Archived from Audio Direction Ltd.
ADL has been investigating digital components ever since they first came out.
Working with digital involves a whole new mind set as the issues involved in obtaining good performance is very different from analog. We have learned a lot from dissecting the upper end components that have appeared on the market. A great deal of our thinking was revealed in an early issue of Positive Feedback Magazine, where writer Doug Blackburn wrote about modifying his Adcom player. We had sent Doug a modified Harman Kardon player that we had reworked and he then applied our mods to his machine and then wrote it up with our permission, of course.
One of the major issues is that the individual digital components, primarily the integrated circuits, generate a lot of noise. We first noted the issue in the early Wadia machines, which went the expensive route, machining a two inch thick piece of billet aluminum into a four sectioned chassis, separating the power supply from the digital processors, from the analog stage, etc.
In experimenting, we elected to shield each transistor and integrated circuit with copper tape and grounding that shielding. The result was a much quieter playback with greater dynamics and fine detail. At the time (1990) we could take a $500 machine and make it sound the equivalent of a two piece combo retailing for $4000.
We still do shielding, but use the more sophisticated ERS paper. This was developed from the military stealth technology and is deliberately designed to be a broadband absorber of RFI. In the case of the military similar technology is used to absorb Russian radar signals, but for audio use, its a broadband RFI absorber. This significantly reduces such things as jitter in any digital machine. Many current players reduce RFI electronically by installing a high frequency roll off circuit. Simply installing ERS can make such players sound too dull if the compensating circuit is not removed.
While originally developed for sound, the installation of shielding has an equally dramatic effect on video quality for those universal type machines. Installation of shielding increases the contrast and black levels, gives greater color saturation and seems to increase sharpness.
Another mod ADL has developed involves increasing the motor speed in the focusing mechanism. The mod is easy but requires a lot of experience as a slip can ruin the CD lens assembly. We simply add ferrofluid to the focus motor coils. This is the equivalent of making a faster, stronger motor. While this can be done through electronic means, most motor controllers these days are contained in a single IC which would be very difficult to modify. By saturating the motor coils with ferrofluid we can accomplish the same effect.
Again the effect is immediately noticed. By having the motor react faster, the data stream is more accurately passed on. This means an increase in dynamics and fine detail again increases. We believe that the laser lens focus circuit is one aspect of all optical playback which has been overlooked by most.
While seemingly simple, such digital mods will easily elevate the performance of a mundane player to the level of machines costing well over double the price. The mods are labor extensive however.
Specification on ERS can be found at the Stillpoints.us web site. Since it has appeared, other manufacturers have come out with similar products, many of which are aimed at specific applications.
We also employ the traditional audiophile tweaks: The use of fast recovery diodes: better coupling caps: the use of diode separation in critical applications in the power supply.