[kalbee]

Quote:

Those SFI's *are* tweeters after all... cranking down the treble is most of the battle with those. 

My SFI in the AudioTechnica RE70 (trying to fake a ATH-2) definitely don't have much treble to it. Which is weird compared to how the SFI's react in those AKG shells.
I might have a clue on what's causing it but as far as I can tell, I can't increase the treble even by plastering the back with reflectors.
My guess is the ~1mm closed space between the drivers and the baffle. And perhaps the holes on the baffle which do not necessarily align.
 
Quote:

Would my YH-1 drivers fit in some Grados?

Pretty sure they won't. YH-1 drivers are just that big.
And as you may have noticed from the thread, you're not going to get the same sound just by dropping the drivers in a different enclosure; you'll have to make considerable modifications to get them sounding right. Where, there's always lucky cases of something that makes it sound perfect, but don't count on that being the case. Be prepared to have to damp it somewhat.
 
From the looks of it you're looking for open-back headphones to place them in?
How about using the same headphone as BMF? 
http://www.head-fi.org/t/111193/orthodynamic-roundup/21765#post_9540230
If he was able to fit TDS-15 drivers inside, the YH-1 will fit. Although you can see he made new baffles and did a lot of cutting.
 
Or if you don't mind the looks, see if you can find one of the headphones in this thread: 
http://www.head-fi.org/t/666109/found-some-vintage-headphones-pleasantly-surprising-results#post_9519176
The ones mentioned all OEMs of each other, but I know at least that the YH-1 drivers could fit in my Dero-D560 (one of the OEM headphone)

 

[bluemonkeyflyer]

KODA Retrofit and Re-modification
 

A very good friend asked me if I'd like to hear his KODAs. I said, "You bet!" He mentioned that the Right channel randomly cut-out and wondered if I might be able to determine the problem and, perhaps, fix it.

 

This is ALL IMO:

 

When I received the KODA's and listened for all of 1 minute, I knew there was something "off" with the SQ. The bass was out of control causing Boomy Bass Bloat (BBB) that muffled the mids. The lower mids sounded really thin. There was essentially no treble hidden behind the BBB. I suspected part of the problem with the SQ had to do with the "Naked Drivers." By this, I mean that the drivers' stock white driver damping material had been removed. In their place was a thick square of felt (~5 mm), with the center cut out, that appeared to be impermeable...it didn't look like it would "breathe," and instead "choke" the driver. I tried many different damping schemes using numerous materials with and without this felt and nothing worked to improve the sound. I ultimately decided the only alternative was to transplant new drivers. So, I ordered a new set of T50RP's, extracted them from their stock baffles, and began the transplant. 

 

After removing the stock drivers, with their stock white driver material intact, I placed them onto the KODA baffles and screwed them down with their 3 (Only 3) screws. Unlike the stock mounting configuration with 2 side snap tabs, the 3 screws, alone, could not handle the pressure and the 3 screw sockets' plastic threads stripped. I checked the 3 original KODA drivers' screw sockets and found that they, too, were completely stripped. Without the added strength of the the 2 side snap tabs, the threads stripped and the driver-to-baffle seal was compromised. I had to fix this problem if I was going to have a tight seal necessary for good sound quality. I decided to use the super glue method that has worked with other T50RP mods. First, I drilled out the 3 driver screw sockets using a 1.7 mm drill bit. Second, I covered one side of each screw compartment with masking tape, filled the enlarged "chambers" with super glue, and "tamped it down and stirred it around" with a piece of copper wire with insulation removed. The super glue cures in 24 hours. Next, I used my Dremel drill press with 1.7 mm drill bit to make "pilot" holes for the stock screws that are 2 mm in diameter. Mounting the driver to the baffle, the stock screws will self-tap new threads. Worked great. The hardened super glue threads are able to tolerate the pressure of screwing the drivers down Tight to the baffles without the added strength of the side snap tabs. I added a bead of GE Silicon II to ensure the seal remained patent.

 

Next problem: Moving my head from side to side caused the Right Channel to cut out sporadically. I started at the Right side of the driver and worked my way, inch by inch, to a section about 4 inches from the cup. Bending the cable below and above this 1-inch section did nothing. Bending the wire at that particular segment caused the Right Channel to cut out every time. I removed the insulation and found that there was a crimp and partially cut wire in that section. So, I cut out the Right and Left Channel wires below the Y-splitter, soldered in new Mogami wire, re-connected and soldered the new wires to the drivers, and added new heat shrink around the joints.

 

With new cable wires and new stock drivers, I was ready to start damping trials. I tried many materials in various configurations. Here's what I settled on:

 

Note: pictures of the KODA build and damping scheme were posted to the KODA thread last year by the maker so I'm not "giving away" any secrets.
 

KODA with 5 mm felt. White felt covers headband
mounting hardware.
 
 
KODA felt removed exposing Naked Driver.
 

Naked Driver removed and wires cut.
 

New T50RP drivers with stock white damping
material ready for transplanting into KODA. 
 

New T50RP drivers removed. Note side snap
tabs at "10 o'clock" position on the baffle
(the one on the right).
 

New T50RP drivers mounted to KODA baffles and
ready for soldering.
 

3:1 heat shrink surrounds new solder connections.
 

Measure stock screws.
 

Use 2 mm drill bit to ream out 3 driver screw
sockets.  Repeat after super glue has cured
to make "pilot" holes for the screws to self-tap
new threads.
 

Masking tape over one side of driver screw
sockets to block super glue. Note the solder
joint on the negative terminal. I accidentally
pulled it loose but had no trouble re-soldering
it with a dab of flux, Kester Eutectic solder,
and iron set to 500 degrees. Tape it down
on either side and get in and out quickly.
 

Fill sockets with super glue, a little at a time.
Use a paperclip or piece of wire to tamp down 
and around to remove air bubbles and ensure
super glue makes good contact with socket
floor and walls.
 

Let super glue cure for 24 hours before drilling
pilot holes.
 

New T50RP driver sockets repaired with super glue
and  mounted onto KODA baffles.
 

Paxmate Plus in cup floors.
 

Paxmate in cup floor and Paxmate segments evenly  
spaced around cup walls. The bass port (near cable
entry) and cup areas for driver "nibs" are not covered.
The final Paxmate Plus segments for the cup walls
were 1x4 cm. I placed 5 around the walls,
evenly spaced.
 

1 x 4 cm Paxmate strips (5) evenly spaced around
cup walls. Leave room for the driver "nibs" to seat
into the cups. Add 0.5 grams of cotton in cup over-
laying the Paxmate Plus. Stiff felt over back of the
driver with a 4 mm hole in the center for a bit
more bass.
 

I tried Angel Hair but cotton sounds better with
this config. 4 mm hole in center of stiff felt that
overlays stock white driver damping material.
 

Paxmate "Picture Frame" around ear side
of driver.
 

Fischer FA-003 pads fit perfectly with double sided tape.        
 
 
I decided to use 'micmacmo's' inner tube flap modded FA-003 pads for a perfect pad-to-cup seal.
 
The sound quality is significantly improved with great bass quantity that's well controlled, warm mids, and good treble details. I like this mod a lot.
 

 

[nick n]

^ Absolutely fantastic . Love the build breakdown and pictures. Well done.

 

[bluemonkeyflyer]

Quote:

^ Absolutely fantastic . Love the build breakdown and pictures. Well done.

Thanks, nick!
 
FYI/FWIW, I found some additional pictures and added them to the pictorial.

 

[aeroG1]

Okay I've got a new project. Gonna get a pair of pro 30s that need recabling. Any recommendations?

 

[nick n]

What are you doing with the others? If it is what i am thinking they may have decent cables. At any rate I really like some of the Sony stuff for cables, especially the really pliable and flexible rubbery silicone types. Should be able to find something at a thrift shop cheapo for those.  If I recall correctly the Pro 30 use some special Aluminum friendly solder, so if you aren't confident you can get it soldered down the first time using the solder that is pre-exisiting on the tabs already, then maybe the easiest thing would be to leave a small bit of stock cable ( a small lead already attached to the driver tabs ) and patch directly onto that instead.
The aluminum type solder points never seems to accept regular solder.
 
And make sure you can melt off the enamel on the new cable wiring if it has that.

 

[bluemonkeyflyer]

What are you doing with the others? If it is what i am thinking they may have decent cables. At any rate I really like some of the Sony stuff for cables, especially the really pliable and flexible rubbery silicone types. Should be able to find something at a thrift shop cheapo for those.  If I recall correctly the Pro 30 use some special Aluminum friendly solder, so if you aren't confident you can get it soldered down the first time using the solder that is pre-exisiting on the tabs already, then maybe the easiest thing would be to leave a small bit of stock cable ( a small lead already attached to the driver tabs ) and patch directly onto that instead.
The aluminum type solder points never seems to accept regular solder.

And make sure you can melt off the enamel on the new cable wiring if it has that.

IIRC, T50RP uses aluminum solder. I've read several posts about how difficult they are to re-solder with regular solder. I've done 3 with no problems using Kester eutectic solder by adding extra flux with a toothpick, taping down the wires on either side of the wire to be soldered, and setting the temp at 500 F. Takes about 2 seconds. Get in and out fast. If it doesn't accept the solder, let it cool, re-apply flux, and repeat.

One of the pix I posted in the KODA re-build shows the negative terminal re-soldered. I agree about leaving pigtails and patching in the new wire. 19 strand SPC 26 or 28 gage wire from navships on eBay works great. It readily takes on solder if you first pre-tin the wire and your iron.

 

[dBel84]

No the original fostex ( and then not all) use alu solder . The t50rp uses normal solder. Alu solder is a real pia , you will want to leave a small piece of original wire to use

 

[Armaegis]

Quote:

No the original fostex ( and then not all) use alu solder . The t50rp uses normal solder. Alu solder is a real pia , you will want to leave a small piece of original wire to use

Ugh, the original Al solder is a bugger. I tried to retain all the original solder and just used my iron and a tiny bit of normal solder to transfer heat without mixing into the Al. Use plenty of flux to keep everything clean and to prevent minimize oxidation.
 
Or yeah, just leave a piece of wire and work off that. Soooo much easier.

 

[bluemonkeyflyer]

Quote:

No the original fostex ( and then not all) use alu solder . The t50rp uses normal solder. Alu solder is a real pia , you will want to leave a small piece of original wire to use

dBel84,
 
Thanks for the correction. Must be misinformation in another thread. That probably explains the ease of making the new connection on the current production T50RP and T20RP mk2.
 
Do you happen to know what type of solder was used for vintage Amfiton TDS 'phones? The TDS-15 was also very easy to re-solder using navships' wire and Kester solder.

 

[nick n]

http://www.head-fi.org/t/558282/wip-custom-headphones-design-with-new-pics/15#post_9566494
 
Interesting thread.

 

[kalbee]

Nice find there.
Always thought the SOL Republic Tracks would make a nice SFI foster, but looks like the interior cavity is as small as I dreaded...

 

[takato14]

Anyone know of an orthodynamic driver that has have enough bass to be used in say, a K1000-like earspeaker implementation? 

 

[Armaegis]

Dual T50rp configuration?

 

[dBel84]

LCD3 , AB1266

? DIY

Actually , YHD1 might do it