spritzer

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...

I'll take a look and see if these won't do. I do see one potential issue though, the cap is only rated at 250v \

Those would be great but anything above 3000 is a better...

The Accuphase it designed so that you can put one of their EQ units in the digital path both via a special link and the bog standard S/PDIF.

Could you post a high-res picture of the resistors and the cap and how it is all wired? As for not wiring up the bias... that's what I'm here for.

So any change?

For me it's nice to have all the outputs and the Lite wasn't available back then. I really wanted the BNC output though as it really is 75ohm. Batteries are ehhh.... yeah.... I'm going to build a Sigma11 for it...

A tweaked BH should do the job nicely. I could even build a tube PSU for it and charge 65k$... since you know... moar is always better.

It sure looks strange with so few outputs.... I do highly recommend a replacement PSU for it as it works well on my unit. If you have an old Iomega Zip drive then that PSU will work very well.