K340 info gleaned from old dealer information pamphlets

[philodox]

K 340

Absolutely top class stereo headphones employing the two-way design concept. Each earpiece contains two different kinds of transducer system. One dynamic and one electrostatic system combine together to form an integral transducer system.

The result is convincing: full, clear bass down to the lowest end of the audible range is reproduced by the dynamic system; transparent, neutral and brilliant treble by the electrostatic transducer.

In the K 340 a crossover network is not required. Both systems are connected directly and acoustically tuned to avoid undesirable phase shifts or uneven frequency response in the cross-over region. Therefore, there is no loss of transparency, and virtually no distortion.

The K 340 is used without an auxiliary power unit, just like any dynamic headphone, since the miniature transformers required for signal voltage step-up are built into the earpieces.

The passive diaphragms provide a well balanced bass range as well as a natural, open, and spatial sound image.

The model K 340 with gimbal-pivoted earpieces, and a cushioned headband which automatically adjusts to any head size, provides exceptional wearing comfort despite its size.

[There is a similar description for K 240, K 241, K 141, K 140 S, K 80, K 41, and K 40. I'm assuming the K 240 are the Sextet model as they make mention of six passive diaphragms.]

Technical Data:

Transducer Type ----------------------------- electrostatic/dynamic

Frequency range ----------------------------- 16-25 000 Hz

Nominal impedance --------------------------- 400 Ohm

Nominal sound pressure level [at 1000 Hz] ----- 94 dB

Maximum power ------------------------------ 200 mW acc. DIN 45 500

Harmonic distortion --------------------------- ≤ 0,2% acc. DIN 45 500

Contact pressure ----------------------------- 3 N [ca. 300 g]

Weight [without cable] ----------------------- 380 g

Connection cable ----------------------------- single sided, helix cable, 3 m extended length

[The same information is also listed for the other headphones I mentioned above.]

Two-way system - the new K 340 design concept

The new AKG two-way design concept has been realized for the first time in the K 340 headphones. This system combines the advantages of both dynamic and electrostatic design principles.

Dynamic sound transducers utilize the motion resulting from signal current flowing through a voice coil suspended in a magnetic field. This vibrating voice coil is rigidly attached to the diaphragm which, in turn excites sound waves in the air. The large diaphragm excursions occurring at low frequencies and high volumes are easily handled by dynamic systems.

Electrostatic transducers consist primarily of a rigid, electrically conductive diaphragm mounted [about the diameter of a human hair] apart from each other. When a signal voltage is applied to these two ?electrodes? electrostatic forces are generated resulting in a movement of the diaphragm.

In this case the applied audio signal voltage must be considerably higher than with dynamic transducers. Therefore, electrostatic headphones invariably require an external power supply unit incorporating step up transformers. Also, for satisfactory operation, headphones of this type must be supplied with a constant electrostatic charge. This can be provided by an external power supply, or, as in the case of the K 340, by a self-polarizing diaphragm with an inherent permanent electrostatic charge.

In the high frequency region the extremely thin and light weight diaphragm can move freely and follow the signal impulses without delay.

• The AKG two-way design concept employs a dynamic transducer for the reproduction of bass and midrange frequencies. This results in a balanced bass reproduction down to the lowest audible frequencies, as well as in minimum harmonic distortion.
  
• The region above 4000 Hz is covered by an electrostatic transducer. Sound reproduction is transparent and free from coloration: the full range of harmonics produced by musical instruments are also retained, ensuring maximum fidelity.
  
• Since the electrostatic transducer system transmits only frequencies above 4000 Hz, the crossover network usually required is unnecessary. The K 340 still requires transformers however, to obtain the signal voltages necessary in electrostatic systems. However they can be made extremely small, since they do not need to handle low frequencies which would call for large iron cores. Therefore these miniature transformers can be built into the headphone earpieces without offering any disadvantage. By using a self-polarizing diaphragm, the AKG electrostatic system can dispense with a power supply for generating the polarization voltage.

With the K 340, cumbersome external power supply units as used with purely electrostatic systems are a thing of the past.

[philodox]

I'll add the scans of the pictures and diagrams once I get them as well.

There is also a pretty funny page entitled "Why headphones at all?" that I will try to transcribe once my fingers stop hurting.

It details how "Headphones are a must in any well-equipped HiFi system" along with the main advantages that headphones have over loudspeakers.

[philodox]

With the K 340, cumbersome external power supply units as used with purely electrostatic systems are a thing of the past.

I found this pretty funny. Yeah, those damn cumbersome external power supplies. You can just plug the K340 into anything and it sounds great. Sure.

[philodox]

sounds like a whole lot of hogwash, to me.

Headphones do have advantages over loudspeakers dummy. Nobody said they were better.

[spritzer]

Thanks for for a great read. It's hilarious how they say that using small transformers mounted in the earcups is indeed a good idea... ... I guess they were copying the Koss ESP6 pamphlets and marketing idea. "Having 2lbs worth of headphone on your head is a pleasant experience". They were also supposed to be used from a normal TRS socket but they did include a speaker cable to TRS adapter just in case.

[deepak]

i still need to hear a pair of K340s. not that i care too much, i mean, they are headphones.

You'd probably like the HD650 a lot more

[JBLoudG20]

i mean, they are headphones.

That got so old, so fast.

it would take 7 seconds to ban you. i've timed it.

--admin

[philodox]

Thanks for for a great read.Yeah, though the one in the K340's is *really* tiny. I think it is interesting that they only need a small transformer since it is reproducing only the highs. I wonder what would happen if you hooked up a larger transformer? Maybe those electrets would start putting out mids and some bass?

[spritzer]

I'm glad you enjoyed it. Some of the other stuff I have yet to scan or type is pretty interesting as well... no time today though, spring cleaning.

I love these old brochures and pamphlets. I have amassed quite a collection my self on everything Stax related.

Yeah, though the one in the K340's is *really* tiny. I think it is interesting that they only need a small transformer since it is reproducing only the highs. I wonder what would happen if you hooked up a larger transformer? Maybe those electrets would start putting out mids and some bass?

That would increase its output no doubt but how much we'd only know through testing.

[jinp6301]

it would take 7 seconds to ban you. i've timed it.

--admin

nice

[Dusty Chalk]

That got so old, so fast.

it would take 7 seconds to ban you. i've timed it.

--admin

Fascist! Did you see that? Now we see the violence inherent in the system...

[Dusty Chalk]

Pfff.

[soloz2]

i still need to hear a pair of K340s. not that i care too much, i mean, they are headphones.

If you're in the next room when Philodox is listening to his k340's you can hear his

[philodox]

LOL, damn wussy low level listeners.

[JBLoudG20]

LOL, damn wussy low level listeners.

Well, that's what it takes to get some dynamics out of the 340, so I can understand your loud levels.

[philodox]

You might be surprised at how untrue that is. Though they sound great at loud volumes, I had few complaints from the wusses.

[JBLoudG20]

You might be surprised at how untrue that is. Though they sound great at loud volumes, I had few complaints from the wusses.

I'm only busting balls.

[philodox]

Yeah, I know. I'm only getting defensive.

[Dusty Chalk]

LOL, damn wussy low level listeners.

Fuck you.

[philodox]

Fuck you.

[soloz2]

LOL, damn wussy low level listeners.

when I'm 60 my hearing will be better than yours!

I think you struck a nerve w/ dusty

[philodox]

when I'm 60 my hearing will be better than yours!

Yeah, but for now I win.

I think you struck a nerve w/ dusty

Nah, I'm pretty sure he was joking.

[Dusty Chalk]

Nah, I'm pretty sure he was joking.

Yeah, I was just demonstrating my non-wussiness. "Posturing", as it were.

You should search on "fuck you, you fucking fuck", or "fuck you, you fucking cocksucker" -- it's almost at meme levels in these here parts.

[DigiPete]

memes... schmemes

[Fitz]

The next room? I can hear Jay's K340s from hundreds of miles away. It's quite annoying when I'm trying to have a quiet listening session with a headphone that doesn't isolate very well.