Fostex T50RP mk III Modded Build - New Cups, Cable, the works!

If you've been following my posts you'll see I usually leave audio products alone once I get them ... kidding ;) I picked up a Fostex T50RP mk3 (or mk III, however you want to write it) so I could see the differences from the original T50RP I modded. Other than a different headband, removeable cable, and different handling of the felt behind the driver, there was no difference, so I suggest if you are already modding, go with the original as it's cheaper and you can set up the felt however you like. If you still want the mk3, You may consider purchasing across the pond, it seems like Fostex has a deal with U.S. retailers that they can't advertise below $159.99, but it averages around $130 in the UK... much more palatable as you're replacing everything anyway.

The headband is worlds better than the original model

The removable cable was a nice new feature on the mk III

I had some very nice wood cups CNC cut for me by my friend Fewzi (if you'd like his contact information, shoot me a message, we're hoping to offer at Zynsonix soon), the quality of the machining is excellent, perfect driver fit. CNC machining has really changed the way a lot of things are manufactured in a positive way, the amount of precision it offers is outstanding. Anyway, the wood cups rock. There is the cup itself, a second wood layer with a square hole that holds the driver in place, and a third plastic layer that holds the ear pads in place.

Driver frame and wood cup, ultimate precision

This picture below shows a wood ring and plastic ring for the earpads, Fewzi discovered that plastic was more durable for the earpads to stretch over (it's a tight fit). 

First the stock pads and foam are removed.

Then the driver frame is unscrewed (4 screws), and the driver unscrewed from the frame (3 screws). There is an extremely thin gasket that sandwiches between the driver and frame that needs to be handled gently. 

The drivers are snipped free and then I had to remember how to get the cups off. I didn't want to read my existing post because I enjoy discovering how things come apart and go back together. Fostex hides the screw behind a thin shroud of plastic, which I believe is sonically welded in place (micro-vibrations that fuse plastic together). It comes off with a razor, and once unscrewed, releases the clamp on the other side.

That's about the only unusual aspect of the assembly. Once everything is apart, the wood cup was fitted. There are little brass fittings included with the wood cup (the original plastic ones are too small) that allow the cup to pivot when screwed in, I found the sizing of the brass fitting and tightness of the screw makes a huge difference in the articulation. 

If anyone has heard a T50RP,  modified or otherwise, they know there is no lacking in the bass department. this is where mass damping plays an interesting part. Adding loaded sheets like Dynamat Xtreme can help curtail flabby bass and tighten things up. Adding foam with a texture can also assist with reducing reverberation / standing waves in the cup. 

The cups included 3.5mm mini inlets, which are great, but I personally like the mini XLR for headphones due to it's locking mechanism, and I could configure it the same as Audeze headphones, which you can read more about here. The driver is fastened on to the wood frame, which was a fantastic fit, with the gasket in place. Wiring up is a simple ordeal, but I wanted to ensure all the original solder was removed so I could replace the tin solder with Cardas Quadeutectic solder. The tabs are marked with a "+" and "-". Below you have a view of both sides being soldered in. 

Once the drivers are happy, the frame is lined up on the cup and it's important to ensure no stress is on the solder pads, so loose wiring is okay here. Then the earpad frames are sat on top and four screws replaced. The foam that was set aside in the first step is replaced in each cup. 

This could be no exciting rebuild without fancy pads. Fortunately there are a couple different types available from ZMF (run by Zack, cool bro), and MrSpeakers. ZMF has a number of pads available, including lambskin, cowhide, protein, and Omni. MrSpeakers offers the Alphapads which are lambskin. Lambskin seems to be the most popular headphone pad material for higher end headphones, for which I am glad, I hate velvet ;) ZMF also has a nice "pilot pad" to provide some extra cushion on the top of your head.

ZMF lambskin earpads and pilot pad

Now that we're all padded up, we have what appears to be a finished headphone, but wait...

...where's the cable you ask?! We won't have any sound if we don't have a cable. Where will we get a cable from?

Fortunately, we have the brand new Zynsonix Ballista cable here, featuring 28 strands of ultra pure ohno cast copper, 12 of which are clad with high purity silver in an alternating geometry, then each are electrically isolated with a clear coat, fed through low loss dielectric, resulting in an extremely well balanced sound with great detail retrieval... completely custom made for Zynsonix. 

There we go, now we're talking! 

I'm now going to reveal a special secret that will enhance your life forever make your cans sound better... you can get the Zynsonix Ballista configured for pretty much any headphone you have. It's the best cable I've made to date, I spared no expense, because you guys deserve it. Use the handy dandy contact link to share what you need. Also if you are interested in purchasing some great sounding cups, feel free to reach out as well. Fewzi is experimenting with some additional woods now, so there should be a variety of species to choose from. 

Anyway, that's all from me. Happy listening, building, etc. and don't be a stranger.

Disclaimer: The above steps detailing the building of a headphone are for entertainment purposes only and not intended to be used as directions. 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.

Massdrop x Fostex TH-X00 Recable - Removable Mod

I was quite excited to head about Massdrop and Fostex teaming up to offer the TH-X00, a headphone created by the same OEM company that produced headphones for Denon (the legendary D2000, D5000 and D7000). I still to this day feel that the D2000 was the best headphone in this price range, and the D7000 is still an amazing sounding headphone compared to the latest and greatest. With this Massdrop Fostex team up, audio enthusiasts would be able to get very solid drivers that are similar to the Denons with luxurious wood cups at a very attractive price point.

An interesting phenomenon with the Denon headphones was that they were extremely receptive to a new cable (despite the stock cable being fairly decent construction). In fact the sound changed more than any other headphone I've heard, aside from the HD600, which was close (try a solid silver in teflon cable and a Cardas copper cable side by side with that one). The TH-X00s seem to follow that trend from my brief impressions (had to get them back to a client quickly).

I found the Zynsonix Xev had nice synergy with the D2000, opening up the highs and adding coherence, so that's what was used with the TH-X00s. The Xev is a silver clad copper design which has a detailed signature. It's hand braided, which you can see below, from a four wire litz braid to two twisted pairs, then sleeved with a soft black non-microphonic sleeving.

Hand braided Xev cabling

This particular headphone would have a removable/replaceable cable cable option, so whenever there is an option, I prefer to use 4 pin mini XLRs. They have a great connection, lock in place, and are used for many Audeze headphones. Since few headphone manufactures use the same connectors, we can try and standardize to some degree, so this design would not only be able to use Audeze cables, but the cable could also be used with Audeze headphones. For that to happen, the pins need to be shorted on both sides (male and female), note the small piece of bus wire connecting two pins below. You can learn more about this in a previous post.

Shorted pins for Audeze compatibility

You guys have seen me build enough cables, so we're not going to cover that, but how the wire is attached internally in the Fostex TH-X00 headphones. The pads have four plastic connectors that fasten to the cups, twisting them to the left allows them to be removed quickly and easily.

Fostex TH-X00 with removed earpad

Four screws need to be removed to remove the wood cup from the frame, then another four screws are removed to separate the driver and wood cup. 

Removing the cup from the frame

The existing cables feed in through the frame, go about an 1/8th of a turn up the cup, then enter the driver chamber. At that entrance point the cable is tied in a knot and there is a bit of epoxy/rubber cement that holds the old cable in place as a strain relief system. It's important to recreate this with the new cable to prevent damage to the soldering tabs on the driver from an inopportune yank. I personally use a special adhesive gun that creates a plastic-like joint holding the cable firmly in place. The wire is soldered to the top two pins, the red marked one being positive, the other negative. These joints should be quickly formed to avoid harming the driver and/or the thin wires leading to the diaphragm. 

Interior driver view with strain relief

While everything is taken apart, it's a good opportunity to add a bit of mass damping to the inside of the wood cup. Dynamat Xtreme, or other automotive based damping materials work here. This helps tighten up the bass. Tweaking the amount can be to preference. Since the cup is nice solid wood, only a moderate amount is necessary. Were it flimsy plastic, it would likely need a lot more. 

Dynamat Xtreme mass damping

The headphones are reassembled the same way they were taken apart. The "pigtails", or little dangling mini XLRs may look like they'd get in the way, but with the headphones on your head they are very hard to notice. Flexible joints assist with that. Removable cables are great for people who like to experiment with different cable types, lengths (portable vs. home), use one cable for multiple headphones... or who have teething pups or curious felines. The Xev is actually pretty strong against cats :)

The finished / modded Massdrop x Fostex TH-X00

If you've taken the plunge on a sweet set of Massdrop x Fostex TH-X00s and are itching for a recable, please check out Zynsonix Audio. 

The Fine Print:

The above steps detailing the modification and re-cabling of a headphone are for entertainment purposes only are not intended to be instructional. 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.

Bottlehead Fix for Full Range Speakers

The Bottlehead Fix is a passive baffle step corrector and treble compensating device that sits between your source and your integrated amplifier, or between your pre-amp and amp. Baffle step correction (if the baffle is narrow) and treble compensation can benefit the sound of full range speakers in particular, so if you are into Fostex or MarkAudio drivers (or even Planet10 / Feastrex modified drivers), this is a great device to check out. Do note, in some cases, the compensation is already being handled by a network of capacitors, inductors and resistors within a full-range speaker.

There are four switches in total. As stated on the Bottlehead website: two of switches on the Fix controls the adjustable baffle step corrector that compensates for the bass roll-off in narrow baffled speakers. The first switch is used to set the bass turn-over frequency for the baffle width of the speaker you are using (selectable in inches). The second switch controls magnitude of the cutoff frequencies for passive bass compensation (which flattens a falling frequency response below baffle step frequency).

The third and forth switch compensate for treble roll-off with typical full range drivers. One switch selects turnover frequency, and the second switch chooses 0,2,or 4 dB of treble compensation above that frequency.

Curious if your speakers could benefit or not? The Fix is only $75 so it's not a big gamble, and given the popularity of full range speakers lately it wouldn't be a tough sell either. 

Normally, the Fix comes with a random colored piece of plexiglass (or similar material) and you either make the base yourself, or order one of Hammond or Bottlehead's for a few extra bucks. The build should be pretty quick as there aren't many parts, and would take the average person a couple of short nights to put together. 

Since I like everything on my rack to be "matchy matchy", I'll be using some alternative materials to put mine together, namely the typical copper leafed wood base and a copper plate. The copper plate I ordered was a remnant online, nice and heavy at 1/8" thick. I taped the plexi plate to the copper one and used it as a drilling template on the drill press. 

After drilling the holes, I sanded with 60, 180, 300 and 600 grade sandpaper, then spray painted it with a matte clearcoat from Krylon, otherwise it would be oxidized with hand-prints the very next day. 

Drilled copper plate

The base is made from 2 inch tall decorative molding from the local hardware store, cut with a miter saw, adhered with wood glue, and braced in the corners with square pieces of pine. It's then copper leafed using generic copper leaf and Mona Lisa Speedball base coat, adhesive size, sealer and antiquing glaze. These items can be found at your local Michaels craft store or online. 

Sitting in a copper leaf base

The first step in assembling the Fix is fastening on the switches and RCA female connectors. A socket wrench is especially handy in this step, however if using the plexi base, caution is advised in the manual as it can crack. In addition, the switches have plastic threading, so they could strip easily if too much pressure is used. 

Switches mounted

Once these items are secure, it's then time to mount the solder tabs. The manual shows corresponding letters and numbers for each solder point, so it's great to write these directly on the plate for ease of assembly. 

Labeling the solder points

I ran a solid piece of Cardas magnet wire for the ground plane and tied any solder tabs that needed to be grounded to it using bus wire. The polystyrene caps supplied are very nice quality. Polystyrene was commonly used for capacitors in the 50s up through the late 70s. You'll still find them today, many of them surplus from overseas. In vintage tube amps you may find them in glass-sealed tubes. This variety has the leads laid-in, and you need to be careful in higher values as they will create inductance based on the way they are built. Also polystyrene caps can melt, so don't put them in areas of high temperature! Those are the cons, but many feel that polystyrene caps are second only to Teflon in sound quality, so it may be worth it to experiment with them.

The 15,000pF caps in the Bottlehead kit are polypropylene, I opted to order some polystyrene to match the rest of the build. These came from Israel and are a little larger as they are 125V (no particular reason, just the smallest value I could find).

I opted to use some Cardas hookup wire and carbon film resistors for the build, just based on my own preferences. The ethernet wire that Bottlehead supplies is extremely high quality, so go with that unless you are a die-hard Cardas fan ;)

Bottlehead Fix interior

With the 15000pF caps installed

Bottlehead supplies a nice piece of black vinyl that has the functions printed on it, as well as an "I" and "O" for input and output. As a final touch, I added the iconic Bottlehead badge to the lower center.   

The completed Bottlehead Fix

I hope you enjoyed this post. Please visit Zynsonix if you need some sweet sounding interconnects for your Bottlehead gear, or any other custom audio cable. Until next time! 

The Fine Print:

The above steps detailing the build of a Bottlehead Fix are for entertainment purposes only, and not intended to be used as assembly instructions. Zynsonix Audio LLC is in no way affiliated with Bottlehead. 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. 

GR Research LGK 1.0 Full Range Speaker

Every now and again I take a break from building cables and amps to build a speaker. Your better half will typically notice a speaker sneaking into the house a little more reliably than an amp or cable, so be forewarned ;)

Since I don't own a table saw or have anywhere to even put one, I enjoy building speaker kits where the MDF/pine or other wood is pre-cut by CNC machine. The industry nomenclature for pre-cut wood for speakers is a "flat pack". You still get to treat the cabinet interior, fit the crossover, and glue everything together, so you don't miss out on all that fun.

The last flat pack speaker I built was the Frugel Horn from Planet 10 Hifi, which was a simple to assemble back-loaded horn which could house a Planet 10 treated driver, or a stock driver from Fostex or MarkAudio. The speaker build this post will be covering is the GR Research LGK 1.0 Full Range Speaker kit.

The LGK 1.0 uses a 3" driver made by GR Research. Yes you read that correctly... 3 INCHES! Many may think three inches is inadequate, but it's all about how you use it (a-ha). This particular LGK driver is happily seated in a very solid 8"x 4.5" x 12"cabinet that's cut by Subassemble.

LGK Flatpacks made by Subassemble

The rest of the parts for the LGK can be procured from Danny at GR Research. The kit from Danny includes a number of nice quality parts, including Sonicaps, Mills resistors, Erse Air core inductors, Electra tube connectors (which serve as the speaker connectors), No Rez, and other minutia including ports, screws, wire, solder, and heat shrink.

The first part of the process is to cut up the No Rez, which is a thick damping material specially designed for loudspeakers which adds mass and reduces resonance and internal waves. The thicker, bottom portion of the No Rez closest to the adhesive takes a little bit of elbow grease to cut with a razor blade. Remember to change out the blade before you start grumbling under your breath.

Mapping out the cuts of the No Rez

Once the cuts have been made, the CNC cut wood pieces are laid out and the No Rez applied after to ensure it won't bump into anything during final assembly.

No Rez lined up on the side panel

I added a bit of sealing caulk around the edges to prevent air from escaping anywhere but the port. The No Rez needs to be trimmed a little bit to allow clearance for the speaker, port and crossover.

Caulking the edges for a good seal

The next task was to assemble the very simple crossover, which acts as a baffle compensator to help boost the bass. The three parts are soldered in parallel. The part values are proprietary per GR Research so I can't share them unfortunately.  

Crossover parts

I cut two pieces of FRP material and mounted some turrets so the parts could be mounted cleanly, with zip ties holding down the inductor. The board is then mounted to the top wood panel with caulk.

FRB Boards fashioned for the crossover

Once everything is in its proper place and you've tested to ensure everything is working, the speaker is then sealed up with your favorite wood glue and clamped from every angle. Excess glue is removed with a damp paper towel. Don't soak it or the MDF will expand, and no one likes wet, expanded MDF.

Speaker clamped down to dry

Here's the speaker cabinets after drying, right before getting a sand with 60 grit sandpaper. A basic electric sander is pretty affordable and save a lot of effort at this step (if you don't already have one).

Unsanded Cabinets

Below is the difference between sanded and unsanded cabinets. Any gaps in the wood should be filled with wood putty, or if you are going to be painting the cabinets with Duratex, you should use drywall spackle per the directions for better adherance. For the corners, I sanded them lightly with 3-4 quick passes, some people like to round them a bit more, or route them.

Unsanded vs. sanded

The next step is to finish the cabinets. You can stain the cabinets, metal leaf them, paint them, veneer them, the sky is the limit! I chose an interesting finish (which GR Research carries) called Duratex. Duratex, which could be the name of a manufacturer in the family planning aisle, is a lot like a truck bed liner paint, it's durable and creates a very dimensional texture. This is especially great if you screwed up somewhere along the way and need to hide your mistakes or you're a sanding slacker ;) 

Duratex, check out that texture!

Duratex requires two coats, you can vary the texture with the included roller a little bit for either a smoother or rougher texture. When the solution is rolled on, it creates bubbles which pop, adding to the unique finish. 

Next the ports should be installed, there is a small ring around the cork cap which is recessed to allow you to put some caulk down to seal it in.

Sealing up the ports on the back

Now the cool little Electra Tube connectors can be soldered on. These are pretty unique connectors; they have a patent pending from what I understand. They are low mass, so they only use the amount of metal necessary, and allow the internal wire to be very close in proximity to the wire within their proprietary banana connector. The nice thing is that I've found they work with standard banana connectors as well, so they shouldn't affect your speaker resale value much if someone is married to their particular Kimber/Nordost/etc. speaker cable. One of the nicest things about these connectors is you just hammer them in with a rubber mallet. The installation couldn't be simpler. 

Electra Tube Connectors soldered in place

Soldering the driver in is a simple affair. Just two wires to worry about. Note the bottom of the driver cutout has clearance for the solder posts. 

LGK driver before installation

You may have to do a bit of Dremel sanding if the driver doesn't fit perfectly due to paint getting in the routed area. Once in place, you can drill a set of pilot holes, then screw in the four screws. All done!

So if you have three Benjamins, don't have a lot of space to spare, and are looking for a pretty resolving desktop speaker, the LGKs are a great bet. You'll note some very impressive bass response and nicely resolving treble. I have a slightly larger full range speaker with a Fostex driver and baffle compensation "crossover" and I like each of these for different reasons. The bass response and treble energy on the LGK is better, and the Fostex offers slightly better presence and midrange.

Overall a great project and a great speaker. Looking forward to see how Danny incorporates these drivers into other designs.

Need some speaker cables for your LGKs or other speakers? Contact Zynsonix Audio for some great sounding options.

The Fine Print:

The above steps detailing the building of a speaker are for entertainment purposes only, and are not intended to be used as instructions. Zynsonix Audio LLC and DIYAudioBlog do not have any affiliation with SubAssemble or GR Research. 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.