Fostex T50RP Incremental Mods and Measurements

Discussion in 'Headphones (full-size)' started by bluemonkeyflyer, Jul 15, 2012.
  1. rikk009
    Opened the driver all well, putting it back the glue sticking the magnets in place had dried up and couldn't hold them in place and as I put the assembly together they came off and stuck to the membrane hard. Putting a hole in the membrane.

    [​IMG]
    [​IMG]

    I guess this is the end of modding journey.
     
  2. William Song
    Ooh that sucks
    May I ask how you managed to do that? did you bend the drivers or something?
    That really is unfortunate.
     
  3. Hutnicks
    Fostex will probably sell you a replacement driver.
     
  4. MF Kitten
    I have a pair of T40RP MK2's that I've stripped the drivers out of. Literally everything else is there, screws and all, still in one piece. I might also have a pair of MK3's that I'm stripping, but we'll see how much I keep after assembling my Open Alpha Dogs.

    If anyone wants to snatch the Mk2's from me, gimme a PM and we'll talk :)
     
  5. MF Kitten
    I've almost experienced a similar situation. I'm guessing the magnets slammed down because they were attracted to eachother. I almost killed my DT770 driver because I was tweezing off a couple hairs from the diaphragm, and forgot to hold it down. Magnet sucked the whole driver up into my tweezer, and the tweezer was jabbed into the diaphragm. Luckily the diaphragm only got a small white dent, and worked fine, with no audible differences :p
     
  6. rikk009
    Yes exactly what happened. Unfortunately, I am in India and Fostex doesn't sell headphones here so can't get a replacement driver.
     
  7. Hutnicks
    Lucky it wasn't the 1770 with the tesla drivers. Recabling my 1350's shocked hell out of me when that damn magnet decided it wanted to try to pull the soldering iron onto itself without warning.
     
    nick n likes this.
  8. hamsandwich456
    Hey all,

    I've been following this thread for a while and but I just now decided to join the forum. Currently I'm running T50RP MK3s with the Shure 1540 pads, Newplast baffle damping, and a balanced cable mod.

    So I'm curious if anyone has tried making custom driver frames. Ive been thinking of machining a set of new frames out of some more ridged material. Does anyone think it would be worth it? Are there any odd things about the design that I might need to take into consideration? Ive talked to one of the professors at my school who specializes in electromagnetism about material choices. He said that using a material like aluminum for the frame could cause eddie currents to form within the aluminum because of the movement of the EM field produced by the movement of the driver which would increase the force it takes to move the driver. Could that be taken advantage of or is it just a negative?

    Thanks
     
  9. Bubblejuice
    Thank you very much, the thread is very useful!
     
  10. Shoewreck
    I'd love to share one of the most efficient T20RPmk2 mods I've ever done. I got the idea from observing various AKG headphone internals. You probably know those funny headphones with huge headstage and lots of internal reflections:
    IMG_1020.JPG
    This little plastic ring brings in loads of upper mids. So much I even started to experience a lack of bass (I'm currently using angled protein leather Brainwavz pads and only a moderate amount of Omnipor behind the drivers). I'm using virtually no stuffing, just don't feel like I need any.
     
  11. Shoewreck
    The resonant ring boosts a narrow band around (340/diameter/2) Hz (speed and sizes all metric). It won't look good at CSD plots but it will sound good to human ear. I was referring to Tyll Hertsens' target curve that's peaking sharply at 3.5 kHz. A ring with inner diameter of 49mm is a good place to start for an average head size (57 cm circumfrence). A rule of thumb would be to change the size (and resonant frequency) by 1% at each cm. I.E.: my head circumference is 62 cm, 5 cm larger than average, so I'd better use a larger ring, about 51 cm. (btw, that's the diameter of a Grado cup)
    The ring pictured above is about 46mm, that woud better suit a child head. It sounded too harsh to me (shifting the peak higher sounds like boosting lower treble). The ring I'm using now is about 53mm in diameter. A little too large for me but sounds really good, just a tad warm, with enough definition and no treble harshness at all.
     
    Last edited: Nov 30, 2017
    HerrWallen likes this.

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