[maul]

I've been helping some people on the mk3 thread with what I know from the mk2s.
Looks like they've adopted the hype thread for modding too

Seems like the mk3s are mostly mk2s with the rear of the driver dampened. Essentially putting felt on the mk2s. I might be ordering some mk3s if I can't get my drivers sorted. Might be a bad solder job on my part

http://www.head-fi.org/t/763009/fostex-new-rp-headphones-t50rpmk3-t40rpmk3-and-t20rpmk3/525#post_12177809

 
Yeah, as far as I know there are no changes to the driver other than the thicker felt with the square opening: http://cdn.innerfidelity.com/images/Fostex_T50RPMk3_photo_CompareDriveronBafflePlateRear.jpg
 
I don't like the "asymmetricalness" of that, I'd probably rip it all off if I were to mod it. I'd rather get the mk2s for $50 less.

 

[SeEnCreaTive]

Yeah, as far as I know there are no changes to the driver other than the thicker felt with the square opening: http://cdn.innerfidelity.com/images/Fostex_T50RPMk3_photo_CompareDriveronBafflePlateRear.jpg

I don't like the "asymmetricalness" of that, I'd probably rip it all off if I were to mod it. I'd rather get the mk2s for $50 less.

For modding absolutly, same cup, same driver. Mk3s are better plug and play

 

[Coolzo]

Does anyone have suggestions for what might cause a channel imbalance, other than sheer damping quantities?

I've had a midded pair of Mk2s (which I love more than any other headphone) for a while now, but after several tuning sessions, the right has become slightly (but noticeably) louder. The screws on both cups do become loosened slightly by the pressure from the foam/cotton; irregardless, sealing the baffles with electrical tape did not change the imbalance. I have exactly one vent open on each side.

 

[c61746961]

Depends on the frequency range. Try to have the damping not touch the backside of the driver directly nor block the back vents directly.

 

[SeEnCreaTive]

Does anyone have suggestions for what might cause a channel imbalance, other than sheer damping quantities?

I've had a midded pair of Mk2s (which I love more than any other headphone) for a while now, but after several tuning sessions, the right has become slightly (but noticeably) louder. The screws on both cups do become loosened slightly by the pressure from the foam/cotton; irregardless, sealing the baffles with electrical tape did not change the imbalance. I have exactly one vent open on each side.

Any mods you do equally to both sides, with change the sound equally for both sides.

I balance comes from something that isn't the same

Could be the hole where the socket comes in is allowing more air, or, like mine, it could just be the socket itself. The socket is natoriously bad on them. You'll see a lot of cases of something like that happening.

Mine had a weird imbalance that changes with volume and frequancy. Took me for ever to find what was wrong, I lucked out when I found it,

I forgot I had that volume knob at 0 when I started playing music, I slowly turned it up, and the right ear kicked in first, playing quietly while the left was still dead silent. Then as I turned it more, the left came on, then ended up growing louder than the right. But of couse would change depending on the volume, or how much is happening in the song in each channel, the frequancy, Odd


10 feet Magomi w2799, 1/4 jack and 3.5mm mono plugs and jacks later, they are now dual entry, and sound pretty good. Would not recommend mono plugs again.


Still waiting on my Paracord, idk if I can jacket the cable now that it's already done, we'll find out

 

[bluemonkeyflyer]

Does anyone have suggestions for what might cause a channel imbalance, other than sheer damping quantities?

I've had a midded pair of Mk2s (which I love more than any other headphone) for a while now, but after several tuning sessions, the right has become slightly (but noticeably) louder. The screws on both cups do become loosened slightly by the pressure from the foam/cotton; irregardless, sealing the baffles with electrical tape did not change the imbalance. I have exactly one vent open on each side.

 
It's possible there is inherent Left - Right driver SPL variance in your particular set of T50RP which is not uncommon.  If so, you'll have to tweak each side's damping scheme so they produce the same SPL levels. Related, it's important to accurately weigh and measure the dimensions of each component of your damping configuration. I use a digital scale down to 0.01 grams and digital calipers.  Seemingly small differences in weight of cotton or fiberglass etc, and dimensions of felt and other materials can make a big difference in SPL and sound quality. This is where a Frequency Response measurement kit comes in handy.
 
As the other guys have suggested, seal the wire entry points into each cup. Also, seal the relatively Big openings (2) around the jack terminal in the Left cup. Hot glue and GE Silicone II work great. You just have to make sure you don't allow either to "ooze" around and into the Left cup TRS jack. You can temporarily seal the TRS jack with a disk of masking tape. Once the hot glue/silicone sets, you can remove the temporary jack entry seal.
 
If your baffle-to-cup threads are stripped (on the Left side??), you will likely have channel imbalance. If so, read the chapter in FIMM about making repairs with super glue.
 
You could try cleaning the quarter-inch TRS plug, the 3.5 mm TRS locking plug and the TRS jack in the Left cup. De-Oxit works great but it's expensive. You may be able to clean them with Radio Shack electronics cleaner or 99.9% isopropyl alcohol....OR, re-cable.
 
Good luck

 

[Coolzo]

Thank you BMF, Sencreative, and c617 for the responses! I'll inspect the cans again, although I was originally sure the holes are all sealed. Granted, I did already have them modded for a dual-entry cable using 4-pin mini XLRs, so it is possible that there is a small gap between the sockets and the plastic. The imbalance also seems rather frequency-specific, mainly the low-mids and sub bass.

Unfortunately, it seems after too many hasty cup openings, that the solder pads on the driver have come undone. Looks like it will be a while yet before I can solve this mystery >.>

I do sincerely wish that I had a scale for precise weight measurement, but things of that accuracy seem to be rather pricey ._.

 

[bluemonkeyflyer]

Thank you BMF, Sencreative, and c617 for the responses! I'll inspect the cans again, although I was originally sure the holes are all sealed. Granted, I did already have them modded for a dual-entry cable using 4-pin mini XLRs, so it is possible that there is a small gap between the sockets and the plastic. The imbalance also seems rather frequency-specific, mainly the low-mids and sub bass.

Unfortunately, it seems after too many hasty cup openings, that the solder pads on the driver have come undone. Looks like it will be a while yet before I can solve this mystery >.>

I do sincerely wish that I had a scale for precise weight measurement, but things of that accuracy seem to be rather pricey ._.

 
If the solder pads have broken off the diaphragm, a repair is beyond my skill set.
 
If the solder pads are still attached to the diaphragm and the only problem is that the wires have broken from the solder pads, I may be able to make a repair for you.
 
If you wish, PM me with photos of both diaphragms/solder pads.
 
You can find a suitable digital scale on Amazon for around $25.00.  I use this one.with the calibration weight.

 

[jerrygp]

I am planning on building the phantom power supply described in this forum thread, and was wondering if I need to ground the PCB board externally if I use a plastic case? Also...do I have to build the stereo supply (or dual mono) in order to use the REW software?

 

[bluemonkeyflyer]

I am planning on building the phantom power supply described in this forum thread, and was wondering if I need to ground the PCB board externally if I use a plastic case? Also...do I have to build the stereo supply (or dual mono) in order to use the REW software?

Grounding is not required for it to work, even in a plastic case.

REW and ARTA measure in mono. No need to build dual.

For definitive answers, ask Frans on diyaudio heaven.

 

[Coolzo]

   
If the solder pads have broken off the diaphragm, a repair is beyond my skill set.
 
If the solder pads are still attached to the diaphragm and the only problem is that the wires have broken from the solder pads, I may be able to make a repair for you.
 
If you wish, PM me with photos of both diaphragms/solder pads.
 
You can find a suitable digital scale on Amazon for around $25.00.  I use this one.with the calibration weight.

 
Thank you for the gracious offer, sir BMF! Unfortunately the Solder pads are completely separated from the diaphragm. Fortunately, I have found a local DIYer who *may* be able to fix my problem. I will post the results here! Also, many thanks for the link. I will definately obtain one as soon as I am able.
 
In the mean time, I have had great success with a pair of T50RP MK3. I must say, imaging is quite a bit improved from my previous T50RP mk2 iteration. It utilizes the Nick N memory foam mod combined with BMF v3, minus the monkey dots and clay mass loading. The result is a quite neutral tuning along with a much lighter-weight headphone. It makes use of the (new mk3) built-in foam damping on the ear side of the baffle, although secured with adhesive felt, as well. 

 

[SeEnCreaTive]

Well here is the rewire. Cable isn't quite done yet (or as good as I'd like it)


They sound 100% better. I knew it would help,but how much blew my mind a bit



That being said, the imbalance is back. The wiring helped, but I wanted to truly fix it. So yesterday I realized I didn't cover the hole where the socket used to be, taped it, now it's even worse. Good news though, when I was testing just holding the drivers to.my ears, they sounded perfectly balanced. Which leads me to believe it's no a driver or wiring issue. Should be an "easy" fix. Having nothing to measure with, and not knowin what mods orajustments will fix it, it will be a big under taking. If I could put my figure on what was wrong, it wouldn't be so bad to figure out what I have to do, heh but I can't even discribe even to me self the problem.

But at least the problem is fixible and not a driver issue

 

[maul]

I've simplified the mod I detailed earlier into 3 strips covering half of each of the white driver squares, covered half the non-driver side vents, masking tape with a small pinhole over the baffle ports. I've been going back and forth and I'm starting to honestly think these sound better than my he-400i's right now (hard to get over the money bias). I'll have to post some pics and measurements soon. 
 
BMF, I have a quick question if you have a sec: what were your results with the alpha pads, did they not perform as well as the Shure 840s - reduce bass, what? I'm seriously considering getting them for comfort and soundstage improvement with the angled pads. It looks like they would also have more isolation than the 840s for increased bass, but I don't know -

 

[bluemonkeyflyer]

  I've simplified the mod I detailed earlier into 3 strips covering half of each of the white driver squares, covered half the non-driver side vents, masking tape with a small pinhole over the baffle ports. I've been going back and forth and I'm starting to honestly think these sound better than my he-400i's right now (hard to get over the money bias). I'll have to post some pics and measurements soon. 
 
BMF, I have a quick question if you have a sec: what were your results with the alpha pads, did they not perform as well as the Shure 840s - reduce bass, what? I'm seriously considering getting them for comfort and soundstage improvement with the angled pads. It looks like they would also have more isolation than the 840s for increased bass, but I don't know -

 
Hi maul,
 
It's been quite a while and memory fades. A starting point is in Post #1 of this FIMM thread @Pad Rolling.
 
I'm happy to hear you're dialing in your mod configuration.
 
Cheers,
 
BMF

 

[maul]

   
Hi maul,
 
It's been quite a while and memory fades. A starting point is in Post #1 of this FIMM thread @Pad Rolling.
 
I'm happy to hear you're dialing in your mod configuration.
 
Cheers,
 
BMF

 
Yeah, didn't see a lot of info on the alpha pads, but I understand it's been awhile. I'll be getting them soon regardless, will do some measurements and post the results here. If anyone is interested, I've simplified the original Maul Mod on this page. It now has 3 strips of thick sticky felt aligned like this: 
 

 

 
 
It achieves the same goal of the original: letting through/sending back the sound 50/50. It brings the sound forward evenly to increase clarity without harshness, and maintains strong bass. This variation is much simpler and sounds just as good if not better. Make sure if you're not using thick sticky felt, to use material like a magazine cover or card stock - something solid. 
 
Here are some measurements (ignore the dip at 8-9 kHz, it's a measurement artifact that occurs in almost all of my headphones, as seen with the mdr-7506 and SHP9500):
 
HE-400i:
 

 
T50RP Mk2, Maul Mod, Variation 35:
 

 
Note: To see the treble without the dip-error at 8-9 kHz, here's a measurement of Variation 32. It's similar to this one, using the original Maul Mod with some changes, and has less bass extension. Treble is very similar though:
 

 
 
MDR-7506:
 

 
SHP9500:
 

 
As you can see it has better bass extension than the 400i, although not as smooth. The bass hump gives it good impact, but it doesn't sound overwhelming at all - I went through a lot of variations to make it that way. Covering the outside vents and adjusting the baffle holes made a big difference. Without those mods it was too heavy sounding, bled into the mids. Although you can see a dip at a low 40 Hz, it is not audible - I am attempting to narrow down what is causing it though. I have a feeling it's the pads, probably nothing can be done. We'll see...
 
Here are the additional things I've done:
 
1. BMF sound damping material / ladder pattern on non-driver side
2. Newplast around the driver
3. Layer of cotton, layer of insulation on top of it - both formed to fill the entire space (like this)
4. 3 of the 4 non-driver side vents covered with masking tape
5. Baffle hole covered using a small piece of masking tape, with a small pinhole
6. Shure 840 pads

 
Overall the sound is very crisp/detailed, tight/strong bass that isn't overwhelming, present treble that isn't harsh (this was one of my main goals). I'd highly recommend this mod to anyone treble-sensitive, and if you don't want an overly dark or bright headphone. The 3 strips evenly bring the sound forward and make things very detailed sounding without harshness, maintaining bass impact as well. Very balanced sounding imo, as I mentioned before I think I prefer this to my HE-400i.
 
Anyway, maybe this will help someone, I'll post more results if I make changes. I might venture future into messing around with the non-driver side dampening -