spritzer

Diaphragm size and the D/S gap are the same or similar as on other models such as the SR-Omega so that isn't a factor. There are really only two variables here, coating material and the diaphragm tension. I think so, can't remember... When tweaking we have to take risks!! Next step is submerging it in molten lava!!

Only the special edition mods feature that and well you can guess what the reference series of mods entail... Btw. Did any of you see the NOVA episode last week where they might have uncovered another viking settlement in Canada? Truly epic stuff and it also mean we own you bitches... The instruction manuals have always stated that though it was something like 90% but non condensing. Change the humidity and you change the breakdown voltage of the air dramatically. Normally it is around 100V/mill so the drivers are setup around that though with plenty of headroom. I don't think humidity is the culprit in the recent driver failing though. It might contribute due to its effect on static charges and stuff like that but at the end of the day the drivers just aren't stable. Being able to restore them to full operation by hitting them is a giant red flag to this fact. Converted to balanced operation.

Authentic 2SA1968's are very rare and expensive too so one does wonder.

Couple of other obvious questions, are you sure all the sand is genuine as that could cause massive issues. Also are there any shorts on the boards or has the flux been cleaned off?

Nah, it will be close enough. Just made sure the resistors is a high voltage unit rated for at least 600V.

You should add a 5M resistor in series with the bias line. The Stax output has a 4M7 resistor on it so you need the extra 5M to meet the Sennheiser spec.

Yeah, Class A is no joke which is why I have so much respect for the companies that do attempt it. Accuphase and even Denon make Class A integrated amps that seem to sell well enough to warrant regular updates.

Even a 30W Class A amp runs very hot so yeah, very low Class A biasing.

Nope, highly nonlinear transducer which needs a less than honest amp. Simple as that. The inside story from Sennheiser is that the HE90 driver yield was truly terrible so they did have some very stringent testing.

Sure, they can be repaired but you will have noise issues unless you just happen to have a working cleanroom...

Even if we were to use all film caps in an amp then there are other stresses that go with high voltage. Film caps are also vulnerable to heat so that is clearly a factor.

Hello servo!! Ohh and running amps 24/7 will drastically cut their lifespan.

There is a lot of work that goes into shrinking the PCB's and often more time than the initial layout. So I'm not going to do it but Kevin might.

Sadly no. Even on the Carbon is isn't capable at all and suffers from all the same issues as it did on the BH back in the day.

Well the HE90 doesn't rock as it has abysmal bass performance...

The film is attached to a large metal ring (that's how Stax have been built since day one) but we could be dealing with a connection issue as to how the cable attaches to the ring. I've never opened up a 009 so I can't be sure. It could also be an issue with the coating or the film tension. If anybody has a broken 009 then I'd love to buy it.

If you use old GEC KT66's then maybe they might work for a while as they were so massively over engineered but anything from the 70's and on wards will not last long. This can't be stressed enough, the EL34 is a oddity amongst the octal power tubes so the logic that any of them will work just isn't even remotely true.

If the diaphragm is stuck to a stator then yeah, we need to show it who's boss!!

Well KT66's are utterly incompatible with the amp and will not last long but please go ahead and blow up your T2. Read the fucking datasheets!!

Kevin is indeed full of surprises... As for the 009, I think a lot of them experience some charge issues. My current set did so I just hit it quite hard on the offending channel. Right as rain after that.

T2 with DHT's!! Me I just did construction today as I finished all of the small projects I'd been neglecting for the past few weeks.

I would have sprung for some wires with spade connectors...

Most of my truly WTF headphones have been dirt cheap so I just viewed them as a learning experience. Glad the ESP9's are working as they should. Not bad at all but one could argue that the Stax sets of the same vintage are better. Certainly more comfortable. Something for this thread though, as most know the new Orpheus had a name change last month (HE1060 to HE1) but what Sennheiser kept to them selves is an embargo on actually calling them "Orpheus". They are not meant to be called that in any official publication or by Senn representatives. Not sure what is going on there but this is a complete change from the earlier days. Ohh and me having this info has nothing to do with me asking how much a set would cost me...

I've lost count of how many basket cases I've received over the years. Buying vintage is a huge risk but so many people don't want to face that.

Considered but found impossible in this universe.