Craig Sawyers
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Posts posted by Craig Sawyers
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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.
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As I said earlier in this thread, Kent swapped out a resistor when he repaired my speaker that he says will help the speaker last longer but will also lower the volume.
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.
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I sure wish I still had the photo of a horn speaker buit into a toilet. The guy's wife called them loo-horns.
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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.
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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
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Looks to me like a case of more = less
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Took my son to see Eric Clapton and Steve Winwood in Birmingham UK. Awesome!
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Doctor Who. i really find myself looking forward to each new episode, this series.
Which one are you up to? Here the most recent was the competing dreams one.
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On our night it was HRH the Duchess of Cornwall. As Americans we were oblivious to the fact that HRH the Duchess of Cornwall meant the infamous Camilla (you know, that Camilla) until our nanny/sitter clued us in afterwards. The audience's warmth and adulation could be described as "subdued."
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.
Fair enough; I suppose that whole hung Parliament thing has put her through the wringer.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
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I have been going back and forth about whether or not to get these Quad ESL 63 For Sale | AudiogoN
I have no idea how only replacing 6 of the 8 panels will affect the sound, and the good side of the brain says it's not worth it in case anything goes wrong I wouldn't be able to service them myself...
The evil side says do it :/
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
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Found an odd growth on my arm awhile back, went to a derm and was told that it very well could be melanoma. Got a good bit of my skin removed around the are and biopsied. That was pretty damn scary as this just happened on Sunday. Didn't want to post until I got my results. Just got a call from the doc and everything's all good! Just sucks I'm out of commission for any physical activities. I just started training for the NYC biathlon too. I'm hoping to be able to run again in another week, lift by the end of the month.
So I went out and had an awesome lunch with some friends to celebrate.
Goddam, Laxx - that must have been scary. Great to know that all is OK, and good luck with the training!
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It has already been installed in my balancing act by Craig and has been doing an exceptionally fine job. I can probably forward you the email from the US distributor if you want.
That would be a help - but no great hurry - we're off on a week vacation, so I'm taking a computer break. Going cold turkey
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I can't believe it took me so long to see the joke
But having at last got it, I remember an incident years ago, when our IT guy Mark went out to Japan to set up the server in the office there. He used to send an e-mail diary. So he's in the Taxi with Guisan, our guy out there, and trying to make small talk.
Mark "Guisan - is there much crime in Japan?"
pause
Guisan "Yes - much crime in Japan. Only in Summer"
Mark "Why only in Summer?"
long pause
Guisan "Because in Winter, much to swippery to crime"
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Hmm, I guess my RF15/2/20K/A was actually a unicorn.
If you have such a unicorn, send me a pic and I'll send it to Collard. See what he says....
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So, Craig, that probably means you were around for the original "Survivors", or the "you can see the walls move" low budget sets of Blake's 7?
Yup. Was gutted when they killed off Blake and dumped the series. But I don't think I'd watch a re-run - times move on. Now if someone did a re-MAKE...without flapping sets...
The big enigma was how the original series of the Prisoner was supposed to end - another 60's classic. ITV pulled the plug, and McGoohan wrapped up the series in a very cryptic way. He always refused to spill the beans of how the story was supposed to end, and took that secret to his grave. Leaving us all to guess. Probably precisely what he intended.
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Spent a strangely wonderful evening with a group of people who spoke no English except for one other person. Since I speak no Russian, the first fifteen minutes or so was awkward, but after that, it was freeing and very comfortable to just sit and enjoy good people and good food without having to say a word or try at anything.
<grin> Reminds me of that episode of Frasier when Niles was trying to communcate to a German sword instructor via someone who was translating from Spanish to German, with no common language. 21st episode, 2nd season (I'm told...). Ended up in a farcical sword fight. Rarely laughed so much. Your evening I take it did not end so eventfully
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it's widely available in HD on the usual bitorrent networks. the new season has been really good. Smith has completely gotten rid of any misgivings i had, and the writing... *ah* well, any writing would be better than the last season.
Yeah - Matt Smith has really developed a Who personality all of his own - hats off. But (pass the walking frame) I date back to the original William Hartnell series, when I hid behind the sofa aged 7 to be secure from the Daleks. It went through a dark period in the 70's when they had no money and the whole effect was completely amateur - but since it was revived in 2008 it has been PDG.
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FWIR, IIRC YMMV AAAY WWJD FTMFL FML LOL PEN15, FWIW.
The best I know is BOHICA - Bend Over, Here It Comes Again
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Thinking about enjoyable, and often pretty hairy, twaddle - do you guys across the pond get Dr Who? If so hang onto your seats - the new Dr reincarnation is superb. Latest series running now in the UK. And they keep upping the budget, so the quality is near pretty close to cinematic.
If you want to watch latest series coming out of the UK on the BBC - check BBC iPlayer - TV Channels . Everything is there from all BBC channels for the previous 7 days at least.
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You are correct, I've downloaded a few seasons and it's called Spooks. It may be my favorite show at the moment. When you say "original series" are you saying there was another series by the same name or are you talking older seasons v. the new seasons?
Older seasons vs new seasons. Reks is right of course - it is total twaddle, but fun twaddle. The ex-head of MI-5, Stella Rimington (1992-96), was on the radio recently as was asked about Spooks. Utter rubbish, she said, because any real operation runs over months and years, so the idea that everything happens at breakneck pace over a day or two is very far from reality - but she still watched it herself.
In spite of all that it is still a must watch, even if all the recent plots revolve around terrorism and Al Quaida, rather than regular bad guy/drug running/etc plots.
Oddly enough, one of the lead guys in seasons 1-3 was played by Matthew MacFadyen. The day before the London Marathon my wife and I went to see Noel Coward's play (a farce) Private Lives, with --- Matthew MacFadyen and Kim Cattrall. Absolutely hilarious. Cattrall kept a perfect plummy English accent 99% of the time, with only the odd word slipping into American.
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Speaking of UK tv shows, I am hooked on MI-5. I think I am on season 6 at the moment.
Nearly fooled me - MI-5 is the US name for the series. In the UK it is called Spooks - and yes, it is a must-watch. It isn't quite as tough as the original series, particularly when one operative had her head pushed into a deep fat frier.
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Has anyone seen the prequel to Ashes to Ashes? Is it any good?
We're well through season 3 in the UK - which is going to be the the last one. I've dipped in and out over the last two seasons, but this one is a real belter and I'm well and truly hooked.
The other one I'm hooked on is the remake of The Prisoner, with Ian McKellern as No. 2
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They won't do any higher than 15k, I spoke with the US distributor about this last year when researching stuff for the T2 project.
Well, I got a response from the P&G factory - the guy I've been dealing with is called Steve Collard. He checked their manufacturing system, and they have no record of ever having made any 20k or 50k audio taper RF15's. The practical limit of 10k is down to their manufacturing process.
So no different alas to the response you guys have got via the US distributor.
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All this talk of work benches, I wish I'd taken a picture of mine before I started loading up the workshop. I might still be able to before I move the rest in tomorrow. There's not quite enough room for me to get it all in frame. ...kinda wish I'd sprung for that EF-S 10-22mm superwide zoom for APS-C cropped sensors.
If you want to have a look at mine (the workbench, that is
), there are links to pics on the woodworking types: old lumber thread
Speaker Porn
in Speakers
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I wonder which ones are the woofers and which the tweeters