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Cheap, crazy good tweak. I have been putting off this tweak for months because I didn't believe that it would be very good. WAS I WRONG!! I filled some zip lock plastic bags (7in x 8 in) with sand then began to play a CD I knew very well. After a few passages, I placed two of the bags on top of my cdp. WOW!! The tightness, dynamics and separation of the sub, bass and mid-bass blew me away! I then placed two bags on top of my amp and got a slight improvement, one bag on top of my pre-amp and again a slight improvement. The longer I listened the better it got. All areas of the frequency range improved in terms of transparency, dynamics, attack and tightness. I could hear the articulation of the performance like I hadn't heard before. What I FELT improved more than what I HEARD. I could go on and on. I believe that better recordings reveal better results than inferior ones. I hope that my experience will help you try this tweak if you have been putting it off like I did.
BTW, I own upper level Arcam digital gear, with Acoustic Zen speakers and entry level Morrow Audio cabling.
kendo
Follow Ups:
I had posted this out on the internet way back in 1998, and had posted it here shortly after the inception of the Audio Asylum.
It was available for years on my DIY website at Geocities, now defunct.
I copy it below, in it's original form.
************************************************************
CD Players and Vibration
I have found a tweak that can provide a great benefit on some CD players. However, it involves taking the lid off, and placing objects inside, so if you are concerned about a warranty, or are not mechanically inclined, etc. don't attempt it. If you damage your CD player, I will not be held responsible.
Jitter has become a hot topic for digital audio, and jitter is real. It can creep in via the digital cable connecting a transport and DAC, it can creep in from the CD itself, and it can occur due to the master clock oscillator crystal inside the CD player or DAC. Yes, the very device responsible for eliminating and controlling jitter, the one that is supposed to make the possibility of jitter intruding into the system impossible, is also one of the weak links in the jitter defense! Crystals are piezoelectric, they generate an output when vibrated, just as they vibrate when exposed to a signal. If the sound from your speakers vibrates the crystal, this will generate spurious signals that will introduce signal related jitter.
How can this be, you might ask? This does not jibe with the common assumption that any corruption of the digital signal, must actually alter or lose a one or a zero. Computer data does not depend on the timing accuracy beyond preservation of actual bits and bit values. During most of it's journey, a digital audio signal theoretically is unconcerned with timing issues and subtle changes to the signal stream too. It is at the DAC, or Digital to Analog Converter where timing accuracy is paramount to accurately reconstructing the analog signal. If the timing is off, then the waveform has been corrupted.
Jitter is any variation in absolutely consistent and perfect timing, for when the DAC converts the digital code into an amplitude value.
What causes jitter in a digital audio system? Simple: anything that interferes with the digital logic circuitry detecting the logic transitions at the proper time will introduce jitter. Noise, RFI, varying power supplies and ground references causing the detection threshold to shift ever so slightly, injected signals, etc. It is ironic that the very digital logic chips that are necessary for the system to function also generate some of the interference that prevents it from reaching it's full potential. Everytime a logic chip changes state, it draws current to send the digital signal downstream, a pair of transistor's is turned on, and the current drawn is sudden and not trivial. How many logic gates are their in a modern CD player or digital audio system? Thousands, maybe tens of thousands? These are all being turned on and off in a complex sequence, some patterns which are unrelated to the signal, and some which are signal related. Often, dozens of gates fire within moments of one another, compounding the power supply rail and ground bounce issues. All of this activity shifts and modulates the timing of the detection threshold of a transition from a one to a zero or a zero to a one by the variations caused in the power supply rails or the ground reference. The popular audiophile press has referred to this as LIM, or Logic Induced Modulation. Even CD's with excessive jitter recorded onto them from the glass master can induce this form of jitter into the system, as the tracking servo works harder and the optical read system has to pass along the jittery data it is reading, the transitions of this read data end up getting into the PS rails, etc. and making it's way to the DAC.
The one device that is supposed to make all this moot, and provide freedom from system induced jitter is the master timing crystal, usually placed very near the DAC, which is responsible for controlling the timing of the DAC analog data clock out. The crystal is connected to a digital logic gate, so right there is a potential problem. Worse yet, the crystal itself can generate spurious signals due to vibrations from the speakers or other sources of sound or vibrations. Many CD players and DAC's use very cheap crystals, which are prone to external vibrations.
Placing sand bags on top of a CD player can help this, as can cones, platforms, air suspension systems, etc. but the most effective way to prevent crystals from contaminating the timing is to control the vibration problem at the source: place a sandbag on the crystal itself.
This needs to be done ever so carefully. All power should be removed from the CD player or DAC, you should discharge any static electricity by grounding yourself before opening or touching anything inside the player, make sure the drawer mechanism will clear any thing you add to the player ( a huge bag of sand is not necessary for this to be effective), and that the cloth or bag of sand will not block ventilation or rest on a hot power supply regulator IC. A cotton cloth, such as a handkerchief should be used as insulation from the plastic of the sand bag, then the limp "baggie" style (not zip lock) plastic bag loosely filled with sand is placed around and over the crystal, tucking the loose sand in around the crystal without getting too forceful.
What does a crystal look like? A small metal can, rectangular in nature, about 1/2" to 1 1/4" wide, from 1/8" to 3/8" thick by 1/2" to 1 1/4" tall, with just two leads. It is usually near the DAC chip, which is one of the biggest IC chips in side a CD player.
Be sure that you do not force any of the parts mechanically, or bend them, If you want to make the tweak permanent, and not subject o falling off the crystal, some dabs of silicone or glue in areas where there are no components, can tack the bag down around the edges, plastic wire ties (not metal twistie ties) can be used to seal the bag, and to hold it in place using the chassis or local mechanical structures, again being sure that the ties are not joined to the drawer mechanism, etc.
Once you have placed the sand bag on the crystal, additional zip lock type bags of sand on top of the re-assembled CD player or DAC will still help some, as other components other than the crystal can be sensitive to vibration, and additional mass and damping will weaken the vibrations that do get through t to the crystal. Once you have sand bagged a CD player or DAC crystal, cones or other vibration control devices may react differently than they did before, so experimentation is the order of the day.
It is not as likely that high-end expensive CD players will respond as much as less expensive models, because the top of the line players are likely to have better quality crystals in them than lower end players, but I am sure there are some surprises out there in this regard. My CD player, a JVC top of the line single play unit responded very nicely to this tweak.
Jon Risch
Jon Risch
Jon - I meant to include a THANKYOU for the tip.
Jon I'm glad you chimed in. I picked up this tip from your site a few yrs back: I made a little lead shot bag for the crystal which worked nicely, quite audible. I didn't try a sand bag and wouldn't predict which might be better - there is the possibility of sand conforming better, but lead has more mass.
try making a mini sand bag to fit the quarts oscillator in your CD player. Use a fine thin fabric so the bag will conform to the oscillator walls.
moray james
Moray, thank your for the feedback. I have never opened my cdp and hence don't know where the quart ocillators are located. Any pointers? I have marble tile weights on my sub, but will take your advice and try the sand bags. Thanks.
kendo
Kendo: the oscillator is usually a flat chrome looking can about a half inch high and three eights wide and an eight of an inch thick usually only one so it stands out and is easy to spot. If you make a little doughnut shaped bag from some spandex you can get a good layer of sand around it and the fit will be snug. A simple bag large enough to flop over the oscillator and a rubber band will achieve the same results if your sewing skills are basic. Works well. You can also use small flat sandbags on circuit boards but be careful to make sure you don't damp components (cover up) that get hot and need to be air cooled. There are special gel filled bags made for this application which have a gel version of antifreeze in them and they actually move the heat away from the device and help maintain thermal consistency across the circuit board. I have seen these installed below and above the board and they are very effective in small cases where the packs couple heat from the board to the case. So they act as both a heat sink and a damping pad at the same time.
If you just want to experiment with the sand bag on the oscillator you can use a small thin plastic baggie filled with sand and place that over the oscillator. If you use a corner of the bag it will envelope the device and wrap it in a bundle of sand. Cloth sand bags can also be placed under boards (in contact) to damp vibrations of sections of a board if you size them and place them properly they will stay in place. Again make sure you take ventilation into account.
moray james
Edits: 07/09/10
Moray, Jon and Wirewizard, thank you so much for the info. Moray do you know where to obtain the gel bags? Have any of you tried Vibration Magic? Wirewizard,do you damp your speakers? I placed marble tile weights on mine and helped a little. I think I will try sand bags also.
kendo
sorry I cannot recall the product name or company and I have searched for some time looking without success. The gel packs were for both thermal management as well as damping vibration of circuit boards in high density applications. The bag material was very compliant and conformed well to devices on the board to optimize surface contact. The bags were also resistant to puncture so they could be used on both sides of a circuit board to sandwich it between the top and bottom of a case. sorry I could not find more but somebody knows what they are called. Perhaps if you asked some suppliers of thermal management products. The link below might also be of interest.
http://www.amecthermasol.co.uk/AmecThermasolFlatCoolPipes.html
moray james
Maybe if there's any quartz in the sand, it might interfere, as do
granite slabs under CD's. Since the top is most likely steel, it
should shield it from interferance.
Edits: 07/07/10
Yes indeed...I use sand bags on my cd player and on my subs to great effect.
I do it all in the name of music!!!
sorry that I gave Moray credit for your sub sand bag suggestion. I will try it. Thanks for the pix and feedback.
kendo
Oh thats ok...BTW I tried granite slabs on the subs and the sand bags work much better;-)
I do it all in the name of music!!!
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