The Beyerdynamic DT770 is a very good headphone out of the box. Anyone who is a fan of these headphones loves the powerful bass reproduction these deliver. When I got mine, I thought the bass was too heavy and that the upper mid range seemed dipped. I decided to modify the ear cups by adding sound absorbing material to reduce the low frequencies, making these a more balanced set of reference headphones.

Online, I found that many people  modify these headphones for bass reduction (some people even use blunt wraps, no joke). The most popular modified configuration for these includes wiring both drivers as opposed to wiring a harness to the left driver that also feeds the right driver and a cable upgrade to replace the flimsy stock cable.

I also painted these; I hadn’t airbrushed in years. We won’t go into the painting process much, as that could be a tutorial on its own.

I keep all my prized cans in flight cases, so for my mod, I wanted a detachable cable that I could store in the case and that would still feed into the unit from the Left ear cup, which meant that I also had to make a wire harness to replace the old one. I decided to use a Mini XLR connector and later found out that it’s one of the toughest connectors to solder as the terminals are tiny (as you will see later).

Overall, I’m very happy with my mod. I purchased a second pair of DT770’s which I’ve properly burned in for comparison (don’t rule out burning in headphones and cable upgrades until you’ve done your own research). I found that my original thoughts about these cans still held up when listening to the stock pair.

In the modified pair, I can still hear a good amount of bass, but it sounds tight and not muddy, it almost sounds like I’m listening to the low end of my B&W 685’s. I can also hear more details in the overall lower to upper mids; I’m getting a nice reproduction of frequencies around 600Hz – 1kHz without overpowering the lower frequencies. The high frequencies no longer have this “tiny” sound to them and I’m also hearing a wider stereo image which I believe is due to the cable upgrade.

This is what a stock DT770 looks like:

This tutorial will be broken up into two parts:

• Part I:
  • Introduction
  • Materials
  • Tools
  • Disassembling the headphones

• Part II:
  • Desoldering and cleaning the connections
  • Soldering the new wires & connectors
  • Modification of the ear cups
  • Putting it all back together
  • Building the new cable

Materials used for this mod

Dampening Material. I had some leftover acoustic foam underlayment from when we put down our floors, and I’ve used the same material under my nearfield’s MoPads to give me a little bit more absorption.

Canare Star Quad cable (L-4E6S). This cable is excellent for headphone builds. It has great shielding and four .21awg wires for our +/- connections.

1/4″ Techflex. I like sleeving my cable builds with Techflex, it gives the cables a good appearance and it stays cleaner than having the bare Canare sleeve, which can get dirty really fast.

3/16″, 3/8″ & 1/2″ Shrink Tubing for the ends of the connectors and the wires coming out of the earcups.

Desoldering Wick. The terminals on the drivers will have a good amount of solder and to be able to see the tiny holes on the terminals to feed the new wires into, you’ll need to pull the solder out using one of these.

Cardas Quad Eutectic Solder. This is considered by audiophiles to be one of two things: The best solder available for high end audio gear or Overrated solder that doesn’t offer any more quality than a much cheaper, high quality lead-free solder. I personally don’t have time to test the quality of various types of solder, so I went for it; I can say that it is very easy to work with, it melts easily and my connections were all nice and shiny (and at the end of the day, what matters most is the best possible connections).

3-Pin Male & Female Mini XLR Connectors. (Redco #RED TA3FB for Female connector & #RED TA3MB for the Male).

Furutech FP-704 1/4″ TRS Plug. This is a cryogenically treated plug for demagnetization. It’s a heavy plug, all-metal 24k Gold Plated.

E6000 Glue. To glue the female mini xlr casing to the left 770 ear cup. This glue chemically fuses plastics and other materials together; makes Krazy Glue look like Elmer’s. You have to use this outdoors and be careful you don’t breathe the fumes.

One #83 “O-Ring” washer. I used this 1/2″ washer at the base of the female mini xlr connector to make it look neater and hide the rough modification to the ear cup.

Tools

Soldering Iron. I have a Weller WLC100 (under $50). This temperature controlled station is good enough for this kind of build and for making interconnects. It’ll make your life easier if you use a small flathead tip for tinning and soldering the wires to the plug’s terminals and a conical tip for soldering the driver terminals.

Tip Cleaner. I use the Hakko 599B Tip Cleaner because using a wet sponge will affect the heating element in your iron by quickly bringing down the heat on the tip (and this iron isn’t as good as the better temp-controlled stations that do a better job of quickly recovering) ; using a dry cleaner like the 599B lets you clean the excess solder off your tip and get back to work quickly.

Helping Hands Soldering Tool. These can be found for under $10 and they usually have two alligator clips and a magnifying glass to help you hold the connectors and wires steady while letting your real hands control the soldering iron and solder.

X-Acto blade.You can also use wire strippers to strip the wires for soldering (yes, I slice my fingers every now and then, so maybe get a good pair of wire strippers).

A very thin flathead screwdriver to remove two rings (one for each ear cup) to get access to the drivers

A small screwdriver to remove the screws that hold together some of the parts on the headphones.

Hot Glue Gun. After soldering the terminals to the 1/4″ plug, pouring hot glue to fill in the gaps between the soldered terminals helps seal the terminals, preventing oxidization as well as providing good insulation; hot glue is an excellent dielectric.

Heat Gun for the shrink tubing. Use one that has a low setting so that you don’t melt the wires’ insulation and techflex sleeving.

A multimeter (analog or digital) to test your connections for continuity. I have a cheap one I bought for about $10 as the need for a sophisticated multimeter for this build and for making interconnects isn’t necessary.

Dissassembly

First, gently pull out the ear pads. Pinch the edge of each pad where the elastic material meets the ear cup and slowly pull out.

Second, remove the eight screws as shown:

The screws are two different sizes, so keep track of which ones go where. One good rule of thumb when taking apart plastic pieces that are to be re-screwed later is to try your best to stick to the same screw per hole, even though they are the same technically, physically there could be slight variations in the plastic.

Once these small pieces are removed, you will then have access to the drivers. Each one has a metal ring that keeps the drivers in place. Use your small flat head screwdriver to pry out these metal rings, but be very careful when doing this as you can go right under the ring and puncture the driver underneath.

These rings snap into the ear cups, I found that just a little bit of pressure towards the center of the driver and then a quick lift took care of it.

After doing so, remove the foam discs and you will then have access to the drivers; here’s a shot of the Left driver. The enamel-coated wires are for the Left driver and the copper and white (insulated) wires go to the Right driver (I was surprised to see the use of enamel coated wire for the Left driver AND an insulated wire for the Right driver on a professional headphone):

Enamel-coated (copper) wire was not designed for use in professional audio applications where maximum insulation to avoid noise being introduced into the signal is desired. The enamel coating provides a very thin insulation which is okay for many non-audio applications, so it looks like Beyerdynamic has skimped on the quality of the cable for this headphone (at least for the L driver, the R driver had a much thicker unshielded wire and an insulated wire going to it as you can see in the picture; wiring should be consistent to all the components).  I believe upgrading the wires and making good soldered connections has helped these cans sound even better.

I also noticed that there was a lot of solder on the terminals, as you can probably see from the picture above. This is not how you want to make your connections. You want an even amount of solder to make a stable contact; too much time spent trying to solder a terminal can damage it and I noticed also that the terminals were a bit bent and the plastic housing behind the terminals was a little warped.

In Part II, we’ll go into more detail about desoldering the terminals, and finishing up this modification.