Audio system optimisation.

 

This article began with the idea of offering inexpensive tips for obtaining the best from your audio system. Of course, what is applicable to vintage gear is equally applicable to modern equipment. As I compiled the list, it became apparent that many of the important points relate to correct equipment support and isolation.

The advice given here is based on my personal, first hand experience. I can promise subjective improvement by paying attention to what initially may appear to be minor details. The improvement following each change may be subtle, but collectively, the overall impact can be stunning.. This approach may also save a great deal of angst and money by eliminating the desire for an expensive upgrade. The changes stemming from correct installation really can be as significant as using a different piece of equipment, so don’t discard anything just yet!

Use a high quality, purpose-built equipment stand for all your units. All your audio gear should be off the floor, including any mobile-home sized power amps. Employ either a very rigid, heavy stand or one which "isolates" the equipment in some manner, usually by some system of suspension or levitation. Both types provide a solution to isolating equipment from external vibration, each using a completely different approach. Both will definitely provide significant improvements over a "nice teak cabinet" or even, heaven forbid, a coffee table. Very rigid shelves screwed into a substantial brick/concrete wall can provide an effective and cheaper alternative.

There is no easy answer as to why good equipment support is so important. The easy and often heard reply is that external vibrations, surface and airborne, are prevented from interfering with sensitive audio equipment. In extreme cases this is obviously a consideration, but what if the loudspeaker volume levels in a large room are very moderate, or you are listening with headphones?  I think the benefits of good equipment support are still to be heard. This suggests that equipment may be susceptible to internally generated vibrations, and indeed some internal electronic circuit components are slightly or very microphonic. However, this theory is rather speculative, so I'll leave well alone just now!

Ensure that CD players and record decks are perfectly level. Don't forget that a CD spins between 200 and 600 rpm, so give the reading laser a fighting chance for optimum tracking performance. In the case of record decks, use a spirit level on the platter to establish it is perfectly level, essential to aiding correct bias, tracking and channel balance.  If you have one, use a good Hi-Fi test-disc to check the tonearm anti-skating (bias). “Buzzing” of the pure tone recorded on the test disc on one channel suggests a bias issue. If there is buzzing only on the left channel, there is too much bias. If the buzzing is on the right, there is too little. If the noise is heard on both channels, it suggests a general tracking issue. Having said all this, in some cases the cartridge may actually play music perfectly, but this is rare.

Attend to the positioning of external wiring. Avoid running mains cables next to signal cables, especially near low level signal cables from a record deck. In theory, decent signal cables should be well screened and earthed, but the quality of screening is often variable, with some manufacturers employing zany cable profiles which are less than effective. For good measure, avoid having loudspeaker cabling trailing next to signal cables.
Coiled-up cabling is never a good idea, whatever it's being used for. It can create unwanted inductance and worse still, in the case of loudspeaker cabling, can destabilise power amplifiers (especially high-powered ones). Overall, poor cable placement and dressing can cause hum, degrade the low frequency and high frequency response, as well as generally "muddying" the sound you hear.

Use good quality mains plugs and ensure that that all connection pins are clean and not oxidised. Personally, I clean 13 amp plug pins with brass cleaner, but this may be a little eccentric! At least spray a little Isopropyl alcohol onto signal connection plugs, if there are any signs of oxidisation (dulling). Proprietary solutions are available from stores like Maplin.

Keep digits away from analogue. To prove my point try this. If you have an FM tuner to hand, tune it to your favourite station and place it near to a working CD player/ transport /digital word clock. When the CD player is playing, and you may be shocked at the amount of interference being picked up by the radio. Some players are better screened than others, but do you really want to risk subjecting your amplifier's circuitry to this tirade?  Incidentally, PC’s, mobiles and mobile phone chargers (switched-mode powers supplies) are culprits too. If you have a separate DAC and CD transport, I would suggest that you keep these apart and avoid stacking them.

Make sure your record deck is properly earthed. You may not experience any obvious hum through the speakers, but improper earthing can allow static-build up on records.  If, when lifting your cherished Shirley Bassey vinyl off the platter the record has a strong static discharge, this may be caused by inadequate or no earthing to the deck. Connecting an earth lead to the deck can in itself create a hum loop, but there is usually a solution to be found.  I can't offer a definite solution as every system/installation is different, but trial and error is as good an approach as any.

Avoid placing speakers too near to walls, and room corners. Unless the speaker is specifically designed to work against a wall (very few are), you will have an exaggerated bass lift effect. Initially impressive, in time you will find that many recordings sound muddled and overblown. You may also hear the lack of a clear stereo image caused by mid-band reflections from walls messing up the phase of the waveform from the speaker. Additionally, referring back to the first point in this article, try and keep the speaker cabinets off the floor. I would propose that even " floor-standing" speakers are not placed directly on the floor unless they have spiked feet or something similar. Vintage speakers are more likely to be disadvataged here. An interesting and radical approach is the Townshend speaker platform which effectively isolate the speakers from the ground. The platform provides free movement of the speaker enclosure allowing it to wobble, but far from instinctively writing off this approach, I have heard some remarkable results where these novel, if quite expensive, custom bases have been used. And no, I don’t have any financial interest here!
In the case of stand-mount speakers, a support of the correct height, placing the HF unit in line with your ears when you're seated, should be utilized. The most common approach is to have a very rigid stand spiked to the floor, and there are many good deigns around.

Mains connection. Remember that the sound heard from your speaker originates as watts drawn from the mains - power doesn't miraculously appear from nowhere! A good mains conditioner may be of benefit to source equipment, especially digital units, but be wary of utilising conditioners for power amplifiers or higher powered integrated designs. Results can be variable so do audition a conditioner in your system before buying. It's well known that mains power is "dirtier" in the evening when domestic TV sets and computers effectively pump “noise” into the grid, messing up the nice, pure 50 Hz waveform. This makes the mains regenerative conditioners the most effective in these circumstances. So if you think your system always sounds better during the day rather than in the evening, it may not be your state of mind after all!

Check the tone arm VTA or Vertical Tracking Angle. This is basically the height adjustment of the pick-up arm; whether it slopes upwards or downwards from the pivoted end, or set parallel to the record playing surface. The cartridge designer would have determined the optimum playing angle for the cartridge cantilever relative to the record, typically 15 to 20 degrees. The exact figure chosen by the designer isn't of importance to the user, but achieving it is. Unless the cartridge manufacturer specifies otherwise, begin by ensuring the arm is parallel to the record surface when lowered. Obviously, records have different thicknesses, so choose an "average' disc to assess the position, rather than a 180 or 200 gram one. Depending on the stylus profile, altering the VTA will have varying degrees of impact. A typical effect of adjusting the VTA by straying away from the parallel norm, is a change for the better or worse in tracking ability especially on sibilance, more or less high frequency and better or poorer stereo imagery. Unless you are discontent with the cartridge performance when the arm is perfectly parallel, there’s no need to alter it. Avoid becoming obsessed with tinkering and failing to enjoy music! In any event, it's highly unlikely that the optimum tracking angle is far off the parallel norm, but a very small adjustment can make a significant change. With some decks such as the B&O, VTA is not adjustable as these decks are designed to be used only with B&O cartridges, so the optimum VTA is guaranteed.