Headphones, Headsets, Noise-cancelling

Guide to Koss Headphones Mod (Step by Step)

Koss Headphones Mod

Guide to Koss Headphones Mod

Our guide to Koss headphones mod emphasizes the point that it seems each year, a new group of audiophiles discover the most important secret in portable audio. Prepare for the unexpected. The truth just might blow you away.

Many of us have a few gray hairs and may recall that these cheap headphones, which sound great, have been around for a decade or more.

Koss launched their most successful product in the 1980’s. The Porta Pro, a staple of the headphone world, is now the most well-known product. The Porta Pro is a perfect fit for Walkman culture, with just the right amount shiny silver highlights, blue, and black plastic and a unique folding shape.

However, just like other electronic products from the era, Porta Pro would have vanished in our nostalgic past if it wasn’t for one important distinction. Their new 35mm and 60-ohm drivers were great. These drivers were fantastic for their time and sound great even 37 years later.

Like any company who has achieved unmitigated success, Koss created a Marvel Universe long prior to the big brother realized this was the key to a major windfall.

Although these headphones are great, there is always room for improvement. Headphone modification (or modding) enthusiasts love a great driver and low cost, as well as the dream of creating massive-killingfrankenphones.

Spoiler alert. I’m one of them. Today we’ll be discussing the most well-known Koss modifications. They are easy to perform and I will show you how they measure up and sound. We will be focusing our attention on the Porta Pro KSC35, KSC75, KPH30i, and KSC75.

Koss Headphones Mod Overview

Three main types of headphone modifications are available (with some overlap).

  1. Cable modifications

Cable Modifications

You will need the following tools

* Soldering iron + solder

* A tiny flat head screwdriver/spudger

* Hot glue gun, epoxy or epoxy

* Dremel rotary tools with small grinder bits

* Xacto knife/break-off utility knives

* Very thin wires

* MMCX sockets

The Koss headphones are, like most cheap headphones, dual-entry. They can also be attached to the earcups. It is not replaceable. You can damage your cable and Koss will cancel the lifetime warranty. All Koss headphones come with a small, discreet design. The 35mm driver is contained in the cup, but there are no mini-XLR sockets, 3.5mm sockets, or 2.5mm sockets. This is why we need to explore IEM socket solutions. The MMCX small socket is small enough that it can be easily fitted and large enough that it can be used by DIY-ers.

This write-up will focus on cable changes as an aesthetic one. Many cables come in a range of different braid patterns, plugs or y-splitters. There are also many wire materials (including silver, copper, and a rainbow variety).

How to add MMCX Sockets to the Koss KSC35

Koss KSC35 Mod Steps

  1. Keep the driver steady in your one hand. Then, pull back to release the driver from the clip. Continue the same steps for both drivers.
  2. Pull the foam pad upwards and take out the little spikes that surround the driver.
  3. Lay the driver flat onto the work surface.
  4. To remove the cable cover, carefully use a small flathead screwdriver/spudger. The cover is only held in place by two small plastic pins. It’s not glued to the wall and is easy to take off. If you aren’t careful, however, you can easily break the pegs. While it is not fatal to remove the pegs, reassembly of them is much easier if they are still in place.
  5. Depending on the type MMXC socket, you will need to modify the cable cover. Although I prefer the threaded socket, both will work perfectly.
  6. Threaded MMCX plug: Use a Dremel tool with a small, circular grinder bit to enlarge the cable entrance hole enough for the MMCX plug to fit in securely.
  7. Peg MMCX connector: With a sharp blade, such as an Xacto knife or break off style utility knife, carefully cut the cable cover at its cable entry point. You will notice that the socket has both a flat and round side. Therefore, you need to make sure the cover fits perfectly on the flat side. It should be just slightly protruding from the cover. Take it slow. It sounds more complicated than it actually is. Start by slicing a bit at a time, and then compare it to make sure the socket is seated correctly.
  8. If necessary, remove any extra plastic parts from the cover to make the socket fit.
  9. If you don’t have the two small wires soldered to the sockets, add a few 0.5-inch wires to the center pin or one of the outer pins. I used an old and inexpensive USB cable to locate ultra-thin, flexible wires that were nicely color-coded in 4 colors. Remove both ends and tin them.
  10. Push the socket into the cover. It should stay in place as tight as possible and remain flush with the cable cover.
  11. You must remove the original cable from driver quickly and carefully (to avoid any damage due to overheating). You will find the solder pad for the colored cable. This is the pad to which you will solder your MMCX center pinwire.
  12. Apply the solder quickly and carefully to the new wires connecting the MMCX socket with the driver’s solder pad.
  13. Test the connection with a compatible cable and ensure that the driver makes no noise.
  14. Make two portions of 2-part epoxy the size of blueberries. Mix it with a toothpick and place on a surface that is disposable (such as a piece of aluminum foil or plastic bag) until you get a uniform color. When mixed, the JB Weld black and white blobs turn to a grey color.
  15. The epoxy should be poured on the cable cover. You don’t have to do this (which is often), but a Lysol wipe can easily take it off. Epoxy doesn’t set for hours. Cover the socket completely and fill in the spaces.
  16. Place the cable cover over the holes in the pegs. It should stay put. You can use a small clamp to hold the cable cover in the correct position if one or both of your pegs were broken during disassembly.
  17. Test the connection with a compatible cable and verify that it makes noise. You have one last chance to correct any mistakes. Once the epoxy sets, it becomes permanent.
  18. Place the driver somewhere safe, and resist any temptation to touch it for 24hrs.

Adding MMCX Sockets to Koss KPH30i

Koss Mod Steps

  1. Use this guide to remove the foam pads and open the earcups.
  2. BE SLOW AND TAKE YOUR TIME. I’m usually fairly good at these things but I only managed to get 2 of 3 mounting clips off each earcup. I held the cups together with small pieces from masking tape for testing. I then applied hot glue to each of the broken taps before final assembly.
  3. Because of the size and shape of my earcups, the pin-style MMCX connector was the best. I made the socket fit me better by removing one of its outer pins.
  4. Once the cup has been cut to fit, solder the 1″ wires into the MMCX sockets. Tint both ends. You should not solder wires to driver yet.
  5. Adhere the socket to the cup with epoxy. Tape the socket to the cup to secure it. You must attach the cups to the band.
  6. Once the wires are dry, solder them to the driver. Allow enough room to maneuver by leaving the wires at least 1 inch long
  7. Decide whether or not you will include the interior rear foam piece. If so, install foam pads or cut or glue the cup front to back.

Adding MMCX Sockets to Koss KSC75

The KSC75 is similar in design to the Porta Pro driver. However, it features a unique cup and wire cover. Although the wire cover can be removed easily, the KSC75’s unique cup shape makes it very difficult to attach an MMCX socket.

Koss Porta Pro

You’ll need:

* Cable with a 3.5mm stereo connector at one end

* Side cutting scissors

* (precision). Soldering tin

* Remove the earphones first from the rack. It is easy as they are just clipped in. Place one finger between your phone and the rack and pull slowly to release it.

* To take further steps, you should also remove protection pads

* Use a flathead drill to remove the blue case which is located on the connectors. You should be careful and carefully lift the blue case from both sides.

* There is a glue-like substance between the connectors. DO NOT REMOVE THIS GLUE. It protects two small wires which transmit the signal to the earphones from the opposite side.

* Place the plugs on the cutting nippers sideways.

* Trim insulation to a minimum of 1,5cm

* Separate each pair of wires from each cable

* In my case, the ground is the one that isn’t extra insulated as shown in the image. The signal is carried on the second one.

* Edit: The replacement cable that was shown in these photos had some problems… unfortunately. The long jack plug is what I believe caused the problem. I was able to find old apple Inear phones with microphones and used the cable. I have now a microphone on my kossPorta pro!

* Use soldering iron to attach the cables’ ends.

* The original cable was not sold with the earphones.

* As you can see, the right connection has an red dot. This is where the signal cable must be sold (in the first picture, the insulated).

* Place the cables in a manner that allows for soldering. This configuration seems to be the best way to attach the cable.

* Solve them and put it all back together.

Koss Comfort Modifications

Most headphone comfort adjustments boil down to just two things:

  1. Headband
  2. Earpads

Koss Headband Mod

A pair of headphones may become too heavy for comfort. You can change the headband or add a comfort band to the ears. The sound may change if the clamping force is changed, but it would usually be very minimal. There is no need to add padding or a comfort strap to the Koss headphones because they are so lightweight.

However, the KSC35 & KSC75 are ear clip style headphones. I don’t like this style of wearing and prefer a more traditional headband. Many of the Koss headphones have the same driver as the headband mounting mechanism. You can swap your ear clips to find a suitable band.

It couldn’t have been simpler to mount the KSC35 and KSC75 Porta Pro. The drivers back has a small, ball-shaped protrusion made of plastic. The socket where the ball clips into is found on the matching band, also known as an ear clip.

It’s a simple, but effective design. Other companies such as Parts Express have also produced sub-$5 headphones that come with a compatible band. The Parts Express headphones sound horrible, but the simple design works well to preserve the light weight and allow you to swap the ear clip-style headphones for a standard headband. Parts Express headphones are cheap and sound good so we can throw them out without regret.

Simply hold the driver and band tightly in one hand and pull out the clips with the other. Simply reverse the process to change the band and insert the driver into the new one. Easy-peasy.

Koss Earpad Mod

Modifying the ear pads is the next step to make the Koss headphones more comfortable on the head. The Koss headphones, in stock form, are very comfortable. However, the ear pads are thin and not thick enough.

You can choose from a variety of standard Yaxi pads in various colors, including red, yellow, orange, black and purple. You have many options to make your Koss headphones stand out. Yaxi claims that the pads are compatible with a wide variety of headphones.

Yaxi compatible headphone models



* Koss KSC75

* Koss KPH30i

* Sennheiser PXC300 (discontinued)

* Sennheiser PX 200-II

Although the Yaxi pads are designed to fit the KPH30i’s unique shaped headphones, Grado headphones can use ear pads. These headphones are one of the most comfortable I have ever owned. They fit perfectly on the KPH30i with the large, bowl-shaped, Gush-cush style pads. These pads are my strongest recommendation for the KPH30i.

Koss Sound Quality Modifications


Stock pads, Yaxi pads, Grado pads, or pleather pads? There are many options for pad rolling the Koss headphones. Let me be completely frank. The worst option for pleather pads is the one I have. They ruin the sound in every sense. They completely ruin the sound.

The pleather pad sounds awfully flat and nasally. There is a significant new peak in the frequency range of 1-2kHz and significant drop-off in the treble. Hard pass.

You have one option: move on to better options.

Comfort is vastly improved. The Yaxi pad is thicker, softer and even more comfortable. They are also perfect for the cups.

The Yaxi pads have a slightly higher mid-bass and more high-frequency reproduction, but retain the same sound signature that made the Koss driver special.

More natural sounding. More comfortable. The Yaxi pads are a definite must-have.

KPH30i earplugs

Because of their unique shape, the KPH30i is easier to fit Grado pads and much more difficult to install Yaxi ones. The stock pads are comparable to the Yaxi (big bowls), S cush(flat stock style), and the expensive Beautiful Audio merino Wool L-cush pads (donut shaped).

Large G-cush foams sound distinctive because of their unusual shape. First, there is no foam between the driver & the ear. The pre-cut hole fits almost exactly the driver. They also hold drivers at the farthest distance from their ears.

Kramer mod

Kramer5150 was a Head-Fi forum user who posted their modified KSC75 list in 2005. The legendary ‘Kramer Mod’ was born!

You will need the following tools

* Snap-off utility knives

* Spudger (optional)

* Small flathead screwdriver (optional).

* Drill

* Awl

* 9/16″ Drill bit


  • Remove the drivers from your headband.
  • The small (1-2mm in width) peg is located through the side of your cup when you remove it from the grill.
  • Rotate your cup exactly 180° from the peg.
  • Insert your knife tip or small flathead screwdriver into the small opening between the grill’s surface and the side of your cup. Don’t insert too deep, as it could damage the grill driver beneath.
  • Gently push the grill upwards so that you can slide your fingernail or thin spudger into the space.
  • The grill will pop out if you slide your fingernail around its circumference.
  • Place the grill on a scrap piece of wood.
  • Make 9 indentions using a sharp-pointed, pointed awl. 8 should be centered between each existing grill hole and 1 at the center.
  • You can drill with the drill bit 9/16″ using the indentations of the awl as guides.
  • Get rid of any pieces of plastic that may be left behind.
  • Then align the grill peg with its matching cup hole, and put the grill back into place.


Koss Headphone Mod Conclusion

If you aren’t interested in the thousands of words that go into modifying inexpensive Koss headphones but don’t have any, then you might be able to read them all. You can do yourself a favor by ordering the Yaxi earpads. You’re done. Stop reading. Go do it now.

This is the only thing you have to do to make this great line of headphones even better. Both comfort and sound quality have been greatly improved. Sometimes the simplest changes yield the greatest results.


FAQ’s: Koss Headphone Mod


Why are Koss headphones such a great choice?

The Koss Porta Pro headphones are very lightweight and can be worn on the ears. The headband is adjustable and flexible. It has a better sound signature than most headphones.  For more great headphones, check out our complete headphones guide.

Is Koss a good brand to use for headphones?

Yes. If you are looking for low-cost headphones, this is the right choice. They are a top-rated on-ear headphone. They’re lightweight, comfortable, and provide a good open sound.