selected for its natural tone. These are multi-stranded Litz wires and the external insulation consists of simply and uniquely a cotton thread wrapped around. These are then treated with the C37 lacquer. This unique internal cabling contributes to the total of the Zenn sound. Another unique feature is that on the input side, four different wires are used. This allows the user to fine-tune his system. The nature of the cable on the selected input is indicated by the color of the LED of the respective input. Generally the red LED input has a Teflon coated solid core silver-plated copper wire, which provide a hard driving sound. The orange LED input is Teflon coated multi-stranded silver plated copper. This is hard and mechanical sounding but less so than the red LED input. The yellow LED input uses the cable of choice, which is the cotton, wrapped multi-stranded Litz copper and treated with C37. The green LED input uses the same wire but is not treated with C37. Even though the different wires are all less than six inches long, the difference in the sound is very audible. This gives an indication of the transparency of a Zenn component and the importance of the internal cabling of an audio component.

Importance of the power supply

An indication of this is that two third of the real estate of a Zenn component is taken up by the power supply. It is not only the sheer size but more importantly the type and quality of components used in the power supply. Use of a tube rectifier to provide the high voltage required by tube equipment is a must. This is used even in the lowest Zenn range. Solid state rectification creates a dry and mechanical sound. No solid state or tube regulation is used as this also has a tendency to produce a sound that is overly tight and electronic. The only regulation provided is soft regulation via the use of a choke. Each audio stage has its own RC filtered supply formed from a non-magnetic carbon resistor and a capacitor picked for its musical tones (a Sprague, LCR or an oil-cap). Unfortunately for the reproduction of music, this type of power supply is hardly used anymore because of its higher cost, greater weight or audio designers do not fully appreciate its musical qualities.

Careful choice of quality parts

Parts in a Zenn component is carefully selected. This is based primarily on the tonal quality of the part. These include non-magnetic carbon film resistors and Jensen paper-in-oil capacitors being used in the main audio circuitry. There are audiophile grade components that may cost more but can sound electronic. There have been some horrendous sounding equipment made using the most expensive audiophile grade components. This came about because the components were used without regard to tonal contribution to the overall design.

Simplicity of circuit and zero feedback

Zenn circuits are simple and direct, using the minimum of parts to get the job done. This is to ensure minimal losses and maximum transparency. All this is accomplished without the use of feedback in the audio range. A simple, zero feedback design tends to provide a sound that is vibrant and full of raw energy but oftentimes can sound hard and edgy. This can be compared to two major schools of martial arts. One school advocates the hard style. Its techniques emphasize speed and power. Movements are linear and attack-orientated. In musical circuit terms this can be compared to designers who use zero feedback. The other school of martial arts falls into the soft style. Techniques emphasizes defense, movements are circular or rounded. The use of feedback in audio circuits has a similar effect of rounding up the edges of reproduced music. Overuse results in a sluggish sound. Both schools have their own merits. The accomplished martial artist is able to use both types of techniques to his advantage. In the past the overuse of feedback had given it a bad name but if properly use, it deserves a place in an audio circuit. This designer has chosen to avoid the use of any feedback in the audio range-, which is widely accepted to be from 20 Hz to 20 kHz. This is to ensure the correct reproduction of the speed and timing in reproduced music. But to avoid the hard and often rough edges of sound produced by many modern audio equipment, a unique circuit was designed to introduce a little local feedback in the over 100 kHz range at every stage in the circuit. At this frequency, it was effectively out of the human hearing range. But in practice it seems to affect the tonal balance in the audio range. This circuit referred to as the "Tai Chi loop" was use to voice the entire Zenn range of audio equipment to give it a fullness of sound and naturalness of tone that is rarely heard in modern audio equipment.


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Z e n n  A u d i o  E l e c t r o n i c s
292 Bedok Road
Bedok Shopping Complex
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Tel :: 4432473 Fax : 4432479
E-mail : zenn@pacific.net.sg


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