Just listened to some Fostex T50RPs today... WOW! - Page 132

Felt over the driver... I guess it will arrest the air movement behind the driver hence will tune the bass. It's basically trial and error, so just put as much as it suits your taste. It's good to have another pair of 'phones for reference on your progress

Thanks guys, are these the pads?

Stax earpads for SR007 Omega II earspeakers. It seems the Brown ones are 40 dollaes cheaper than the black ones

I'll probably get them at some point. I know I can effect the sound of my Grado's quite a bit depending on which pads I use; and I plan on probably doing the Thunderpants mod at some point. I'll try the felt when I open them up and trade out the blue tack with some plasticine. Maybe not I'll probably just want to try and discern what the plasticine does first. At any rate I'll probably have these things open a few more times.

Mine should finally arrive tomorrow. They're all sold out in the UK so I had to import them from the states. Jeez!

Line-out struggles to power them?  I hope you mean a portable headphone jack.  Because there are few if any headphones ever made that can be powered at all properly from a line-out directly.  Bad bad results.

Quote:

Originally Posted by Reticuli2 

Line-out struggles to power them?  I hope you mean a portable headphone jack.  Because there are few if any headphones ever made that can be powered at all properly from a line-out directly.  Bad bad results.

fixed. 

The less expensive, more plentiful T40rpMK2s out there being sold new are the exact same driver in a closed earcup, correct?  How easy is it to get inside those and add damping?  I'd be interested in getting the drivers entirely put inside sound isolating cups if damping could make them sing in a different sized, plastic cup.

The driver isn't as nice according to smeggy. 

headfonia <dot> com/the-fostex-orthodynamics-t50rp-and-t40rp-mk2/

T40RP MK2 VS T50RP

The T40RP mk2 is a closed design model, also equipped with an orthodynamic driver. Positioned as one model below the T50RP, it’s similar to how the Sony ZX700 is to the Z1000. However, the drop in sound quality of the T40RP makes it a hard model to recommend to you guys. First of all the bass rolls off quite early and is not as deep as the T50RP. The midrange is also less composed, less weighty, and more honky than the T50RP. Overall the sound is clearly inferior and not as well composed as the T50RP. The housing reverbs are also more evident on the T40RP, adding a small amount of plasticky timbre compared to the T50RP. Well, at least the bass is not as boomy as what I remembered the T20RP Mk2 to sound.

Surprisingly all these difference comes from a simple differences in the housing. The T50RP’s drivers have openings on the slots, where the T40RP Mk2′s totally closed. Another difference is a slight change of damping material positioned right behind the drivers.

Both Fostex orthos are relatively efficient and easier to drive than the Hifiman and Audez’e full size orthodynamics. An Ipod can do a decent job, but a Hifiman HM-601/602 have more than enough voltage swing for these orthos, likewise a simple entry level DAC/Amp box like the Audinst HUD-MX1.

Surprise, surprise. Same driver!

The slots are semi open on the T50RP. They are fully closed on the T40RP Mk2.

Differences in damping: pay attention to the small piece of felt cloth around the middle of the housing. This is the T50RP's housing.

And this is the T40RP Mk2's housing.

So the driver is the same. If I'm making some thunderpants then I may aswell get the 40's eh? cheaper.

Super find, bluemonkeyflyer !  now, let's see how this works out in practice - the 40's are certainly more abundant (at least until the word gets around).

Quote:

Originally Posted by bluemonkeyflyer 

 

 

headfonia <dot> com/the-fostex-orthodynamics-t50rp-and-t40rp-mk2/

T40RP MK2 VS T50RP

The T40RP mk2 is a closed design model, ....

Surprisingly all these difference comes from a simple differences in the housing. The T50RP’s drivers have openings on the slots, where the T40RP Mk2′s totally closed. Another difference is a slight change of damping material positioned right behind the drivers.

.....

Surprise, surprise. Same driver!

.....

If they are the same, why do they have different max voltage specs?

T50RP: 

1. Naked plastic cups and baffles

2. Vented with thin felt over the vents

3. Small thick 3/4" tuning felt on bottom of cups

4. Thin white gauze over back of drivers

5. Pressure equalization vent hole in baffle connecting cup volume to outside on ear side

6. Same driver asT40RP MkII (but different max voltage spec??)

7. Cup volumes look the same as T40RP MkII

T40RP MkII:

1. Same

2. Non-vented

3. Same

4. Thicker/denser white gauze over back of drivers (to compensate for lack of venting?)

5. Assume same

6. Same driver as T50RP (but with different max voltage spec??)

7. Same cup volume as T50RP?

Hypotheses:

1. Stock T50RP needs less damping, therefore, thinner white gauze than Stock T40RP MkII because the T50RP is semi-vented as opposed to non-vented T40RP MkII.

2. Venting Stock T40RP MkII and changing the thick white gauze to thinner material will essentially transform Stock T40RP MkII into a Stock T50RP.

3. Modding with Paxmate or similar damping material in cups, 1 reflex dot on center of driver backs, uncovering 1 of 4 vent slots in T50RP (or opening 4 vent slots in T40RP MkII and covering 3 with felt), and mass loading baffles with plasticine obviates the need for any white gauze on the backs of the drivers; thus accounting for reports of improved SQ after removing the white gauze and making the aforementioned mods.  Note:  I have not tried any mods on T40RP MkII.

Only $6 cheaper:  $69 for T40RP vs $75 for T50RP at BHPhoto and Full Compass.  T40's probably more readily available, at least at the moment.
 

Quote:

Originally Posted by HDMan 

So the driver is the same. If I'm making some thunderpants then I may aswell get the 40's eh? cheaper.

i see $67us at bhphotovideo & $89.78cdn locally (axemusic) for the t40; t50 out of stock at bh currently and totally unavailable locally.

<edit> with the revelation that senn 558 uses same driver as 598, an ugly truth seems to be creeping out --> make a driver, put it into decent housing = top of series; take same driver + make housing progressively worse = subordinate models.

do the wires in the cabling look exactly the same for t40 & t50?  what about the wiring traces for the 'pcb' components of the drivers?
 

Quote:

Originally Posted by bluemonkeyflyer 

T50RP: 

1. Naked plastic cups and baffles

2. Vented with thin felt over the vents

3. Small thick 3/4" tuning felt on bottom of cups

4. Thin white gauze over back of drivers

5. Pressure equalization vent hole in baffle connecting cup volume to outside on ear side

6. Same driver asT40RP MkII (but different max voltage spec??)

7. Cup volumes look the same as T40RP MkII

 

T40RP MkII:

1. Same

2. Non-vented

3. Same

4. Thicker/denser white gauze over back of drivers (to compensate for lack of venting?)

5. Assume same

6. Same driver as T50RP (but with different max voltage spec??)

7. Same cup volume as T50RP?

 

Hypotheses:

1. Stock T50RP needs less damping, therefore, thinner white gauze than Stock T40RP MkII because the T50RP is semi-vented as opposed to non-vented T40RP MkII.

2. Venting Stock T40RP MkII and changing the thick white gauze to thinner material will essentially transform Stock T40RP MkII into a Stock T50RP.

3. Modding with Paxmate or similar damping material in cups, 1 reflex dot on center of driver backs, uncovering 1 of 4 vent slots in T50RP (or opening 4 vent slots in T40RP MkII and covering 3 with felt), and mass loading baffles with plasticine obviates the need for any white gauze on the backs of the drivers; thus accounting for reports of improved SQ after removing the white gauze and making the aforementioned mods.  Note:  I have not tried any mods on T40RP MkII.