The Orthodynamic Thread

[spritzer]

I figured this topic deserved a new thread and I'll kick it off with impressions of my new Koss UR18 foster phone. Those that have been following the ortho thread on HF know about the SFI drivers that cost next to nothing yet deliver in spades. I found a Koss UR18 cheap brand new today and it had all the right characteristics of a good foster phone, pleather pads, dual entry (I just like it like that) and thin earpads and a small enclosure. By sheer luck they had drivers which were exactly the same diameter as the SFI units so conversion was easy. Remove the old drivers and insert the new ones.

Here you can see one earpiece and how I damped the housing. I didn't use the loo paper in the end and used some fiber paper instead. As you can see I left a few of the ports on the back open but heavily damped. The old drivers are there for comparison.

The drivers have been glued in place with some old epoxy I had and more damping added to the baffle. I didn't really experiment with this but now that I have them playing the chassis could do with some more damping as it resonates quite a bit.

They are now ready for assembly. I used 3 sheets of fiber paper over next to the driver, then came the stock foam damping and last came one sheet of fiber paper next to the earcup to damp the ports.

Two really similar headphones so now we know where Stax stole the design. Also note the different size of the earpads. I just stuffed some rubber tubing I use to make cables under the pads and twisted them so the middle part is double the thickness of the ends. The Lambda pads were a great idea so why not borrow it... It really helps the imaging by controlling the angle of the drivers.

As to the sound then they have no right to sound this good since the stock headphones are horrible. The bass is tight and controlled, plenty of treble though never bright and the midrange has great presence. The soundstage is what you would expect from a supra aural though slightly diffused. They haven't even been trough a 700 hour burn in yet they sound great. There are some nasty resonances due to the chassis and therefore low level detail isn't up to ESP level but who cares as these cost less then 50$ new. They are also foldable and come with a 3.5mm jack so portable orthos!!!

Edited January 4, 2009 by deepak
added back images at request of thread starter

[Smeggy]

Nice job Spritz me old mate! I have to admit I do like the little SFIs, cheap and good. I'm having fun with mine.

[spritzer]

Great little drivers but this particular version will never be used with an ipod. I just borrowed my brothers 80gig unit and it hasn't got the power to push them to anything more then background listening.

I have to admit that I'm nowhere as crazy as you though with your quadro setup

[Smeggy]

It might be crazy, will it sound any good, that's the question. In the meantime I have to do some thinking on how to mod the Sonys.

[spritzer]

It might be crazy, will it sound any good, that's the question. In the meantime I have to do some thinking on how to mod the Sonys.

I have a ECR-400 and the drivers are true works of art. An SR-X type of chassis might prove to be very good indeed.

[Smeggy]

I have a ECR-400 and the drivers are true works of art. An SR-X type of chassis might prove to be very good indeed.

The drivers look to be in sweet condition. The subdued highs seem easy to remedy, I took the drivers out of the housing and there's plenty of treble there, just not realized in it's current configuration. The foam in the back is rotting and the brass fixing frame is corroding a bit so I'll do some cleaning and see what's what. I haven't taken the box apart yet to see what's going on in there but I feel there's a huge potential with them. Perfect channel balance and way more bass than your average stax or ortho. Mine are fitted with SR-5 pads which are an almost perfect fit. Luckily I had a new set laying around.

The SFI and ECRs are just reinforcing my view that planars are what I like best. I'm now down to 2 dynamic types. K1000 and KSC 75.

[Duggeh]

I'm down to one dynamic, the Float 2. The last dynamic I bought was the DR100 and they lasted only 3 days (the time until the SFI drivers arrived) before I took them apart. Then the Orthodome was born.

Currently running on 1 AMT, 1 stat, 1 piezo, 1 ortho, 1 dynamic and the surrounder, which defies classification. But I'd make room in my bosom for many more, K1000, Ergo 2, Yamaha YH-5M, they'd all be nice.

The iPod is right near the top of its amp output to get the Orthodome at listening levels I'm comfortable with, but perhaps I listen at a lower volume than many people. Or perhaps the method and type of damping and the housing plays a big part in the overall efficiency.

[Smeggy]

Talking about the ECR, can I get a stax cable and wire it to the ECR drivers and plug it into my Stax transfos? I'm assuming 'yes'. Too many boxes right now. I need to consolidate.

[swt61]

Nice work!

I'm still undecided as to my two pair of SFIs. I bought some old Pioneer donor phones that I may use, and I'm thinking of woodies for the second pair. It may be a while before I get to those projects though.

[spritzer]

The drivers look to be in sweet condition. The subdued highs seem easy to remedy, I took the drivers out of the housing and there's plenty of treble there, just not realized in it's current configuration. The foam in the back is rotting and the brass fixing frame is corroding a bit so I'll do some cleaning and see what's what. I haven't taken the box apart yet to see what's going on in there but I feel there's a huge potential with them. Perfect channel balance and way more bass than your average stax or ortho. Mine are fitted with SR-5 pads which are an almost perfect fit. Luckily I had a new set laying around.

The SFI and ECRs are just reinforcing my view that planars are what I like best. I'm now down to 2 dynamic types. K1000 and KSC 75.

So there is foam damping in your set? The ECR400 I had (in parts now due to channel imbalance) had mineral wool as damping though it wasn't as thick as the stuff Stax used.

The SR-5 pads are nearly identical but I suppose SR-007 pads would fit as well...

I'm down to one dynamic, the Float 2. The last dynamic I bought was the DR100 and they lasted only 3 days (the time until the SFI drivers arrived) before I took them apart. Then the Orthodome was born.

Currently running on 1 AMT, 1 stat, 1 piezo, 1 ortho, 1 dynamic and the surrounder, which defies classification. But I'd make room in my bosom for many more, K1000, Ergo 2, Yamaha YH-5M, they'd all be nice.

The iPod is right near the top of its amp output to get the Orthodome at listening levels I'm comfortable with, but perhaps I listen at a lower volume than many people. Or perhaps the method and type of damping and the housing plays a big part in the overall efficiency.

You polygamist you... The amount of damping has a huge impact on the SPL level as you are wasting away energy to tame tame the drivers. I'm getting a modified Toshiba Gigabeat soon that shouldn't have any problem driving the phones

Talking about the ECR, can I get a stax cable and wire it to the ECR drivers and plug it into my Stax transfos? I'm assuming 'yes'. Too many boxes right now. I need to consolidate.

That's what I did. Call up the US distributor and ask about a replacement 202 cable. You can also buy a whole lot of Koss extension cables but they are a bitch to work with.

Nice work!

I'm still undecided as to my two pair of SFIs. I bought some old Pioneer donor phones that I may use, and I'm thinking of woodies for the second pair. It may be a while before I get to those projects though.

Woodies would be nice as the drivers are quite good. If I find a better headphone then the UR18 I might just mod that as well for kicks. I can always buy more drivers...

[Fungi]

Smeggy, I have the ECR-500 manual I picked up somewhere if you want it. It's just photos of the manual but it's pretty much a service manual. With energizer internals shown too. http://www.mediafire.com/?ebatcybdxn9

[spritzer]

Smeggy, I have the ECR-500 manual I picked up somewhere if you want it. It's just photos of the manual but it's pretty much a service manual. With energizer internals shown too. http://www.mediafire.com/?ebatcybdxn9

Thanks for that. There appear to have been 3 different drivers, color coded. My ECR-400 had red drivers but what's in the ECR-500?

[Duggeh]

You polygamist you... The amount of damping has a huge impact on the SPL level as you are wasting away energy to tame tame the drivers. I'm getting a modified Toshiba Gigabeat soon that shouldn't have any problem driving the phones

Yeah polygamy is great. I was thinking about constructing an elaborate metaphor to describe my relations with each headphone in wife terms, but I cant be arsed.

I get better amplification for the Orthodome out of my Sony MZ-R91 minidisc player than out of my iPod Photo and the minidisc player has got to be like 9 years old now. It only gets use when I've forgotten to charge the iPod though. I dont like being limited to one album despite the fact that I tend only to use my iPod in 15-20 minute sessions.

What would these modifications to the player be btw?

[spritzer]

I get better amplification for the Orthodome out of my Sony MZ-R91 minidisc player than out of my iPod Photo and the minidisc player has got to be like 9 years old now. It only gets use when I've forgotten to charge the iPod though. I dont like being limited to one album despite the fact that I tend only to use my iPod in 15-20 minute sessions.

The old mini-disc players were much better then the Apple junk and some even very good. Mini-disc was so very cool in 1995...

What would these modifications to the player be btw?

100gb disc and Rockbox. I might go to town on the output and fit a high pass filter off the dac or dsp chips bypassing all the active crap.

[Duggeh]

The old mini-disc players were much better then the Apple junk and some even very good. Mini-disc was so very cool in 1995...

Hi-MD is still cool in 2008. I would love an RH1.

100gb disc and Rockbox. I might go to town on the output and fit a high pass filter off the dac or dsp chips bypassing all the active crap.

Hax.

[Smeggy]

Cool stuff, I'm glad this thread is taking off despite our small numbers. Steve, I'd be interested to see what you'd come up with for the SFI drivers. I currntly have the ECR-500 stripped down to it's pieces with a view to modding and replacing the old foam and cable etc.

Fungi, thanks for the offer. I downloaded the service manual a while ago as I've been looking for some ECRs on and off for over a year now so I'm set.

[Fungi]

I currntly have the ECR-500 stripped down to it's pieces with a view to modding and replacing the old foam and cable etc.

Oh god what have you done to my baby

[spritzer]

Oh god what have you done to my baby

It's for its own good.

[Smeggy]

It's for its own good.

[Fungi]

If there's one thing Sony got right (besides the driver) it's the cable. I hope you're not replacing that.

[Smeggy]

If there's one thing Sony got right (besides the driver) it's the cable. I hope you're not replacing that.

What's special about the sony cable? I was thinking of replacing it with a stax one so I can cut down on the number of transformer boxes I have littering up the place. I don't want to reterminate the end.

[spritzer]

What's special about the sony cable? I was thinking of replacing it with a stax one so I can cut down on the number of transformer boxes I have littering up the place. I don't want to reterminate the end.

Nothing really. Bog standard kettle cable.

[Duggeh]

You'll want rid of it then. I upgraded my kettle to Nordost at Patrick82's recommendation and it made my pasta taste much better, biggest improvement was tea though, bags tasted like the best loose leaf.

[Fungi]

What's special about the sony cable? I was thinking of replacing it with a stax one so I can cut down on the number of transformer boxes I have littering up the place. I don't want to reterminate the end.

I like the feel of it.

[Smeggy]

I like the feel of it.

Lol, and there was me thinking Sony had it fitted with some superwire Yes it does feel nice, certainly nicer than the Stax ones.