So that's pretty simple huh? A cap and resistor in series that is connected to your speaker or amp in parallel. A snubber, a Zoebel, an R/C network call it what you like. The hard part is the construction. The cap could be a Wima metalized paper cap, a Vishay polypropelene or any other mid priced cap. Don't use a cheapy. If you don't buy a good cap the sound will suffer. A minimum of 100 volt should be used. The Wima is X rated (250 volts) I find the cap to be critical in performance so spend what you can.
For resistors I like the Vishay metalized film 1% tolerance 1/2 watt. Mills and other good resisitors work.Good carbon comp resisitors seem to be my favorite.
Now to values: many use a .01 cap and a 10ohm resistor. You can use a higher value of resistor as well. I know others that use a .047 with a 100 ohm resistor. Look at Chris DeCostas pdf and look at his cascading values. Sorry it's hard to find now. You can make the filter with multiple R/C networks in parallel. DIY is nice cuz you get to decide! But really just use a .01 and a 10 ohm.
Don't skimp on quality on either part. You should be able to get all four parts for a pair for under $10. Spend more if you want better. You'll need a lot of other materials.
Here is a list:
Spades or Bananas - get at least some decent ones $5-10 ea. or more you need 4 Wire- use good solid wire 12/14 ga. copper or silver .Don't use stranded Important- The wire needs insulation no bare wire! Filter Body - you can use garden or other hose, tubing or model rocket body at least .6" ID Copper foil sheet or tape with adhesive back - this can be a bit costly Silicone (clear) caulk that dries "rubbery" not hard Solder - silver is better!
So you can see you can easily spend $30-40 or more in parts plus shipping to get them if you don't have some or all on hand.
Solder the cap and resistor together and the lead wires to the opposite ends. . These solders must be VERY GOOD so the stress of use doesn't break them. Also remember to make the total length of the cap/resistor short as possible so it doesn't need a large tube body to cover it.Solder the solid wire one piece to each end. Three inches is usually a good length but the distance the plus and minus terminals are apart from each other may be very wide where you might need more.
Cut your tubing in which you will insert the filter for proper length. You should have about 1/3rd of an inch of the heavy wire you will attach either a banana or spade inside the tube. After you have that situated fill the tube totally full with your silicone and let it dry. This dampens vibration and helps relieve strain when you put pressure on the hook wires.If you use silicone don't worry about the mess, you can clean up any excess easily when it dries.
Attach your bananas or spades to the wire ends. Did you remember to make a polarity mark for positive and negative? Remember positive goes to the cap side, negative to the resistor side. Attach your foil tape/sheet carefully. It should be wider then the filter body so you can fold the ends over. . Fold the ends over so they looks nice.
Lastly use pliers to bend the wires into the correct
position to mount them to your speakers or amp. Hold the wire as close
to the body as you can with needle nose and bend the wire ends with the
connectors to the spacing you need to mate with your speaker or amp.
You'll need to measure them on center to know this. I hope I made this easy to understand. At some point I will have pictures to go with this. Feel free to email me with any questions.
And now the disclaimer. This info is for your own personal use. If you don't have experience with electronics you shouldn't try this or should do so knowing there is a risk on several levels which includes hurting yourself or your gear if improperly made. It's always good to test the filter and make sure it does NOT have a dead short due to miswiring or bad soldering etc. If you don't understand this you shouldn't be doing this. Sorry.
DIY VERSION OF THE AC FILTER
This AC filter has been discussed at length at Audio Asylum in the "tweaks" area. Thanks to all those that posted on this. Audio Asylum has a great search tool if you want to see posts on the topic.
First a disclaimer YOU ARE WORKING WITH AC POWER IF YOU DON'T HAVE THE PROPER TOOLS AND KNOW HOW STOP NOW, THIS IS NOT FOR YOU! YOU MUST USE X OR Y RATED SAFETY CAPS AND FLAMEPROOF RESISTORS FOR SAFETY!!!
OK, that's done. The circuit is easy to build, it is simply four cascading resistor/cap/resistor values in series tied together in parallel. Here is the schematic. It does differ from the filter we sell. The difference is this DIY version does not have the resister/inductor string that goes from neutral to safety ground.
Well that's it.Lets talk about the safety ground though, which is omitted from the above drawing but should be used. There are folks that build this filter both with and without using it. Most often the above parts are put on a little board that is then put in a small P-Box. I prefer the ABS boxes which I then line with copper or TI Shield for RFI/EMI rejection. These "shields" conduct so the board must be isolated from the conductive shield. You could cover the board and parts with silicone on all sides and then cover it with black tape to be SAFE! If the safety ground is utilized the shield should have a drain wire connected to that utilized safety ground. You can hard wire a 3 conductor AC cable to the circuit or get a chassis mount IEC connector to put on the P-Box that allow disconnection of the power cable.