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.

AKG K1000 Extension Cable with Spades

Any headphone enthusiast worth his/her salt is going to be very familiar with the AKG K1000 headphones (or more appropriately, earspeakers). The K1000s succeeded the K340s in AKGs lineup and make use of a dynamic driver, and with a low 74dB/mW free field sensitivity, they take a good amount of wattage to sound their best. When they were initially released, they commanded a sticker price of $1200. Now that they are discontinued, they still garner about the same amount on the used market. I've had the pleasure of hearing the K1000s at a number of meets; they have a sound all their own with a very enveloping, larger-than-life soundstage.  

The AKG K1000 Earspeakers

Because they require so much juice, many users opt to use an adapter tail for the K1000s to plug into a standard speaker amplifier, more often than not, a tube-based amp that outputs 10+ watts. This post is focused on the creation of an adapter tail for the K1000s so the owner can use said speaker amplifier to power them. 


The process begins by selecting a nice suitable wire that is flexible, but is also able to transfer a suitable amount of juice to the power-hungry AKGs, something two to three times as thick as a typical 24 gauge wire. In this case, I'm using a thick, internally-litzed Cardas conductor in Teflon dielectric.  

How nearly all Zynsonix cables start their life

This wire is hand braided in a litz formation of four wires so that the cable maintains the same EMI/RFI rejecting geometry all the way across the length of the cable. 

A hand-braided litz of Cardas wire

Once this process is complete, the braided wire is fed into a sleeve of soft black nylon multifilament to not only give it a nice, vintage look, but help prevent microphonics when the listener inadvertently brushes the cable against something. At the Y-split, I melt the multifilament together to ensure that it does not separate when pulled or tugged. 

Wire sleeved with black nylon multifilament

There are many different ways to handle a Y-split on a cable, whether a simple bit of adhesive heatshrink, cable pants, or something fancy like ViaBlue splitter. In this case I'll be using the barrel of an unused RCA connector just for the sake of making it look nice. 

RCA Barrel that will be covering the Y-split

Once this barrel is slipped over the split, heatshrink and adhesive is used to keep it in place. 

A heatshrink covered RCA barrel

Now that the dressing is complete, a four pin gold Neutrik female connector is installed on one end and identifying heatshrink is added to the speaker connector ends of the wire. The Cardas wire is stripped and the enamel is melted away using some piping-hot 900 degree solder. 

Nearly complete with Neutrik 4 Pin connector

For the speaker connectors, I'm using some very nice Homegrown LOK rhodium over silver plated spades. Rhodium requires quite a bit of heat to solder to, so the wire is set in place and ample solder and iron heat are used to make a solid connection. Before this is done, additional heatshrink is slipped on the speaker ends to fasten the sleeve to the termination and keep it from moving. I also added a set of clear heatshrink to cover the positive and negative identification tags for aesthetic purposes. 

The final cable

The cable is finally complete! If you're a K1000 owner (or any headphone owner) looking for a headphone to speaker cable, Zynsonix.com would be happy to help.