spritzer

You would notice the recess and nonlinear LF and HF response instantly so it must have been a SR-Lambda.

I have done something similar myself to a few adapters. You shouldn't be able to damage anything but it's always wise to pop the hood on modified gear. The wires from the speaker input can lead to 3 places, to the switch at the front (how it was done stock), directly to the pcb or the purist way of directly to the transformers. The recessed midrange is the Lambda Pro. The SR-Lambda is nothing like them and much better IMO. If you really want to rock out with the SR-Lambda then I'd try them without the mineral wool in place inside the cups.

Very, very different no matter how you tune your SR-007. The 4070 bass has tremendous extensions but very little bloom and can never hit as hard as the 007. There is also a bit of overhang with the 4070, similar to the SR-Omega but different though this isn't really noticeable unless you push them hard.

We are all looking for different things but you can't have a great sound without a great design. My standards are fairly high so even if I do enjoy every ESP I've heard they need to do something more then merely sound good to set them apart. That being said there is no one phone for everybody but after having heard almost every high end model ever made (haven't heard the Qualia yet) there is no headphone better then the SR-007 for those that want the truth unblemished. That is my definition of best as it simply plays what it is being fed without mucking it up to much. I judge sources, amps and cables by the same criteria and I'm certainly not a big fan of things to tailor the sound to some specific fashion.

They are laid back in the same sense as the Quad ESL57 is laid back i.e. it simply presents the music for you and doesn't force it. Choose the best cables and source for them and they are anything but dark. Amplification is an issue but the old Hafler should be fine with a rewired SRD-7 or an Illusion.

They are the best from a technical standpoint. No other ESP can do soundstage layering or have the same amount of control under a lot of stress i.e. large dynamic swings at high volume. You may not like their laid back presentation but there is no denying the quality of the design.

Regarding the pads then I have mine somewhere between the temple and the eyes so what works best for you is the right one. The SR-Omega has the pads pointing towards the chin (directly forward) but they are rather different and fixed in place. The SR-007 loves to be cranked and needs all the power you can give it, hence my plans for a very upgraded Blue Hawaii with rare output tubes. That isn't hype... they are the best. Period.

A good session with Megadeth on the SR-007 makes you forsake all other phones...

The 4070 is the best closed headphone I've ever heard and it manages to be the best monitor headphone there is. It is a power hog but still sounds good on Stax amps and other low power designs but needs the grunt of the Blue Hawaii to really strut its stuff. It will never challenge the SR-007 or the SR-Omega but it gives the Sennheiser HE's a good run for their money. It is also a marvel of engineering (as closed ESL has always been the holy grail) and it shows just how good the SR-404 driver really is when freed from that awful Lambda housing.

Are the subwooffers grounded at the powercord and if so have you tried a cheater plug? If it is some form of a groundloop it might work.

The He90 is designed to run on 500v (bias or polarization voltage) but more importantly it was designed for a 10Meg bleed resistor. Stax specs 5meg for most of their headphones. The resistor controls the charge on the diaphragm so you might have to install a 5 meg ohm resistor in series with the bias wire on the adapter. If the phones are of the 2005 production run then this shouldn't be an issue and I run mine from a Stax pro bias output without any issues. In fact I use them out of my, identical T1 without any issues. You can also send them back to Senn and have them modify the drivers to be able to handle the Stax spec. That is a nice collection. If you have any 6 pin version you could recable one of the normal bias Stax phones. They are also very nice outboard PSU connectors. I might have to buy some for my upcoming upgraded BH...

They do exist. Creating a normal bias supply is as simple as pie. A voltage doubler was the Stax way but there are others.

All you need is an adapter cable to borrow the bias from some other source, i.e. one Stax socket with two male plugs. You can also put a resistor on the Pro bias line to prop the voltage. KG explained how to do it over on HF.

While the parts quality could be better (I'm rather picky... ) the transformers are some of the best you can buy. I've toyed with the idea of building one of these and add a volume control, Stax transformers and a bias supply, 4 pin dynamic output connector and swap the 6SN7 for a 7N7 by changing the socket. I'd most likely go for the VT-25 version as it sounds better then the 300b though with less power.

Congrats!!

I have a late model SRM-1 Mk2 P-P sitting in Japan and I'll try it with the 4070 as soon as I get it. The 4070 is tough to drive (much like the Sigmas) but I do like them out of every amp I've used them with. They don't turn all dark and bloated as the SR-007 and Sigmas. I even used them for a month or so out of the puny little SRM-Xh (predecessor to the SRM-212 and 252 amps) in my computer rig and I didn't find anything missing. Ditto.

You can buy something like this and install a potentiometer while building it.

I'd rather say vomit inducing. Still its tradition and they aren't all bad. yesterday we had a special day where the nation as a whole eats creme filled buns (a very busy day for my bakery) and today we are supposed to eat salted lamb until we drop.

Brennivin is ok but hakarl is nasty!!! There are also sour sheep balls, sour sheep heads and other nasty stuff.

Sorry for the late reply but I really needed those 12 hours of sleep. The SR-007 isn't for everybody as they don't add too much color of their own. I'm sure the ES1 and 2 sounds good but do they have enough power for the two Stax phones to fully break away. We are talking about the two things that go mixed up in the Rudistor thread on HF, i.e. technical ability and how it sounds. The stock BH works fine for the SR-Omega but needs more power for the SR-007 so it needs a better PSU, bigger CCS and maybe some new output tubes. It sounds great now but there is always something missing. So I need to start planning an electrostatic meet soon, huh? The 4070 is one hell of an headphone and I would certainly rate it on par with the HE90, HE60 (each with own strengths) with only the SR-Omega and SR-007 doing better. It's analytical without ever becoming sterile and the lack of bass bloom makes it very easy to discern the smallest note. At 700gr they sure are heavy but very comfortable although I wished Stax had designed some Lambda style leather pads for them. Her summerhouse is close to ours so you could have a place to rest nearby while stalking...

I'm definitely getting the SR-007A and the other Stax phones I lack but after that I'm mostly done. I'll continue to search for obscure headphones few even knew existed as that is one of the only fun aspects of this hobby left. The one last thing to do is build the best amp I can to drive my collection.

Good to hear. Mine are still pretty much unchanged as I simply like them too much the way they are. Perfect for computer duty.

How is the SR-X Pro??

An upgraded Blue Hawaii would be my first place to start. I've spent some time recently chatting with an ES-1 owner why impression of these phones are so different between the amps and it must be down to the basic design. I've even been toying with the idea to buy a used ES-1 and compare it but I'd rather spend the 3k$ on building a new, souped up BH. I don't want to derail the thread but since I've been shifting my focus in the hobby recently this issue has been bothering me as to where I should go.

It's a good tube for just that, massive amounts of SET power. I've been looking into the deHavilland amp for my upcoming speaker rig and there is a reason why it sounds like that... the parts quality is awful. They are cheap so that was a given but some more life could be squeezed out of the beast. Btw. I have this itch to see what the GM70 can do for the SR-007 through custom transformers to replace the need for output caps. Who needs lights when you have four GM70's in a row... The 1.3 grill will have a large impact on the sound as it reflects part of the backwave. It would be much better to use some damping before the grill but that would result in a sound similar to the Lambda Pro. You really need to hear the SR-007 and SR-Omega out of a real amp. The ES-2 might be expensive but I'm not sure it cuts it...