Speaker Amp to Headphone Cable

I'll be showing off a rather unique audio cable today: a cable that connects the outputs from a speaker amplifier to a pair of headphones. You may be wondering why someone would be using a speaker amp for a pair of headphones. A typical headphone amplifier will output relatively a small amount of power compared to the speaker amplifiers (in small fractions of a watt measured in milliwatts). The Audeze, as well as certain other planar magnetic headphones like the HiFiMan, really benefit from some added wattage to sound their best as they aren't the most sensitive drivers. Hense, in some cases using speaker amplifier can be worthwhile.

Obviously speaker amps were made with speakers in mind, so there will be compromises involved. First and foremost, one can blow out or damage sensitive headphone drivers if turning up the amplifier volume too high. There are also some impedance differences, typically a speaker amplifier outputs at 8 ohms (and in some cases 4 or 16) while headphones will typically range from 35 to 600 ohms. Another factor to consider is that speaker amplifiers may not have a quiet black "background" when used with headphones due to noise, magnetic flux from the transformers or other reasons. Even still, with all of these factors, many audio enthusiasts still prefer listening through their speaker amp.

I'm starting out with some thicker-than-typical wire to braid. Using thicker wire not only assists in delivering a little more juice to the headphones but makes the soldered (or screwed in some cases) connection to the spades or bananas at the speaker amp end of the cable stronger. With a thin 24 gauge wire that would typically be used as a headphone cable, the joint would not be able to take as much abuse as a thicker, heavier wire. 

Silver plated copper with a thick dielectric

This wire is braided and an unbalanced Neutrik locking female is soldered in place. Note that an unbalanced connector is okay for use as the speaker amp has shared grounds (the left and right ground are connected with no resistance), otherwise this would not be acceptable and a balanced connector would be required. Note below that the two ground connectors are soldered together to the ground pin.

Braided silver plated copper in PTFE wire

The cable is now sleeved with the typical Techflex brand Nylon Multifilament in the 1/4" size and heatshrink is applied at both ends. I think it's visually appearing how the cable geometry is fully visible thanks to the tightness of the sleeving. The four lengths of wire are left unbraided at the end for the amp-side connections (sometimes the binding posts can be spaced relatively far apart). 

Sleeved with black nylon multifilament

The white wire was then covered with thin black heatshrink to match the color of the rest of the cable. Note that the heatshrink, just like Teflon tubing, can be resistant over long distances and can require a bit of patience. Once in place, a heat gun is used to shrink it down by starting at one end and moving to the other to avoid air bubbles getting trapped in the middle. 

Speaker ends being prepared

Now the spades could be soldered on. These particular spades are made by LOK and available at Homegrown Audio. They're gold plated and feature a high copper content (over 68%) and fit a 1/4" or 3/8" binding post. Each connector is labelled "L" for left, "R" for right and "G" for ground.

Below are photos of the final cable

Completed cable

And here is an example of the same type of cable for balanced operation. this particular cable uses a Neutrik locking female and rhodium plated spades.

Balanced 4 pin cable to rhodium spades

Need one and don't want to mess with a soldering iron? Zynsonix offers custom-made speaker amp to headphone cables (and many others), please contact them 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.