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 Post subject: Another project started
PostPosted: April 17th, 2017, 4:29 pm 
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Joined: January 15th, 2015, 7:19 am
Posts: 417
Location: Baltimore MD
with more than a dozen unfinished
Quad 57 in the house Serial numbers show they are from 1981


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PostPosted: April 17th, 2017, 4:33 pm 
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Joined: January 15th, 2015, 7:19 am
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Location: Baltimore MD
actually heard them play (sort of)
took one apart to see what the hey
not much there, should be fun, time to get educated


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PostPosted: April 17th, 2017, 6:15 pm 
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Joined: October 21st, 2013, 6:53 pm
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Hey Elliot,

Is this an electrostatic, or a planar magnetic?

Thanks,

Chris


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PostPosted: April 17th, 2017, 6:15 pm 
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Joined: October 21st, 2013, 6:53 pm
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Hey Elliot,

Is this an electrostatic, or a planar magnetic?

Thanks,

Chris


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PostPosted: April 17th, 2017, 8:19 pm 
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Joined: January 15th, 2015, 7:19 am
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Location: Baltimore MD
The Quads are Electrostatic.
My maggy's llla's are planers are sitting in the background
The Quads Stators are charged at 3 to 5k vdc depending who you are reading.
Any way I will be replacing the Diode board in the power supply, the caps in the xover.
Removing the dust covers, felt batting and eventually building a stiffer hardwood frame.
I like the look of the metal grills but these are banged up some and will been some TLC to get presentable


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PostPosted: August 5th, 2017, 12:29 pm 
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Joined: January 15th, 2015, 7:19 am
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Location: Baltimore MD
Almost four months later and project is almost finished
They are playing nicely. This was my first try at there electrostatics.
I made many mistakes along the way and had to go back and order bits and pieces and it just took time
replacing the dust covers on the panels was troublesome mainly from just not having a suitable clean work space.


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PostPosted: August 5th, 2017, 1:05 pm 
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Joined: July 24th, 2015, 4:17 pm
Posts: 504
Location: Parkville, Maryland
Actually for purposes of accuracy -- the tweeter panels and the woofer panels share the same bias supply. However, the center treble panels pick up their required bias of 1,500-volts from nearly the beginning of the bias supply-voltage multiplier chain and the woofer panels get their 6,000-volts bias voltage at the end of the voltage multiplier.

Peter Walker "killed two birds" with one bias supply. Simple yet sweet.

The same goes with the audio transformer. Different winding's for the tweeters and woofers to perform as an inductor-based crossover with a couple of high-voltage rated capacitors to dial it in. Also sweet.

Paul had the stones to do a full disassembly and restore the speakers to like-new performance. With his wood-working skills he can stack two pairs, add ribbon HF tweeters and together with his Janus sub-woofers he will have a DIY Mark Levinson HQD system. For htose that do not know what HQD satands for it is Hartley - Decca - Quad.

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Walt


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PostPosted: August 5th, 2017, 1:43 pm 
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Very, very cool. What is the Hartley part of the equation?

Tom


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PostPosted: August 5th, 2017, 1:53 pm 
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Joined: July 24th, 2015, 4:17 pm
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Location: Parkville, Maryland
Two big-ass 18-inch sub-woofers. The Decca part was the ribbon tweeters without their horns. There are better ribbons out there now with better sound and efficiency.

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Walt


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PostPosted: August 5th, 2017, 4:42 pm 
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Joined: January 15th, 2015, 7:19 am
Posts: 417
Location: Baltimore MD
The dust covers were a pain I had I had four bass panel to redo, two dustcovers each.
the frames were fragile, needed regluing the corners after scraping and sanding I used 3m FastBond 30-NF (same glue I used to rebuild Maggy panels)
to glue the heat shrink film to the frames. The frames are held in place on each side of the bass panel with just plain 2 inch wide packing tape.
the hard part is handling the completed panels without damaging the film while reassembling the speakers.


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