Pioneer SE-700 Vintage Headphone Cable Mod and Balancing

The Pioneer SE-700 were the company’s flagship headphones released back in 1974. The driver is an unusual piezo-electric type. I am personally not aware of any other headphone manufacturer that offered this type of driver, but feel free to share in the comments if you know of one. The SE-700, SE-500 and SE-300 all use a similar element. 

An old advert for the SE-700 touting their specs

I’d describe the sound as airy, crisp, and similar to an electrostat with a detail emphasis. Bass quantity is very low, which I believe is typical of this type of driver. The simple metal frame and gimbals look rather elegant, and the overall unit is pretty light. The way it rests on the head is slightly odd compared to modern headphones, but it’s still very usable.

The piezo-electric driver is a very thin piece of metal foil with a frame going around the perimeter, with the positive and negative connections at the bottom. It is covered with bright yellow foam resembling a dish sponge. It is also quite delicate, so even opening the headphone can damage the driver. The unit is sealed shut with rubber cement or a similar adhesive so it must be opened very slowly and carefully to access the inside. 

An image from the user's manual circa 1974

The wire connections for the driver are circled in red below:

If you’re looking to purchase one of these you can keep an eye out on Reverb, eBay or similar platforms. Price for a good example will generally be between $80 and $150. You’ll probably want to replace the wiring including the 3-meter cloth-covered cable, and the vinyl headband and ear pads which will likely be flaking.

My client Steve who sent me the headphones had already replaced the pads and requested the inner wiring be replaced. The existing wiring contacts had been twisted together and covered with heatshrink (see above image), which seemed like an odd manufacturing choice and not an ideal connection. Running single strands from the connection would sound better. You’ll note both sides of the headphone below after the cabling was replaced.

The headphone was reassembled using 3M double-sided tape so it can be more easily opened if needed. Steve will be crafting a calfskin headband for the unit as a replacement for the original vinyl headband, which I feel is the only visual let-down. It appears EricJ from HeadFi created an excellent tutorial back in 2007 on creating a replacement headband which you can find here. Below you'll see the refurbished/modded unit.  

I hope you enjoyed this post on one of the more interesting vintage headphones out there. If you have a headphone that needs a cable upgrade please be sure to visit Zynsonix.com. 

Disclosure: Please remember that using a soldering iron and/or modifying headphones can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a modification posted above and cause physical harm to yourself or your surroundings. 

Avantone MP1 Mixphones Balanced Headphone Cable Mod

Not a headphone commonly discussed on HeadFi, but certainly deserving of some merit, is the Avantone MP1 Mixphones. They are touted as “suitable for use in live sound, DJ, studio recording, mixing playback and listening applications“. The earpads and cups are quite large, isolating, and comfortable, and house sizable 50mm drivers inside. A client of mine, Steve, with a penchant for unusual looking electronics sent me one to work some magic on to see how we could improve it.

The headphone comes with a 3.5mm input on one side and a little switch on the other side with a rudimentary circuit for adjusting the sound to your liking. Steve had tried the unit with an aftermarket Zynsonix cable first, but wanted to run it balanced, and the only way to do so was to remove this little device, which I assumed would help with the clarity anyway.

The circuit, switch and the 3.5mm inlet would all be removed in favor of mini XLR connectors on each cup. Brainwaves XL Hybrid earpads would also replace the stock pads, which Steve mentioned were comfortable but tended to flatten out over time. I indeed read the same thing from other reviewers online so it appears to be a common issue.

The sound had nice body and warmth, but wasn’t super clear, and the resolution on the lower end of the spectrum was somewhat lacking. I knew some mass-loading damping material would help with this and tighten up the bottom end a bit. On the inside, there are more metal parts than you typically find inside a headphone as metal, while adding mass which can be a good thing, tends to weigh things down. Fortunately the headphone remains comfortable. Avantone lists the weight at 550 grams, however it didn’t feel that heavy on my head. I recall Audeze’s EL-8 titanium as the only headphone I found was heavy enough to be uncomfortable, although some have said the same thing about the new HEDD Audio HEDDPhones as well. Good weight distribution goes a long way in assisting with this.

I placed some damping material on the driver surround and the inside of the cup strategically. You don’t need too much to get the desired result. Once everything was put back together with the new balanced cable, circuit delete, damping material, and pads, the sound was notably more resolving and controlled in the lower-end especially. Note the damping placement below:

Steve’s impressions:

Now, to the unmodified and your modification versions of the Avantone Pro MP1 headphones. Both have Brainwavz XL Round Hybrid earpads. The unbalanced version has a Trebuchet cable. The balanced version has a Ballista cable. They are both driven, not at the same time, from the headphone outputs on the front panel of the Soekris dac1541. Source is a Nuprime CDT-10, output set to 192kHz sample rate, AES/EBU connected to the DAC. Good results began after 15 hours of operation; my observations here are at the 25-hour mark.

As much as I liked the unbalanced version, the balanced version has more of the good stuff: crispness, bass extension, expansiveness, body, blacker background. Surprisingly, this results in a less dry and less analytical presentation than the unbalanced version. This balanced version is easier to listen to for longer sessions. I did try line level balanced output from the Soekris into an XDuoo TA-20 amplifier. [FYI, for this amplifier, balanced in and out is noise free. Any unbalanced, in and/or out, is too noisy for me.] This was not as good a combination. The Avantone headphones, probably because of their very low impedance [16 ohms] and very high sensitivity [113 dB] need the stability and the low noise of solid-state amplification. All in all, a worthwhile and satisfying result.

 

You can see some images below of the unit. Steve took some of the latter. I took far more images during the process however my Canon T7i decided it was time for a summer vacation and didn’t save the images to the memory card.

Anyway, hope you enjoyed this write up, and if you’d like an aftermarket cable or complete recable of the Avantones or other headphones please contact Zynsonix Audio. Thanks very much to Steve for generously sharing his thoughts and time as well!




Disclosure: Please remember that using a soldering iron and/or modifying headphones can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a modification posted above and cause physical harm to yourself or your surroundings.

Recabling a Pair of Beyerdynamic DT880 Headphones

Beyerdynamic is a family-owned audio equipment manufacturer based in Germany that produces headphones, microphones and wireless audio systems. The headphones produced by Beyer are very solidly made, I'd imagine the rugged designs have the travelling DJ in mind. Still, the sound produced by Beyerdynamics top-tier headphones is something the discerning audiophile can really appreciate. The DT770, DT880 and DT990 models are ideal choices for the listener on a budget, and if one likes what they hear, there are pricier Tesla-based models that Beyer has recently introduced, namely the T-1, T-5p, and T-70.

The Beyer DT770, DT880 and DT990

The differences between the 770, 880 and 990 are surprisingly not subtle. The DT880 tends to be the most chosen for neutral listening, it is a semi-open design and has the most well-balanced presentation of the three headphones. The DT770 and DT990 are much more bassy, with the heaviest bass response coming from the closed DT770. The fully-open DT990 seems to have slightly less bass and a wider soundstage than the 770. I personally think that the 770 is the ideal movie and gaming headphone, the 880 is the best for analytical listening, and the 990 is good for audio enthusiasts who need a fun-to-listen-to headphone that matches a typical speaker system's bass response. 

While the sound of each headphone varies, the process of recabling them is nearly identical. Aside from the driver and cup design, the headphones appear to be identical inside and out. For this post, I will be recabling the Beyerdynamic DT880 headphones. Below is a stock DT880.

The Beyerdynamic DT880 Headphone

The wire for recabling a Beyer and still keeping the single-entry look takes a little bit more care than a typical headphone cable. When braiding, the wire should go from a litz braid to two twisted pairs about 2 and a half feet from the end. One of these pairs is nearly trimmed off, only leaving enough wire to get to the driver within the cup. The other twisted pair will be run through the headband. 

The braided Beyerdynamic cable

The wire is then sleeved and the long twisted pair gets some heatshrink to distinguish each side. 

Sleeved Cable

Then a four pin Neutrik connector is attached for balanced operation. If you are interested in reading more about 4 pin balanced connectors, please check out my post creating a 4 pin to TRS adapter cable. 

Cable terminated with a Neutrik 4 Pin XLR

Now that the cable is ready, the first step to getting inside the headphones is to remove the velour pads. These pads stretch over the frame of the cup, so there are no screws to remove, etc. You will notice a number of perforations on the inside of the pads, these holes make a big difference in the sound, covering them adds unwanted reverberation. If one replaces the velour pads with leather, it is preferable (in my humble opinion) to get the leather pads with the perforations inside. 

DT880 pads removed from the cups

The next piece is removed using a typical envelope opener to pry the plastic ring out of the cups. The plastic ring retains the driver and driver surround. Once it has been removed, one has access to the driver terminals. 

DT880 driver and driver terminals

There is generally a marking on the driver to determine the positive side. In this case it is a yellowish gold mark. I take the time to use a multimeter and verify this is the case before snipping off the stock wires. The left driver has three terminals, the center is the right signal which is not electrically connected to the driver but the wire that runs across the headband is connected to this terminal. The ground is also run from the ground of the left driver to the right driver. This is all removed and ignored as dedicated wires will be run directly to the drivers in the recable. This will remove unnecessary solder joints in the signal path and isolate the ground for balanced operation. Below is a photo of the shell of the DT880 stripped and ready for the recable. 

Beyer DT880 Shell

The latest models of the 770, 880 and 990 have a square opening that the stock wire is fed into, This square hole needs to be dremelled out so that it is round, then heatshrink built up on the new cable for a perfect fit. A custom retaining system is set in place to keep the cable from being tugged out of the cup. 

Wires soldered to the DT880 driver

The wire is soldered to the driver terminals with the assistance of engineer helping hands. The wire is then fed through the little grommet to the other cup. The headband is now placed over the wire and sealed back up using the zip-lock bag type mechanism. 

The wire is fed through the little grommets in the cups

The second driver is soldered on the same way, and we have a complete headphone!

Completed headphone

This headphone also has a balanced to single ended adapter so it can be used with both types of amps. 

Another angle

I hope you enjoyed reading this post. If you'd like your Beyerdynamic headphones (or any other headphones) by an experienced recabler with some excellent sounding cable, contact Zynsonix. Since the 770, 880 and 990 are all quite similar on the inside, each can be modded / recabled the same way. Here's a Beyerdynamic DT990 PRO with a recable with both a standard mini and a Pono output to maximize utility out on the road. 

Beyerdynamic DT990 modded with new cable, mini and pono connectors

The Fine Print:

The above steps detailing the recabling of a headphone 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.

 

Recabling the Venerable Koss KSC75 Headphones

The Koss lineup of portable headphones is truly legendary, from the Portapro that was released in 1984, to the KSC35 that features the same computer-optimized neodymium iron boron magnets in a clip on version, and the slightly newer KSC75 with more comfortable ear clips and a titanium coating on its diaphragms. All three of these products can still be purchased, all of which are under $40 street price (although it's a little more difficult to locate a retailer carrying the KSC35 than the other two). 

The Koss KSC35, KSC75 and PortaPro

Of Koss' three legendary offerings, the best value has to be the Koss KSC75. Surprisingly detailed highs and thick bass reproduction make for a fun presentation and one can purchase this little guy for about $15 on Amazon, likely the best $15 you'll ever spend. Below is photo of some newer packaging for the KSC75 (circa 2012) selling them as "Pulse Clips", same thing, different package. 

KSC75 aka Pulse Clips

Of course, an audiophile can never be satisfied with things as they are, and will tweak and overhaul to get the maximum amount of performance out of something, even a $15 headphone. So, why not put a cable on the headphone that costs several times as much as the headphone itsself? :)

Once removing the plastic shell and ear clip, the solder tabs are exposed. Note below a Xev headphone cable soldered to the KSC75 driver and secured with heavy duty adhesive. 

A Xev cable soldered to the KSC75 driver

Below are a couple of different finished KSC75s:

Xev wire and soft nylon multifilament covering

Xev wire and black chrome covering

How's it sound? Much more Hi-Fi; highs are crisper and more detailed and bass is much more controlled; it's really like a new headphone. Worth the extra cost? That depends entirely on your wallet and sanity level ;) Want a recabled KSC75 of your own? Contact Zynsonix for details.