TheSloth

Haven't you already?

That would be me.

No, and that's because there is no output buffer at all. The output stage of the Micro DAC is the AD822 opamp. The rationale is that as it will only ever be connected to very high impedance loads, the opamp does not require a buffer to supply adequate current. The other advantage is of course less stuff in the signal path.

What's going on here? I LOVE SILTECH!

Bravo Yikes. I live with the same machine (but Max Modules), so I'd also be curious to hear your impressions.

Did the Hi-Fi 2200 ULE sound any better? From all accounts, they are supposed to be less peaky and harsh. I hate sending things back, but I'm still shocked at what they sounded like at that price point. Have they not heard the competition?

Because they are SO far off that I don't consider burn-in to be relevant. I have never ever heard a piece of audio equipment (and I have heard quite a lot - considering you are in the business, probably not as much as you) that changed from being horrifically coloured to somewhat accurate through the burn-in process. From a design standpoint, it would be nonsensical and impossible for the manuf. if it did. How do you design a driver that only works correctly after it's been used for 300 hours or so, and up until that point produces an unrelated output result? My issues with the ProLINE 2500 were purely ones of FR, as perceived by my ears. It was un-natural, and not remotely reflective to the instrument/s that I work with 8 hours a day, every day of my life. FR does not change dramatically with burn-in. And I do happen to have some recordings of my own as test material. On top of that, I have a touch of sensitivity to peaky upper midrange frequencies, resulting in mild tinnitus after any exposure to peaky headphones in that department. I simply cannot audition such a headphone for a long period of time, nor should I need to put up with such to be able to come to a conclusion as to whether it is worth something or not. I auditioned the K701 over a period of months, for all of the reasons you described, and then decided it wasn't quite for me, despite being excellent in most areas. However I only knew to bother with such time invested with the headphone based on my impressions over the first day of use and burn-in - yes there were small changes to the sound through burn in both of me and it over the following months, but not enough to make my initial impressions baseless. Moreover, when I read the impressions of people who said their initial impression was negative, but they 'got used to' the qualities it posessed, I see that as having nothing to do with burn-in and more to do with the listener becoming used to and coming to believe in the innacurate presentation of instruments. Without a baseline I can see that happening, but I live and work with the same material that I listen to - there is no getting used to that goes on here. If someone else wants to leave their money invested in them for extra days, burn them in and abuse their ears to give them a shot, then go for it, but that won't be me!

And regarding ultrasone, I'm still curious about the Hi-Fi 2200 ULE, because from all accounts these are quite the opposite of the peaky and strident 2500's, with a rounded and supposedly warm response. I've actually never heard a driver with titanium coating that didn't sound worse to my ears than the same driver without the said coating...

The K340's are bothering me at the moment - I still haven't found quite what I'm after. They have some qualities that are superior to the 650 to my ears, but at the moment the 650 is slightly better balanced within itself throughout the spectrum. I'm still working on it, but I can't afford to keep headphones I don't really use so if not there will be a FS for some darn nice condition modded K340's (having removed the squealing bit of cotton - thanks philodox).

Well it was worth a shot! The went off in the mail today back to HeadRoom, despite the fact that after I ordered it they seemed to stop selling them. Back to the 650 I go...

OK, I burned them in hard all day, have boxed them up and they will be in the mail to HeadRoom tomorrow. Firstly, the sort-of-good parts. They have very a very powerful bass response. They might even please a bass head, but possibly not quite up to that level. They are definitely bassier than the 650 though, in a somewhat controlled but slightly boomy way. It sounds a little like a subwoofer set too high next to your ear. The soundstage is interesting. I don't belive a word of this ULE, or S Logic stuff, however the driver placement at the rear bottom of the ear cup does cause a slightly different interaction with the ear. I did find the soundstage to be quite good, particularly with respect to centre panned instruments that did not seem to be drilled into my head. Of course, not surround sound, and not up to a good crossfeed. Now, the rest of the sound. It's peaky, and yet subtractive at the same time. It's definitely bright, but more in the upper midrange than anywhere else. Wooden stringed instruments sound like they are made of plastic. Singers sound like they have sinus infections and severely blocked noses. The extension, both top and bottom is good, however it is not in balance with itself. There is a distinct lack of body to the sound, with the midrange sucked out until the high end of its range. There is also a discontinuity between low, mid and high frequencies, none of which blend properly into a believable texture. For $100 this would be an interesting headphone considering the competition. For $200 it would be overpriced. For $400, it's just plain rubbish. It alarms me that recording engineers who work constantly with real life instruments could possibly believe that what they are hearing from these headphones is what is on the recording itself. It isn't even close. By the way, as this is just basically an open Proline 750, I covered the outer cups to get a sense for the sound of the closed version, and unsurprisingly everything that was bad just got worse. Especially the bass, that was just monstrous, boomy and uncontrolled, and the rest of the frequencies that were compressed and closed in. I am finding the current choices in the dynamic headphone world increasingly depressing, with regards to real fidelity.

I've read recording engineers wax lyrical about how neutral these are. This might be an explanation for the horrific quality of so many recordings since the inception of Ultrasone...

So this rather strange headphone just arrived from HeadRoom. What is even stranger, is that after I ordered it, both it and the 2200ULE disappeared from the HeadRoom site alltogether and have yet to return. Is it something I said? This headphone is pretty weird, and I have to say that without any burn in it sounds like rubbish for $400. More later!

They replaced all the drivers, but the electrets were the dead ones. They just used to replace all the drivers for matching reasons.

I'll investigate later, but I actually don't have spares - I just sold the other/damaged on to PsychoZX. If I'm going to have a second K340, I'd rather it was a fully functional stock one for comparison/change, rather than the slightly mutant one that I ended up with.

And now the left electret has started squealing at certain frequencies... AAAAAAAAAAAAAAAAAAARGH. DAMN YOU AKG for having none left.

Latest update - I'm back to the Headphile screens, a ring of cotton behind the driver, and some thinned out cotton wool to sort of close up the hole at the back. Best balanced I've found so far.

Well I got my second pair of K340's and did some listening, and some swapping of pads and screens. To cut out all the stages, I do actually prefer the original screen - it just seems slightly more balanced throughout the spectrum, though there is a slight reduction at the very top end. It gives slightly better continuity between the two drivers to my ears. I can see why people would want more high end, but it sounds a little artificial that way to me. I never bothered to keep the original pads from my first K340, which I now realise was a little silly because the pads change the sound more than any other tweak. The velour pads are nice, but the inner dimension is just a few mm smaller than the original, possibly constricting the sound a bit. Also, because of the lack of reflectiveness of the velour, it has different acoustic properties. The velour seems to enhance the mid-bass, very slightly reduce the midrange and therefore highlight the treble a bit. The pads on the second pair were however too compressed to compare more than that, so I might get hold of a newer pair of the original pads for comparison. For now, I am running them with the original screens, cotton behind the drivers and open back. Strangely close to stock, huh...?! I would however like to get hold of the original cotton piece from behind the drivers, or at least a piece of flat circular cotton that is equivalent just to know exactly how these did sound stock.

The red brick battery pack from HeadRoom does wonders for the SB3! 10 hours of battery life, and you can't use rechargeables because the voltage is too low, but that's a great 10 hours you get!

Well just to experiment with the screen, I've just bought another K340. I'm very curious to see how these two will compare when the second one arrives. I like K340's!

So what do people think about running a pair of these straight off a STAX amp? 20V of bias isn't that significant is it?

Well considering the design of the rest of the headphone, I do think it might have been taken into account with the design. There are equations to determine the size of holes in a screen versus frequency response, and I'm sure AKG gave them at least a passing glance. Anyway, not the end of the world. I got BlackMax cabling. I didn't like the fully sealed back - too compressed and top heavy. I like your idea of partially closing it up, with some small holes in the tape. Might give a good balance of sound. I also think that the rear of the housing is a bit resonant, so a nice covering of blutack might help there. Once I've sorted out the back, I'll experiment with damping.

I received my modded K340's back from Larry a few weeks ago. I have to say that I preferred the sound before - to my ears, despite an increase in isolation, I felt the entire response tipped up to the treble, with a slight discontinuity between the two drivers (an example of which would be hearing the same HF harmonics sticking out as distinct from the fundamental when they ought to have blended in). The sound was clean, but as far as I am concerned on the brighter side of neutral. I decided to undo some the reversible mods one by one - first I removed the sealant tape that was covering the back of the driver housing, opening up the enclosure somewhat - huge increase in bass, too much in fact. Larry had used cotton wool to damp the enclosure, but for some reason had installed it in a semicircle covering only half of the back of the driver. I removed that, and found a better overall balance. However there is a relatively significant resonance around 250hz in this current configuration (no damping, open backs), making the bass muddy and bloated (noticeably more so than a 650 if that gives a reference point). I'd be quite curious to see what effect the original cotton ring has on the sound.

Did anyone receive any modules yet? When are they supposed to be shipping?

Slightly sucked-out midrange though.