AKG K240 Sextett--Grado'd AKG? - Page 10

The foams in mine are practically crumbling away. Is there an alternative replacement for these foams before I try contacting AKG?

Cheers!

It's called reticulated foam, and is also known as filter foam, such as the kind used in air and water filters. Any acoustically transparent foam will work if you cut a piece of it to fill the earcups. Its primary function is to serve as a spring between the two sections of the earcup. I have a large roll of the stuff if you want a piece off of it.

The $26 sextett showed up. I's a late production model.

I haven't listened to them yet - still in the middle of the deep cleaning process. But of course, that requires full disassembly.

It seems to me that the paper on the inside of the 'cup' is heavier than the paper used in my middle-production sextett, but perhaps still not as heavy as my early-production k240-M.

The middle-production sextett paper is very flimsy and almost see-through when held up to the light. This late-production paper has more of a fabric feel to it and completely blots out the light. The K240-M paper is tough and, well, papery.

Does this match what others have observed?

You are referring to the black paper? Yes it is thicker on the later ones, but I have not tested whether it makes a difference because it seems like it would be of lower significance compared to the other differences. If you want, I will do a FR plot comparison with the same drivers/baffles using different earcup pieces, once I finish replacing all of my test equipment that got destroyed a few weeks ago.

??? Is there a good story there?

Not really, just a sad and wallet-draining one.

Thanks for the offer. I'm afraid shipping over to me might cause a bit too much though. Do you think those foams that come with computer components (motherboards, etc) are usable enough for replacement purposes?

I've seen a lot of different kind of foams with computer parts, so I dunno. To avoid affecting the sound, it would need to be completely open, where you can see straight through it with little difficulty. Regular open cell foam would likely alter the sound from the original design. It also needs to be about 1/4" thick to serve any purpose.

It wouldn't cost much for me to stuff some in an envelope and send it letter rate. The foam itself has virtually no weight.

It used to be readily available at most home improvement stores. It came in a loop to be used with old style humidifiers. Not sure if it's still available that way, but you could check. Also check your local pet store. The same foam is used by Marineland in their H.O.T. Magnum filters. It's a replacable part that you can buy to slide over the corregated filter, as seen here...

http://www.thatpetplace.com/pet/prod/213952/product.web

On the subject of K240 mechanics, I remember sometime ago somebody saying something about the headband having an internal crimp between the headband wires and the solder posts, which may be subject to reliability issues. I was stripping down a couple broken headphones for parts, a K270S which uses the same headband as K240, and the K141 which uses the lower profile version of the same headband. Both had the plastic blocks at the ends of the headband wires broken completely, and inside there was no crimp or other transition point... the solder posts are the ends of the actual headband wires themselves. The wires just are bent at a slight angle to go out to where they need to be, then molded in the plastic block.

Just thought I'd get that down somewhere in case it ever comes up in the future.

Yeah, that was me, and my foggy memory. It was a K301 frame that had that issue, dunno why the heck i was thinking k141/k240.

so it's possible that the k(4,5)0(0,1) series may have that problem. Or not.

Peeking through the grilles, mine seems to be the MP variant (and it has orange backing). I may missed it but are there any sonic differences between different Sextett batches?

Yes, the primary difference being a decrease in bass from one to another (early having most bass, late having least bass). Middle production is my favourite one. The differences are due to the baffle changes, but there are also small variances between drivers, which I currently suspect is due to inconsistencies in the black paper used on the front of the driver capsule. These are normally only visible on frequency response measurements and not through actual listening though, but the baffle differences are very obvious even during brief listening.

The pair I have definitely has bass leaning on the heavier side (not as strong as a bass-heavy K340 anyway).

Can I take you up on the offer for the reticulated foam, Fitz? Let me know how much it will cost to send them my way.

Cheers!

Mine which are late production (correct me if I'm wrong Fitz) have about the same amount of bass as my bass light K340. Maybe just a little bit more.