Hi Gang,
The lineage goes like this Langevin, Sphere, Quad Eight & Langevin. All 4 were owned by the same parent company. Many of each's designs use the other's components. So basically they are very similar console design and the exact same in some cases. Later John was given a budget to design two different pre's for the Langevins.
The real jems are the older Q8's, Electrodynes & Sphere's (certain early Langevins also). These have John Halls propriety op-amp design in them. He sealed them in epoxy so they couldn't be back engineered and never did a schematic for them. Late one Sunday evening the sales guy who was Quad Eight (I wont give his name out) and the manager for Electrodyne copied all of Electrodynes schematics. Quad Eight the manufaturer was born. Edyne sued and won. At this that time the AM4 op-amp was born. It was Quads attempt to copy John Halls op-amp and he says they missed! But owning both designs they are very very close and I use both.
As Scott mentioned earlier we did a shoot out between all these modules and in the end it prompted my to sell my Neve BCM10 full of 1073's, that's how strong I felt about the Edynes & Quads! I'd say the sound sits right in between the Neve's and the API's and for the money they sit way above those two.
Check out the article that will be in Tape-Op, probably wont be out for a couple issues yet but it gives a lot of insight into the industry at that time.
Most people have all the stories screwed up. Deane Jensen inhertied (if you will) his most famous op-amp design, but that's another story and one I will probably never be able to tell.
BTW Paul, there's a mastering version of those Sphere graphic EQ's out there and I'm viciously trying to hunt then down. I own 8 of the mic-pre/graphic 712's now and am buying as many as I can find. My Electrodyne console is a 15x4 and is full loaded now! Also if anyone has any Quad CLS 22 compressors they want to sell. I'll take 'em for our Pacifica !!!
Larry DeVivo
www.silvertonemastering.com/stone