DNM began designing hi-fi equipment in 1978. Now DNM produce amplifiers that are small, lightweight and unique in many respects. Most importantly, they are made in this way to increase sound fidelity.
Since 1984 all DNM casework has been made in an attractive acrylic, an ideal material for an amplifier case because it's a good electrical insulator, so it doesn't interact with the signal and DNM's light, flat-panel construction ensures that casework resonances remain at a low energy level, reducing microphony and improving all aspects of performance.
The acrylic that DNM selected is not a standard "off-the-shelf" type - it is a precision material, much more expensive than most metal casework. DNM use plastic in all parts of the construction, the chassis parts and even the fixing screws are strong nylon. We use plastic because of the extra performance it gives our products - and as a bonus the lower weight actually boosts the sound quality as well!
DNM's work on the hi-fi system has resulted in the development of many new components. Where possible we have made these available to other companies and several of the most significant Hi-Fi companies in the world use components designed by DNM. The Slit-Foil and T-Network capacitors are examples of DNM components available for all to use.
DNM produced the original solid core interconnect and speaker cables - first invented in 1984. Little changed in design since their introduction, the cables were designed to work with DNM amplifiers - but they're also universal in their application for home use.
Read the Stereophile article about DNM Design including an interview with Denis Morecroft (opens in a new window).
DNM Design - technical advances in the last 45 Years
DNM Solid Core Cables
These were the original solid core cables and they are still the best audio cables for home Hi-Fi regardless of price.
Battery powered Pre-Amplifiers
DNM were among the first to make one; in fact we were second!
Power supplies for amplifiers
DNM made power supplies dedicated to amplifiers during the late 1970's and put the importance of power supplies on the map.
Slit Foil Capacitors
DNM invented the first electrolytic capacitors to overcome the problem of eddy current distortion.
Another DNM invention, the first electrolytic capacitors to silence the rectifier, they filter 11dB more and filter three times higher in frequency than conventional electrolytic capacitors. Best of all, they are available to everyone.
DNM optimised the design of transformers, volume controls, heat sinks, cables, equipment stands and connectors in the search for the ultimate in high fidelity.
Materials technology in amplifiers
The DNM Series 3 Pre-Amplifier designed in 1984 saw the first use of construction materials that do not interact with the amplifier's magnetic fields. DNM are still the only ones doing this over 20 years later!
Printed Circuit layout technology
DNM were the first to control magnetic field effects in circuit layouts and also the first to use true three dimensional layouts to improve performance.
Precision feedback control
DNM's in-depth research into feedback and its link to sound quality made possible transistor amplifiers that outperform even single ended valve designs.
The first amplifier with 3 dimensional circuits
All the developments listed above were made to improve sound quality. Sound quality drives every aspect in the design of DNM equipment - to allow full enjoyment of the music. Someone has to do it!
DNM made the first impedance controlled audio circuits to reduce high frequency reflections and to improve resolution.
Hi-Fi News included a vintage review of the DNM PA3S power amplifier in their April 2023 issue :
Click to see the full review.
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