spritzer

Engineers can be deceptively stupid sometimes but Stax has been known to make a lemon or two over the years. The 727 for instance is an abomination compared to the 717 but it has no NFB. Did they intend to make a worse product then the predecessor? Not a chance but it happens but change something and it can all fall apart. It's not all bad as they have finally fixed the SRM-3/313 mess with the 323 which is as good as the SRM-1 if not better. As I covered before, Stax had to fix these issues and they took the route they deemed best. Two of them involved "compromising the design" as I like to say since they had to increase the size of the ear cavity (also position the drivers further way from the head) and get rid of the squealing. Enlarge the ear cavity and you open up a Pandora's box of issues and keeping the drivers sealed off is a needed to make them more linear by keeping the damping a constant. I just worked on the SR-Omega/007 hybrid yesterday and fully sealing off the drivers has brought a very positive change in bass depth and lack of overhang.

78-S6S is the socket 86-71-6S is the plug These are the WPI P/N's so they should work everywhere.

Interesting they are and 400$ is certainly not a bad deal. Out of the 007t they will be pretty midbass heavy and slightly rolled off on top so they are more dependent on the music chosen then anything else. The founder of Stax was a classical music nut and the normal bias Sigma was his favorite of all the phones they made.

The sound is rahter different, the normal bias model has a thicker sound with more slam and attack while the Pro's have a wider soundstage but never "gel" like the normal bias model. Neither will work well from a 007t given the massive power needed to make them shine. Put some SR-404 drivers in that housing and the 007t should be able to drive them. Most just assume that they have Pro gear...

I know where you are coming from with this as they have a similar presentation but the SR-007 can stop being laid back when driven properly and/or the music calls for some balls. This is something the LNS can't do even when driven balls to the wall by a BH.

He may not like it but this is the true high end forum as we don't care about bling gold screws and demand internal pictures.

Nothing wrong with a new take on things.

Ditto!!!

That's about correct.

I fail to see the point here as silicon will last for decades. I have silicon baking mats in my bakery that are specc'd to last 1000 trips to the oven at 300

That's not something that will last 30 years. Felt might be ideal as it can let through air but it won't do it easily. It will be the point of least resistance though so there would be minimal noise.

It's about the current going rate for a nice set.

They added the port to remove the fart problem and brought along with it no deep bass and a large midbass hump. I'm sure that some compromise could be found through damping where the ear chamber can breath but it doesn't kill the bass.

Every electrostatic makes some noise when forced but very few make that squealing sound due to their design. The He90 is probably the worst with the "peeling " sound though... It is a very good headphone indeed but it's simply not good enough in my book compared to the original. I do believe that Stax made a blunder here and the faster they realize it the better but all professional reviews will just tell us what we know i.e. that this is the best production headphone with no comparison to the older model or a SR-Omega. Since you brought up the 4070 then it isn't a well known fact but there are two versions out there, the ones produced in 2001-2002 and those made after 2002. The original design didn't allow for the earcups to fully swivel and that made the phones unsuitable for a large number of users. Stax shaved a bit off the housing and the problem was solved. If you read the pamphlet for the Mk2 then the extra bass response is noted but said to be due to the earpads (more solid material so certainly possible) so it could be that Stax wasn't aware of any problems and the distributors think that it is all down to nonsense like burn in. I simply can't believe that this mess of a midrange was done on purpose as it is not linked to the port issue. I really need a second SR-007 Mk1 to use a basis for the mods to see if this can't be reversed. Anybody have a Mk1 BL they want to get rid off...? Ignoring something is always my first choice but if you can make the problem appear and disappear by wiggling the cable then it is time to buy a new SR-303 cable.

Happy birthday!!

Talcum powder (or something like that) is what Stax uses and it's great, especially for the fork mount.

The Lambda frame is the same one in use on the SR-x0x line and is the basis of the 4070. It's the Sigma which has the drivers perpendicular to the head. I posted a picture of one a few pages back. The squeal is caused by air trying to escape from the airtight (ish..) space next to the ear due to changes in pressure. It will also present as a suction noise when they are trying to draw air into the space. It's the diaphragms (all 3, 2 dustcovers and the mylar unit which produces sound) which get pushed around to try and let air in and let it escape. None of the older phones had this problem as they all leaked some air, under the earpads, around the drivers etc. so Stax installed a port on the new SR-007 Mk2/A to went the space and eliminate the noise. It also produced mad midbass which they thought was an improvement but IMO is was a very, very bad move.

Correct. It's easy to do but always cover the drivers with a piece of cardboard or something when soldering as a stray drop of flux can damage/destroy them.

I believe that is true. He sent payment for the mods after approaching Mikhail about his intention of selling the amps after months of waiting. That was in February and the amps were supposed to have been completed then. If Mikhail wasn't dodging his phone calls then it might make sense that there were some unresolved issued to be worked out before shipping...

That would only be the case for the SR-003 or the SR-007 mk1 where such a seal is needed. If a Lambda does something like this it is bad news indeed.

My guess is that Mikhail is full of shit as usual but for Michael's (Elephas) sake I'd love to be proven wrong. Why would you ignore your customer when his units are ready to ship out? He should take those pictures ASAP to prove that he's not a lying sack of shit and that includes full internal shots to show the upgrades.

Yup, that's the spring. It's nearly flat on the Mk1 but not so on the new model.

This could be due to dust but the cable would be my first guess. The drivers are a pain to work on so open up the phones and swap the cable around to the other side and see if you can reproduce it. The wiring for Stax cables is always the same so out of the 3 wires to each side, the one with the printed line is +, the one in the middle is the bias and the last one is -. But did you also move the spring from the Mk1 over to the A? Looking at the phones side by side then the spring is very close to base plate on the Mk1 but it sits nearly 10mm away on the A. The pads clearly stand out a lot more on the A/mk2, much more then either the SR-Omega or the SR-007. Increased driver/ear distance is never a good idea with planar phones. I got "our" set () back last night and pushing them towards the head seems to calm the midrange but the port mods makes it hard to easy A-B comparisons and I don't have much time to focus on this. It is possible but takes an extremely steady hand and sharp razorblades. Use a large blade to separate the stators from the bias charge ring (brass ring). Do not try to separate the two brass pieces as that's where the film is glued. When the diaphragm and stators are apart you need to clean off all glue residue with a razor blade, 2mm from the diaphragm. Needless to say, one slip and it's all over. Do that and the drivers can be glued together again but the right glue is crucial, so no super glue or epoxy crap. A special rig is also needed to glue the drivers in and lest them sit for 12-24 hours until the glue has settled.

Dumping them for a Mk1 might be the best course of action for now as I'm still not sure that the damage done by Stax can be fixed without some major surgery. I don't really believe that any synergistic amp will make the Mk2/A sound better (or rather as it should) but I have been thinking about the problem and I have a theory. The only two things that really are different with the Mk2/A is the port and the distance from the drivers to the ear. While the pads are different in shape then the sound should be more similar to the SR-Omega/007 hybrid which isn't the case due to the similar pad design. That only leaves those two factors and with the port plugged it's probably the distance between ear and driver that is causing some unwanted reflections in the larger pads. One of the complaints about the Mk1 was comfort for weirdos (me included) with large ears so Stax increased the gap. A quick test would be to force the headphones closer to the head by a few mm and a more permanent solution would require modding the spring which holds the earpad. My set is out on loan so I can't test it but please do and report back... just mind the backwave!!!

Very nice!!! It looks much better without the hideous HE60 connector...