The AKG K 250 (history, pictures, and a review of this forgotten dynamic K 340/K 241 hybrid)

Welcome to the year 2012.

Now, let's go back to the eighties.

• K 250 Quick Contents
• 1. Timeline (<- you're here)
• 2. Aesthetics
• 3.1 Sound (vs. vintage DT 990)
• 3.2 Sound (vs. K 340)
• 3.3 Sound (vs. KSC75)
• 3.4 Sound (vs. K 240 DF)
• 3.5 Sound (vs. K 241)
• 4. Current availability & pricing
• 5. Frequency graphs
• 6. EQ the K 250?

The AKG K 250 is a curious pair of headphones. You can browse your way to the AKG product archive and look for information on that model – but you'll find that it's not even listed. You can do a K 250 search on Google – your first results will likely be a few for-sale ads on Head-Fi and a vague reference on Wikiphonia. You can do a Google Image search, possibly finding your way onto a particular German hi-fi forum, where someone has asked people to put a price on his pair of K 250. That person is told that his phones aren't worth much, and that his best bet would perhaps be to sell them to some old fogie on Head-Fi (they really said that).

Strangely enough, the AKG K 250 is indeed relatively obscure, despite the fact that it's sitting right within the extended family of the popular K 240 series.

Info on the K 250 is likewise scattered thinly across the internet, and not all of it is reliable.

In this thread, I'd like to collect as much knowledge on the K 250 as possible, so that when the next person googles them, they'll have a concrete source to go to. In addition, I'd like to do a little bit of myth-busting and picture-posting, as well as pointing out some of the general strangenesses of the K 250.

Instead of cramming all the stuff I want to say into one entry, I'll break it up into separate posts to make it more readable. I'll start with some history now, and follow up with other aspects of the K 250 (aesthetics [= more photos], sound, etc.) in later posts.

I'd like anyone to feel free to point out any erroneous claims I make, and to offer any bits of information that they have regarding the K 250. As I said above, I would like this thread to be a place of concentrated K 250 knowledge (however little there is), so that it might help people in the future who are seeking that information.

1. Timeline

The premise right now is this: no one knows when the K 250 was introduced, or when it was discontinued, or anything*. People even go as far as to say the K 250 is a rebadged Realistic Pro 50 (it's not!).

(* Head-Fi member tyre was able to dig up the K 250 service manual, which you can see a picture of in his post here – and as a bigger image here. [The same post has some quotes from an AKG representative on the K 250, although his words are somewhat ambiguous.] The service doc is dated 11/1981, which is the most concrete official date related to the K 250 that I know. This means that the K 250 most likely was around in the early 1980s, although I suppose that the service doc may have either preceded the actual sale of the model, or have been updated after the K 250 had already been discontinued.

Some musings on the product code of the K 250 and what it might reveal us about the release date here.)

So, let's try to orientate ourselves in this maze that is the K 250, and a good way to do that is to start with some AKG history.

In the above graph (you can click it for a bigger version), I've done my best to represent in a visual way some of the recent historical headphone developments of AKG. Since getting accurate dates for their old products is a bit difficult (ambiguous sources), I've chosen a rough division of time. Each decade is thus divided into three parts: early (years ~0-3), mid (~4-6), and late (~7-9). (Again, if someone would like to point out any inaccuracies, please do.)

The main problem in the context of this thread is that we don't know where on that timeline we should put the elusive K 250. There is indeed no such data readily available. I've written AKG/Harman, but it may take a while for any answers to come around. If any does come, I'll update the chart accordingly, and also if some members here can provide more accurate information. In the meantime, I've taken the liberty of tentatively placing the K 250 somewhere around the early 1980s. There are a few reasons for my having done this, which I'll explain next.

To illustrate, here's a picture of the K 250 driver baffle.

See the six rings around the driver? (Well, you most likely do, but this is rhetorical.)

The idea of placing covered openings around the driver to improve sound originated with the K 240 Sextett. You can see a picture of a Sextett baffle here, courtesy of pistolsnipe. (Most of you know all about the Sextett already, but let's try to make all this clear anyway.) The Sextett driver rings were called passive diaphragms. They look a bit more complicated than the rings around the K 250's driver, no?

This is because, while the passive diaphragm stuff was all fine and mellow in the mid 70s, by the end of the decade AKG got to thinking about money. They found the passive diaphragms too costly to manufacture, and started looking for alternatives. The result: sound ports. The product: AKG K 241, which was introduced in 1979. Here is a picture of the K 241 driver baffle featuring the (then) new sound port technology, courtesy of killkli at AndAudio. As you can see, the basic idea remains the same as on the Sextett, but the more complex passive diaphragms have been replaced with simpler acoustic material(s).

Since the K 250 also feature these sound ports, and assuming the K 241 was indeed the first AKG product to have them (according to this), I should think that the K 250 originate from sometime after 1979, so possibly no sooner than the early 80s, which is reflected on the graph as a more strongly shaded area. (However, it should be noted that AKG is notorious for messing around with their products; it's thus possible that there were earlier versions of the K 250 which had Sextett-type passive diaphragms. At this point, I have not seen any evidence of that. I'll return to this diaphragm business in a later post, but it suffices to say for now that, based on what I've seen, the K 250 is not a rebadged Realistic Pro 50 [nor vice versa] – just like the K 241 is not simply a renamed Sextett).

These days, it's somewhat rare to find the K 250 for sale (but not exceedingly so – I was able to track down about 10 K 250s that were sold in auctions in 2011, though an amount which is still notably less than for your usual K 240 models like the Sextett, Monitor and so on). So why are they a bit rare today? Did they break easily back then? Were they not very popular in their time? Or was their availability limited – were they discontinued in short order?

I don't know whether it's related to the fate of the K 250, its inception, or neither, but apparently there was a bit of a craze for portable headphones when the original Walkman came out in the late 70s and early 80s (older Head-Fiers can possibly provide further insights on this?). AKG got in the fray by producing the K # line (K 1 to K 4) – but for some reason their portable cans weren't well received after all, as is lamented on in this quote from an AKG "biography" (archived here): "[The compact headphones] do not sell. Hi-fi enthusiasts simply want "big cans" for their money."

Now, the K 250 is pretty big. You can check out the picture at the top of this post again to confirm it. Its cup is notably larger than that of any of the K 240s. A question that's on my mind is, what's the relationship between the big size of the K 250 and AKG's foray into small phones in the early 80s – and can this relationship help date the K 250? In other words, if AKG was already producing the K 250 before their K # line, i.e. before or in the early 80s, did they discontinue the K 250 due to its size (given that they were already producing the equally cumbersome K 340)? Or did AKG start producing the K 250 in the mid 80s in order to get another "big can" in their line of products?

I don't know. But hopefully someone on Head-Fi does.

Even though the AKG product archive makes no mention of the K 250 and it almost seems like they never did exist, they came in a box that was very much like that of comparable AKG phones of that time. Here's a collection of similar boxes from four different models:

(Image sources, from left to right and top to bottom: 1, 2, 3, 4.)

I'm not sure when this grid-style box was adopted and when it was replaced by something else. Wikiphonia has an AKG brochure from 1979 on their AKG page that features the same grid styling. The box that AKG used in the mid 1970s was a bit different (a picture here), and I believe there was another change when coming into the 90s or so. The grid-styled K 250 box (I've seen two pictures of a K 250 box, and they were both of this grid type) doesn't offer any tremendous help in dating the K 250, but in any case it confirms that the model was available at least around the time when AKG was using that type of product box.

Lastly, regarding the dating of the K 250, AKG changed their sound port design considerably somewhere around the late 80s or early 90s. I'm not sure when this was exactly, but feel free to chime in if you know. In any case, here is a picture of two K 240 DFs, with the left one showing the more recent sound port design and the right one having the older one. As I haven't seen any K 250s with those modern sound ports, I would assume that the K 250s were not produced after that change was introduced. (But again, AKG were inconsistent with their product changes, and this is not a reliable way to date much of anything.)

To sum up, the K 250 were probably produced in the 1980s. Based on the knowledge I have, I don't think I can offer a more accurate number than that. I might say they were possibly not around in the late 80s anymore, as AKG seems to have made a push towards lower-ohm phones then – and the K 250 don't exactly seem like studio phones either, which retained their high ohms well into the 90s.

That's all I can say about the history of the K 250, so in the next post (here) I'll take a closer look at their aesthetics. But there's one more thing I'd like to mention before that.

If you look back to the picture of the K 250 driver baffle, and then compare it to a baffle from, say, a K 240 Monitor (here, here, and two DFs as a comparison here), you'll notice that the white rings don't align the same way on the K 250 as they do on those K 240s. On the 240s, the white rings are neatly aligned on one hemisphere of the cup, but on the K 250 the pattern is offset by one (you can also see two other K 250 baffles here and here). I would assume that (and it looks like) the rings are of varying thicknesses – thus having them in a different arrangement would possibly create some audible difference, but I don't really know what AKG was after here. It may be an adjustment that was necessitated by the differently-shaped cup, or nothing but an aesthetic curiosity, which the K 250 have quite a bit of.

With the K 250 looming ominously over us all, let's hazard some words on its aesthetics.

2. Aesthetics (and construction)

(Head-Fi user hgabi00 has posted an album full of K 250 pics here.)

(A picture comparison of the K 250 and K 241 baffles here.)

See this picture (an ordinary K 240 Sextett, whose production began in the mid 70s [image by Jon L of Head-Fi]). Then, see this one (an ordinary K 141, which was introduced in the late 70s). Finally, see this (a K 340, who likewise was given birth to in the late 70s [image source]).

Keeping these three images in mind, look at the K 250 again. Which of those three models does it resemble the least?

Might I suggest – the K 240 Sextett?

The K 340 and the K 141, we know, were both released in the late 1970s, following the success of the mid-70s Sextett. While the Sextett featured a general round motif to its design (everything in it is round), the K 340 and the K 141 mixed it up by introducing rectangular elements (see the plastic side panel things)!

The rectangulariness on the K 141 is stretched, while the K 250 retains the K 340 look. (Note that the thing on the K 141 has been set lower than normal to compensate for lost elastics.)

Unfortunately for the K 250, in my opinion, both the K 141 and the K 340 look way more classy. It's as if the AKG designers had a coffee break right in the middle of designing the K 250, then suddenly, while the people were having their coffee, the big AKG sales boss came in and took off with the K 250 prototype. The K 340 and the K 141 feel as if their elements add up to a whole, while the K 250 is an omelette.

Now, if you look again at the K 141 + K 250 group photo above, you'll notice that it's the right side of the K 250 that you're looking at. If you refer to the picture at the top of this post, you'll see that, in that one, you're looking at the left side of the K 250. So what?

Well, do you see the letters 'AKG' anywhere? Or even the AKG logo?

I don't know why, but the only part where it says AKG is on the headband. Nameplates on both sides display the model number and differ only in that one of them reads L and the other R. The famous "MADE IN AUSTRIA" is at least on show – but even that is rendered in dull plastic black as if to hide it from view after all.

With the K 240 DF.

Below is AKG's original rectangular line of headphones! Meaning phones released around 1978-81 that had rectangular side plates rather than the ubiquitous round ones.

Other aspects of the K 250 are familiar AKG stuff. You've got the usual AKG pleather pads:

(By the way, the modern AKG velour pads fit well on the K 250 – but the sound becomes such that it's not to my taste. A notable amount of body is lost, and the highs go shrill.)

Your familiar AKG elastics are to be found as well.

The cup design on the K 250 is semi-open I suppose – even though the back of the cup may look fully open, there is in fact a closed plastic cover with some number of holes arranged in circular patterns. No fillings inside the cup on this particular pair.

Unfortunately, I can't fully open the cups, so I don't have a picture of the driver. However, the back of it looks like this, but white (image courtesy of Shoewreck of Head-Fi, of his K 240 Monitor). In other words, the driver capsule on this particular K 250 has the three-hole design, which may or may not mean anything.

To sum up, the K 250 doesn't quite know what it's doing when it comes to looks (in my opinion). It takes elements from here and there but doesn't take the time to combine them in a way to make a whole. It's a bit of a leftover, but one that has its merits I think.

That's it for aesthetics and construction. In the next post (here), I'll talk about the sound.

There's some interesting information posted here, thanks all!

tyre, that K 250 service doc looks interesting; it's very strange that they haven't added it to the AKG product archive. There are two possible things the AKG rep may have meant by "original model K 250" I think. He could either be implying that there's an earlier K 250, or he was making a clear distinction between AKG's own (original) model and the one made for RadioShack. His wording is very ambigous, though. There are magazine ads (here, for instance) that seem to place the Realistic Pro 50's introduction to late 1979 – so an earlier K 250 would then have had to have been from the late 70s. If you could upload the service doc PDF somewhere so that the part names would be visible, that would be much appreciated (if you don't have a space for it, drop me a PM and I can upload it to mine). (I don't mean to imply that you or anyone else has intentionally misled people – although I do feel that the image of the Pro 50 baffle that you posted [here] could do without the number 250 in its filename. To be honest, the AKG rep was misleading you, if anything).

Deep Funk, I bought the Philips version of the K 260 some while ago, so maybe I can do some comparison between that and the K 250.

zeno, in the context of your prototype theory, would the fact that the K 250 contains no trace of the AKG logo mean anything? Since tyre's service doc has the date 1981, and if the K 240 Monitor/DF indeed spelled doom on the K 250, then maybe the early 1980s (and maybe the late 1970s?) were when the K 250 was around.

I'll update my first post with the K 250 service doc information later today.

Quote:

Originally Posted by zeno 

It not having the logo is probably more of a general aesthetic choice than anything here....since there have been other AKG models that did not have any logos, and some that did and do. the AKG logo is also on the K250 box....The fact of the K250 model being so hard to find any evidence of it even on the AKG web site etc, is more of an indication that they did not go full throttle with it than not having a logo. Looks like the K250 not having any lgo was with keeping it's "spartan and "cleanliness" of it's over all design. To me it comes close to having a "Scandinavian" design.

 

Which AKG models didn't have the AKG logo on them? (I don't doubt you, I'm interested.) It's definitely very adventurous of AKG to drop their logo from the K 250 considering that all their other models at that time seem to have come with one. Although, as Fitz has said, AKG was very adventurous.

When I saw that the K 250 had no AKG logo on it anywhere, I suspected that it may have been due to the K 250 having been meant as a specialty phone of some sort (kinda like this K 141) for whatever context where a logo wasn't desired. I couldn't think of any such context, though. And, of course, the headband has "AKG" written on it with massive letters even if there is no logo as such.

The thing about the K 250's design that irks me is that the rectangular side panels (are those called sliders or what?) stand out too much. They look oversized – they look too much like they were simply taken off a K 340 and put on the K 250. On the K 340 the shape flows around the cups, but on the K 250 it connects to nothing. This, of course, is just subjective opinion on my part, and I don't know much about Scandinavian design.

Regarding the K 250 service manual, how reliable is the date on that exactly? I quickly looked up the service doc for the K 260, which had a date of 1993 on it – even though, according to http://20cheaddatebase.web.fc2.com/AKG/AKGindex.html, the K 260 were discontinued in 1989. So either that manual was updated years after the K 260 had been discontinued (possible, to reflect part availability or whatever), or that website isn't too reliable.

I've just realized that you can view the actual full-sized image that's hosted on Head-Fi if you copy its URL from the "full-sized" view (you know, the view you get when you click on an image to have the bigger version, where the screen goes slightly dark). Thus the service doc image that tyre posted here became perfectly readable.

Having a quick look at the parts list, the most curious thing is that the K 250 driver capsule part is listed as 2030 Z 0007. On the general K 240 service doc (here), the same driver capsule is listed for the K 241 (and only for the K 241).

I'm not sure if that's the capsule that the K 241 originally used in the late 1970s, or if it's just listed in the docs because it's the most suitable driver still available. I'm also not sure how accurate AKG's part numberings are – how much variation one would expect within a part of a specific number. But if the K 250 and the K 241 do use the same drivers, then that's pretty neat. The K 250 would in that case most possibly be a further development along the Sextett––K 241 continuum that AKG had going back then (and might explain why the sound port placements, which I mentioned at the end of part 1, had been slightly tweaked from how they were on the K 241 – AKG experimenting with their new sound port tech).

(I'm still working on the sound review. I've already got notes and so on, but I'd like to get to know the phones a bit more before I say too much.)

Thanks, that's well appreciated. It would've been a shame to not give the K 250 at least some exposition.

zeno, do you mean the very first pairs of Sextetts that came out in the year 1975 (like, the first 100 pairs or whatever)? I checked out pictures of a few early Sextett pairs and they had the logo, same with the middle-period pairs and the later ones.

tyre, that diaphragm holder thing is pretty telling, though maybe it could also be a carry-over from the Sextett naming convention of that time? I checked out a few service docs (K 340, K 260, the modern K 240 one), and the name of the disc seems to vary quite a bit. It would be interesting to see the original 80s service doc for the K 241 and what the disc was called in that one, since the K 241 for sure didn't have any passive diaphragms ever. In the list of K 250 questions I sent to AKG about three weeks ago I asked whether the K 250 ever had a version with passive diaphragms, so hopefully some AKG person has something non-ambiguous to say about that.