spritzer

That's very interesting!! Did he have any specs on it?

Yup, one works and the other is faulty.

Happy birthday!

They suffer massive channel imbalance which is most likely tied to some structural issues. It might be very hard to repair but I'll just have to wait and see.

There will be a full report on them and any/all repair attempts of the old drivers. The seller told me how they failed so it might be tough to bring them back...

Ok, I admit it, I lied!!! I just bought them! Not a bad price though for some spare parts for my other set.

Excuses, excuses...

...and why isn't there an amp on the way to you now?? ... There are some speakers which would work with the amp due to their high impedance and efficiency but they are rare though compatible drive units could be found with relative ease.

Til hamingju me

Those pics would be beyond great to have.

The Nova has the newer arc assembly (same as the new phones), the current TOTL cable and better earpad material then the Signature but I find the sound to be good on the Nova but they are just boring and lifeless compared to the older phones. All of the T1 amps use the same PCB but the T1 is RCA only while the T1S and T1W are multiple input and one has XLR sockets. The T1W also has variable bias on one output and a passive preamp function. I prefer the sound of the original T1 by a hair but they are all good amps that can be made better with a few simple mods. The ED-1 is a hot item for some strange reason so they can go for 200$ and up to 700$ depending on the market so nailing down one amount is tough.

Those that know far more then I about Quad's say that they will go very load with the right amps and if the speakers are in perfect condition. I've heard one restored set driven by some old ARC tube amps and they went very loud indeed though we didn't want to push them into protection mode. As the speakers age, the crap glue used by Quad comes apart so all tolerances go out of the window and amp has to work much harder to get the same dB level. The speakers are also often used with very badly matched amps which may have a lot of power on paper but since the RMS figures are worthless when it comes to driving ESL's lower can be much better.

The dynamic speakers are just that, dynamic so much easier to make properly then the ESL63 which no industrial engineer did ever touch. PJW was one of the best audio engineers of all time but coming up with an efficient way of building said designs wasn't his forte. The Quads will go well above 100dB in the right system so the loudness crap is just like the "common knowledge" that electrostatic headphones have no bass. Some of these speakers have been in use for 30-40 years so it's no wonder they are starting to show their age.

The He90 is just badly designed and so is the SR-Ω for that matter but the SR-007 is much, much stronger. The drivers are bolted to a plastic subassembly which is then mounted to the aluminum frame. The only real flaw with the Mk1 design is the ineffective strain relief on the cable which can cause the cable to break but it's easy enough to replace (100$ for a new cable if I'm not mistaken) and if you have have a SR-007BL then the new Mk2 cable should fit where this isn't a problem. Even though I baby all of my gear, my old SR-007 did fall to the floor once ,when I turned my head to fast and the headphones stayed in place, but there wasn't a mark on them and they still sound excellent. The PCB stators are indeed what makes them so good yet strong along with the attention to detail i.e. how to get rid of all the resonances inside the drivers. Both the He90 and the SR-Ω get "confused" at high volume as the drivers can't get rid of all the energy (a major issue with all planar design) while with the SR-007 the energy is transferred out of the drivers, through the housing and into the head. This also makes the stators very inert and stable so they can sustain shocks and bumps much better then other designs.

I would start off with anything made before 1980...

I would never buy a stock Quad as the build quality has only deteriorated over the years and especially with the new Chinese plant. Get the refurbished and rebuilt by somebody who knows what they are doing so that they will sound like they should have in the first place. There are always risks when buying used headphones but if you stay off ebay it's mostly all good. That being said electrostatics are often easy to fix if you know what you are doing and have steady hands... The SR-007 A/mk2 is good step down from the old model. Just get a rebuilt one from the likes of Electrostatic solutions or Quads Unlimited, that's what I'm going to do. Quad's were always badly built and the only testing they did was to line up two speakers at a fixed position, play a squarewave through them and if they canceled each other out then it was a matched pair. They might even still do this today...

Somewhat?? I do like his DAC though so call me fan as well.

To match the SR-007 on a BH you need some serious kit but a basic Quad can do amazing things. I've heard the new model briefly and it sounded pretty much the same as I remembered the 989 sounding. It's the same speaker and the brace doesn't really work as the elements are "floating" inside the speaker so just buy a 989. I've been under a gag order for quite some time now so it's good to be able to talk about the Koss...

The M-L's are all meh at best but the CLS did show some signs of greatness and at 2k$ or less used they are a good buy but the Quads are better. The CLX is way too expensive and the Apogees should be very good but small scale of manufacturing really bumps up the price along with the magnets.

Sure thing. I have at least 5 or 6 quads of UK milspec tubes here though I've never used them. They, amongst others, are for the BH I'm building.

I can supply the tubes as I went a little crazy when buying 3D21A's...

It's really not that bad or rather it shouldn't be. I'll see if I can find some cheap headphones to mod if you'd like to try it out.

True... I'll break out the tools and start work on it.

It's all built into a small PCB which as all the connectors as well so there is nothing protruding above the drivers.