Craig Sawyers

Happy birthday!

Oh - OK. Geddit. I was thinking about how you could possibly know that I know Paul Messenger and Martin Colloms, or that I was CTO of Wharfedale in the early 90's. I clearly overthought your comment

Huh?

And another belated Happy Birthday! Hope you had a great one.

The solder tab on the body connects through to the cable connector shell. Unless the body of the connector is connected to chassis that gains you nothing. You need to connect pin 1 to chassis as directly as possible. Reducing the loop area is the aim of the game. To do individual grounds at each XLR you have to clean the paint or anodizing off around the fixing screws so the solder tabs at that point are shorted to chassis metal. I do that with a Dremel before I start installing hardware, so it is easy from there. It also ensures that the shell of the XLR (and hence the shell of the cable connector) is tightly grounded too.

Is that a Moog modular?

It is just that it can give rise to difficult to understand problems. Like a phone doing a cell search on maximum power, and suddenly zzt zzt zzt. The best papers I'f found on this are the Rane Notes http://www.rane.com/note151.html and http://www.rane.com/note110.html and http://www.rane.com/note166.html The nub of it is: connect each pin 1 to chassis ground as directly as possible in heavy gauge single strand wire - the goal being zero length. Even a very short direct connection inside the box is not ideal. Many professional amplifiers use a two terminal tagboard on the rear panel for + and - signal, and a screw terminal to the case. So pin 1 is grounded outside the case and shield current never penetrates the case. Pain in the ass for domestic gear where you want to disconnect it easily, but OK for permanently installed studio gear.

Who's at the wheel - Elon Musk

Looks really good! Minor point on the XLR wiring. You've got pins 1 chained together and then via a wire to chassis. And yes - pin 1 absolutely has to go to chassis, but by the shortest possible route - a separate thick wire from each pin 1 to a ground solder tag at the nearest XLR screw. With the arrangement you have, any RF intercepted by the balanced cable screens goes into a tuned radiative loop (from the dimensions, several hundred MHz) and spray it inside the chassis. And conversely any radiative interference from those class D power amps gets coupled onto the XLR cable screens.

Jeeze what a dreadful story. What an unholy mess up and such a sad and distressing end. RIP Jake.

Yup. My amps have Neutrik 32A Powercons on the back, then 32A cable to 30A NEMA connectors on a distribution block. Got to keep that mains impedance low

Did Jacobson die from liver damage? Did he die from alcohol induced dementia? No. He continued working as a freelance journalist and writer after an illustrious and prize winning career in war journalism, pretty much until he died age 79 - from meningitis. But wow - did he live a classic Fleet Street life!

Absolutely - I have a pair of LX521, which I am about to upgrade to LX521.4 . His speaker designs are absolutely awesome. They simply disappear acoustically. The LX-mini is much more forgiving of room layout, since it is a monopole and not a dipole. Someone I know has the LX-mini, and came across and we did a shoot out between them and the LX521. The only significant difference was the relative lack of bass on the -mini, which is overcome when paired with the subs. They also sounded more "forward" as compared with the LX521. But still pulled off the disappearing trick. And they are a whole lot cheaper to build than the LX521 by a very long margin. Nelson Pass has done a discrete FET analog crossover for the -mini (see SL's site), circuit boards for this are apparently going to be made available on diyAudio. SL is apparently very happy to let people come over and listen - and since you are local, why not get in touch with him? LX521's in my listening room

No - that is not what I'm saying. There is simply more than one way of skinning the class D cat, and is more to do what you have patented. And Diavelet's website is an absolute nightmare - it has more to do with production values than finding products. And they are seriously plugging their rather strange spherical speaker. They have invested 50 million somethings (US Dollars, UKP, Euro - they are all pretty similar nowadays) of investor's money in the design, so not surprising.

Well the Diavelet is something more akin to the Quad current dumping technology. They have a very have quality class A amplifier that does the first Watt or so, an then a class D "dumper" that takes over duty for high current drive. The basic company funding that generated their first product came from the French government. I don't have one by the way. The Hypex N-core class D amps have absolutely astonishing performance, and show what is possible nowadays with pure class D. ATI does a stereo power amp that uses N-core modules and a linear power supply (which apparently makes the amps sound better than the Hypex switched mode supply) for $1,895.00 weighing in at 39lbs. You get a whole lot of amp from ATI. http://www.ati-amp.com/AT52XNC.php Even Bel Canto have gone across to using N-core! For a company that has used their own class D technology for 15 years. Or you can buy a monoblock kit directly from Hypex for 650 Euro. Times 2 for stereo, so 1300 Euro (=$1600). None of these options fits the $1000 budget of lkong though.

I used to drive my ESL 57's with an Audio Research D125 hybrid. Solid state front end, and a bunch of 6550 tubes. Sounded great. But an old friend (now alas dead) used a Diavelet to drive his much more recent Quad ESL's. But that will be outside your budget.

The main problem back in the day was that phono stages were generally crap. Indifferent RIAA accuracy, poor overload margin, and high distortion. I have a circuit of a '70's period ortofon MC phono stage somewhere that had an array of parallel 680uF 3V tantalum bead capacitors between the cartridge and the (100 ohm) load. Ugh. Ugh, ugh uuughhh! And it was not cheap. An even modest quality phono stage now runs rings round that sort of nonsense.

The real cantilever tour de force was the V15-V stylus, which was a 0.5 mil thick beryllium tube 20 mil in diameter. They made that out of beryllium shim stock cut to tiny size, and rolled it around a rod in a miniscule jig. Put it in an annealing oven to stop it just springing open and take a set, and then adhesively bonded the overlap and took the rod out. It calculates out as over 4 times stiffer than a current generation boron cantilever in megabuck moving coil cartridges. US patent 4,473,897 from 1984 describes the beryllium cantilever manufacturing process. Then Shure lost faith in vinyl when CD came in, and lost all the beryllium tube know-how and junked the kit. So all they can do now is bog standard aluminium cantilevers.

Although my main rig is a Garrard 401/SME IV/Zu DL103, I have just set up a classic system, Thorens TD150, SME3009 improved, fixed headshell, and a (the horror, the horror) Shure V15-IV with a Jico replacement stylus. That ends up going through a Blue Hawaii and SR007. And you know the strange thing - 40-odd years since that deck/arm/cartridge were current products - and it sounds bloody superb. The V15-IV with Jico standard hyperelliptical stylus is a true bargain in moving magnet land, and tracks absolutely anything at a measly 1g force. Having said that, the 401 is late 60's as is the DL103. And the SME IV was introduced thirty years ago. So that is a pretty vintage system itself!

I have a permanently grumpy expression too. Wish someone would pay me that much to put my big old face on a product.

Oh wow - I have read so many of her books. RIP Ursula

Re-reading (for the first time in a loooong time) Asimov's Foundation trilogy. Three very slim books from the early 50's that left a lasting impact on sci fi.

Flythough of the Orion Nebula from JPL/NASA. Simulated of course, but pretty impressive.

I mooted the idea of traps in the room that houses my main system with my better half. Her response was definitive. There are some battles you know you aren't going to win

I didn't interrogate eBay, but I caught sight of $6k per tube for NOS as I was googling trying to find out how much they cost in the 50's. I failed miserably to find that out. But they were originally designed for telephone system amplifiers, so they must have been pretty cheap.