How long do your K340's take to warm-up ?

[Spiug31]

I've just recieved a pair of lightly modded (bass heavy) K340's in the post today and after 7+ hours with the sound still improving I am wondering how long yours usually take to warm-up and in particular whether getting them modded by headphile shortens this time ?

As these continue to play they are becoming better balanced, much more detailed and far more responsive to the music.

It's becoming quite addictive to listen to

The K340's have had the 'screen mod' done and I've added some dampening to the outside rear face of the cups but are otherwise as stock. I am driving them from the 1/4" of apogee mini-dac, all components in my signal chain are past 600+ of burn-in and I would consider them settled and stable.

[boomana]

I never noticed mine having a "warm up" period. I had them stock for a couple weeks and heard no changes, then had them modded, which made quite a difference, but I've noticed no changes since.

Is your amp brand new?

[holland]

Probably your pad mod is breaking in to your head, changing the sound from subtle position shifts.

Get an amp for the K340.

[aerius]

5-10 minutes or so at most for my pair, though I suspect it's basically the pads warming up and sealing themselves to the side of my head & face.

[boomana]

5-10 minutes or so at most for my pair, though I suspect it's basically the pads warming up and sealing themselves to the side of my head & face.

Which pads are you using, velour or pleather?

[Looser101]

I had this happen to mine. It seems if they sit without being used for a long time they need some break-in time. I attributed it to the electrostatic driver re-energizing itself.

Renato

[Spiug31]

It has the pleathor pads

The screen mod was done by its previous owner.

I have had the phones on and off throughout the day and while the pads getting settled may account for a little recurrent change, there has been a huge shift in presentation and quality throughout the day (all for the better ).

The mini-dac's 1/4" output has had many hundred hours of use with low impedance phones (16-32 ohm) but this is its first time with the 400 ohm K340's.

I hadn't thought of that, the 1/4" burning-in with a high ohm load may well be part of it .

Looser101 once charged did yours ever lapse back ? and how long has been the longest yours have gone without needing another recharge ?

Thanks for the replies

[aerius]

Which pads are you using, velour or pleather?

Pleather. I have rather oily skin which makes fabric pads smell funny, and washing them is a pain in the ass. So I use pleather, which wipes clean in seconds.

[spritzer]

I had this happen to mine. It seems if they sit without being used for a long time they need some break-in time. I attributed it to the electrostatic driver re-energizing itself.

Renato

They are electrets so there is no recharging as they are permanently charged.

[boomana]

I'm using the velour pads, which have a tighter fit for me. The pleather pads with the weight of the headphones and my small head, moved around a lot more for me, even if just slightly turning my head. The velour stay put better.

[philodox]

I don't know the science, but I agree with Renato. I've noticed that if you leave them for a while they need a good couple of hours to get back into shape. I find that, in general, a half hour or so brings them up to peak performance once they are in regular use.

[boomana]

How do you experience the change? Are you sure it's not your tube amp still warming up?

[Nanoha]

Knowing how electrets work, I'm pretty sure it's not the K340 that needs warming up but the amp.

[Spiug31]

I've just taken the K340's from my mini-dac to try on my 1/4" of my dads sony speaker amp. The sound of the headphones has definately changed hugely over the last 8 hours, it seems the sound from my mini-dacs 1/4 has also improved compared with this morning so I am happy to say it seems to have been both

I'll leave them unplugged overnight and post what I find happens tomorrow.

Hi boomana, I too have a small head and experience a fair bit of slipping when I wear the K340's, what do the velour pads originally come from and is there a reliable source ?

The mini-dac is solid-state despite its warm sound so its warm-up cycle is nearly instant.

They are electrets so there is no recharging as they are permanently charged.

In this thread http://66.102.9.104/search?q=cache:JxUbrpR15xsJ:www.head-fi.org/forums/showthread.php%3Ft%3D183459%26page%3D2+charge&hl=en&ct=clnk&cd=3&gl=uk it is mentioned that the K340 has a shelf life of around 30 years after which the drivers could lose charge.

wow!! you guys type too fast

[boomana]

They are AKG part # 2955Z2601 and can be bought for around $13 each.

Frank Rodriguez

Sales/Parts Administrator

Harman Pro North America

8500 Balboa Blvd

Northridge, CA 91329

Ph: 818-920-3279

Fax: 818-920.3208

You have to be bit of a pest: calling, faxing, calling, faxing, and calling again just to get his attention, but you'll get them eventually. Someone may have an email address. I never did.

[Fungi]

[email protected]

I ordered a set of K701 pads. First shipment, wrong pads. Second shipment, ONE pad. Still waiting for the reply on that.

[Nanoha]

I ordered a set of K701 pads. First shipment, wrong pads. Second shipment, ONE pad. Still waiting for the reply on that.

Wow, that is bad. When I ordered parts, it was e-mail reply within 12 hours and express delivery free of charge.

[catscratch]

I haven't really noticed any warm-up changes. They sound good out of the box so to speak and the sound good hours down the line. However, I haven't specifically listened for it either. With the K340's on, it's more about the music and less about the sound.

I haven't noticed any fit changes either but that is because I pretty much have to hold my earcups in place in order to get the right fit. So, there's no gradual sealing going on.

I will eventually mod them and replace that ridiculous headband assembly. These headphones need substantially more clamping force than that stupid headband assembly can provide. The fit makes such a critical difference in sound that you really do need the headphones to basically force the right fit from the start.

[Spiug31]

Thanks for the velours' item code, it seems from this http://www.akg.com/forum/index.php?topic=1765.msg5331 that AKG in Germany has them but I will try the UK service address and see if I can get them locally first. I'll only try the US sources after these as it'll save a little on postage

Fungi, did the K701 pad fit ?

[Fungi]

Wow, that is bad. When I ordered parts, it was e-mail reply within 12 hours and express delivery free of charge.

Yeah, he gave me free shipping and he was quick to reply and of course didn't charge for the correct shipment, but I'd like all two of my pads sometime soon

[Looser101]

They are electrets so there is no recharging as they are permanently charged.

Thanks I couldn't remember the proper name.

It's definitely not my amp warming up. They don't do it day to day. It was really obvious when I heard them for the first time after I bought them. The change was in the highs so something was going on with the electret. If not charging up, then does anyone have a plausible explanation?

Renato

[Spiug31]

There is a process called "electret relaxation" that seems to describe the gradual relaxation/dissipation of charge on/in an electret over time, might this be why the K340 seems to need to regain charge after a long period of inactivity ?

[boomana]

What info do you have on this? I'm interested as I've never heard of it before.

[spritzer]

Thanks I couldn't remember the proper name.

It's definitely not my amp warming up. They don't do it day to day. It was really obvious when I heard them for the first time after I bought them. The change was in the highs so something was going on with the electret. If not charging up, then does anyone have a plausible explanation?

Renato

The transformers or some other part of circuit could be going through some warm up or there is dust or some other debris on the electret diaphragm that is causing some charge migration or shorting out the driver.

There is a process called "electret relaxation" that seems to describe the gradual relaxation/dissipation of charge on/in an electret over time, might this be why the K340 seems to need to regain charge after a long period of inactivity ?

What you are describing is the eventual death of all electrets and that has nothing to do with charge migration. The diaphragm is permanetly charged during manufacturing over its entire surface so there is no bias ring or surface resistance resisting the charge.

[Spiug31]

Hi spritzer thanks for the extra info, much obliged.

This morning the K340 when switched on was playing at a quality nearly comparable to its peak after 15 hours of music yesterday. I heard a relatively miniscule but noticeable improvement in depth, detail and tone for the first half hour of use today but since then it has steadied

Whatever was the cause yesterday the huge alteration in its sound seems to be over and it now seems to just be a short warm-up to get from ok to very good

and yes, I agree I do need an amp