[ProLoL]

The K340 bass heavy was very very pleasant for me, incredible.
It leaks sounds quite a lot though.

 

[Mellowship]

The K340 bass heavy was very very pleasant for me, incredible.
It leaks sounds quite a lot though.

It is a semi-open design, with the back of the dynamic driver in direct contact with the exterior.
Mine is supposedly the bass-light green dynamic one, but with the new cable, pads and balanced amp, bass is rather enjoyable.

 

[plmon]

I got me a lot of different pads for my four k340s and one is really striking

https://de.aliexpress.com/item/33040658281.html?spm=a2g0s.9042311.0.0.1aa54c4dpMX5rX
Its not so thick as most other leather pads and i found it to be more bass intense than other pads i tried.

For me the best pads i have tried and ill order more..
its really crazy what velour or other pads do to their sound.

for me still the most pleasant sounding headphones i have..

Ohh, I need to check those out. I kept going back to the stock pads because other pads seemed to change the sound slightly due to how thick they were.

I recently tried Brainwavz pads as well since others said good things about them with the k340. I tried all the materials (velour, sheepskin, perforated, etc) but they all gave the k340s a tinny sound. Thin mids, bright, and muddy bass. I thought maybe it was the thickness here too since the Brainwavz pads use pretty thick memory foam, but the sound didn't change when squeezing them.

After comparing them with the stock pads, I thought that it might be the mesh covering the hole since the stock pads don't have a mesh. Turns out it was, cutting a hole in the mesh got the sound back closer to normal.

 

[Krassi]

ah nice!
Well i totally love those pads. They are very comfortable and you dondt get earcancer from touching the grills of the headphones.
Also i hate that plastic from the stock pads.

I like my k340 more and more.. i cant make out a big difference with Kaldas RR1 on an SRM-t1 to those even with just a weak atom amp.

 

[plmon]

ah nice!
Well i totally love those pads. They are very comfortable and you dondt get earcancer from touching the grills of the headphones.
Also i hate that plastic from the stock pads.

I like my k340 more and more.. i cant make out a big difference with Kaldas RR1 on an SRM-t1 to those even with just a weak atom amp.

I finally received the pads you suggested and wow, they are perfect! They don't thin out the sound like the Brainwavz pads and they made the bass cleaner than with the stock pads. I had fiddled around with some mods to the k340 to try and get the echoey mids out while retaining the bass, these pads were the final piece of the puzzle!

 

[Krassi]

Cool! And that went fast for aliexpress!

And its great to hear that it was not some weird impression from me that they boost the bass.
Also i have worn out elastics on the headphone and its perfekt this way.

The thickness and firmness ist great and also the leather is very soft.
I will still have to order two pairs and hope they arrive this year

Did you remove/change the dampening wool inside and remove the grill or what else did you do?

 

[plmon]

Cool! And that went fast for aliexpress!

And its great to hear that it was not some weird impression from me that they boost the bass.
Also i have worn out elastics on the headphone and its perfekt this way.

The thickness and firmness ist great and also the leather is very soft.
I will still have to order two pairs and hope they arrive this year

Did you remove/change the dampening wool inside and remove the grill or what else did you do?

Yeah, I removed the dampening material and tried it with the grill off as well. This got rid of some of the echoeyness, but there was no bass without the wool and the sound became hollow. I heard about taping the backs of the passive radiators, so I used some electrical tape and that brought the bass back. I tried some different meshes to cover the drivers, but didn't have anything satisfactory on hand so I ended up putting the grill back on. The bass was a bit boomy and muddy, but the new pads fixed that up and added some more slam too.

At this point, it's sounding pretty good, but the mids seem a touch thin. I'm thinking about putting some new cotton back in to see if that helps. But I'm wondering if I've changed too much haha, I'm not sure if I've retained the original sound anymore.

 

[Krassi]

Ah interesting!!
Until now i had not thought of modding anything myself.. i wanted to send them to the USA for a full mega tuning.. but at the moment i am broke and really love the sound!
Especially with my tube amp that was build for making the k340 sound awesome

 

[Coug]

Just picked up a pair of bass light (green driver) K340s in good shape. Put a pair of aftermarket K240 pads on that sounded better than the old flattened stock pair (they can never go back on a K240 though - stretched out). I'm feeding them from a Bottlehead Crack with Speedball with the tubes that came with the kit.

After listening to the K340's for a few days I finally opened them up to fiddle with the cotton, and found they had already been fiddled with. Cotton lightly wrapped around and not very consistent in density. I tried with the cotton pulled out but bass went away too much - didn't like it. Bought some "cotton rounds" make up remover type cotton circles, large size, (about 3"/75mm diameter). Finally settled on two discs with the center cut out to slip over the driver and cut a slit to allow getting around the wiring. The diameter just about covers the passive drivers, and two are about 3/16" (4mm) thick. To me, this sounds about right. Bass is nice, everything is coherent on most songs, but some tracks get that weird detached low to high frequency discussed before about the K340.

Example tracks/bands - Ten Years After, Steve Miller Band (non-radio stuff), James Gang, Grateful Dead, Fleetwood mac, Pink Floyd, Gorillaz, "Can't Stop the Bleeding" by Tom Morello, Gary Clark jr, and Gramatik - this one is a favorite with the HD650, they are the only ones that seemed to get the drop at about 2:45 right - the K340 now kept up without the veil -, "Flight of the Cosmic Hippo" by Bela Fleck - This was a recent find and favorite with a pair of HD250's, but now - K340, the bass is still good and strong (maybe not quite as clear, maybe...) and the banjo, piano, and cymbals just have the right energy and clarity. The K340's were good when I got 'em, but the cotton pads really seen to have pulled things together for me.

Makes me wonder if the different sound qualities reported has as much, if not more, to do with the cotton stuffing degrading as with different drivers (red/green sextett style, grey/black Monitor style).

Ooh, Stevie Ray Vaughn "Tin Pan Alley" just started playing - Wow! Never sounded better.

 

[JadeEast]

Makes me wonder if the different sound qualities reported has as much, if not more, to do with the cotton stuffing degrading as with different drivers (red/green sextett style, grey/black Monitor style).

Treatment of the ear cup cavity has an influence for sure on the sound, if you've played around with the stuffing there's some obvious changes if you mess around there. That said, there's so much going on with the k340. Not only two different technologies in the drivers but passive acoustics tucked in there too and a big baffle space with a semi open back to the cups... and lots and lots of plastic and a sprung metal suspension that's not decoupled from the headphone that well. It's a wild design. I love them but not always in the mood for them. I've found they are best at low and mid volumes as the tonality seems to work alright there. They can get a bit peaky with big recordings but somethings just sound great and can beadictive once you adjust to the tonality and oddities. Guitars and plucked strings with the transients work so well. Ear pad seal and elastics for clamping I found were key to the low end. I don't even remember what's in the cups of my pair as far as when I left them.

Lets see.... they are just over there...

Apparently nothing. Now that I opened them up my last tweak I did was add some dynamat to the back of the green capsule and around the driver holding cup. Back of the ear cup has a bit of loose synthetic fabric padding crammed into the space behind the vent and the capsule. That's it. I remember now just deciding to let their oddities kind of be as I never could get the tonality quite right and bass was good in this configuration. So, I kind of just went with the inherent oddity of these magnificent Austrian odd ball / jewels from an era when AKG was so far out the box and adventurous.

 

[SteveM324]

I’m the original owner of my K340 that I bought around 1992. I had it extensively modified by Headphile in 2009 with dual entry pure copper Black Top cables soldered directly to the drivers. This bypassed the internal circuit board and wires. The plastic grille was removed and replaced by a transparent fabric. The driver was also modified. I usually listen to them a few times a year and then put them back in my cabinet for storage. I’ve made quite a few changes to my digital front end and tweeks to my vacuum tube amp in the last month.... so this morning I thought it would be a good time to take another listen to them.

My modded K340 sounds better than ever. I like listening to female vocals and the midrange on this headphone is magical .... tonally nearly as good as I have ever heard. Imaging is very precise with excellent separation within the soundstage. My K340 must be a bass heavy version because there is plenty of quality bass. The sound is slightly warmer than neutral but very liquid, smooth and non fatiguing in any way. Voices and piano sound very natural. I’m going to keep these headphones in my regular rotation with headphones that cost more than several times their price and that includes the cost of the mods. I’m not saying my modded K340 outperforms my current headphones listed below but for sound quality it’s not outclassed either. Build quality is another matter, a lot of cheap plastic. This headphone definitely scales as I have improved my system over many years. I think it excels with a very powerful vacuum tube headphone amp and a well matched high quality source.

For reference, my current headphones include Susvara, ZMF Verite Open, Utopia, and the LCD 4z.... and I just sold a ZMF Verite Closed and Aeolus. My amp is the Auris Nirvana tweeked with a NOS Brimar CV4003 input tube, Sophia Electric EL34 ST tubes and a Synergistic SR Orange fuse. My digital system goes something like this: router > Triode Wire Labs Freedom ethernet cable > Uptone Audio EtherRegen with Paul Hynes SR4T LPS > Triode Wire Labs ethernet cable > Aurender N100H > Curious Evolved USB link > Innuos Phoenix USB Reclocker > Curious USB cable > Bryston BDA3 DAC. All components are plugged into a Equi=Tech 2RQ 20 amp balanced power conditioner. This power conditioner is a real game changer. All components are powered Signal Cable or TG Audio power cords.

 

[Krassi]

I’m the original owner of my K340 that I bought around 1992. I had it extensively modified by Headphile in 2009 with dual entry pure copper Black Top cables soldered directly to the drivers. This bypassed the internal circuit board and wires. The plastic grille was removed and replaced by a transparent fabric. The driver was also modified. I usually listen to them a few times a year and then put them back in my cabinet for storage. I’ve made quite a few changes to my digital front end and tweeks to my vacuum tube amp in the last month.... so this morning I thought it would be a good time to take another listen to them.
..........

Oh thats interesting that you mention the modding from headphile.
I was in Contact once with him but then came.. you know what this year ...

So a good pair with the full mod would be a good idea i guess with xlr plugs and the full allinclusive tuning (i got 3 pairs)

Also as you mention regarding amplification a friend of mine that build me a tube amp also made a prototype of a the bijou tube amp.
Its absolutely amazing how they scale with extreme amplification.
i turn it on 90% and windows volume higher than 30% volume would make it explode but still no distortion at max volume.

i really love my k340 and prefer them over anything i have.

 

[Coug]

Just picked up a second pair hoping for a bass heavy version - they were a pretty good deal so I figured if they were another bass light, I could resale for my cost and not loose money. Well they were bass light (again). Pretty good shape and fully stock. Decided to go ahead and do the more in depth modding route. Pulled all cotton, completely covered the cups inside with dynomat with a hole to keep it open, cut out the grill, rewired dual entry (nothing special - Mogomi mini quad star), and bypassed the PCB for the dynamic driver. Sounded pretty good. No reflections. Bass boosted a bit. But it still seemed the sound was somethimes wonky. I had noticed on both pairs that if I wore them "backwards" (left on right, right on left) the sound changed, but it was still wonky. Well, I took a look at both pair and realized the driver plate is the same left and right. That means the PCB is towards the front on the left and towards the rear on the right (i.e. one passive driver is in front of your ear on the right, and behind your ear on the left)`. So I decided to "fix" this issue.

I pulled the left driver assembly back out, used the remains of the grill (now just a mounting ring) as a jig, marked the driver plate and drilled new holes 180 degrees out of original alignment. I don't remember the size bit, but just matched the diameter to existing holes. Drilled it carefully with just finger pressure (it's just plastic after all). Using a hack saw blade I recreated the slot at 12 o'clock. Put everything back together, and viola - even sound left and right - wonkiness is gone. Now putting them on "backwards" results in a significant change in tone. No more detached high to lows - nice and even. I'm going to try this on the other pair and go back to stock cotton to see how I like that...

OK, Just did the other pair with out unwiring it even. All back to stock except the relocated driver plate. I like it... but I like the modded ones better.

How to:
Remove the grill, pop out the driver plate, rotate it 180 degrees and place it out of the socket just enough to cut the alignment slot/notch. A hacksaw blade seems to be about the right width and is easy to cut the plastic. Be careful not to stress the wiring too much - don't want to break it. The slot should be centered above the old bottom hole (now on top). A few strokes should be enough. If you cut all the way to the original screw hole, you probably went too far.

Put the driver plate back in place using the new notch for alignment. Put the grill back in place over the driver plate. Insert your drill bit (using fingers ONLY, NO DRILL MOTOR) through the grill's screw holes and start your holes in the driver plate. After all the holes are marked you can remove the grill.

Now continue to drill - with your fingers ONLY! Once the drill bit gets stuck, stop drilling on that hole and go to the next. When the drill bit gets stuck it's because you are about to break through. Don't go deeper at this point or you'll drill into the screw boss and mess things up - also why you DON'T USE A DRILL MOTOR.

Once all holes are to the "stuck" point, lift the driver plate out of the alignment post and rotate it so the holes no longer align with the screw boss (that little sticky uppy thing the screw goes into). Now finish the hole. The driver plate will have to be held well because the alignment notch is no longer holding things in place, so be careful and don't break your wiring. You might need to use a pair of pliers to rotate the bit to break through because the drill bit will be "stuck". Finish all three holes, and rotate the driver plate slot back onto the alignment post. All the holes should line up perfectly. Replace the screws, done.

As much as I liked the K340 before, this is what really made these what I had hoped for... much better.

If anyone is going to or has made some major mods, I think this is the best step to be taken.

 

[Andrew Seeley]

Looking like the Bass heavy variant. Bought these a while ago. I am sure these will be lovely with circumaural pads...

Good closed cans for sure. Especially happy for the dollar. I was considering th-x00 biocellulose but with pads i think these are quite fun.

 

[ProLoL]

Looking like the Bass heavy variant. Bought these a while ago. I am sure these will be lovely with circumaural pads...

Good closed cans for sure. Especially happy for the dollar. I was considering th-x00 biocellulose but with pads i think these are quite fun.

Yes, it's the bass heavy version, the best one. Enjoyed mine.