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Reducing vibration at source is more effective than later addressing the same problem externally in my experience. The CDP/DVD player of medium quality (Denon 2910 in my case) again demonstrated this and I suggest that even those with significantly more expensive players may find it well worthwhile to check the following tweak (if they can gain access with the component cover off, tray out, power off and CD unit cover off or its equivalent for top-loaders).
It's simply that the fast-rotating drive with the imperfectly circular CD or DVD (even after beveling) generates so much vibration that it can overwhelm the insulation provided by the floating tray holding the track for the laser-reader to pass slowly across the radius of the disk. If you have ever moved your vehicle out of a parking spot at the same time as another moves in so that there is no absolute reference point, the mere thought of a simultaneous vibrating CD and laser-reader is an anathema. In the case of the Denon, I could not observe how effective the little rubber flanges (on which the laser-reader track floats) were as insulators so experimented with the sound outcome of placing different amounts of Rope Caulk and GB Duct Seal in different locations. It turned out there was an improvement in sound image definition and tone quality from placing a little piece of Rope Caulk on each corner. The reduction in blurring around each note made it possible to hear deeper into the music that then sounded more detailed and sophisticated.
Switching off the LED display and cleaning the laser-head with Isopropyl alcohol audibly improved clarity and tone. Using a color-marker on the laser floating tray over-sharpened musical dynamics to discord while black rendered the sound flat and two-dimensional. Apple-green and orange work well in the CD tray itself but purple creates discord.
DG
Edits: 02/18/15 02/19/15Follow Ups:
I’ve had GB Duct Seal on the plastic support over the CD tray and the interior sides of the CDP (Oppo 980H) for several weeks now. Much quieter back ground with a increase in clarity and dynamics. The tray was painted last year with paint pens (green, orange and blue) revealing more detail and clarity.
Pixelphoto,
You see all those multi-wire connectors going to and between circuit boards in your pictures. I have found that disconnecting one end and twisting them a time or two more before re-connecting them again (as well as further twisting other pairs/ fours) audibly increases the access to musical detail from my Denon CDP/DVD 2910.
Dryginger
Very nice! DG
Hi DG, I'll try your suggestion on the Sony DVP-S7700 I just received from Bay. I sold the Oppo 980H; the one you see in the pict.
Ditto Pixel.
Nice work. I have used DynaMat Extreme constrained layer material to do pretty much the same areas as you have done. It is tricky however as it is NOT removable after being placed. One can use more than 1 layer as thought necessary. It is designed and engineered to reduce vibrations (frequencies), usually the lower ones. Seems I saw a "shoot out" of sorts of different materials and brands thereof some time ago, likely for high end Auto. HiFi applications.
robss
.
More sweet pics!
Pixelphoto,
Thank you for the excellent pictures. Did you compare GB Duct Seal to Rope Caulk?
DG
That was my intention but the dumb asses at the big boxes had know idea of what I was talking about. I've used rope caulk before and did want to compare. I feel lucky I found the GB Duct Seal. At any rate its working at its unintended job. A great tweak!
Pixelphoto,
Rope Caulk is an 'Ace' product and any of their hardware stores will stock it if you have one anywhere near you and want to acquire some in the future. It's easier to work with than the denser GB Duct Seal which stays rather too messily stuck down to the hands and everything else. It's indeed fun to make a big improvement for little money almost by accident sometimes...
DG
Thanks for the info DG. Ace Hardware it is. I'll get some and stow it in my official "Tweaker Kit".
Pixelphoto,
Have just been reminded what a distinct improvement to sound quality results (at least with the Denon CD/DVD 2910 and presumably other universal players) from selecting the 'CD' rather than DVD 'stereo' or 'multi'sound setting. Although all three settings produce sound when playing a CD, it's all too easy to forget to reverse the setting after playing a DVD and then immediately remember why the CD sound is degraded when the display is off.
The sonic enhancement from the 'CD' setting is presumably attributable to the reduction in circuit noise after power to the the video board/s has been switched off.
DG
Hi DG, yes I discovered the same after listening to the various settings.
One of the issues of optical payback is the correction circuit. The laser lens needs to move up and down, and side to side to track the "groove". If the movement is warranted the sled motor becomes involved, too and it is this movement which affects the playback circuitry, in the sense that the more the correction circuit is involved the ore the sound becomes.
One issue is that the correction circuit is a feedback system. IT becomes involved when an error is sensed. There is always a slight delay for it to "kick in."
Modern error correction circuits are mounted on a single IC chip and pretty much standardized. I have actually added ferro fluid to the correction motors (around the laser lens) and that has had the effect speeding up the correction motor speed: adding dynamics an detail.
CAREFUL. practice on an old machine first. Spilling the fluid will ruin the lens assembly, and you need also to balance the amount on the various motor coils or else the correction circuit will move assymetrially and NOT focus properly.
Uncle Stu,
I lightly oiled each rail of the laser-track that was less than silky smooth after twelve years but see no evidence of access to correction motors on this machine.
Would placing a dampening blob of Rope Caulk on the one-inch-square video chip introduce a problem? The chip does not get hot.
DG
older Harman CD player circuit.
Second is photo of laser assembly.
Harman had relatively sophisticated CD machines for its time and cost. Notice the copper shields on particularly noisy IC's. The DAC chips are also placed under the board to provide more of a ground plane and EMI isolation. You can see the outline of the chips on the top of the board.
The laser assembly shows the shield off. You can see the copper coils surrounding the lens assembly. On the large coils are two smaller coils on each side. I soak those coils in ferro fluid ( CAREFULLY!), not dripping. Most laser lenses assemblies have similar motor assemblies although the orientation may be different.
The next generation of HK machines were even more sophisticated with star grounds and special EMI casings (7450, 7600). Note all analog output stage. Suitably modded they could sound as good as a Wadia separate (IMHO).
Unclestu:
What kind of ferro fluid do you use (type/viscosity),
and where can it be obtained?
Many Thanks!
Dan
Dan,
I just let a pipe cleaner absorb some MG Chemicals 801B Super Contact Cleaner and applied its soft narrow bent head to all visible contact points and running connection lines of parts on the floating tray including around the vicinity of the laser. The dynamics and flow of the music now dance effortlessly as Uncle Stu describes so ferro fluid may well be the best long-term solution but it is not a short-term requirement for those wanting to use a contact cleaner instead.
DG
AN oblique shot of the laser head. A gentle push to the laser head will reveal that the copper colored windings will move up and down, back and forth. The white rectangle to the right of the picture, right of the lens is the hinge assembly.
The copper winding boxes a pole piece for a magnet, and there is an additional pole piece outboard both coil windings. It is on these coils that I add the ferro fluid. Care must be exercised as the pole pieces will attract the ferro fluid !
Idea is that the ferro fluid fills in the gaps between the coil wires and thus increases the magnetic intensity of the motor, strengthening the field and making it react faster to the servo correction circuit.
In experimenting with this, it brought to light the importance of the correction circuit for audio in all optical drive systems. It also showed how poorly designed most correction circuits are. There hasn't been a laser mechanism which did not show dramatic improvement by adding ferro fluid to the motor coils.
Caveats: ferro fluid is a colloidal suspension of ferrite in mineral oil. Spill into the laser well and kiss the laser goodbye: you can cnot clean it out. The mineral oil will eventually dry out. That being said the ferrite material will already be lodged between the coil wires, exactly where you want it anyway
Uncle Stu,
Have you heard the result of adding contact enhancer to where wires are soldered to the circuit board/ volume pot/ speaker output terminals/ case in an amplifier? Be interested to read your comments if you try it.
DryGinger
Uncle Stu,
You're 100% right! Lacked the understanding and nerve to mess intimately with the laser in order to access its coils as you here articulately describe so was surprised with the beneficial outcome of contact-enhancing every visible tray connector/connection.
Thank you for sharing outstanding tweaks that invariably inspire multiple ideas for testing in my brain. The outcome of one was unexpectedly and remarkably productive. Since it can be applied at virtually no cost to considerable sonic benefit by any audiophile, I'll start a new thread later to give it a higher profile.
DG
bought mine off ebay; no data. use very little!!1
Unclestu:
I find you work with the ferro fluid on the laser to be quite interesting!
Is it possible that you could start a thread where you would have 1 or 2
very close up pictures of the coils, and where exactly you are putting the
ferro fluid? A few arrows would also be good. It sounds like you are applying the fluid to the copper wound coils - is this between the coils and the magnets, or just on the coils (as in soaking into them)? Also, what do you use to apply the ferro fluid to the coils?
It sounds like the fluid you use is just something you found on e-bay... would you say that it is a typical ferro fluid as far as viscosity?
Many thanks for all you great tweak posts and in-sightes! I have worked
in the area of lab vibration analysis for decades, and an quite attuned to the concepts of damping movement, resonances, and vibration.
Dan
might take a while for photos. if you're patient I will eventually post.
I only soak the COIL assemblies. Since the correction motors move and can move a lot allowing too much ferro fluid to the point where it bridges the gap between the coils and the magnets or pole piece greatly increases the risk of splashing the fluid onto the optics. BIG NO NO!!! It is impossible to clean the mineral oil off(don't ask, but I've tried)
IF you place too much ferro fluid and you form a bridge, a piece of kleenex can absorb excess. I use a #5 stainless forceps to control the tissue, although you can fold it into into a triangle and apply.
Before placing ferro fluid, always analyze the motor assemblies. All laser assemblies have some kind of shield, usually plastic clip on.Remove to see the coil assemblies.Remember the lens has to move in two planes, so you may find four or even six coils. Each has to be loaded with about approximately equal amounts of ferro fluid (I've never been really critical because my mechanical dexterity is not so great these days.
If the laser motor coils are not overflowing but don't track well, I simply add more till I can see the ferro fluid build up in the coils themselves. The static magnetic fields will tend to hold the ferro fluid in place. Be careful as the magnets will draw the fluid straight to the pole pieces and magnets themselves. If that occurs I wipe the magnets and pole pieces clean to avoid bits flying off.
I used to use a diabetic insulin needle to apply the ferro fluid. Thin and it doesn't need much, but I do find it difficult to control the syringe itself. I use a toothpick these days and I actually have better control leaving a tiny droplet of ferro fluid on the very tip. As you approach the coils you can literally see the magnetic field "pull" the ferro fluid into the coils (power should NOT be on). HINT: move very slowly and carefully observe the tip and the destination...
Top photo is the common Sony KSM 2xx series.
Motor coils are large and easily accessible. Notice the larger square box is color coded copper and the two ring coils on each outboard side are coded gold. These represent the vertical and horizontal coils. All need to be soaked.
You can easily pull the motor coils to one side for greater ease of application. Even though applying from one side the ferro fluid will flow and usually equal out after a few seconds of playing (don't be surprised if sound is slightly distorted in the first few seconds.
Remember you want roughly equal amounts of ferrofluid on both sides,
Second photo is the ubiquitous Philips design CDM -12.
Motor coils are sandwiched between the magnet structure in a very tight position, Application is tricky as you need to approach from the front or rear accordingly (90 degrees to coil structure). Fluid will bleed to magnet so be prepared to wick away access
Great pics! Stu.
Sweet pics!
Uncle Stu,
Thank you for illustrating the coils via the picture.
Your mentioning the special EMI casings reminds me how in the case of this Denon the substitution of plastic for their brass covered stainless steel machine screws positively degrades audio and video. It not designed to have a domestic ground connection (no ground pin) and, given the number of small tingle shocks from the case, I suspect that all the circuit boards/ case use neutral as a ground alternative like space vehicles.
Never fail to be surprised how much inexpensive audio performance many manufacturers leave on the table because they exhaust intellectual bandwidth/ time/ money or are more concerned with engineering than sound quality.
DG
Very cool project!
So even though the disc doesn't touch the tray during playback you feel there is audible benefit? I wouldn't be surprised as stopping anything from vibrating usually helps.
E
T
ET,
Please accept my sincere apologies for a misspelled, mis-titled and incomplete posting made when distracted.
In the case of the case of Denon CDP/DVD 2910, the suspended tray holds both the 2.75" long laser-track and the shaft mechanism that rotates the CD at high speed (not perhaps self-evident from the original posted image). The use of suspension ensures only that this tray becomes an island of vibration whose impact on the unit's four circuit boards has been minimized. So the suspended tray is holding the shaft that rotates the CD against the free-spinning center in the unit cover together with the tracking laser-reader.
When the side-loading CD tray closes, the angled suspended-tray levels itself, the shaft pushes the center of the CD up against the free-spinning magnetic top in the aluminum cover, the high-speed rotation begins, the red laser reads through its green lens top and the amount of vibration on the suspended tray reflects the lack of complete CD circularity that not even beveling and use of a Marigo Audio Ultima Signature Mat can achieve. Damping the vibration on the suspended-tray provides more nearly constant timing over the whole disk when power calls for laser re-read positioning are at a minimum and interfering least with other unit processing activities. At least that's my understanding and the result is deeper bass, more natural musical tone, mid-range and treble notes firm, well-defined without audible fragmentation.
Interestingly placing rope caulk directly under the rotating mechanism (where there is no motion) does not produce good sound whereas adding rope caulk around the spinning center inside and on the top of the CD unit cover does contribute positively. All told the improvement in sound quality for $3.79 of Rope Caulk is both unexpected and substantial for this Denon. Fully appreciate that others with more expensive CDPs manufactured to higher performance standards may get less benefit.
DG
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