[TiEx]

Good evening ortho lovers. I need some inspiration on the future project. Basically not an ortho transplant but rather whole new headphones. So here it goes.
 
Most important: the drivers. I am planning to go for Amfiton TDS-7 - the soviet flagship isodynamic headphones. Impedance is 8 Ohm. 1 Watt max input power. Very difficult to drive for mainstream headphone amplifiers. However people reported great results when connecting to speaker power amplifier terminals, most of which are intended for 4 or 8 Ohm load, not very convenient though. Then I thought, wait a minute last technologies gave us small and efficient class D amplifiers. They are small and also sound good. Also there is a boom of small class-D boards with low voltage supply and power of around 1-15Watt. 
 
Here are just a couple of class-d amplifiers with 1Watt (THD under 0.15%) output power into 8 Ohm load, with digital volume control (don't even need volume pot) and 5V supply. You can use a 5v usb AC adapter or maybe PC usb port, maybe even regulated 5V linear supply that can be overkill for class-D amplifiers.
 
 
 
 
 

 
These would be just awesome to drive these vintage orthodynamics with pride.
 
Little bit about TDS-7. Many info in Russian language, and most people claim that their full potential opens up with open back construction with proper damping. Some guys took measurements that looked ruler flat from 20Hz to 1Khz and very good extension to 20Khz without big dips or peaks. After modification some preferred them to LCD-2 and HE-500, they are that good.
 

 
 
Now about the driver. The size of square membrane is 4,5 x 5,5 cm or 1.8 x 2.2 inch, a very big surface. The cups that hold membrane with magnets together are 6,5 x 7,5 cm or 2,6 x 3 inch.
 
 
 
 
 
 
 
Ok, now is the time to think of a good donor. I need super comfort, and super isolation, big assortment of accessories and solid build quality. Heck is this even possible?! Yes. Few moths ago stumbled upon David Clark headset for pilots and aviation purpose. Read a lot of reviews on these and realized that this is perfect for transplant, as it totally matches above criterias. You can buy these headset from many shops online or ebay. Also a wide variety of cords, ear cushions, headbands etc. available. 
 
The model H10-76 seems very good with many positive reviews about their great comfort for long travels and massive isolation needed in noisy air crafts. Also cup size is little bigger then needed for TDS-7 drivers.
 

 
 
Now how about a very important aspect of headphones, the ear pads. I found very nice David Clark silicone gel filled ear seals also with many good reviews about even greater isolation than stock pads on this headset. They are deep and big and rest on head, but not on the ear.
 

 
 
About construction and elaboration of this project I don't know. This idea is only on the paper so to say. Of course there will be definitely open construction. Need of cutting down the cups to accept the driver. Maybe some sort of grill on the outer side just for pretty design. There are plenty of damping instructions on orthodynamics both in english and russian. Also a simple electret microphone for measurements as well as some headphones for reference with existing measured frequency response (like on InnerFidelity or headroom or Purrin(from CSD thread)).
 
Constructive criticism and new ideas or suggestions are most welcome!
 
Best regards.
 
Alex

 

[TiEx]

Addition to above post. The idea to use deep ear pads with big openings came from Sony XB-500 and XB-700 headphones. They have excellent deep bass response according to IneerFidelity measurements.
 
http://www.innerfidelity.com/images/SonyMDRXB500.pdf
 
http://www.innerfidelity.com/images/SonyMDRXB700.pdf
 
Probably those large soft earpads help with low end extension.
 
 

 

[wualta]

TieX: Very exciting development. I've been hoping a TDS-7 would show up and that someone would modify it or transplant its driver, which, now that I see your photos, looks like a cross between the Technics EAH driver and a Fostex T50/TDS-15. 
 
If you have a large membrane able to move plenty of air (and good seals so the bass doesn't go where it shouldn't), no reason you can't have a circumaural headphone. 

 

[TiEx]

Quote:

TieX: Very exciting development. I've been hoping a TDS-7 would show up and that someone would modify it or transplant its driver, which, now that I see your photos, looks like a cross between the Technics EAH driver and a Fostex T50/TDS-15. 
 
If you have a large membrane able to move plenty of air (and good seals so the bass doesn't go where it shouldn't), no reason you can't have a circumaural headphone. 

 
Hello Wualta. Thanks for response. This is just a project for future. For now I have modded Electronika TDS-5m and what i really like about them is excellent mids and smooth highs, vary moderate midbass (almost without any emphasis), and the problem is lack of deep low end response. There is an audible roll off starting at around 35-40Hz. I would love to have something similar to LCD-2 but with greater comfort. 
 
I don't own this TDS-7. Pictures are just for reference. 
 
As far as TDS series goes the TDS-7 is flagship and TDS-15 is "upgraded" version of TDS-7. They differ just a little in membrane thickness and in its surface area. TDS-15 is 4 x 4 cm while TDS-7 is 4.5 x 5.5 cm. So TDS-7 have biggest membrane from USSR orthodynamics.
 
Circumaural design must bring comfort as well as good isolation to keep that low end rumbling between driver and ear without going outside. Hope that membrane size is enough to make ruler flat response from 20Hz to 1kHz like on LCD-2. BTW the membrane area in LCD-2 is 6.17 square inches vs membrane area in TDS-7 of 3.96 square inches. But on the contrary even 3.96 square inches is bigger surface than on 40, 50 or 55mm round driver corresponding to 2, 3.14 and 3.8 square inches. Look at Sony XB500 with its 40mm driver producing an earth splitting bass with right construction. I'm concerning only for linearity of frequency response, so the good low end wouldn't come with a sacrifice of recessed blurry mids and non existing highs (like XB500). My goal is frequency response dead close to LCD-2 if not the same.
 
God those TDS-5m do sing really good, but really would like a better comfort and deep bass response as well just with the same liquid mids and smooth highs.
 
P.S. I think the key feature to extend low end response in to 20Hz is a very good seal of driver --> cup --> earpads --> head. So hard work on construction is welcome. Also just like any other ortho a lot of experiments with damping materials and their amount with many intermediate measurements. Don't want to rely on my hearing with such a high end project.
 
P.P.S. Here is a link describing the effect on sound of Beyer DT770 with Gel filled ear pads compared to stock leather. http://www.head-fi.org/t/266192/beyerdynamic-manufakturs-gooey-gel-ear-seals-770-880-990 There is differenca according to this review. This thread also gave some inspiration for ear pads.

 

[khbaur330162]

TiEx: Those TDS-7 images you posted are gorgeous. A big thanks to you for sharing and to whoever took them in the first place.
 
Look at the waving on the traces and diaphragm in the image where the diaphragm is propped upright on a piece of the magnet assembly. Tension is next to non-existent. I agree with wualta, this reminds me of my EAH-820 quite a bit. The diaphragm substrate doesn't seem to have the same milky haze as the TDS-15, however. This lends me to believe it is in fact PET instead of the -well, we think- urethane substrate that was used in the 15 which makes sense given the tension. Idk, it reminds me a little of the Wharfedale ID1, too, where the pleats are replaced by just a baggy 'phragm.
 
Anyway, what do I think of the transplant? I think you've got a poor man's Wharfedale ID1 driver in these TDS-7's and I'm rooting for bass in a circumaural. They certainly look up for the task. Do I think you're going to get monstrous bass? Well, I'm sorry, but no I don't. I do, however, think that you can get these to sound pretty darn flat in the right circumaural housing with enough work (I could try to be even more ambiguous, honest), and to that end it seems like you're on the right track.
 
Did you see my Sennheiser HD535/T50RP project? You don't have to tell me what you think of it, I know it's butt ugly, but what it sounds like is what's important. For whatever reason I think the TDS-7 drivers could benefit from similar treatment.
 
The Beyer gel pads are cool. They could fit a Superlux model, I'd assume. They can also fit Denon Dx000's.

 

[nick n]

When you actually get around to the David Clark headset there can you tell me how you got into them I can't figure it out, though I haven't looked close but I see no screws obvious at all.
 Yeah mine is pretty much the same as the picture.
 
Really interesting project idea going there.

 

[wualta]

Eh? Nick, you've got a David Clark headset? did you swipe it out of a Cessna?

 

[nick n]

from the crashed luminescent egg shaped craft in the woods next to my place.
 
Actually( not that you bought that previous line ) from a second-hand place . It came with that big Blaupunkt Tube radio I got a while back. Freebies. A really awkward design the rear cups remind me of two giant M&M's that are gummed to the baffles. In need of a good cleaning, if I get to it prepare for pics.

 

[wualta]

Interesting. They've been selling that same design for oh, nearly 40 years now, and advertising it in things we used to call "magazines", like Aviation Week. I'm sure there've been refinements along the way.
 
However, David Clark Co. has long been busy making other neatokeen aerospace/aviation stuff. Guess what Felix Baumgartner was wearing when he did the big jump. The airtight seal is something this company knows all about. So I applaud the use of a DC headset, though comfort might be a problem in typical NA humidity. The amount of acoustic isolation could be psychologically disturbing for some people as well. Still, for preserving maximum bass, this is about as good as it gets.

 

[nick n]

oh no...I guess that means you just made me start considering  a suitable driver to graft in there.

 

[leeperry]

So what happens when you slap j$ beyer earpads onto a YH100, huh?
 

​

 ​

​

 
My friend loved the YH100 I modded for him but its flimsy earpads were hurting his ears after a while = problem solved

 
And I'm still as weak as ever because I've got another aniso HP1 heading my way, it's hard to let those things pass by.........I tried to resist, I really did! But I'm hoping that the previous one I had was a dud, because I'd love to mod it to be a compromise between the HP1 3D SS + the YH100 bass.....the worst case scenario being that it'll go back to where it came from.

 

[nick n]

What do you find in the way of changes to the sound with those new pads? Looks like something I could fall asleep with.
nice work.
 
You get that black boxed HP-1  that just sold?

 

[kalbee]

Just a little update on the ATH-RE70 retrofitted with SFI drivers.

Spoiler: Pretty%20happy%20with%20my%20HP-1a%2C%20HP-2%40MusicPeople%2C%20YH-3.

 

 

They're not perfect, and comfort could be better considering the flattened pads on the HP-1 and starting to flatten YH-3 (HP-2@TheMusicPeople pad business on hiatus; see that huge dropoff at 3kHz), but my main problem with them is that I cannot really use them as portables. I do occasionally take the HP-1 out on my commutes, but they don't isolate much and also leak a bit or even considerably.
 
So came the idea/project for putting SFI drivers into ATH-RE70 drivers (that dynamic lesser clone of the ATH-2). Now it surprised me a bit how cheap the plastic on the RE70 seemed, and despite being a closed headphone they do not isolate very well. In fact the plastic resonates outside noise to some extent. So after cleaning out the shells and putting the bruma-found SFI drivers inside I used them for a few days with minor damping. The cups really lack isolation...! Considering I use them on the bus and metro, the ambient lows really do creep in as without anything covering my ears. So I decided to create better isolation.
 
There was a small ring inside the cups where the surface is lowered. I started with filling it with blue tack, and covered most of the inside surface of the cups with stiff felt (leftover from my first attempt at damping the HP-1a--- either 55mm or 52mm). The isolation effects seem minimal. Thinking of making a layer of reflective barrier inside the cups, I took the stiff felt out and decided to put things under it.
 
Around the blue tack ring I smudged flat a wide ring of plasticine, just to increase the mass of the cups. On the center, where the screw that connects to the headband is, a circle of memory foam (the donut hole from the earpads I made for the HP-2@TheMusicPeople), and a bit of polyester fill around it still. Taking a cardboard circle (cut from one of those Blizzard invitation cards) that is slightly larger than the stiff felt, push it flush to the bottom of the cups. Making sure the polyfill doesn't stick out from around the cardboard, use blue tack to pin them down on parts of the perimeter. Finally, the stiff felt goes back on top of the cardboard.
 
As for damping, I used loose cotton and a square of arctic bamboo placed diagonally. The orientation is only so that it doesn't cover the screw holes. On top of that a small piece of the red oak wood trimming I had on hand, about 6mmx11mm. The whole thing is harder to close now but definitely still closes. The sound became something like this...

1kHz~4kHz is quite shelved, but the effects aren't so bad considering there is a lot of female vocals in my music repertoire.
This is the 3rd iteration of the mods. Compared to the previous one (same setup but without the isolation effort), it certainly did decrease the sound stage since the cup volume decreased as well. Isolation... did improve, but I'll have to wait till another day of commuting to know how it really fares. As far as I can tell the isolation issue was mostly coming from the lateral face of the cups, so hopefully the blue tack will help a bit in that regard. In any case, portable ortho, check!
 
Wish I had taken pictures of the innards--opening them up right now my screw something up so I'll pass on that for the moment.
 
On a side note, the weight of these things since the stock form with dynamic drivers, surely more than doubled!

 

[TiEx]

Quote:

TiEx: Those TDS-7 images you posted are gorgeous. A big thanks to you for sharing and to whoever took them in the first place.
 
Look at the waving on the traces and diaphragm in the image where the diaphragm is propped upright on a piece of the magnet assembly. Tension is next to non-existent. I agree with wualta, this reminds me of my EAH-820 quite a bit. The diaphragm substrate doesn't seem to have the same milky haze as the TDS-15, however. This lends me to believe it is in fact PET instead of the -well, we think- urethane substrate that was used in the 15 which makes sense given the tension. Idk, it reminds me a little of the Wharfedale ID1, too, where the pleats are replaced by just a baggy 'phragm.
 
Anyway, what do I think of the transplant? I think you've got a poor man's Wharfedale ID1 driver in these TDS-7's and I'm rooting for bass in a circumaural. They certainly look up for the task. Do I think you're going to get monstrous bass? Well, I'm sorry, but no I don't. I do, however, think that you can get these to sound pretty darn flat in the right circumaural housing with enough work (I could try to be even more ambiguous, honest), and to that end it seems like you're on the right track.
 
Did you see my Sennheiser HD535/T50RP project? You don't have to tell me what you think of it, I know it's butt ugly, but what it sounds like is what's important. For whatever reason I think the TDS-7 drivers could benefit from similar treatment.
 
The Beyer gel pads are cool. They could fit a Superlux model, I'd assume. They can also fit Denon Dx000's.

 
I can post even more images of TDS-7 if you like.
 
Your HD535/t50rp project is very cool, I hope it sounds good to your ears. I've got the idea of tight seal between the driver and cup.
 
About TDS-7 bass, well... In russian forums there are people who did modded them totally and extracted that deep low end rumbling down to 20Hz (open back construction with big circumaural earpads). I hope to do the same. As I mentioned in above post, I think the quality of connection between the driver, cup, earpad and head is most important to make this. Well maybe deep low end can affect the highs making them recessed, but I'm ok with dark signature sound. Think it is a matter of construction and damping.
 
Quote:

When you actually get around to the David Clark headset there can you tell me how you got into them I can't figure it out, though I haven't looked close but I see no screws obvious at all.
 Yeah mine is pretty much the same as the picture.
 
Really interesting project idea going there.

 
I didn't seen any screws either. Don't know yet how to disassemble them, but drill, hacksaw and rasp would do the job with any headphone or headset. This is a matter of DIY experience.
Repeating another time, this is just a project on a paper, I don't have any of these components yet. That is why I need some insight and suggestion from you guys, maybe I'm doing something wrong.
 
Quote:

Interesting. They've been selling that same design for oh, nearly 40 years now, and advertising it in things we used to call "magazines", like Aviation Week. I'm sure there've been refinements along the way.
 
However, David Clark Co. has long been busy making other neatokeen aerospace/aviation stuff. Guess what Felix Baumgartner was wearing when he did the big jump. The airtight seal is something this company knows all about. So I applaud the use of a DC headset, though comfort might be a problem in typical NA humidity. The amount of acoustic isolation could be psychologically disturbing for some people as well. Still, for preserving maximum bass, this is about as good as it gets.

 
Many reviews all around the internet are reporting the same things for David Clark headsets: great comfort, very good isolation, reliable construction. And great knowledge accumulated by this company of airtight seal did caught my attention. Can't think of a better companion. About the comfort, you probably mean the sweat problem with gel ear pads. This is only a problem with painted gel ear pads as far as I know. I found however clear gel pads for DC headsets. http://store.acousticom.com/aviation-headset-ear-seals so it shouldn't be a problem. About great amount of isolation disturbing some people... Everybody have different taste, and I'm fine with airtight seal (considering that have CIEMs for portable use and like them).
 
Quote:

oh no...I guess that means you just made me start considering  a suitable driver to graft in there.

 
The only concern in this project is the right driver for the purpose. And Nick, can you please describe the comfort and seal of your headset, as well as construction reliability?

 

[leeperry]

Quote:

What do you find in the way of changes to the sound with those new pads? Looks like something I could fall asleep with.
nice work.
 
You get that black boxed HP-1  that just sold?

 
I didn't get to hear it yet but he told me "SS has drastically improved in every way, trebles are unveiled, bass is much tighter/less bloated and the sound is just much more detailed". I soldered a DHC plug onto it for that matter, which also improved clarity: 
 
 
Well, the j$ beyer's are made of über-comfy memory foam and very soft and thin high-grade lambskin, these are pretty much as good as it gets if you like circumaurals(I've grown tired of it personally).
 
Yup, that would be me.......you only live once you know, and I'm not in the market for neo-orthos so it's not like we have a million choices available when it comes to feeding the ortho hoarding OCD monster