Jump to content

K340 info gleaned from old dealer information pamphlets


philodox

Recommended Posts

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.

Link to comment
Share on other sites

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. :P

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

Link to comment
Share on other sites

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. :laugh:
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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?
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.