[wdahm519]

Nice comparison BMF!  Thanks for doing that.  It's good to know the 20's are a viable option perhaps for a mid-fi modification perhaps for a travel set.

 

[leeperry]

good to see that the same driver ref doesn't necessarily mean that they're the same, I never bought the story that the d2k and d5k shared the same drivers(neither could anyone prove it). Only a service manual can attest for this(as for the sa3k/sa5k for which it's written black on white in the SM).

 

[Nevod]

Quote:

good to see that the same driver ref doesn't necessarily mean that they're the same, I never bought the story that the d2k and d5k shared the same drivers(neither could anyone prove it). Only a service manual can attest for this(as for the sa3k/sa5k for which it's written black on white in the SM).

Why it's good? I still think the drivers are exactly the same.
Besides, there's enough difference between them to make the observed results. They differ the most in bass region only, and T50s are more damped than 20s, and 40s, being closed, seem to be overdamped.

 

[leeperry]

 
Quote:

Why it's good? I still think the drivers are exactly the same.
Besides, there's enough difference between them to make the observed results. They differ the most in bass region only, and T50s are more damped than 20s, and 40s, being closed, seem to be overdamped.

It's good because things are not always what they seem...they don't even share the same max input spec in the Fostex datasheet. For what we know this is the ref of the PCB, not of the driver itself...they prolly share the same PCB but not the same diaphragm. That will avoid all the business that's surrounded pimped d2k's supposedly sounding better than stock d5k's to start all over again.

 

[Nevod]

Quote:

 

It's good because things are not always what they seem...they don't even share the same max input spec in the Fostex datasheet. For what we know this is the ref of the PCB, not of the driver itself...they prolly share the same PCB but not the same diaphragm. That will avoid all the business that's surrounded pimped d2k's supposedly sounding better than stock d5k's to start all over again.

I don't think that is a good thing About the input spec, we have already speculated here that it may be due to Xmax limitation rather than peak power rating - IIRC, drivers are rated for 15 watt short-term - 20s have less damping, due to no felt over the ports, and 1 db higher rated sensitivity, 2000mW X 98 db ~ 3000mW X 97 db.
 
Guess the only real way to find out would be to write a letter to Fostex.. IF they would answer that. OR..
 
 
BMF,
Would you be so kind as to try and remove the damping felt from T50Rp's bass ports and also remove the cap on the central column, and compare the result to the stock T20RP? The dust cover over T20 bass ports also could probably make a difference, but most probably not.

 

[rhythmdevils]

Very cool idea!  I do agree that the subtle differences in damped vent/closed vent/undamped vent could make this much difference though (it makes a huge difference as we know).  So I don't think it's conclusive one way or the other unfortunately...  grrrr

 

[Taowolf51]

I think I may go ahead and switch out the cable in my T50rp's. I just found my old Zune 30 (yay Wolfson DAC!), and I'm going to make a portable setup out of the Zune 30 and the Fostex's. To do this, I want to make the cable shorter, and more 3.5mm friendly. I've heard about the Vmoda cable people are using for the Fostex's. Which one is it (and where can I get it)? Does it stay in place (I'm going to try to use the stock earcup 3.5mm jack port for now)? Does it sound good? How does it change it? Would it be better than options from mogami/monoprice?

 

[proid]

Quote:

I think I may go ahead and switch out the cable in my T50rp's. I just found my old Zune 30 (yay Wolfson DAC!), and I'm going to make a portable setup out of the Zune 30 and the Fostex's. To do this, I want to make the cable shorter, and more 3.5mm friendly. I've heard about the Vmoda cable people are using for the Fostex's. Which one is it (and where can I get it)? Does it stay in place (I'm going to try to use the stock earcup 3.5mm jack port for now)? Does it sound good? How does it change it? Would it be better than options from mogami/monoprice?

IME, recable with canare star quad make the most improvement in high frequency.

 

[Taowolf51]

Quote:

IME, recable with canare star quad make the most improvement in high frequency.

I've never soldered before.
Well, once, when I was fixing a mistake I made when modding the Fostex's.

 

[Lurkumaural]

Quote:

I think I may go ahead and switch out the cable in my T50rp's. I just found my old Zune 30 (yay Wolfson DAC!), and I'm going to make a portable setup out of the Zune 30 and the Fostex's. To do this, I want to make the cable shorter, and more 3.5mm friendly. I've heard about the Vmoda cable people are using for the Fostex's. Which one is it (and where can I get it)? Does it stay in place (I'm going to try to use the stock earcup 3.5mm jack port for now)? Does it sound good? How does it change it? Would it be better than options from mogami/monoprice?

Get the audio-only cable, not the phone cable, because the point is to use the 45-degree plug at the headphone entry; basically used in this way, the cable is upside down.
 
Best (maybe only?) place to get it is from the v-moda website.  It's like 10 bucks I think.  No beating that unless you a) DIY or b) buy a cheap cable, like from Monoprice.  Tradeoffs may be implied.
 
I haven't used it, so I can't report.

 

[Magick Man]

http://v-moda.com/audio-only-cable/

It's in stock in red, which is what I bought. It looks great, feels well made, and fits perfectly. Can't beat that for $10.

 

[Taowolf51]

I may end up simply doing that, thanks. Didn't want to pick it up from Vmoda because of how much the shipping is, but I guess its my only option. May recable it in the future, though I'll need to buy cable and supplies to do the recable, so I may wait on that a bit.

 

[cn11]

I just got a black/dk. grey one.... those are in stock too. It looks like everything but all black is available.

 

[jschristian44]

Wow those are very close in performance.

 

[bluemonkeyflyer]

Quote:

 
BMF,
Would you be so kind as to try and remove the damping felt from T50Rp's bass ports and also remove the cap on the central column, and compare the result to the stock T20RP? The dust cover over T20 bass ports also could probably make a difference, but most probably not.

I removed the stock black felt ("damper" - part # 17) and the headband hanger compartment cover ("plate" - part #18) from the T50RP. I measured this otherwise stock set with the baffle port open and then sealed (electrical tape) compared to fully stock T50RP and fully stock T20RP.  All measurements were made on the left side.  All graphs are for the corresponding headphones, all on the left side whether indicated, or not.