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Offered without comment. Other than HC may have to up its lipping game.

Time for some impressions of this rare beast. The Icelandic distributor has a set on loan and they carved an entire afternoon out of the schedule for me to try it and do some comparisons. I showed up with the HE90 I built from spare parts, Aristaeus, Carbon amp and a port modded SR-007Mk2. Since they were using the built in dac on the HE-1, I just plugged both amps into as well to equalize the comparison. Over all, I like the build quality of the headphones. Imagine a HD800 built properly and you are pretty much there. The leather earpads are super nice and the headband has nice extension to even fit my large melon. I don't think they are super comfy though as they are fucking heavy (550gr) and all of the pressure is on the top of the head. The Stax 4070 is just about as heavy but far more comfy due to the suspended headband design. The earcups get a bit warm due to the internal amps but only about 5-7°C above ambient. The cable is also pretty nice and not microphonic at all but more on the amps etc. later. Amp itself...well it is just fucked up. I get that they were trying to cater to some nouveau-riche people who just want something expensive but the wank factor is off the charts. I also have serious doubts about what's hiding in that nice marble shell... As for the headphones them selves... well the drivers look pretty much identical to the HE90 units and the few pictures of them that exist, point to that. I wanted to rip off the earpads to check further but people get antsy with something this expensive... One worrying thing I noticed though is that both sides of the drivers have porous dust covers. They look identical to the woven nylon found on the HE90 and well...I would expect solid covers. Now for some actual impressions. As I said above the HE-1 dac was the source for all the amps. To that you have to turn off the headphones so no direct comparisons were possible but I know how both systems should sound so not a big problem there. The source feeding the HE-1 was a Macbook Pro running itunes but I bypassed that with my own FLAC files and player. There are some major changes compared to the older system, this one can do bass and isn't as horribly colored either but over all...I was not impressed and the system never made me really interested in the music. It doesn't engage like a good 007 system can, where I sometimes just sit in awe even after owning a set for all these years. Here, it just doesn't pull me in. This is clearly a midrange issue as there just isn't enough presence there. First off the major issues are the bass, treble and the soundstage. Let's start with the bass, it has this annoying hump to it sort of like the old Lambdas. I'm not sure if this is the mosfet driver (could be, the Cavalli crap boxes have similar issues) or the headphones but it is a clear coloration and once you notice it, just annoys the fuck out of me. Now on some tracks it wasn't as noticeable but always lurking in the background none the less. Next up is the treble...which is both subdued and bright at the same time. I know plenty of people complain the 007's lack sparkle and with the Mk1 this was mostly true but they could be bright if the source called for it. The HE-1 manages something different, the treble is just flat and boring but then it suddenly bites hard. Now I was listening at higher levels but still nothing super loud, only about 12 o'clock on the dial. This also wasn't like the upper midrange bite of the 009's, more lower treble fizz but the source material didn't call for this. I'm so used to listening to SR-X Mk3 Pro drivers now (which are pretty much the gold standard for treble) as they are in my DIY headphones and nope, nothing like this. I suspect the amp is a huge influence here too but no way to verify that... Last major issue, the soundstage. Many will know my stance on the old HE90 where it sounds like you are listening to some people playing in dense fog and you can't quite make out where they are. This time around it is much improved but the lack of pin point accuracy is still apparent. The soundstage is also a bit too far away for my liking and it just doesn't throw the same huge headspace the 007's can. This also affects the midrange and the whole "disconnected" feeling I got from the whole system. I once reached for my phone as I was just a bit bored listening to it. Over all I like that Sennheiser built this but they really should have spent more time on the electronics. I don't think there are any improvements to moving the amps to the cups over something like the Carbon where I can burn 50+W as heat and overcome the small capacitance in the cable. Next post will discuss the tech specs of the system but I'll end with another picture of it all... It was really dark in there and I suck at taking pictures... Now for some technical discussion. I found the specs in the back of the manual and it turns out the bias is 650VDC and the amps run at +780VDC. This makes this more than compatible with Stax so I see no issue with removing the internal amps and rewiring one of these for Stax use. I have been asked to that before but I'm really hesitant to mess with something this expensive. That said, moving to proper amps which are not just the HEV70 rehashed can only be an improvement. I've never found any mosfet device with sufficiently low Cob to work in this role so I truly don't get what Senn were thinking. Some other info, the entire amp only consumes 40W per the user manual which doesn't leave a lot for the actual amps. So we have 8 tubes running with heaters plus all the motors in there. HV supply for the tubes, another for the output stage and well...not a whole lot of power to spare here. Compare that to the BHSE, Carbon or even the T2. All of them use far more power and it is just for one goal, to power the headphones. I also played around with the amp and I could swear that the volume control feels like a RK27. No way to know but how it felt when moving to the extremes...it was just like a RK27. Now as a proper volume control aficionado... ... they all feel a bit different. TKD feels nothing like a P+G or a RK50... Until somebody opens one of these up, take it how you will. It is also clearly a volume pot and not a chip or some other setup.

Scary Clowns?

But it's going to be 10% moar better.

so after thinking about it a while, something is wrong with the hv delay circuit which turned on with the tubes cold. this has to be fixed first. when the tubes are cold, the output voltage is going to go to +500v, and thru the 100k feedback resistor is going to put 500v on the cathode of the input tube. With the filament of the input tube grounded, there is 500v cathode to filament. Guaranteed to cause a light show and permanently trash the input tubes.

It's been cranky for about 3 1/2years. That'll change in about a week.

The advantage of a simple circuit is there are only a limited number of things that can go wrong.

BINGO!! One of the DN2540s was indeed bad. I had not tested those as well as I had tested the 10m90s because I had it in my mind the 10m90s were the place to start. JimL, you saved me many hours of replacing all the silicon which was going to be my next step. LIFESAVER!!!! Thanks!

More on the T.Rex

^ that. And also, what's the plate voltages reference to ground when you are seeing the 120V delta between the plates?

Adele - 25

First, I would take the 12AT7 tubes from the bad amp and substitute them one at a time into the good amp. If the tubes balance in the good amp, then they are not the problem. While the tubes are out, you can re-check the plate resistors to make sure you didn't somehow put in the wrong values. Assuming they are good, that leaves the tail current sources. If that is the problem, I would replace all the DN2540s in both input tail current sources.

Do you have the cold channels bridge to ground? Edit: and volumen pot to 0

Google could only guess at it ..

Bump in the low mids, like old Lambdas (I think about my Lambda Signature), check. Lacking some excitment compared to Staxens, kinda german coldness in the mids, check. Sometimes biting in the highs in spite of flat high mids (Sennheiser tone for me), check. All around I pretty liked them, but there's indeed something a tiny bit too cold / distant compared to what may be a coloration from Staxens. Don't completely agree with your assessment on soundstage though, but looks like you're a man of deep layered soundstages more than volumic ones. Eager to see you daring tear them apart and hardcore modify them Ali

Everyone these days is drinking the Veblen Kool-Aid, ceterus paribus. Or maybe it can be described as some perverse form of parity.

Ooooh, didn't see the price. Yeah, that ubiquitous $4K headphone trend doesn't interest me. I have speakers, so...

It's the $4000.00 price tag that will keep me away. Someone should sell me their old K1000 when they upgrade.

Ah, the good old Cardas Smurph cable. That takes me back.

post the build sheet for your 911

Jonathan Valin: "Oh, and I’ve saved the best for last. Not only are the 30.7s the handsomest-looking large Maggies of all time (in their blue trim and snow-white panel covers), they are also among the best deals Maggie has ever offered. They cost $29,000 the pair (release slated for January). That’s not chump change, I grant you, but compared to the price of the six-figure speakers they so successfully compete against, it makes them, perhaps, the greatest bargain in ultra-high-end history. " http://www.theabsolutesound.com/articles/magnepan-307-loudspeaker-part-one/

Extension cord -- 1000 euro a meter. Paint job -- 5000 euro. Senn really testing what the market will bear ...

A little T2 tube rolling goodness

In addition to a regulator for the PS, a CCS plate load for the first stage will decrease distortion, a CCS cathode load for the second stage will also decrease distortion, and using a MOSFET instead of the awful 6080 will decrease output impedance, lower noise, and decrease distortion. It will also allow you to eliminate the 6080 heater power supply which is the most likely source of noise, and the source of tons of heat that needs to be dealt with. A first stage biasing scheme that does not involve an RC filter will also do good things. While we're at it, a 6SN7 gives you too much gain for nearly every headphone out there. That means that you are attenuating and then amplifying, which is a source of both noise and distortion. There are a number of ways to lower gain - the easiest might be simply eliminating the cathode bypass cap (this also increases plate impedance, so whether it can drive HF into the next stage will be an issue, but it is probably fine, but it has the benefit of getting rid of that RC filter). You can also find a lower mu tube, or perhaps a pentode with a low impedance plate load to lower gain. Or you could use a step up transformer on the input. I've now replaced every part of your amp

I finally got the Spider legs for my ESL57's and after some boiled linseed oil and lacquer, they were installed yesterday: It has changed the sound quite a bit but it mostly makes them easier to live with such as cleaning underneath them and stuff like that. The panels are 49 years old at this point so the SQ is suspect but they play amazingly well for their age. Perfect balance with no noise or arcing at all. Next step will be to replace the panels, paint them and have the covers re-anodized black.