DIY Hi-Fi Cable Projects

We have added a few new DIY Hi-Fi Audio Cable Projects to the main website.  Here is a quick summary of the new cable projects.

Belden 89259 Interconnect Cables

DIY RCA Interconnect Cables with Belden 89259 Coax
A couple of weeks back we added detailed instructions that were put together by our friends at auDIYo.com to construct the popular Belden 89259 line-level RCA interconnect cable design by Jon Risch. The cables are a simple unbalanced RCA interconnect cable design that uses the high-quality and low capacitance Belden 89259 coaxial cable. Through the use of TechFlex Expandable Sleeving, shrink wrap and good male RCA plugs, a novice can put together a very nice looking set of Hi-Fi interconnect cables that will deliver the performance and not set you back a few hundred dollars. For full details, see the Belden 89259 DIY RCA Interconnect Cable project page. The photo below are DIY Belden 89259 RCA Cables put together by Paul from Kent, UK. Click the image to enlarge.

Cross-Connected Belden 89259 DIY Hi-Fi Speaker Cables

Using the same Belden 89259 coaxial cable as in the project above, step-by-step Instructions are also available outlining the construction of Cross-Connected Belden 89259 DIY Speaker Cables.  The cross-connected speaker wire design is also by Jon Risch.  For full instructions outlining the assembly process, see the Cross-Connected Belden 89259 DIY Hi-Fi Speaker Cables project page.

DIY Low-Inductance Speaker Cables
We have also added instructions to construct simple DIY low-inductance speaker cables. Adam has put together these fine looking speaker cables for his DIY 3-Way Hi-Vi Tower Loudspeakers. The cables are very simple to construct and consist of plain 16 gauge wire that is twisted together in alternating directions. The alternating cable geometry results in a speaker cable that has a very low-inductance and the equivalent wire gauge 10 and thus the cable resistance is also low. For that Hi-Fi finish, Adam uses a set of high-quality gold plated banana plugs, TechFlex Expandable Sleeving and a custom laser etched decorative oak sleeve. The results are a sharp looking speaker cable that rivals the performance of commercial speaker cables at a fraction of the cost. For full instructions, see the Low-Inductance DIY Speaker Cable page.

DIY Low-Inductance Speaker Cables

More DIY Cable Projects

• DIY Silver RCA Interconnect Cables
• DIY Shielded RCA Interconnect Cables
  
• Belden 83803 DIY Mains Power Cable

What's Playing: Roy Orbison - In Dreams (live)

Coldplay - Left Right Left Right Left [2009]

While not DIY, I thought I would let you guys know that Coldplay is offering a free album download.

Quote from Coldplay.com:

"... The free download of Coldplay's new live album, LeftRightLeftRightLeft, is now available here on Coldplay.com ...

Today [May 15, 2009] is also the day of the band's first North American tour date, in West Palm Beach, where the first copies of the LRLRL CD will be given away.

The CD will then be handed out to all fans at every remaining Coldplay live show in 2009 (apart from Festival shows). The free download will also be available from Coldplay.com until the band play their final 2009 show."

The download is a 54.5MB .ZIP archive containing 9 .MP3 tracks which are recorded live. The MP3 tracks are 192 kbps and sure they are not the pinnacle of sound reproduction, but it's music and FREE.

Here is the link to download Coldplay's Left Right Left Right Left live album [54.5 MB].

Track Listing:

1. Glass of Water [4:43]
2. 42 [4:52]
3. Clocks [4:40]
4. Strawberry Swing [4:16]
5. The Hardest Part / Postcards from Far Away [4:15]
6. Viva La Vida [5:24]
7. Death Will Never Conquer [1:39]
8. Fix You [5:38]
9. Death And All His Friends [4:22]

The images of the album cover are and a screen shot of the track information is included below. Click on the images to enlarge them.




What's Playing: Coldplay - 42 (mp3)

DIY Lightspeed Passive Attenuator

Alps Blue Velvet, Bournes, TKD, Alps Black Beauty, DACT Stepped Attenuators ... If you are familiar with some of these names, you likely have an interest in high quality passive attenuators and you should continue reading. The noted items have a few things in common - first off, they are potentiometers that are often used as attenuators or volume controls in audio equipment. As a volume control, they also have another thing in common - they all used some form of "contact point" to attenuate audio signals. In the case of a potentiometer, this is typically a "wiper" which slides along a conductive material forming an adjustable voltage divider. If you are passionate about audio reproduction, you are fully aware that these "contacts points" can be the source of unwanted noise. Now it certainly does not make sense to spend money on high quality interconnect cables only to run the signal through a dirty potentiometer that you infrequently spray with with a contact cleaner like Deoxit.

When people talk about the "sound of capacitors" someone will inevitably say that the best sounding capacitor is "no capacitor" - that is if it can be eliminated. So following that principle, one could argue that the best sounding attenuator is one with no contact points in the signal path. Enter the Lightspeed Passive Attenuator.

The Lightspeed Passive Attenuator uses optocouplers to establish the level control and this is done with no "contact points" through the attenuator. The optocoupler is a LED and Light Dependent Resistor (LDR) is one housing. The operation principle of the Lightspeed is simple - by adjusting the intensity of the LED you can change the resistance of the LDR. By using a series and shunt combination of matched optocouplers the attenuator produces a constant input and output impedance, regardless of where the voltage control setting is. Hmmm, an attenuator with constant input / output impedance and no contacts points - great idea!


Uriah has put together a detailed set of instructions to build a DIY Lightspeed Passive Attenuator. I've built one of the attenuators for myself (photo below) and I think it's great! It is a remarkable improvement over all the passive potentiometers that I have tried. The attenuator is very simple to build, so if you have an interest in higher quality volume controls take a look at the instructions.


The attenuator design could easily be scaled upward to include support for multiple channels and used as an effective way of controlling several of channels for a Home Theater setup. For full information, see the DIY Lightspeed Passive Attenuator.

What's Playing: Marta Gomez - Canta

Simple DIY Monitor Speakers

We recently received an email asking for some clarification about the difference between line-level and speaker-level Baffle Step Correction Circuits with a reference to the DIY S.E.Xy Speaker Project over at Bottlehead.com. This message brought our attention to a very simple speaker project that we thought we would point out to our readers. A photograph of the S.E.Xy Speaker Project is shown below.


In short, the small sealed monitor speakers are comprised of inexpensive Fostex FE166E fullrange drivers and housed in prefabricated Dayton Audio 0.25 ft^3 cabinets from Parts Express. This is a very simple speaker project and the only woodworking required is a couple of holes through the front baffles for the drivers (electric drill and a hole saw should do).

What caught my attention with this project was the fact that the 6.5" Fostex drivers actually fit in the small prefabricated speaker cabinets. While I have used the great looking Dayton Audio speaker cabinets in the past, I never bothered to check if the 6.5" Fostex drivers would fit.

Fostex FE166E vs FE167E
Of course some of you may prefer to use the Fostex FE167E fullrange speaker driver in place of the FE166E and that should not pose any issues. The FE167E has the same efficiency of 94dB but with it's higher Qts it will be able to produce more bottom-end which will allow you to lower the crossover point and possibly even allow you to get away with just one subwoofer. The figure below shows the modelled frequency response of the two drivers in a 0.25 ft^3 sealed enclosure.


The modelled response shown above uses the T/S Parameters noted on the Fostex data sheets. However, based on our experience with measured T/S Parameters from other Fostex drivers, expect Qts to be a little larger than noted on the data sheet. This means that we can expect a little more bass than what is shown on the plot. In addition to getting more bass out of the FE167E, you may also prefer it as it does not exhibit the rising frequency response of the FE166E which some may find too shouty.

Baffle Step Compensation: Line-level vs Speaker-level
This speaker project was meant for use with the 2W Bottlehead Single Ended eXperimenter's amplifier and therefore Line-level Baffle Step Compensation is the most practical choice as it won't waste the precious power of small tube amps. If power is not a concern, you can use the Baffle Step Circuit Calculator to come up with suitable speaker-level circuit.

For those wondering about the line-level BSC I have run a couple of simulations. I did not know the input impedance of the Single Ended eXperimenter's tube amp so I assumed 100k-ohms.



It would be a good idea to try the BSC on a protoboard and adjust the values to suit your room and personal taste. I would start without the 1.2nF (0.0012uF) capacitor, especially with the FE166E.

The inexpensive Fostex drivers work well in sealed enclosures. I am still very happy with my Sealed Fostex FE127E Bipole Speakers. For those of you afraid of woodworking, the prefabricated Dayton Audio cabinets are for you. Also, for the time being PartsExpress is offering free shipping on most orders over $98 (limited to USA).



More DIY Bookshelf Speaker Projects:

• Fostex FX120 DIY Bass Reflex Bookshelf Speakers
  
• Fostex FE127E DIY Bass Reflex Bookshelf Speakers
• Fostex FE167E DIY Bass Reflex Bookshelf Speakers
  

What's Playing: Emilie Mover - That Song