Maintained by Sanjeev Arora (arora@cs.princeton.edu)

(This page describes various audio DIY projects ---one speaker cable, four interconnects, and an AC line filter---that I did as per the recipes of Jon Risch, which may be found here. Jon is one of the moderators of the Audio Asylum bulletin board, which is a good source of information on hifi matters. Jon himself will answer questions addressed to him. A great guy. Other good sites on hifi include Soundstage, Stereophile, UHF Magazine, Good Sound. Another site with a great bit of noise and some useful information is audioreview.com.)

Reviews:

My reviews of these projects can be found in these two places: cable, filter. The filter had the most dramatic improvement on my system, and the cable had a less dramatic, but still quite noticeable effect. My experience suggests that one should build the filter before doing any other tweaks or projects, otherwise the junk in your AC mains will prevent you from hearing the (subtle) effects of your  tweaks.

General Notes on Construction:

The projects below do not require much skill, time or expense. I spent more time wading through relevant posts on Audio Asylum than on the projects themselves, which were completed in one long weekend. (1 speaker cable, 4 interconnects, and the line filter, and they took maybe 20 hours total and maybe $250 in expenses.)

You require the following tools (maybe a friend can lend you some of these for a weekend):

WITH ALL PROJECTS, TEST FOR SHORT CIRCUITS AT THE END.

Speaker cable using Belden 89259 wire

This cable uses the Belden 89259 coaxial cable. Jon researched many bulk wires before deciding upon this one. I got 100 ft of the cable from the local Anixter and it was enough for a 12ft pair of speaker wire and 4 interconnects.

I am assuming you have read Jon's fairly thorough description. Here are some additional suggestions summarized from Audio Asylum: (a) Use a coaxial cable stripper ($6.99 at Radio Shack) to strip the cable. A craft knife will also work, with some care. You do not want to nick the copper while stripping the insulation. Just nick the insulation lightly --don't cut it---and use a plier to gently bend the insulation a few times. The insulation is brittle teflon and will break where you scored it (kind of like a brittle metal). Practice this a few times before trying to assemble a cable. (b) Follow Jon's recipe, which involves some soldering. Some people do not solder and just twist the necessary wires together, but Jon thinks this leaves open the possibility of accidental shortcuts. Soldering gives some mechanical strength to the joint, with only very slight harm to signal purity. (c) When Jon says "comb and dress the braid" he is referring to a process similar to what you might do with tangled hair; people with long hair probably know this process. In case of the copper braid, you do this with a pointed but smooth object such as a long nail. Do not use a sharp object such as a knife which can cut or nick the copper. Proceed patiently, taking maybe 5 minutes for combing a 4 inch length of braid. All this sounds complicated but is easier to figure out once you have the stripped wire before you. (d) The recommended termination is a crimped-on spade lug. People have had good experience with spades from Radio Shack (very cheap), XLO Audio (moderate), and Kimber Postmasters (expensive). I found that Radio Shack no longer carries gold spades, and got mine from Parts Express (part number 263-549). Get some extra; they are cheap and you don't want your labors stalled if you mess up a connection. Standard size spades do not fit some speaker terminals. In this case Jon recommends spreading the spades a little with a plier (making them V-shaped rather than U-shaped) or using a drill to widen the opening.

I wasted some time trying to figure out from Audio Asylum what "crimping" is and how it is done. Here is the explanation. To crimp, you get a simple crimping tool. I got a $6 wire stripper/crimper from parts express; it has various sized jaws for different wire thicknesses. (The Belden speaker cable is 12-14 gauge.) First, you slip on the spade's insulation jacket onto the wire. Then you put the bare wire --maybe coated with Caig Pro Gold---into the spade terminal, then crush the terminal between the  appropriate jaws of the crimp tool. The spade terminal deforms and grips the wire. Do it another time. Check the connection by using some force to try to pull off the wire from the spade. If it comes off, you have to cut off the wire and start with another spade. If it is fine, you slip on the insulation jacket onto the connection.

The only other comment on the Risch recipe is that two cables are twisted together to form a speaker cable. (So you need about 50 ft of cable to make a 12 ft pair of speaker cable.) You want to terminate one end ---including soldering and some use of heatshrink to hold them together---and then twist the wires together **before** you try to strip and terminate the other end. I terminated both ends before twisting and had to undo my labors.

You use heat shrink to hold the twisted wires together as Jon describes. Jon in his description recommends heat shrink with adhesive but many people find it too stiff. Heat shrink without adhesive (such as 3M VFP-876) is fine and makes the cables reasonably flexible. If you do not have a heat gun to shrink the tubing (I didn't either), then you can use a hair dryer (or gentle heat from a stove top;  I was able to make this work with some care).  In this case, get heat shrink with a shrink temperature below 100C. Parts Express sells such heat shrink too but a cheaper source is Allied Electronics or Digi-Key. You need a small amount of the 1/4" (maybe a foot) variety for the leads and a larger amount of the 1/2" variety.

Interconnects using Belden 89259 and 89248

Jon has two recipes. A simple one involves a single run of 89259. I made three pairs of these for components that are not so hifi (VCR, a Denon Tuner etc.). Each pair took about an hour  each once I got  the hang of how to strip the wire. A more complicated recipe involves a twisted pair of two wires, and takes maybe 3 hours. I made one of these for the CD player. I used Dayton RCA plugs from Parts Express (part number 091-1270), which are popular with people on Audio Asylum. Their build quality is impressive for the price, and they use teflon insulation (Jon's recommended material).

Jon's description of how to solder the wire onto the RCA plug sounds complicated, but is easy to understand once you have the plug and the cable in your hand. Jon recommends soldering the ground wire (which is the twisted braid in the case of the single-cable construction) to the inside of the plug, not too near the "hot" terminal. Here is another description by Sean, which also has useful soldering tips for the neophyte.

The twisted pair seemed easy to make too. (Instead of Belden 89248 I used Belden 82248, which is available from radio shack.) The only question is how to strip off the Teflon jacket from the wires: you do it using a craft knife --remember that the teflon is easy to cut because of its brittleness. (It is also quite frictionless, which allows the copper braid to slide off easily off the inner teflon.)  Then I came to the part about adding a shielding braid. Here  Jon says that you cut up the teflon jacket of the inner conductor using a craft knife, and use this as "spacers" between layers of teflon tape. I gave up because it sounded too complicated. I was using unshielded ICs already (Kimber PBJ) anyway so I hope unshielded ICs will be fine. Jon does not recommend unshielded cables but says they may be OK if not placed close to other cables, power cords, or components. Moreover, he adds that adding the insulating braid  with improper spacing ---easy to do if you're not very good at such projects---can harm the quality of sound. This decided the issue for me.

Another note: with both IC designs, you wrap some teflon tape (available as "Plumber's tape" from Home Depot; get either the pink or yellow variety) on the ends of the cable before you slide them into the RCA plug. This makes the fit snug and helps protect the solder joint from mechanical stress. Then you shrink some heat shrink on to the RCA plug and the wires to provide more mechanical strength. (You can slide the heat shrink on after the soldering since the Dayton plugs are narrow enough to pass through.) The heat shrink gives a really professional look to the cable; mine look more professional than Kimber PBJs. (Kind of similar to the cable here.)

A soldering tip: when you solder onto the RCA plug you can't hold it by hand since it gets very hot. Sean describes a fancy way to hold the RCA plug with special tools and heat sinks etc. I used a simpler technique: I plugged the bare plug in the back of an old cassette deck. This left both hands free for  soldering. The cassette deck probably also acted as a heat sink and prevented the teflon insulation from melting. In general, teflon resists melting quite well (as you know from your kitchen).

Line filter and surge suppressor

This project had the most dramatic effect on the sound from my system and is highly recommended. Jon's description of this project is somewhat incomplete. Although he gives precise descriptions of the circuit and which electrical parts (inductors, capacitors etc) to buy, he leaves details of the enclosure and construction to you. This is the forbidding part to a neophyte: you don't want to mess with AC mains with a flimsy construction that leaves you and your loved ones susceptible to shock and injury. Some people --such as Lukasz-- have assembled the line filter using wooden boxes, whereas Jon recommends a metal enclosure (both for shielding and for safety from fire in case some part fails). However, I could not find any metal enclosures at Radio shack, Digikey etc. that have cutouts for outlets, circuit breakers etc. Finally, I was able to improvise with stuff picked up at Home Depot.

Lukasz Fikus has his own version of the Risch filter using do-it-yourself inductors, but Jon feels that this recipe is not to be recommended for people who do not know what they are doing. (The underlying problem seems to be that Jon's recommended inductor, JW Miller part 5524, is unavailable in small quantities ---here's information on how to get it in quantities of  >25--- which led to Lukasz's improvising.) Also, Lukasz's inductors are big and would not fit the enclosures I am using. So I used Jon's recipe and his alternative for the inductor,  JW Miller 5520..

Some people note that amps seem to get somewhat reduced dynamics when you use Jon's recipe. I am currently not using the line filter for the amp  (I am just using the front part of the Risch filter, without the inductors, for the amp.) (ADDED TWO WEEKS LATER:  I recently discovered that the peak current draw of my Sim Audio Integrated is only 3A, so I felt emboldened to try plugging it into the filter with the inductor. I don't detect a noticeable effect on the dynamics, so now I have it plugged in all the time.)

Some notes: (a) Here is a better schematic of the circuit; the one on Jon's page does not display correctly. (ADDED 2/10/01: Jason Pannell has provided an MS Word document with the schematic.)(b) People not used to reading circuits should not be intimidated; once they have the parts (and some hookup wire--I used 14 gauge hookup wire from Home Depot) things will be clearer. Note that most parts such as capacitors, inductors etc have long lead wires, which you can use to connect/solder without using any hookup wire. (Wrap the exposed leads  with electrical tape after soldering, to prevent short circuits.) (c) See Jon's note here, especially the last paragraph for a helpful tip on placement of the varistor. (d) For the enclosure, I used off-the-shelf components from Home Depot. In the "circuit breaker and fuse boxes" section you will find aluminum enclosures for circuit breakers. These can be fitted with electrical outlets (I took the most expensive, "industrial" version of the outlets; $8.50 for a pair) and plates that go on top of the outlet. The largest box can take 6 outlets (3 pairs), with a little gap left between them. I recommend using only 2 pairs per enclosure, thus having a larger gap on top. The reason is as follows. (e) Jon cautions that the circuit components, especially inductors, should be spaced 1 inch away from the metal enclosure. If you have only two outlets on the top of the enclosure, you have some empty space on the top, which you can cover with a piece of plywood. The inductors and most of the circuitry can go under the plywood portion instead of under the outlets, which are made of metal. (f) The aluminum enclosure has some screw holes on the bottom. I used these holes to  screw the enclosure onto a piece of wood (ask at Home Depot if they will cut you a wood piece of the appropriate size). I also screwed on  thin strips of wood on the floor of the enclosure to give a nonconducting surface on which to assemble the circuit. (g) When you buy it, the aluminum enclosure does not have a hole to let in the mains cable. You can knock out 1/2 inch holes using a small hammer (see the picture below; or ask a salesman at Home Depot). To fit the wire into this hole you need a "wire clamp" which is in a nearby bin at Home Depot. I knocked out two holes, one for the wire and one for the circuit breaker. (To my relief the Potter & Brumfield W28 series thermal circuit breaker   fitted beautifully inside this wire clamp. This was an unplanned improvisation.) (h) You can use  1/2 inch pieces of bare copper wire as a "terminal" onto which you can solder capacitors, wires etc. At the end you can fix this terminal onto the wood floor using silicone glue or improvise in some other way. I also fixed runs of insulated wires onto the wood floor of the enclosure using thin nails (more like staples) nailed to the wood and the bent gently onto the wire. At the end I poured some glue onto the wire to further fix it onto the wood. (i) The shielding braid on the mains cable is left floating (unattached) inside the enclosure. It is attached to ground at the plug end. (j) Jon recommends using one of the outlets to plug in a 100W lamp, which must be kept on at all times. This is to "damp" the circuit, which I don't understand but have obeyed. (k) The metal enclosure must be grounded for safety reasons. The outlets then ground automatically through the mounting screw.

PICTURES:

wpe2.jpg (11479 bytes) 

(A general view of the enclosure, which is screwed onto a piece of wood. The round "ports" on the side walls of the enclosure can be  knocked out gently with a hammer to create a hole. Note the two holes on the right ---one for the mains cable and one for the circuit breaker---and the use of  metal clamps. Note that the top of the enclosure has holes for 4 pairs of screws. The screw that come with electrical outlets fit exactly into these holes (everything is standardized).  The picture shows one of the outlets mounted on the left edge, and the other will be mounted on the right edge, on top of the circuit breaker and the wire inlet. The open space between the outlets gives "room" to the inductor as Jon recommends, and will be covered with thin plywood. Note that the enclosure has holes for 4 pairs of screws on top, which allows you to do this. The outlets will be covered with standard plates available from home depot; the finished appearance is similar to the electrical outlets on your wall.)

wpe3.jpg (16290 bytes)

(A closeup of the circuitry, where you see the wood strips screwed onto the bottom of the box. You can see that cleanliness is not my forte, though the untidy appearance here is somewhat accentuated by  loose wires waiting to be hooked up to the outlets.)