The Non-tweaker's Guide To Tweaks Page 2
Retrieval of information from digital storage seems inherently less subject to tweaking than the retrieval of analog information (who ever heard of tweaking a computer's hard drive?). So for some time it was assumed that, in the absence of circuit changes in the digital and/or analog sections, the sound of a CD player is what it is. If you don't like it, get a better player. (Or, many would say, play an LP.) Fortunately for those who love music and whose funds are not limitless, it is possible to improve CD playback without buying one of the multi-kilobuck machines: a tweak here, a tweak there...
Shorted digital output: Philips/Magnavox players, and reportedly others as well, sound better with the digital output shorted. Just insert a shorted RCA plug (you can buy one at Radio Shack or make one by soldering a wire between the positive and ground terminals) into the "Digital Out" jack.
CD damper rings: These have been tested/discussed at some length in Stereophile and elsewhere. No, they don't seem to affect the error rate or jitter. The effect may very well be a secondary one, perhaps acting through power supplies. If you have a high-end CD transport, you probably don't have to bother with damper rings; in fact, they're incompatible with the full-disc clamping method used by transports like the Teac Esoteric P2 and P10. However, with lesser transports, like my Philips CD650, before/after comparisons I've done in every case favored the ringed disc.
Centering the Monster rings is a royal pain, and they should be well-centered if unbalancing is to be avoided. The new Sims Reference Bands, distributed by Sumiko, which fit around rather than atop the disc, obviate the need for centering, are compatible with a broader range of players, and the sonic benefits appear to be superior to those of the Monster rings.
CD Stoplight: Yes, this is the green paint, and yes, it does work, and better than ordinary green marker. Some claim that if you use the Sims Reference Bands it's not necessary to apply CD Stoplight to the edge of the disc. Maybe so (I haven't done careful comparisons), but the CD Stoplight treatment is cheap and easy enough that I do it anyway.
Internal tweaks: For these, you have to open up the machine, having disconnected it from AC and affixed the transport lock screws. As manufacturers frown on "unauthorized personnel" tampering with their products, internal tweaks have to be done after the warranty has expired or you must adopt a devil-may-care attitude if anything goes wrong while you're tinkering inside. Still, there are a couple of internal tweaks that are easy to do and pretty safe.
First, if the player has a headphone output that you don't use and if the headphone amp is on a separate board connected with a plug-in type of wiring harness, disconnect it. Just a little more ambitious is the application of damping materials inside the chassis. This is a trick used by some specialty manufacturers in their modifications of Philips CD players. The rule here is to put the damping material wherever you see exposed vibration-prone parts of the chassis. Just be careful that you don't interfere with the operation of the transport. (A&S Vibration, Inc. markets a "Tweak Pack" of Navcom sheets that's probably best for this purpose.)
Digital Interconnects: For those with an outboard digital converter, the link between CD player/deck and converter has to be considered. The jury is still out on fiber-optic links, so the safe solution is to use a conventional interconnect. Since the wire has to carry only the digital on/off pulses, any cheap interconnect will do, right?
Would that it were so! This connection is absolutely critical, and different cables sound as least as different as they do in a pure analog application. (Please, no cracks about how this could be taken to mean that there are no differences here either.) Comparing a variety of audio and video cables as digital interconnects between my Philips CD650 and Aragon D2A, I have found Music and Sound's masTER LINK LP (Gray) to be superior by a surprising margin. The digits come out sounding more like music! (It's also a very fine analog interconnect.)
I've found two important preamp-specific tweaks: shorting of unused inputs (do not short the outputs!) and disconnecting tape outputs when not making a recording. Shorting of inputs (with shorted RCA plugs) can bring about a noticeable widening and deepening of the soundstage; my guess is that much of the advantage of the direct connection of CD player to amp derives from the lack of interference from "dangling" inputs. At the output side, it appears that tape-deck recording electronics present an uncomfortable load to the preamp if not energized, so if you're not using the deck for recording, you should turn it on anyway, or, as suggested, pull out the plugs from the "tape out" jacks. I first discovered this effect when I noticed a deterioration in my new preamp's performance after connecting a tape deck. The proviso is that the effectiveness of both of these tweaks depends on the design and construction quality of the particular component. With really good isolation of inputs and buffering of outputs, the effect may be minimal, but it's certainly worth checking out.
Power amplifier Tweaks
No specific suggestions here, but several of the points mentioned under "System Tweaks" are applicable.