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Since the Tuner will never be on when other sources are running it should act as a weight for the preamp right?

You see this as good or bad?

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Are there any other materials that I could use such as isolation pads or some cheap tweak to isolate the shelves?

Go the the sporting goods store and buy a bag of raquetballs. Cut them in half. How were you going to get the archery points to stand upright?

I think if you keep searching you will find low profile spikes/cones and floor savers for under $20 per shelf. Another option is to forgo the cones for isolation and go with rubber or sorbothane.

http://store.acousticsounds.com/category.cfm?section=equipment&id=61

You could use 3 spikes per shelf in a triangle configuration thereby cutting the # necessary.

My SolidSteel rack is this way and is very stable. 2 spikes in front, 1 in the back center.

Some people say this provides more isolation by having only 3 contact points.

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Good, there are products that you can buy as weights for the top of your components no? Mrlowry mentioned using them.

First, do not automatically assume that what works for one system works for all systems. Each component is different and responds to different tweaks.

Second, the idea of mass loading a component is typically done with a mass that extends over the entire or most of the top plate, not just resting on four points of contact.

Do more thinking here.

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How much do the balls compress? When there is weight on them do they go almost flat? I don't want much space between the MDF shelves and the frame...

You build to suit your desires. If you don't want much space but want a particular device under the shelf, you build to suit that device. However, without listening beforehand, do not assume the tweak that worked on the other guy's system will automatically work on yours. Make this a rule most especially when you are moving from isolation by mechanical diode type devices like spikes to resonance absorption devices like racquetballs or Sorbothane.

Part of DIY is providing the ability to experiement to find what suits your system - now and in the future - and what suits you.

No, the raquetballs do not squish.

http://forum.stereophile.com/forum/showf...part=2&vc=1

In most applications spikes are used point side DOWN as they are meant to channel vibrations AWAY from the component. So the flat side of the cone would come into contact with the bottom of the shelf and the point would come into contact with the rack.

The spike can contact the rack directly.

The kind of paint that they are talking about is something similar to this:

http://www.dynamat.com/products_car_audio_dynaspray.html

Laminating MDF? I'm not sure what you mean by "laminating'. There is no grain to MDF so you cannot oppose the grain in alternating layers. Are you talking about coating the shelf with a plastic?

All materials sound different under your equipment. MDF is cheap and dimensionally stable so it works well for shelves while providing a fair amount of damping. Some people feel MDF overdamps the sound of the system. Try thinner MDF for a different sound. Or two layers of MDF with a damping compound between the layers. Try plywood, glass or bamboo and you'll have a different sound coming from your system.

Read up on "constrained layer damping".

One of the negatives of stacking components is that their power supplies are really close and the radiated noise from one power supply could have a negative affect on the other component's sound. Even when off most electronics are still drawing current and part of their circuit is always on. Preamps deal with some of the smallest and most delicate signals, particularly those with phono stages so safe guarding the preamp is of paramount importance to creating a system with as low a noise floor as possible. The other negative is that of vibration again. Some times stacking components becomes necessary but try to avoid stacking anything on top of or below preamps because of the small signals that are inside or power amps because of their relatively large power supplies and the amount of noise they can radiate. If you have to stack two things I'd probably look at stacking the CD player and tuner, when listening to one turn the other one off. That won't completely eliminate the drawbacks of stacking but will minimize them. I'd try the CD player below the tuner first because of how many vibrations the spinning motor generates.

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Second, I can just take the feet off of the tuner the components have the exact same dimensions. That would be complete metal on metal contact over the entire surface area. However, even though the concept makes sense I doubt that it will improve the sound.

It would also cut off air flow through the amplifier. Best not to stack if it's avoidable.

You can buy veneered and laminated MDF. Be certain it is MDF and not a pressed board core. As long as there are no voids in the layering a thin laminate shouldn't affect the sound overly much.

Ya, you could stack the tuner on the tape deck, or vice versa. That would be better than my suggestion putting it on top of the CD player. I forgot that there was a Tape deck in the equation.

You can certainly spike some of the shelves and try other stuff under the other shelves. At worst you could always go back and spike the remaining shelves later.

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Isn't this what you guys have been telling me all along?

I've been telling you to think and reason before you cut any material. I've suggested you look first at what has come before in aftermarket and DIY racks and isolation devices and methods to benefit from the knowledge and experience of others.

Have you been doing that?

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I've been telling you to think and reason before you cut any material. I've suggested you look first at what has come before in aftermarket and DIY racks and isolation devices and methods to benefit from the knowledge and experience of others.

Have you been doing that?

It looks to me as if he has. Not only in this thread but in the others it seems like he is asking all of the right questions and also comes back with information from other sources to ask about it. He seems quite willing to change directions when the information he finds isn't in line with what he originally wanted to do.

Yes, for the most part I would say he has. I'm curious to see if he thinks he has. There's a lot of information of gather and digest in just a few days, and a lot of it will lead you in different directions - such as constrained layer damping. I don't think this is a weekend read and then pull out the saws type of project.

Why did you take my post as intimidation and criticism?

The level of your present system makes no difference to building the best product you can afford. Do you plan on this being the last system you ever own? If so, you want to get the best out of it. If not, then plan for the future.

If you've been taking my advice, you will have discovered many of the goals of a good rack are contradictory. If you want isolation, you have to sacrifice rigidity. If you want rigidity, you normally need some degree of mass; mass leads to higher degrees of lower frequency resonances and this is especially true when you are working with more traditional materials. Resonances are what you are trying to minimize. Knowing just one or two of those things will cause you to believe you've solved the puzzle when in reality you've actually complicated the maze.

I've been telling you to think this through and reason before you act. There's quite a bit of information out there to be found and taken in. There are good sources for the information you require to do the job correctly, not the least of which will be found in some woodworking books - if you stick with traditional materials.

Just being fed information only serves one purpose.

The design sounds good to me and Maple should be a good choice of woods. MOST components are a little over 17" wide some of the bigger rack mount stuff can be up to 19" wide. So I'd recommend a shelf width of 20 to 21" so that the rack doesn't limit your component choices in the future. Depth is a little trickier because some amps are super deep but if you did 20 to 24" you'd be able to fit just about anything. If it wasn't that deep you'd still probably be able to cheat by letting the amp hang out the back anyway or build a separate amp stand if you ever get on of those huge amps.

Three spikes are used often times because three points are all that are necessary to define a plane. Also three points offer less contact, and thus area for vibrations to enter a component.

With respect to placing the spikes under components I usually try to make sure that one spike is under the power supply because they do create small vibrations. With CD players try to make sure that one spike is directly under the CD tray to help drain as much of those vibrations away as possible.

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If you want rigidity, you normally need some degree of mass; mass leads to higher degrees of lower frequency resonances and this is especially true when you are working with more traditional materials.

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The shelves will be made out of MDF at least 1 inch thick with laminate on all sides.

Mass loading typically means exceptional amounts of mass spread across large surfaces or large amounts of mass situated on a very small contact point. There are components that react poorly to mass.

Otherwise, keep thinking until you're ready to build.

So the legs are going to 1 3/4" x 1 3/4"? A bit thicker might be better if it's possible maybe 2-3". The 1 1/2" shelf supports might also benefit from some extra thickness unless they are deeper that 1 1/2" in which case you might be fine. Do you have any way to calculate how much weight each shelf will support? I'm asking out of ignorance because I don't know much about wood. If every shelf could support 50 pounds you'd be be safe for just about any future purchase. Even 30 pounds would most likely be fine. But of course if the shelf that was meant for the amp could hold a little more weight that wouldn't hurt either, again mostly for future needs. The top looks ideal for a turntable.

I'm surprised that dbowker hasn't dropped by to offer his thoughts. He's a forum regular that's done some impressive DIY wood working projects related to audio.

MDF can be good for shelves BUT longer than 20" and it will bow over time. It's very inert compression-wise, but not in length. You really need some way of keeping it flat, like a hardwood frame glued around it, or a support glued/screwed underneath.

Obviously, the weight of the components affect how much, but that's a big thing to keep in mind. Maple is great upgrade option- and you might be able to find pre-glued up boards (like for tables or counters) that are not overly expensive. Maple has a good sound to it as well, though I don't quite believe it's a magical as the Maple Shade studies guys make it out to be.

Yes- you'll be fine at 18x18 size.

Have you thought about suspending the shelves rather than supporting them with spikes? Cut two small dadoes in the underside of the shelf and run a cable across the shelf to reach from side to side of the rack structure. Or hang the shelf from the wires only at the ends of the shelf? Or, support the shelf from the sides by spikes running horizontally through the rack uprights? Or a combination of these techniques?

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Have you thought about suspending the shelves rather than supporting them with spikes? Or hang the shelf from the wires only at the ends of the shelf?

Yes if someone had an accelerometer to find out what resonant frequencies they were tuning to that would be good too. Other than that it's pure guessing as he wouldn't have a reference to compare it to so he wouldn't know if he'd gotten the tension on the wires wrong. Maybe if the tension was adjustable he could do it by ear with lots of trial and error but that could drive someone up the wall.

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Or, support the shelf from the sides by spikes running horizontally through the rack uprights?

Finite Elemente does that and their racks certainly can help take a system to the next level performance wise. My only worry is that they use special spikes that I've never seen for sale that allow to really, really tighten things down. They publish numbers showing at what frequencies their racks work and the percentage of the reduction in vibrations. They use maple too.

I think you're taking my suggestions too far. I don't mean to tune to specific frequencies, that's too much for DIY. But suspending the shelves or supporting them from the side provides another layer of isolation that a hard mechanical connection between spikes facing up/down into the rack cannot manage.