Secrets of the DIVA
T S Lim explains what makes a great preamplifier
Translated from an article by C K Tham, published in Lianhe Zaobao,
a Singapore Chinese language newspaper.
Translated by W K Fong
Having been in the hi-fi equipment industry for many years, Mr T S Lim has discovered that the performance of a preamplifier not only depends on the components that it is made of, but more importantly on the designer's own music background.
I have been testing audio equipment for a great many years and have long ago thought smugly that I have heard all the best. However, after having tested Lim's Diva Classic 200 preamplifier, I could not resist the thrill of owning a unit. So I bought one.
Its wonderful transparency, spaciousness and the rich musicality of its presentation deeply captivated my attention. Indeed with all its great innate attributes, if only the exterior packaging of the Diva could be more aesthetic, and perhaps stamped with an exclusive "Made in XXX" label, I would be hardly surprised if its marketed price can be marked up by three times.
The pre-amplifier is quite an established scientific product. The enthusiast only needs to apply the correct electronic circuitry and he would have made a functioning pre-amplifier without much ado.
But what is it that makes each pre-amplifier sound so different from the rest? Is it possible for "artistic talent" to be such an influence? Well, since Mr TS Lim already has 12 years of expertise in this field, I naturally had to seek him for the answer to this mystery.
Mr Lim says that the amplifier design circuitry was already established in 1940s, and all the possible design configurations have been well tested and implemented by his predecessors to their ultimate perfection.
Even then, there is still a great knowledge gap between the theory and the implemention of vacuum tube amplifier design (such as how to control and regulate feedback, construction of vacuum tube signal paths etc)
Negative feedback in the form of vacuum tubes or solid state devices are already commonly used. These are able to increase the pre-amp's stability, reduce coloration, enhance the extreme low and high frequencies, reduce noise, heighten input impedance and lower output impedance. In other words, proper negative feedback usage in the audio world can either convert an ordinary pre-amp design into a masterpiece or sink it.
Mr Lim explains: "Not enough negative feedback, the sound becomes rough; too much of it, the sound becomes dead. Negative feedback amount and design configuration has many possibilities, and there is really no magic formula that can be used; it requires endless and repetitive experiments to pick out the best configurations. With regards what constitutes the 'best', that is wholly subjective and lies in the designer's musical foundation, background and cultivation."
The well known audio designer James Borgiono (of Great American Sound & Sumo) aptly puts it: "Negative feedback's influence is just like money and women - when used correctly, it can give great satisfaction, but used wrongly, hell hath no fury like a woman's scorn."
When I turned to the question of component selection, Mr Lim shared with me an industry secret: while many well known companies boast about their expensive gold plated components to justify their exorbitant pricing, in reality electrical resistance plays very little role in the quality of audio performance. The great deciding factor is, in reality, the quality of the filter, de-coupling and signal coupling capacitors."
For the pre-amplifier, the most important factor in design is the quality of the power supply.
Mr Lim explains: "Even though the amount of power required by a pre-amplifier is very low, in my designs like the Classic 200, I have over designed its power requirement by ten times so as to ensure that it can get the cleanest uninterrupted power possible."
Another distinguishing character of the Classic 200 is that it does not incorporates any voltage regulator, the reason being if the you have too much voltage regulator, the sound becomes tense and nervous. This harms the overall presentation of the music, making it sound very mechanical and unnatural.
Examples of previous illustrious audio designs which do not incorporate voltage regulators include the Marantz 7, Quad 22 and McIntosh 22, all of which are well-noted for their natural ease of music presentation.
Having heard Mr Lim's discourse on his pre-amplifier design, I believe that most of you by can now understand why audio equipment design not only requires a thorough technical plan but also the touch and dedication of a master craftsman.
Every designer brings to the audio equipment its own audio signature that comes about from the experience and wisdom of its creator, and it is only up to the ear of the beholder to distinguish the pearls from the plastic.
Mr Lim emphasizes that in the planning stage of his design, his primary aim is to ensure that the final product has to sound balanced and natural, and is full of vibrancy; the musical resolution has to be detailed and yet possess a feeling of coolness, akin to the cool gust that blows up a mountain that causes a tingle of clear freshness.
Readers who wish to experience such "winds of cold beauty" would do well to audition the Diva Classic 200, to truly experience its cold but refreshing clarity.