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January 31, 2013

Keith Michael Kirby

Very sad news, Keith Michael Kirby, the maker of very fine custom audio chassis, passed away on Tuesday, Dec. 25. Per the Albany Democratic Herald, Keith passed away peacefully at his home at the age of 50.

Keith Michael Kirby

Please view the Obituary.

Keith made it possible for many in the DIY community to build beautiful tube amps with his custom chassis.

Keith's beautiful custom chassis

Without Keith I would have never been able to complete my projects like this Dynaco mkIII monoblock amplifier below. He was always extremely friendly and he had a great passion for audio. It saddens me greatly that we won't be able to discuss our personal projects any longer. The DIY community simply won't be the same without his great contributions. May he rest in peace. 

My Dynaco mkIII featuring Keith's chassis

Contributions in memory of Keith may be made to SafeHaven Humane Society, P.O. Box 2018, Albany, OR 97321.

January 20, 2013

Furez Copper Subwoofer Cable

A subwoofer only reproduces a limited range of audio in your system, most likely a frequency range within 20Hz and 100Hz. With this being said, subwoofer cables aren't as critical as the interconnects responsible for a much wider range (in my humble opinion). So, if you're weighing the benefits of subwoofer cable versus a pair of interconnects between your CD player and amp, I'd say go with the interconnects first. Still, as audio enthusiasts, we can't simply ignore our poor subwoofers, can we?

Today I will be assembling a pair of subwoofer cables from Furez FZ162AA audio cable. This is a reasonably priced cable that features thick 16 gauge oxygen-free copper conductors (99.997% pure, aka 4Ns), a very adequate foamed polyethylene dielectric and a dual-shield (tinned copper braid and a aluminum foil wrap) to help protect against EMI/RFI interference. I'll also be using some Furez FZ100BS black and grey sleeving to dress up the cable a bit, and a set of Cardas GRMO Rhodium over silver-plate RCAs.

The cable itself is nice and thick, thicker than the Cardas Crosslink 1i interconnect cable.

Furez FZ162AA Audio Cable

Taking a look a little closer, you'll notice the thick 16 gauge copper conductors. Normally audiophile interconnects are between 20 and 24 gauge, so this is a bit thicker than typical and thus will have additional capacitance (Capacitance @ 1KHz: 20.86 pF/ft). One could even use it for a speaker cable at this thickness. Whether or not this will be beneficial when used as a subwoofer cable remains to be seen.

Furez cable detail

As mentioned above, I'll be using some Furez FZ100BS black and grey sleeving to dress up the cable. This sleeving is made specifically for Furez products by ViaBlue. To see some of ViaBlue's bling, check out this mini to RCA cable made using their products. The FZ100BS is made from Monofilament Polyethylene Terepthalate (PET) and Fiber Fillers.

Furex FZ100BS black and grey sleeving

Do note that a hot knife is needed to cut the sleeving, otherwise it will fray, as you will see in the image above. The hot knife melts the sleeving together and prevents this. Also note that as you sleeve the cable, you will lose some length as the sleeving is expanding slightly. This amounted to several extra inches for each five foot cable length.

Noting the cable stripped below, you will see the two 16 gauge conductors, one in red dielectric, one in black. You will also see the mesh copper shield. For this particular cable, the mesh shield will be soldered to the ground on the source side and not connected on the other (floating shield configuration).

Stripped wire

Here is the opposite end of the cable after tinning the conductors. Tinning simply means covering the conductors with solder in this case. On this end of the cable, the shielding is not connected, so it is trimmed down and isolated with 3M electrical tape. Note that the black conductor (ground / return) is cut slightly shorter intentionally.

Tinned conductors

Now we will be soldering the Cardas RCA connector to the conductors. This is done by removing the barrel of the connector, then sliding it over top of the cable with the tinned ends and lining them up with the appropriate solder terminals. The red conductor (signal) goes to the center pin and the black conductor (ground / return) is soldered to the inner barrel. The Cardas GRMO requires quite a bit of heat to ensure a proper joint. I find that a solder station with adjustable temperature is necessary. The joints should be strong and shiny when complete. 

Cardas GRMO soldered in place

Once the soldering is complete, the RCA needs ample time to cool (they will be extremely hot to the touch). Then the outer barrel can be screwed in place and 1/2" adhesive heatshrink placed on top to act as a strain relief. 

Barrel and heatshrink added

I tend to like to cover about half of the Cardas barrel with the heatshrink so that some of that shiny gold bling is still visible on the completed cable.  

Heatshrink in place over barrel

All that's left is heating up the heatshrink with the heat gun and we have a completed cable. A second identical cable was made for the right channel and now we have a very fancy pair of subwoofer cables.

A complete set of subwoofer cables

Hope you enjoyed reading this post. If you are interested in having your own custom subwoofer cable (or any other cable) made, please contact Zynsonix for a quote.

The Fine Print:
The above steps detailing the building of a cable are for entertainment purposes only, and not to be performed under any circumstances. The owner of this blog and all associated parties can not / will not be held responsible if you attempt the process posted and cause physical harm to yourself, your surroundings or your property. Please keep this in mind.