Craig Sawyers

I've put a paper that I wrote about this beast here http://www.tech-enterprise.com/tekstuff/LorenzSZ42/Paperupdated.pdf . Also Tony Sale's website has lots of other information about BP's code breaking efforts here WW II Codes and Ciphers . Tony is the guy who spent 14 years rebuilding Colossus starting with 7 black and white photos. Tony is really getting on now - must be in his 80's - but a fascinating bloke. The thing that really made my neck hairs rise up was when I realised the significance of this particular SZ42. Before operation Overlord, false intelligence was placed with the Germans to the effect that the main attack would be to Calais. An intercepted SZ42 message from Kesselring showed that they had fallen for it and withdrawn quite a number of troops to defend Calais. That crucial message went through the SZ42 that I restored. And yes - I've read Cryptonomicon twice. I think the thing that frustrates me about the book is that there is a ton of details about how Captain Crunch should be eaten, and similar heavyweight detail about codes etc etc - which is all absoutely great reading. But the end, when the gold is extracted from the mountain, is all shoved into the last couple of pages. It is almost like Stephenson got bored with the book and finished it off in a rush. To those who get a chance to visit Bletchley, definitely do so. It is incredibly "amateur" in a way - the Bletchley Park Trust has nothing like enough money to properly restore whole chunks of the site, and parts of the original site are now housing estates. In fact it is only during the last ten years that the site was saved from developers, who wanted to buldoze the lot and build houses over the whole site.

It'll be interesting to see who is hosting on the BBC. It used to be a bit of a national treasure called Terry Wogan, who was a lifelong radio DJ and presenter. He took Eurovision with a large dose of salt, and a large bottle of Scotch, getting progressively pissed during the evening. He retired a couple of years ago, and kind of took the fun out of it for me.

Spent the day at Bletchley Park trying to get just about the planet's only Lorenz SZ42 cipher maching working. This is the machine that triggered the invention of the electronic computer (Colossus) to break the codes, and this particular one was Feldmarchal Kesselring's during the Normandy landings. The only other complete example is in the National Crypographic Museum in Maryland. Only around 200 were ever made, and were used exclusively for communication between the field commanders, and between them and Hitler's bunker. Restored it about 8 years ago, but in the meantime the 70 year old mains wiring had got leaky, so was tripping the earth leakage breaker. Sorted that out with temporary rewiring, and then the mains transformer developed a short in one of the windings, and the transformer got very hot very quick. I'd already had it remanufactured since the original had an open winding - so I guess I'm in for a conversation with the transformer suppliers to get another made (after they have diagnosed the reason for the problem). Easy to get one remade, since Lorenz used what became a standard ISO lamination size!

Sounds like a case for sabotage.

I took my 21 year old daughter to see Jarre - I snagged tickets right in the middle of the front row of the 13,000 seat National Indoor Arena in Birmingham UK. Great to be so close to the action, but crap for the light show. Daughter said, after Jarre's typical spectacular entrance "Oooh - he's cute" to which I said "Oooh - he's six years older than me!". He clearly dyes his hair at least, and there is certainly some botox and maybe more going on to hold his face in place and make him look 35 and not 60. But an amazing show, all played on a total of 35 keyboards of various and irreplacable vintage. I'm not sure how Oldfield works in concert, since all of his recordings are just him multitracked. VanGelis would be a good one to see though.

More on the resistor. I've now got what seems to be the latest schematic for the ESL63. There is a printed circle around R14, for which the schematic value is 100k, but the note says that its value should be selected on test for 5.25kV. So the summary seems to be: In early versions there are two VDR's (to compensate for line voltage variation) and two 180k resistors. That was then changed to one VDR, two 220k resistors in series, a 180k and a 56k resistor. It was finally changed to one VDR, two 220k resistors in series, a 180k and a nominal 100k with a note to select this on test to give 5.25kV. So it would appear that they knew that there was a problem with the version with a 56k resistor, and modified it to ensure that the EHT was set to the original design spec of 5.25kV.

In my quest to see as many ancient rock stars as I can before they all die off, the wife and I went to see Rod Stewart last night in Birmingham UK. Absolutely excellent show, especially considering he's 65, and has a 4 year old son. All possible ages were there, from teens to the elderly in wheelchairs. A lady who looked to be in her early '80s and flanked by two middle aged daughers was boogying with the best. Baking hot - it got up to 30C in the UK yesterday. So in the last 18 months, me (plus either wife, daugher or son) have seen Leonard Cohen (73, and fantastic), Bob Dylan (69, and difficult to know what he singing), Jean Michel Jarre (60, superb), Deep Purple (amazing - 34 years since I last saw them!), Eric Clapton (65 and showing it) and Steve Winwood (62 and in good shape), and now Rod Stewart. Regret never seeing Queen, Stones or Jimi Hendrix, but Neil Young has to be a must when he next tours.

The Silurians are quite convincing. Consequence of having a big bucks budget. When they last appeared in the '70s and the budget was about a dollar fifty, they just looked like guys in a cheap suit - a bit like Adam West when he was in the Batman series.

Well done! You might have a bit of work to do to get them back on song, but it is seriously worth it. A properly sorted pair are most definitely not treble shy. Check my posts for the odyssey of fixing mine, which now sound absolutely awesome. I suspect from your description that one or both of your treble panels is burnt out - most are. This not only clobbers the high frequency response, it also slugs the EHT voltage to the bass panels too - so the bass is quiet as well. There are plenty of places that will supply replacement treble panels if that is indeed the problem. You can easily check this - take the rear grille off (screws around the edge and under the plinth). Now lift up the felt that is behind the centre treble panel - you will easily see if it is burnt out (carbon charring, perforated dust cover etc). If you do replace the treble panels, be sure to retrofit the protection clamp board that prevents too much voltage getting to the treble panels and burning them out. The jumper is a voltage setting - select whatever the nominal local mains voltage is (110V, 240V etc). Let us know how you get on.

That is indeed interesting. Issue 1 and Issue 2 EHT boards seem to be identical, with the final Issue being changed. I guess that what Kent has done is replace the 56k resistor with the originally fitted value of 180k. 15% on EHT voltage should change the sensitivity by around 1.2dB. It is odd why Quad did this, because the loudness is a function of the electrode spacing only - over a level defined by that the film hits the stator and burns out (hence the many protection circuits in there). So changing the EHT only changes the sensitivity, not how loud they will play. But Kent is certainly right that a higher voltage may well limit lifetime. These sort of things tend to go as a high power law, like fourth or thereabouts - so increasing the voltage by 1.15 may well reduce the lifetime by close to a factor of two. Is there anyone close to 'jack who is skilled with a hot stick and can do the resistor retrofit? If I wasn't 6000 miles away, I'd voluteer

Way to go! Well done - and remember that if your legs don't hurt you could have run faster, so it looks like it was mission accomplished

It looks like they have the reflex alignment wrong - it should be possible to get the response quite flat (4th order Butterworth or Bessel or any one of a myriad of others). That said, the problem with bass reflex (or ported boxes) is that they store resonant energy in the air within the port - it is an extra mass/spring system - and to my taste they all sound boomy to a greater or lesser extent as compared with a dipole or sealed box. But if you are trying to get extended bass out of a small box and small speaker, and not run into driver excursion limits, they are about the only game in town.

The really neat thing is that this is a trivially simple circuit for measuring resistances in the T-ohm range using a watch to measure the time between flashes . Costs pennies, or built out of the spares box. Not as accurate as a proper meter, but around five or six orders of magnitude cheaper! The problem with PJW retiring was that he handed the reins to his idiot son Ross. Ross has a degree in economics and doesn't have a technical bone in his body. Under his stewardship he piloted Quad into financial ruin. In Kessler's book about Quad, he interviewed Ross Walker, and it is clear that he blamed the engineering team for telling him porkies about the maturity of the new remote handset controlled range - and on that basis, like a fool he launched the product. He missed the point entirely that it was his responsibility to know - and if he had done what all good small company CEO's do and walk around the shop floor on a daily basis he would have known what was going on. It was what Hewlett (of HP) used to call "management by walking around". PJW for sure would have known precisely what was happening on an hourly basis.

The end was absolutely not what I was expecting - buckle up for the rest of the series, and wait with anticipation for the last episode. I never watched Life on Mars, but I must get the DVD of that series and catch up. Just bought the first season of Commander in Chief (Amazon - cheap).

I wonder which ones are the woofers and which the tweeters

Correction to the leakage resistance of a panel in relation to neon flash rate. The important thing is that in the time between flashes, the panel self-discharges. When the difference between the panel voltage and the charging voltage exceeds the difference between the striking and sustaining voltage of the neon, the neon fires and recharges the panel. A typical panel neon has a difference of 30V between strike and sustain. During the droop time, the panel is essentially constant current discharging into the leakage resistance. Since the voltage droop is 30V in 3 seconds for a good panel (and longer for an excellent one), that enables the leakage resistance to be directly calculated. That gives a rather astonishing 3000G-ohms. The 47nF cap in parallel is there to ensure there is enough stored energy stored to actually strike the neon. That implies a CR time constant of 600 seconds. Note that this discharge rate means that the panels hold their charge for a very long time indeed - to get down to 50V takes 48 minutes. Which is why I guess that Quad recommended about an hour after switch off before servicing.

That is interesting. I've been peering at the ESL63 schematic, and can't see where an obvious resistor mod could be carried out. More details please? But what scrutinising the schematic did show is that the neon flasher is permanently installed in the ESL63 HT charging circuit - same values as One Thing suggested, which indicates that is where they got the idea (they also rebuild ESL63 panels). The service manual indicates that anything significantly faster than one flash per second is bad news.

I sure wish I still had the photo of a horn speaker buit into a toilet. The guy's wife called them loo-horns.

Last ever episode of Ashes to Ashes. Mind blowing - you get an "oh shit - *that* is what it is all about" over the last fifteen minutes.

Completed the last part of the ESL57 odyssey. This involved collecting two remanufactured and matched treble panels and a bass panel re-dust-filming kit from One Thing Audio. Ron gave me a one hour practical demo of how to do the dust cover, and how to solder to the rivetted on tags to the stators without melting the stator plastic. One "trick" is to use spray on carpet glue to stick the film to the wooden frame, and trim the edges flush with a soldering iron (quicker and easier than a craft knife). Then on the frames that have the tag board, first shrink the bottom few inches only and apply a strip of their thick edge banding tape as strengthening of the bottom inch or so of the film. Preparing the naked bass panels involves checking them for electrical leakage. The trick is to feed 6kV from the supply via a neon flasher - 10meg series resistor, then a neon in parallel with a 47nF cap. A flash every 3 seconds or more indicates a good panel (I calculate that means a leakage resistance between the film and frame of >10G-ohms). There are various possible leakage paths - either a conductive track has formed from the stator metallisation to one of the many rivets. The rivets all connect to the film, and are at 6kV whereas the stator is at 0V when there is no signal - so tracks can slowly form from points of high potential gradient, like the sharp edges of the rivets. Mine only needed vacuuming and then a wipe over with a pad moistened with iso propyl alcohol to remove surface grot - at which point one flash every 6 seconds or so. After taping on the dust cover frames and heat shrinking the film, all four bass panels gave one flash every 10 seconds or so (so 30G-ohm approx leakage R). After complete speaker assembly minus rear cover, and as a final check, the neon circuit was used again. One flash every 10 seconds on both speakers. The consequence of new treble panels and refurbished bass panels is that they charge up stonkingly quick. I left them for half and hour, and they were at full sensitivity - I could actually have put music through them before that. The reason that people on the web reckon that 24 hours is necessary I suspect is because of bass panel leakage (what One Thing term a "lazy panel"). The Quad manual actually reckons only 30 seconds is necessary, but they advise that 1 minute might be necessary to get full performance - for a new or completely refurbished and checked speaker of course. One interesting thing, that Ron at One Thing warned about with refurbished treble panels, is that they sound a whole lot brighter. Reason is that the sensitivity of treble panels falls as the decades tick by, mainly through leakage - so old ESL57's always sound treble shy if they have old, original and not burnt out treble panels. Anyway, imaging is needle sharp now, and balanced (ie not skewed towards one speaker). All this was a 2-day operation, the majority of which was spent on the bass panels. Craig

Looks to me like a case of more = less

Took my son to see Eric Clapton and Steve Winwood in Birmingham UK. Awesome!

Which one are you up to? Here the most recent was the competing dreams one.

Heh. Prince Charles basically ownes Cornwall - hence one of his titles is Duke of Cornwall. So Princess Diana was the previous Duchess of Cornwall, a title now held by Camilla. And yes - no-one in the UK now has much time for either Charles or Camilla. Nah. The Queen is a tough old bird - she's seen just about everything in her 50-odd years on the throne, so all the hung parliament thing will have washed right over her. While Queen she's seen 12 Prime Ministers come and go, starting with Churchill. Royalty has very little real influence over the Government anyway, although formally she does. The last time a British Monarch directly appointed a prime minister was back in the early 1700's. Surprisingly all this stuff is now on the inevitible Queen website Welcome to the official website of the British Monarchy . What might not be known across the pond is that the family name was originally Saxe-Coburg-Gotha since the current British Monarchy has its roots in Germany - indeed George I (1714-1727) spoke German and had hardly any English. The name was changed from Saxe-Coburg-Gotha to Windsor in 1917 because of anti-German feeling during WWI. Gets even more complex because the Queen's husband Philip was Greek, originally being Prince Philippos of Greece and Denmark, of the House of Schleswig-Holstein-Sonderburg-Gl

QS&D certainly do not look cheap. There are other Quad refurbing places on both sides of the pond that are a whole lot cheaper than that and just as good. Sheldon's Audio Designs in the US, One Thing Audio in the UK and several in Europe. The company in Germany who took over the technology from Quad (including their film stretching jig and oven) when they stopped doing repair parts charge less http://www.quad-musik.de/Quad_classics.pdf . They even supply a completely new build ESL57 pair for Euro 4500. Craig