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Old 24th August 2013, 06:15 PM   #41
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The information from this forum is outstanding!

The 1996 literature from Lucas on their ESL step-up Xfmr says it is their "77-1" manufactured "especially for them by an American company, and of course it is much better than the Triad S-142a many others are using which is now out of production." The primary wires are brown, red (c/t) and orange. The secondaries are yellow (common), green (2 ohm), blue (4), violet (8) and white (16 ohm).The resistance between the orange/brown primaries is 8Kohm, FWIW.
Now that the mystery of the Interface is solved, I will probably take it out of the circuit anyway because my Jazzmans are cut off below 330hz and don't need any bass EQ. And, when I get the funds, I will probably upgrade with new toroid Xfmrs per Charlie and Jer and keep the Lucas Xfmr for the Lucas ESLs I still have.
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Old 24th August 2013, 11:23 PM   #42
Pyramid is offline Pyramid  United States
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Default ESL Bi-Amp

Like everyone else it seems, I decided to go hybrid and bi-amp with my own line level electronic crossover at 300 Hz. Did the filters with Burr Brown OP2604's; 4 pole Bessel response (0% overshoot, constant group delay). There is a slight dip at Fc (<2dB), but no ringing on transients. I needed a little more gain for the tube amp that runs the panels, so the HPF has a 12AU7 SRPP output stage, the LPF uses another BB2604. I put the amp section in a housing I used for a GPS device in a former business and put the power supply in its own extrusion.
Attached Images
File Type: jpg DSCN0643.jpg (237.5 KB, 128 views)
File Type: jpg DSCN0645.jpg (237.5 KB, 106 views)
File Type: jpg DSCN0648.jpg (267.5 KB, 105 views)
Attached Files
File Type: pdf BAMPFLT.pdf (73.7 KB, 16 views)
File Type: pdf Power Supply.pdf (63.1 KB, 7 views)
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Old 24th August 2013, 11:45 PM   #43
Pyramid is offline Pyramid  United States
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Default David Lucas 77-1 Instructions

I found my original copy of the instruction sheet that came with the ESL step up xfmrs from David Lucas.....
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Old 25th August 2013, 02:33 PM   #44
Pyramid is offline Pyramid  United States
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Default ESL Hybrids

Quote:
Originally Posted by CharlieM View Post
I'm a recent convert (4 years ago) to ESL's and I'm not familiar with the Lucas speakers. Can you post a description and photos?
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Charlie-

Just checked out your website; very nicely done. Your instructions are a whole lot better than what came with the David Lucas kit.

To share some info about my build experience:

I had the perf panels custom made by Diamond Perforated Metal Products in Visalia CA, and I believe they have facilities in Chicago, Seattle, Denver, LA and Houston as well. I had them perf the metal sheet (18" x 48") with seven 6" x 16" windows. That left a nice un-perferated frame around the windows and the perimeter of the sheet to attach the 3M VHB tape. They have a minimum order size, so people may have to combine their requirements to get to that minimum, otherwise you end up with a lot of excess metal (I had ~50 sheets made for $1K). They shipped on a skid by truck and were VERY flat. Metal was 18 gauge steel, 0.127" holes on 0.188" centers which yielded 41.38% open area.

I had the panels powder coated and attached the electical connectors AFTERWARD by scaping off a 1" square area and used 2-part silver epoxy to attach the flat flex circuits to the metal work. I created my own flex circuits by sandwiching a strip of 0.003" stainless sheet (available from Small Parts FL) between 2 pcs of kapton tape with each of the pcs cut shorter on the ends to expose the SS strip at each end. This makes a nice flat 3/4" wide flexible conductor that is insulated to >5KV. The third conductor (to the diaphram) was similiarly epoxied to a 16" x 3/4" SS strip and contacted the conductive surface of the diapharm between the 3M tape, similar to your copper ring, but only along the bottom edge. I coated one side of the diaphram with graphite after tensioning, but before attachment to the stator. I found that a lot of mechanical tensioning was needed and as a final step (and to remove all wrinkles) using the heat gun treatment. If I tried to tension them using only heat, I found the panels would "relax" over time and sag, causing arcing.

The bass drivers are Scanspeak 25W/8565 10" woofers mounted in a 6 cuft (17" x 27" x 26") MDF box with 4" x 9.33" vent. The sides and supporting frames for the panels are 3/4" mahogany.
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File Type: png ESL.png (823.0 KB, 94 views)
File Type: png ESL2.png (856.5 KB, 52 views)
File Type: jpg Flex Conductors.jpg (90.7 KB, 54 views)

Last edited by Pyramid; 25th August 2013 at 02:40 PM. Reason: Add pix
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Old 25th August 2013, 02:59 PM   #45
AVWERK is offline AVWERK  United States
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Very nice Pyramid, I like it!

Regards
David
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Old 25th August 2013, 05:09 PM   #46
tyu is offline tyu  United States
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Vary good looking ESL setup....flat the best sounding to me...i have ML also.......thanks for the pic......
Do you find with your ear at the panel....that you lose ANy output as you move up the panels?...........are dose it have good output at the top?.....i find the bias......AN coating to be Vary inportant......Did you use any high V bias wire?
thanks
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Old 25th August 2013, 08:02 PM   #47
Pyramid is offline Pyramid  United States
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Quote:
Originally Posted by tyu View Post
Vary good looking ESL setup....flat the best sounding to me...i have ML also.......thanks for the pic......
Do you find with your ear at the panel....that you lose ANy output as you move up the panels?...........are dose it have good output at the top?.....i find the bias......AN coating to be Vary inportant......Did you use any high V bias wire?
thanks
I agree, flat panels seem to sound better than curved. Between my David Lucas kit and these, I bought a pair of ML Requests; was never happy with them. Not much bass and the curved panels just lacked that breath-taking imaging, especially on female vocals and acoustic instruments.

I don't notice any difference between sound output from bottom to top. I made sure the graphite coating on the diaphram was uniform and fairly heavy; I used a cotton gauze bandage to smear it around until the mylar had an "even" gray sheen to it. Also, you want to vacuum the panel and work area extensively to clean up any graphite dust. Graphite powder is messy and you don't want it getting anywhere that you don't want conduction. A good way to measure the coating is with a couple of copper pennies and an ohm meter. Move the pennies around the panel spaced several inches apart and measure the resistance with the meter by touching the probes to the pennies; should be <100K for under 6" spacing.

The connection from the box to the panels is the flex cable I described; inside the box (from bias supply to flex cables) I used HV anode wire designed for TV CRTs.
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Old 25th August 2013, 09:18 PM   #48
tyu is offline tyu  United States
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As for your an all others.... ML panels are only half on.... So all the panels are rolled down.....thay were saleing panels at the time............i have re-worket the ML panels an ran new bias feeds..get 3-5db more output an bass match much better .......but i buy the R. Sandres Flat panel setup...low dispershion...




Funny other dont talk about graphite coating ?....I know David Lucas did .....We all know about it.... an i have used it mixet with outher coathing.....Vary ezzy to find... at Home dep...or lowes...it in small littel tubes at were Key are cut......where did you get your .graphite .....an do you know if there is diff types??......

Last edited by tyu; 25th August 2013 at 09:24 PM.
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Old 25th August 2013, 11:58 PM   #49
Pyramid is offline Pyramid  United States
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Quote:
Originally Posted by tyu View Post
where did you get your .graphite .....an do you know if there is diff types??......
The graphite I used was the standard hardware store variety. I'm not aware if there are different types....
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Old 26th August 2013, 02:17 AM   #50
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I used Graphite on the my very First panels in 2003, and, I have too tell Ya it was one big PIA!!!

It got everywhere and the only kind of coating I could get that would work had a low resistance.

I had quite a few diaphragms that would work at First and then fade away because the coating would come off and it would get all over the stators causing them to short out as well and the diaphragm would lose its charge.

The graphite I used I got in an art store at 10$ for a big bottle in the mid 80's and I still have it.
I now use it mixed with white glue to make my Graphite charge rings.

Shortly (about a month or two) after that Licron had just came out and I sent away for a sample can and they sent it to me and that is what I have been using ever since.
In fact I still have that very same can and it is still about half full.

jer
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