Fostex T50RP Incremental Mods and Measurements
Sep 25, 2013 at 9:42 PM Post #722 of 2,832
Just thought I should post a bit of an update. 
I posted my build in post #690.
 
Since then I have put maybe 100 hours on these guys. I use them all the time. While the velour shure pads are not perfect - they provide a solid 4 hours before I begin to "feel" the headphones. I am currently driving them from my Matrix M stage w/ stock op amp and 0dB gain. They sound perfect, and it puts me right in the middle of the volume pot with 3/4 volume on the computer. These headphones provide excellent soundstage - the clarity still amazes me. 
 
I did some hot swapping between my HD650s (one of my all time favs) and these and while the HD's still woo me with their sound signature, I love the clarity of the T50s. With the fitz mod my DV336se also does a great job of driving them, but I personally prefer the M stages sound signature. 
 
Big thanks again for developing this mod plan, I built mine pretty much straight DBV3 w/ cotton balls, and I love it. 
 
Oct 23, 2013 at 7:50 PM Post #724 of 2,832
I'm pretty sure I have a few empty shells. If no one in the US gets back to you, drop me a line.
 
Oct 24, 2013 at 12:17 AM Post #726 of 2,832
I know this has been done to death but here is yet another simple riff on BMF incremental mods:

Lined sides and bottom of the cup well, above and below the hanger (not the bass port), and laddered in all with 4mm of adhesive wool felt**.  This brought all the felt up flush.
Plasticine in the baffle
Removed felt from ear side of driver (really helps treble IMO)
Back of driver stock
Alpha Dogs
Wool stuffing** (I tried regular wool quilt batting and it was no good, too coarse, fluffy and not very dense)
 
The wool is where I riffed on BMF's mods.  I really packed it in using a 120 x 70 mm panel folded in half thinned in the middle to allow for the hanger.  I had to peel away a thin layer because it was just too much to get the cups closed. 
My thinking was this: if according to BMF (and confirmed through my own tinkering) more stuffing = better treble but less bass what if I packed in so much material that I no longer need to cover the bass port to control bass bloat.  The wool stuffing from madisound has very long, fine fibers and is dense/heavy and I think is what allowed this to mod work.  Covering the bass port now has a very minimal effect (I leave it wide open) but the mids and treble are excellent, and compare favorably to the detail of my SR-225's but without the sibilance.  Bass is fast, deep and punchy with no bloat in sight.  I have no measurement gear to back this up but FWIW 16-20k sweeps are all there and sound very smooth to me.
I am going to audition against a friends more traditional BMF t50 mod, which also sound excellent, just to see if there is any tuning that could squeeze more out.  For now I'm very pleased to let this setup ride.
 
** material left over from a speaker build, all from madisound
Source gear is a pile of schiit (bifrost > asgard)
Many thanks BMF for making this all possible.
 
Oct 30, 2013 at 4:15 PM Post #727 of 2,832
I finally got my Alpha Pads after around one and a half weeks in shipping.
I bought them directly from Dan after I had some issues with the address (problem with accents in letters like "é" which is common in France) when I wanted to buy them directly from his website. I exchanged some PM's with Dan, explained the problem and everything went very smoothly. Also he's a very nice man!
 
Pictures galore!:

 

 

 

 

 

 

 
Impressions:
Holy S*** these pads are extremely comfy! I think these are one of the most comfortable pads I've ever tried. As comfortable as the LCD-3 pads but just slightly behind the Stax SR-007 and SR-009 pads but at that price, I can only give high praise to the Alpha Pads.
The pads feels very luxurious and has a very good leather quality.
Sound quality wise, they are a huge improvement over the Hifiman pleather pads that I used. They make a much better seal on my head especially when I'm wearing my glasses since they have quite thick arms which makes them loose some low end.
I think, due to the angle of the pads, I noticed a much more wider and a more natural soundstage with more forward mids, bringing the vocals up front. There's more low end content and a bit tighter bass. Treble is much more natural and no longer tizzy sounding.
I really love these pads that I bought two pairs. One for my T50RPs and one for my Hifiman HE-500.
 
Thank you so much Dan! Your pads are awesome!
 
Oct 30, 2013 at 4:24 PM Post #728 of 2,832
^Are your T50RP's configured to DBV#3? I definitely didn't like the standard DBV#3 with Alphas, they required a fair amount of tweaking. Obviously the DBV#3 mod was tuned to 840's.
 
Oct 31, 2013 at 2:16 AM Post #730 of 2,832
^Are your T50RP's configured to DBV#3? I definitely didn't like the standard DBV#3 with Alphas, they required a fair amount of tweaking. Obviously the DBV#3 mod was tuned to 840's.


My T50RPs aren't tuned to DBV#3 but rather they are my mods with my choice of materials but I had some inspirations from the DBVs.
They were tuned using Hifiman Pleather pads which are quite stiff pads with not much cushion on the foam.
When I was using the Hifiman pads, they made my T50RPs sound quite bright with a metallic sounding treble. Now with the Alpha Pads, they sound much smoother.

The materials that I used are:
Thick adhesive foam (used for automotive applications)
Fiber wool
Plasticine
And that wool thingy that you often find on speaker enclosures.

VortexBlast where are you now? Are you still in south east Asia? If so, how sweaty will it be lol. since without air conditioning, sweat is a given in almost any country there...


I'm in France right now where the weather is quite chilly but I did try to use it when it was a bit warm. They are surprisingly breathable and they don't make you sweat too fast.
 
Oct 31, 2013 at 10:57 PM Post #731 of 2,832
it is too cool for words that Dan makes these pads available to everyone.  I agree with all the points made by vortexblast; the alphas make the t50 world class and all for less than 2 bills. 
Too bad you didn't grab the comfort strap before shipping to France as well.  Call me crazy but in addition to making the cans disappear on my head comfort wise I could swear the bass improved with the more solid seating the strap provides.  Oh well, an old belt works too.
 
Nov 1, 2013 at 7:02 AM Post #732 of 2,832
Is there any mod that would give the Fostex an LCD-2 type sound ? Did a quick search for LCD-2 on this thread just before and going to read though more, but if anyone knows of anything please let me know !
 
Nov 1, 2013 at 8:06 AM Post #733 of 2,832
  Is there any mod that would give the Fostex an LCD-2 type sound ? Did a quick search for LCD-2 on this thread just before and going to read though more, but if anyone knows of anything please let me know !

Well, in the first post you can see that BMF had his measuring setup essentially calibrated to his LCD-2's frequency response plot that is provided with the headphones. However, his final T50RP mod has a much flatter response in the treble region where the LCD-2's are fairly recessed. I think the best thing to do would be to complete the DBV#3 mod and then do some incremental tweaking to lower the treble (i.e. don't add a treble reflector, or add less cotton/fiberglass).
 
Nov 1, 2013 at 2:15 PM Post #734 of 2,832
  Is there any mod that would give the Fostex an LCD-2 type sound ? Did a quick search for LCD-2 on this thread just before and going to read though more, but if anyone knows of anything please let me know !


Echoing Thujone:
Make you t50 what you want, the basics are all there, sound stage, detail, etc.  Frequency response is tunable to your liking.
I followed BMF initially but ultimately did my own thing, they suit my taste in music, my preferences etc.  It's all about having fun, not stressing about emulating something.  I generally prefer brighter (or thought I did) more forward sound and detail, but when I could experiment I took a new direction and that is what is so cool about modding.
Treble is in my opinion more difficult to tweak, bass is easier you just have to watch out for boominess.
Enjoy the journey.
 

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