spritzer

I'm always ruthless as I don't like compromises. They do have their moments though and I have to see what I can do to help them along. One things for sure, those dust covers will have to go as the holes are much larger then the ones used by Stax. You can stay tuned for some exploratory pictures in the next few days...

Right now I'm sitting here with a Jade on my head. The build quality is quite horrible to say the least and the pads are way too stiff to serve their purpose and should really be tapered. The cable is far too stiff and has to go which is something I will be doing. They really look like a 20 year old used Lambda covered in small nicks and scrapes except they are new and everything is just stuck together with some glue. Now onto the sound. Simply dropping them into my computer rig instead of the SR-Omega/007 is quite a cultural shock. The soundstage is far too wide, so much so that is messes with the stereo image. This makes the soundstage very 2D and they have no depth to speak of. They are certainly forward and just a tiny bit aggressive in the top midrange but I'll have to spend more time with them to know if some etch is hiding behind it. The midrange is ok but nothing spectacular. The bass is very much like the He90, all show and no go. It lacks the presence, depth, control and texture of even the SR-Omega let alone the younger brother, even the ESP950 has cleaner bass from memory. The bass goes deep and can be impressive at times but it is slow and sloppy, pointing to the chassis not being able to soak up all the extra energy. There are also some strange things going on with the lower midrange/upper bass, some suck out which makes them appear a bit thin in places. Now these are just first impressions after a few hours out of the box (they aren't new though) so they might change. They are pretty common but sought after on the headphone forums fetching about 250-300$. Well worth it though.

Also if you checked the internal picture there are 4 wires leading to the transformer which usually means that the transformer works on the two systems.

As can be seen in the pics there is a switch on the back to change the input voltage.

Ahhh so pretty.

Buy a CNC machine? I'd start off with plastic or fiberglass cups as they are easier to handle and you will have to make a few prototypes.

I just wanted to be sure it was the actual mylar membrane that you looked at and not the dustcover. You'd be surprised how many don't realize the difference. The SB unit is just like a mains powered unit except that it draws the AC voltage from the audio. They are are both limited by zener diodes so the input voltage can never exceed 100v.

There are no parts available for Gamma phones (earpads, housings, drivers or arcs) so you are out of luck there. Stax did say that they might be interested in making some drivers for us but that was some time ago and it would have to be a large order. As for the damage... well I didn't think that was even possible as Stax always put silistors on the normal bias outputs to limit their output voltage but Pro drivers are immune to arcing with the drive voltages present. Did you remove the drivers from the housing to check inside as that is the only way to check?

Here is the Koss schematic.

Look at a picture of the stock phones and you can see the cup design... They are the same size as a Lambda but just deeper so the flat part of the housing is about the same size as a Lambda When you remove the damping you expose some of the things they were trying to hide in the first place, namely the upper midrange etch and some bass issues. Look at the last picture of the baffle and notice that the long sides have a notch cut into them. That's the port.

KG redrew the Koss schematic and I should have it here somewhere. I'll have to look for it though... The SRM-1 I don't have. All the Lambdas have the foam lining the inside of the cups and it should be available from Yama's.

Nope, the SR-Lambda is simply better as it doesn't have the midrange recession and the uneven bass and treble of the Pro's.

I have no idea what wood was used as I never opened my set but they use the standard Lambda baffle (i.e. flat) and the port is in the baffle. There is a cut out running almost the full length of the baffle from top to bottom on each side of the driver. Here are the only pics I have:

True but I've never seen either a dead SRM-1 or a L-Pro.

Does anybody have any internal pics...?

You are aware how electrostatic membranes function, right? On traditional constant charge drivers such as the ones Stax builds, the membrane is highly resistive and single ended. The bias supply is high impedance (as in it has little to no current to give) so the bias is just "pushed" onto the diaphragm. There is no flow as it is an open circuit so it's hard for it to get rid of a large charge that just sits there in one of the isolated "hot spots" which appear, mostly due to the uneven resistivity of the diaphragm.

It is indeed a static parasitic charge that builds up and the bias supply has to get rid off. The bias supplies are by design very weak so it can take them a while to overcome the charge. It's enough of an issue that Sony designed a semi conductive housing for their electret drivers as with them there is no way to reach the membranes from the outside. I have no idea what causes it but there seem to be a lot of this going in in the last month or so with all manner of Stax phones.

What does happen with electrostatics is that a charge of the opposite polarity sits on the diaphragm, impedes it movements and it takes the high impedance bias supply a while to get rid of it. This has happened to my O2's once and took a few hours to get rid of it but the effect was very strange indeed. The best way to prevent it is to always discharge the diaphragm when unplugging the phones. This is also the main reason for the dreaded channel imbalance and can be a PITA to get rid of.

Damn crappy eco friendly glue.

Ok, that's much better. Crossovers have never been my strong suit (full range FTW!!!) but the cap acts as a high pass filter for the tweeter so it is definitely "seeing" the whole voltage. A silver mica 1kV unit would be both small and easy to fit.

They're planar so instantly cool.

The 717 is rated at 450v RMS which means it reaches 600v P-P easily but the final voltage the phones see is tied to the volume level. Now whether or not this is a problem depends on the cap and the circuit. The piece of tape hides part of the circuit though and I couldn't make out the colors on the small resistor which is above the tape. To save bandwidth, why don't you just upload the pictures here? The site accepts 4kx4k pictures up to about 8mb.

Hopefully not but driving something out of spec is never a good idea. Just ask Mikhail...