Fostex T60RP Teardown

^ @rhythmdevils The T-X0 first version is based on T-50 Mk II.

Nice offer @Philimon .

 

Just needed a little solder to fix a crack in the cable where it had originally been joined.

Both drivers measure near perfectly matched.

..dB

 

even equal to a new pair and worth spending a lot of time on?

thanks for the resurrection @dBel84

so the first version txo doesn’t have pad lips on the baffle and has light gold metal headband rods? If so that’s interesting I didn’t realize there were 2 drop versions.

 

I dont know if its worth effort. That was your task.

@CEE TEE probably helped develop the T-X0 so I’d wager he knows. Also, Ive attempted modding another pair of T-X0 (v1) before and it was indeed a t50rp mk2 baffle.

 

I got the T60rp back from the ortho Dr @dBel84 and it’s working again so I’ll see what I can do with them. We’re back on @E_Schaaf !

 

The rattle is usually because of the diaphragm being slightly buckled (bad QC, ty fostex) which is a problem as it's completely untensioned, and these areas where the diaphragm is bowed then slam into the magnets creating the rattle. Sliding in a gasket either side of the diaphragm like what Zach did with the Blackwood / Ori solves this though it does change the sould obviously ~ makes everything smoother, bass impact reduces a bit and the treble is slightly less grainy. But MAN how many times I've fucked up a driver taking the magnet sandwich apart is unholy

https://imgur.com/mZV4WoD
^ZMF gaskets, if I managed to actually link an image

 

Less bass impact is not a good thing for this driver. And it is already capable of incredibly smooth treble. I would avoid that mod like the plague.

 

It works really well when sealing the baffle and adding thicker pads + the russian magnet mod. Without that it's a no-go like you said. The Ori has this and slams harder than my LCD2's but as soon as you start changing literally everything with a t50rp you should just start with a different headphone in the first place really.

 

first half-ass 30 minute attempt, pretty straightforward approach - die-cut some fatter denser front baffle rings and mashed a thick piece of melamine in the cup. Removed vent filter. Took off rear driver tape (it's bare). No more TP. Swapped to some undersized fuzzy donut pads.



Treble needs some work. Bit of glare in the mids. I'd like to settle with more backwave airflow if I can do so without any problematic reflections, not sure what's best there yet. Totally unaware of what a 'Russian magnet mod' is. Fun to mess with, definitely not the same as working with a closed back dynamic. I feel like even if I hit a near-perfect response here I'll still be left wanting next to my TH900, but that's not fair... I poured like 4 hours a day every day for almost a year getting those where I wanted. Not bad for a first effort here though. Maybe more tomorrow I'll mess with the back a bit more.

I'll have to dig up old measurements of the Paradox Slant I borrowed from captkirk. Even though the treble here is bothersome to me (really it's just that sparkly 8k peak), there was more of a V on those (upper mid depression and bounceback) which I found even more bothersome.

edit - I'm going to line the cups with either felt or microfiber cloth next, mass load the baffles, keep trying pads, maybe do radial cup stuffing (concentric filters). Melamine is great for not killing off transient impulses (you can hold it up to your face and breathe right though it). But it does reflect that 8k area quite a bit when compressed, or at least it did the same thing with my HFMs when used as a full-coverage rear filter.

edit 2 - trusty modded HD600 for reference, taken just now:

 

Put adhesive poly felt on the side walls of the driver. Bit of dynamat in the side cavities. Under the thinly cut visco foam (about 1/8" thick) is a layer of rug liner on the back wall. Then two strips of the adhesive felt holding the foam in place. Driver rear naked. Solid thick front foam rings. Plushy hybrid pads with fuzzy fuzz openings.




Liking this quite a bit. There's still a bit of midrange coloration but I think that'd just a characteristic of the driver. Bit more sparkle than I'd like but it's tolerable. Not bad on the Magni next to my Senns. Next I might try to open up more space behind the driver and try a different rear filter. I'd like to swap to another pad too, these are ok but I like a shallower fit.

 

Look what came in the mail today all at once!




I’ve already got a huge garbage bag full of earpads and only 2 show some promise for working with my mod. Working on tweaking it to work with the pads. I wish I could make my own earpads! Hopefully some of these will be better.

 

I have about 30 kinds myself, whatever it takes to find that perfect synergy! Can I buy the stock T60RP pads off you if you don't use em? I like them on other headphones funny enough.

 

Sure I’ll have to see if I use them or not I tend to want to hoard earpads. But if not I’ll just send them to you for free.

 

T50rp mk2 baffle part for order, since I know you are not a fan of mk3 @rhythmdevils .

 

i haven’t worked with them enough I should admit to say for sure. I just don’t like the new driver damping and a few other changes that mean more modding work. But they could be workable. I’ve got a pair here on my to mod list

 

So my T60rp has lost connection to one channel twice now which is why I haven’t come through with a modded pair here. It’s being fixed AGAIN by @dBel84 who is gong to thread a whole new cable through the headband.

and I have now had 2 T50rp mk3’s in a row lose connection to one side just as I’m finishing the mod. It’s not the solder joints I’m very careful with those. It’s the cable that goes through the headband.

I was really hoping to mod these commercially but I can’t even get a pair modded before they break.

Has anyone heard of this issue before? Is this a known problem or am I somehow just extremely unlucky?

Even if I start over on a new pair I can’t sell something that’s so unreliable. The T50rp mk2 was built like a tank. Never had a single one go bonkers on me even after opening them up hundreds of times till I strip the screw housings and have to fill them with glue, drill and re-thread and I had to do this multiple times to keep them going as I experimented. But the cabling was never an issue.

at least it’s hipster orange now though

 

The cable is not terrible - it is enamel coated multicore within its own sheath - better than some of the nastiness that you see on some earbuds. It needs to be pretty flexible and I suspect that what happens is that the point of solder is high risk as it bends and cracks, losing connectivity. I fixed the T60 by splicing in a small length of supply cable and removing the primary stress on the enamel wire

 

Hmm does it look like it’s something I’m doing when I have them open then? That would surprise me. But all three have lost connection while being open. If that’s the case I wonder if there’s a protective measure I could take. (I already don’t ever pull on the joints)

 

I think the little strands are at risk at the point of the solder junction - even if you are as careful as you can be, there will always be some stress - they were not engineered for this type of manipulation, and unlikely to have field failure stock or after a successful mod

 

I don't have experience with mk3 units, but I've break the wires a couple times on my mk2s. The solder makes cable stiff. Where stiff thing joins with soft things, problems are likely to happen. It's sort of a protective mechanism for the wires to break. If your wires are too hard to break, the solder pad may snap off, and it's painful to fix that. It happened once when I dropped my last pair after the first fix... One dirty way to prevent this might be apply some hot glue around the solder joints. I don't know how well this works, but I did it for my current pair (when I break the wires a little earlier...)