[ludoo]

Quote:

Originally Posted by Kabeer /img/forum/go_quote.gif Ok, firstly I think something needs to be mentioned and it's something which will hopefully revolutionize damping for everyone. It's Ludo's (all credit to him, I just continued the Euro Yammy Wings work) theory of 'Differential Damping'. This theory works by damping the driver strategically based on where it makes most bass and most treble.

The first phones I damped this way were the non-bass-heavy HP-3 I sent to Ireland, where this was the only way to preserve the bass while damping the other freqs.

I did a similar thing tonight with the T20, which had been lying unused for weeks, and..... surprise! Tons of bass, and a pretty well balanced sound, just this side of underdamped which suits me fine for the moment. Very smooth, very musical phones, with hard hitting bass that on certain songs makes you feel like you had a subwoofer strapped to your ears. I did not expect them to sound so good. I sometimes wonder what I would be listening to if wualta had not rescued orthos from oblivion.

 

[d.phens]

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[wualta]

I think we should call Kabeer's damping technique Belly Button Differential Donut Damping.

Keep in mind that in HP/YH-X drivers, the center of the diaphragm is clamped and can't move. The SFI, Fostex and Yamaha YHD and YHE drivers are similar to one another in that the point of max excursion is in the center.

Still, I say if it works, it works. Good job staying with it until it yielded up its ancient secrets, Kabeer.

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[scompton]

I just bought a Panasonic re-7670 receiver at Goodwill. I bought it because it had a FET sticker on it. It must have been made when FETs were the latest and greatest thing. From the little I can find on it, it was made in the early 70s and came with speakers.

I did a quick listen with my YH-3 and it sounds decent, although it needs contact cleaner on the volume knob. It takes about 1/3 volume to drive the YH-3.

Surprisingly, it gets good FM reception sitting on the basement floor without an antenna.

Edit: I just plugged in my TRS terminated AT-706 and it couldn't drive it. It took full volume to get much sound and it was clipping like crazy.

 

[ludoo]

Just a quick note to let those of you who like reggae know, that the damped T20 are the best reggae phones I ever had in my hands. I'm pretty sure they were not designed in Tokyo, but instead by a secret Fostex branch in Kingston.

Of course the Yamas beat them with every other genre, but their great synergy with reggae and their excellent comfort are quite enough to make me love the T20 a bit.

 

[Kabeer]

Amfiton TDS-7 auction listing:
Ðаушники ТДС-7 "Ðмфитон" (490593494) - Молоток.Ð*у .
Its going to finish v.soon. If someone wants it grab it!
I think the largest ortho driver?

(I know im breaking my own rule here, but Im pretty sure no one but me on this thread had spotted this.... and if I am wrong...sorry!)

 

[Serge44]

Don't hurry, he is selling these broken band TDS-7 about a year. I saw these headphones a dozen times in the same listings.

 

[cetoole]

A pair of Realistic Pro30 hit my porch today, and sound about how I expected. Not real bassy, kinda muddy, and there are definitely some holes in the FR. I saw FV's damping scheme, but what else has been tried?

Hey Ludoo, what does your current T20 damping scheme consist of? I would kinda like to try something new one one of mine.

 

[wualta]

Quote:

Originally Posted by smeggy /img/forum/go_quote.gif I wonder if Fostex would be willing to sell just the earpads and driver capsules.

We've been having trouble getting Fostex to sell any parts online. But try a local dealer and lean on them until they cough up some earpads. Then work your way up to driver/baffle assemblies. Stealth be our watchword.


Quote:

Originally Posted by scompton /img/forum/go_quote.gif I just bought a Panasonic re-7670 receiver at Goodwill. I bought it because it had a FET sticker on it. It must have been made when FETs were the latest and greatest thing. From the little I can find on it, it was made in the early 70s and came with speakers.

Check with the AudioCharmers on this one, but unless a receiver or amp is from the late-late '70s, it won't have power FET output devices. However, using an FET at the antenna input in a receiver's tuner was a new and wonderful thing in the late '60s and early '70s, and is probably responsible for your getting basement reception.

You'll probably have to drive your A-T electret from the speaker outs via a headphone coupler.



Quote:

Originally Posted by ludoo /img/forum/go_quote.gif [my T20 now has]Tons of bass, and a pretty well balanced sound, just this side of underdamped which suits me fine for the moment. Very smooth, very musical phones, with hard hitting bass that on certain songs makes you feel like you had a subwoofer strapped to your ears.

I assume you mean a T20v2, right? For some reason I got out my T20v2 (which still has its original mod) and my T40v1 (ditto) and my T50RPv2 and played them on my Panasonic XR55 and I couldn't agree more about the sound of the modded T20v2. You've nailed it. Mine are underdamped a tad too, but the bass was deep and hard and very reggae-ready, just as you say. The T50RPv2 (stock) had bass intermediate between the T20 and T40. Without another earpad revision it won't ever have bass as deep and strong as the T20v2's but it's certainly going to be a usable iso headphone. Which is a relief.

Again, we need to see if the same earpads are appearing on the T20RPmkII. Is anyone about to darken the door of a retail Fostex dealer? Uh... Smeggy?


Quote:

Originally Posted by Kabeer /img/forum/go_quote.gif Amfiton TDS-7 auction listing: grab it! I think the largest ortho driver?

That's what our Russian friends say.

Even if, as Serge44 says, the headstrap is broken/repaired, we should try to grab one, assuming the price isn't outrageous ($106 is approaching outrageous), just to harvest those drivers. I have no experience successfully getting any of these headphones out of the Federation, but I have not given up all hope.

That poor slob has been trying to sell those things since July, at least. The final insult: He's only selling the Amfitons because he now owns an HD 650! O the pain!

But the Easter egg hidden in the auction is the .pdf file the seller links to: A feature-length 1981 article about the design and contruction of the Амфитон ТДС-7! How cool is that!


Quote:

Originally Posted by cetoole /img/forum/go_quote.gif A pair of Realistic Pro30 hit my porch today, and sound about how I expected. Not real bassy, kinda muddy, and there are definitely some holes in the FR. I saw FV's damping scheme, but what else has been tried?

Why not strike out in a new direction? The Pro 30's been jiggered just about every conventional (if we-all can be called conventional) way possible to jigger a commercial SFI headphone. It's one of the few isos to've gotten the full rip-off-the-back treatment.

Yeah, in stock form it's blurry and there's not much bass. Despite the ad copy, transient response was poor (well, they did at least try). Let the transformation begin.

Now that most of the entire library of Radio Shack catalogs is scanned and online (!), I can tell you that the Pro 30 was introduced in the fall of 1980 for the 1981 model year and sold for $39.95. This came down to $35.95 for 1983 and $29.95 for 1984. It stayed at that price through the 1986 model year, longer than I thought. So we should see some drivers marked with a four-digit number beginning with 6. Does anyone have one of those? My newest is from 1985.

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[mypasswordis]

smeggy (and wualta), Fostex Parts eventually emailed me a phone number. I'll PM the number along with my address since I feel like they're being secretive for some odd reason, as well as ask for a price quote on the T40 parts. Thanks again.

The more I think about the T50RP, the more I want it. Then I'll have pretty much the entire line, albeit in various production versions. I won't really actively be looking out for the T10 or T30, though.

Quote:

Originally Posted by wualta The T50RPv2 (stock) had bass intermediate between the T20 and T40. Without another earpad revision it won't ever have bass as deep and strong as the T20v2's but it's certainly going to be a usable iso headphone. Which is a relief.

It's been so long since I performed the mod but I genuinely believe removing the stock white 'diaper' damping on the T40 helped bring out the bass, although it is still slightly rolled off. My T20v2 is also still underdamped, but I used it as a studio headphone as it was, which was quite fine for the job. I'll get to more damping soon...

Edit: Come to think of it, the roll-off in the bass might be because of the pads. I will report back if that is the case.

 

[wualta]

Quote:

Originally Posted by mypasswordis /img/forum/go_quote.gif smeggy (and wualta), Fostex Parts eventually emailed me a phone number. I'll PM the number along with my address since I feel like they're being secretive for some odd reason, as well as ask for a price quote on the T40 parts. Thanks again. The more I think about the T50RP, the more I want it. Edit: Come to think of it, the roll-off in the [T40's] bass might be because of the pads. I will report back if that is the case.

Yay, Fostex awakes!
RE the T50RP, you don't need to buy the most expensive one if the driver, as ericj has pointed out, is the same and most importantly, the earpads are the new v2 type, so possibly save some $ and investigate the newest T20RPmkII. If it's got the new pads, rip it apart and mod that sucka.

Sigh. I remember when $70 for an isodynamic was way too much. But the Fostex are worth it. Just don't expect the big bass that the earlier pre-2006 T20v2 was capable of.

You used the T20v2 as a studio headphone? might we ask where/how?

Yes, I'm sure the T40v1 would have its missing bottom octave restored with different earpads. No doubt about it. EQ does bring up the bottom, so it's not entirely gone, but the lowest lows are still weak with a simple tone control. A parametric seems called for. Or... new earpads. I do admire Smeggy's growing skill at quick-fabricating earpads..

 

[mypasswordis]

Admittedly it is very amateur studio recording... in mono since I currently only have one mic, but I record myself from time to time, when called for. I use a Shure KSM109 into my E-MU 0404 USB, which also drives my studio 'phone of choice, usually one of the Fostexen.

As I've hinted at before, I think rolled off or otherwise bad treble is much more offensive than rolled off or otherwise bad bass. Unless the bass is covering up the rest of the spectrum, then mods must ensue, and if unmoddable, selling/discarding.

The Fostexen are a bargain in the world of orthos nowadays, with the Yamahas steadily gaining in price. Now even the cheapest Yamahas are too much for me and I'd rather just get a pair of new Fostex than deal with dirty, old Yamahas with dying earpads. I honestly don't mean to sound hateful of the Yamaha Orthodynamics, I just am baffled at how much some of them go for.

Also, I kind of dig the copper color of metal on the T50RP, and would be willing to pay a slight premium for it. I'm weird like that.

 

[smeggy]

Yeah, I think I may give an RP a go.

I'm not overly fussed about the deepest notes, as much as I like them. The Wharfeys sound excellent even though they start rolling off at about 50Hz, much like the K1000 (they are more similar than I like to admit with a little tweaking). The Wharfeys have the only driver I know of that don't need any mods at all. The housing introduces a little boxiness which is easily remedied by funneling the sound directly to the outer cup holes via foam strips. Running the drivers outside the housings with only the earpads gives an outstanding sound. They have the best balance of any ortho I know.

They have nice bass if a little light, deep but lacking some power there. The mids are smooth, clear, very cohesive and no obvious spikes going up the range. One of the nicest aspects is the treble, smooth sparkly and much more apparent than any other ortho. They don't play very loud before distorting in the bass and they need an absolute buttload of power to drive. They are harder to drive than any other orthos, the K340 or the K1000. My floorstanding speakers are easier to drive. However, with sufficient power you are rewarded with a most impressive sound. Impressive in that they do almost nothing wrong. They are extremely neutral and natural. Good soundstage and the weight/size distribution makes them easily the most comfy ortho ever.

They are very nice to listen to for very extended periods because there are no nasty parts anywhere in the frequency range, no annoying colorations once the boxiness is fixed. The cups/pads are so big that you barely notice them. Your ears don't get hot or sweaty. The coiled cable is a welcome alternative to the standard straight wire common today. I'd forgotten how convenient a good self-coiling cord can be and I like it.

It's the oldest, and until I hear a T50v1, the best ortho driver I've heard. To me it easily creams the others for sheer accuracy of reproduction, no mods needed. The thing is great and while other orthos can be tweaked up to a high level, they almost all need tweaking, to a sometimes extreme and time consuming level, not to mention the frustration... None are anywhere close for comfort either.

The Wharfey is an excellent phone that may not suit everyone, and also, it will hit a ceiling very quickly as it's almost optimal as-is. Unlike all the others, If you don't like how it comes, there's not much you can do with it that doesn't make them sound worse.

I'm going to see if there's any manufacturing drawings or parts specifications available in their archives. I doubt anyone from that era still works there but hopefully somebody kept records.

 

[ludoo]

Quote:

Originally Posted by cetoole /img/forum/go_quote.gif Hey Ludoo, what does your current T20 damping scheme consist of? I would kinda like to try something new one one of mine.

As mypasswordis says, the first thing I did was to remove the white damping from the driver assembly. Be careful when you open it as the entire driver might spring open (it happened to one of my drivers).

I then replaced the white fluffy thing with a disc of moorbrook cashmere felt, the black very dense stuff I sent you for the Yamas, and closed the driver.

On top of that, outside the driver assembly but pushed tight into the recess, a donut of a synthetic felt slightly more dense than ericj's red felt.

Then I cut and shaped a square of foam very similar in both material and thickness to the original foams, so that it fills the entire cup. The stock foams might also work, even though they are round and leave some of the cup insides exposed.

This is the underdamped mod, which preserves a lot of bass, at the expense of treble which is slightly muted. An additional disc of ericj's blue felt on the outside of the driver assembly, between the moorbrook and the donut, kills off a bit of bass but brings up the treble nicely and adds a bit of soundstage. You could experiment with the blue felt by making it a donut with a smaller or largish hole, to keep more of the less damped bass.

Edit. I made the blue disc smaller and pierced a smallish hole at its center. The put the denser donut back in its place against the driver snugly fit inside the assembly recess, and placed the smaller blue disc-with-a-hole on top. The phones have to be closed with the front of the baffle facing down otherwise the smaller disc moves around, once closed the foam will keep everything tightly pressed together. As might be expected, this halfway damping preserves most of the bass of the undamped scheme, and brings out the treble much like the more aggressive scheme. They do really sound nice. The power of the Progressive Donut Damping (™ the Yammy Euro Wing).

They sound magical with music where soundstage and instrument placement is not very important, or where it detracts to the "compactness" of sound, like reggae. Music just flows from them. The only minor flaw is -- with the more aggressive damping -- a slightly muted deep bass: it's there but it does not rumble as much as with the less aggressive damping. Which might also work towards making the music flow.

Edit. The stock cable is pretty good but kind of warm and I generally use 1/8 plugs instead of its 1/4, so I made a cable with the last small piece of Mogami I had lying around, and it seemed to make them a little bit more transparent. Neutrik angled mini plugs are a perfect match for the socket on the left earcup, so the T20 also make ideal phones to try out different cables.

Quote:

Originally Posted by smeggy /img/forum/go_quote.gif The Wharfeys have the only driver I know of that don't need any mods at all. The housing introduces a little boxiness which is easily remedied by funneling the sound directly to the outer cup holes via foam strips. Running the drivers outside the housings with only the earpads gives an outstanding sound. They have the best balance of any ortho I know.

Which brings us again to the question of custom drivers.

How hard would it be to replicate the Wharfedale's drivers?

 

[ludoo]

Totally unrelated: I bought from ebay 200 assorted shoelaces for the grand sum of 2 euros. I received them yesterday and there's some great stuff inside the box, so expect more creative cable sleeving from me in the future.