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Old 20th December 2011, 01:51 PM   #11
expert in tautology
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Would love to see pix of a David Lucas speaker. It MIGHT be the only one in the world!

Seems like he was mostly a rip off, or a well intentioned fool who got in way over his head. No idea who he was/is or where he was located.

waldtraut, there are many threads on here regarding DIY ESLs... many successful builds. I'd suggest taking a leisurely browse through, and maybe you will get motivated to build a new and properly designed set of ESLs for your listening pleasure that actually play at NORMAL volume levels!

Please do post pix of your David Lucas DIY speakers!

_-_-bear

PS. potting material - depends on what it is. If it is black tar, then not hard to melt. Hot glue? melt it. Epoxy - Baaaap! No melt. Silicone Rubber compound, cut and pick ur way in... post images, then it may be possible to see what it is.
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http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]

Last edited by bear; 20th December 2011 at 01:53 PM.
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Old 20th December 2011, 02:00 PM   #12
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Quote:
Originally Posted by bear View Post
No idea who he was/is or where he was located.

Around the corner and up the block from my place. Looks like it sold a bit back.
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Old 20th December 2011, 03:04 PM   #13
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Default David "adman" Lucus

Yeah I was desperate after one of my Acoustat M4's was stolen and saw those ad's. Think I threw three and half bills, got my kit with two numbered "licensed certificates" one for the plans to build a flat panel one for his ML curved secrets exposed. Sorry to say my house burnt down and have no pics of a rare finished product. Trannies looked Sad so I'm glad I didn't spring for the wonder of the world upgrade. Actually the kit was pretty a pretty decent little thing (by the looks of it other than the tranny) don't know if anyone else was promoting a diy product with self adhesive foam spacers and conducting foil tape. The ad's were a hoot especially all the different limited edition "Secrets" of this and that soon to be released. I still have the two build instruction booklets somewhere. Pre www days got to love em. Soooo I'm dipping my feet in the water again, soon haha. Had my wire and licron for a year now, my mylar about a month and ready to-any day now-order my acrylic egg crate. Sidetracked last winter in Az restoring a 1951 Flxible bus and the last month running around snagging all the free/cheap craigslist tube organs in my area. Built a couple amps so it's goning to be stat time for me finally! I had those damn Acoustat's since 79 or 80. Still have the one and bought a servo amp which also needs work before I bring it up.
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Old 21st December 2011, 01:14 PM   #14
Atom66 is offline Atom66  Canada
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Only thing I ever got from him is the Direct Drive all tube ESL amplifier Schematics designed by Alan Kimmell. Uses 8 x 6HV5 and a couple of 12AT7 per channel.
Andrew
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Old 21st December 2011, 05:13 PM   #15
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I would be interested in seeing the schematic if you still have it.
I just found some 6HV5 tubes on ebay for a fair price.

jer
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Old 22nd December 2011, 04:29 AM   #16
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I second that thought. I remember seeing a Alan Kimmel article w/OTL build plans and recognizing the name from the Lucas ad's gave it read. Not sure if it's the same animal. Good chance I'll find it in my files, I'll look
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Old 20th December 2012, 02:27 AM   #17
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Having read about Jazzman's ES project, I have been inspired to revisit building a new set of ESLs based on his plans. Hopefully I will be more satisfied with them than I have been with my Lucas ESLs which I built in 1996. I built 4 2' x 3' panels using the trannies and other electrical components supplied by Lucas. They still work, but aren't loud enough for my tastes (60-70s "rock," and other stuff) and they take up too much space. The picture attached shows two of the panels (one channel) hinged together. With both channels unfurled it is like I have a wall of sound more than 8 feet wide, but I have to sit on the floor 3 feet in front of them to get the full impact of the sound. Each channel is powered by 125 watts (Marchand amps) and bass is mainly provided by a very attenuated VMP subwoofer. In the picture you can see the segments that are about 6" wide and the 1/2 inch square spacer dots in each segment. The dots and segments, and the perimeter of each panel, are made with 1/2" wide x 1/16" foam tape. The Mylar is graphite coated, heat shrinked. The other pic shows the electronics for each panel. The white box is a potted Lucas circuit which provides the bias voltage using power from the amp. Don't know what the voltage is, but Lucas claimed it could be as much as 10KV. The other blue box is another Lucas potted circuit that is an equalizer. Again, don't know how it works but it provides "equalization" per Lucas, helps to provide a constant load to the amp and allows bass to be adjusted, either "high" or "low." The caps are part of the selectable cut-off circuit. And there is the tranny provided by Lucas. I wanted to respond to the interest (such as it is) in the Lucas ESLs, sorry it has taken so long to respond. Anyway, I moving on to better ESLs soon and if anyone has any questions, lemme know and I will try to respond.ESL Electronics.jpg

ESL.jpg
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Old 20th December 2012, 06:01 PM   #18
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Are you running those Lucas panels full range?
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Old 21st December 2012, 03:32 PM   #19
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It is very cool to see a finished David Lucas setup !!!

I you can easily make a resistor divider network to measure the output of the bias supply.

I have my doubts that it is actually 10kv though.
How thick is the stator coating what type is it.

I have found that you need at least 8 mil of thickness in order to insulate 10Kv with common spray clear acyrlic enamel and red primer.
I have had 10 mil or so be able to sustain 13.6 Kv without any issues.

A Segmented Stator Desktop ESL


If you got an actual reading of the voltage then you can find out pretty close as to were they should be performing and providing you know the step up transformers ratio as well.
If you do know the transformation ratio that info would help a lot if you posted it.

I have always wanted to try building some out of lincan.

Have you tried setting them up so that the 6" segments are vertical?
This would help to widen the horizontal dispersion of the higher frequency's a bit.

You should be able to be getting some decent bass out of that much surface area.

If you were to stack them and add a smaller tweeter panel of say about 3" or 2" wide segments might make a very nice addition to them such as Charlie's panels.

I did some simulations showing "Panel width vs horizontal dispersion" staring at about 9cm or 3.5" and smaller and it can be found here,

A Segmented Stator Desktop ESL

I will take your dimensions and produce some simulation charts for you and see if you are getting the same results in the real world.
The simulation seem to be fairly close to the real thing as far as my experience in testing my panels, although it is not exact but it is really close.

Greetings !!!

jer

P.S. The First thing I would do is to build a bias supply that has a constant voltage output.
As the voltage output of the Lucas supply may be varying quite a bit with the signal and if it drops by half it will reduce the panels output by 6 db for each halving of the bias voltage.

Last edited by geraldfryjr; 21st December 2012 at 03:52 PM.
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Old 22nd December 2012, 03:22 PM   #20
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The panels were marketed by Lucas as full-range.But, with his "interface" added in the circuit, there may be some bass cut-off. There is a switch that allows choosing "low" or "high" bass, and my panels are set on "high." Don't know what the cut-offs or slopes are: Lucas never revealed that info. I have to admit I am reluctant to play them really loud because I don't want to burn up them up, so I am always riding the volume.Maybe I should get over that?
I have a high-voltage probe and will take a reading as I am curious about variable bias being a problem.
The Lincane (gold-anodized aluminum) was sprayed with one coat of Rustoleum (hey, I'm still learning...) A thicker coating might be a good idea, but I don't have the capability to use automotive sprays or powder coats. Will have to investigate what I can do about that. Also, I think the perf pattern is too small. I remember reading somewhere that Lincane is 40% (ratio of holes to metal) and that isn't good from what I've read in this forum. I will definitely switch to other perf panels such as those used by Jazzman.
I expected a narrow sweetspot with these ESLs and tried to compensate by building four panels, which helped. Haven't tried rotating the panels vertically...might give that a shot.
Merry Christmas everyone!
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