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Pete B
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Art Dudley's Article on the Advent Restoration

Nice work by Art Dudley on the Advent restoration this month. It seems that I am probably the world's expert on them. This happened by accident when I restored my parent's old speakers and got a bit carried away when I went to document the Large Advent. There were more variations than I thought and I therefore wanted to know about all the differences:
http://baselaudiolab.com/ADVENT_LA_XO.html

Just a few notes, those are *very* early tweeters that I believe are rare and a bit fragile. The much more common later revision had tinsel lead in wires that were visible, and a mesh metal grille. If the rear input plate is metal then the box is also very early.

The woofers have been replaced with the much later round magnet Jensen version. This version has a paper dust cap as can be seen in the photos. The masonite type is the correct woofer version. A thread covering the different woofers that I've come across:
http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=2931

My older brother pointed out years ago that they did not sound right in the midrange being very bright and forward. We were building our own speakers by this time and I was exploring transmission line bass loading so I was not to worried about it since they were not my speakers.

I tried adding line level baffle step compensation (BSC) when I restored my parents pair and this seemed to cure the boxy (papery) sound in the bass-midbass, and the bright character. I am highly impressed by their sound with BSC. There are a few comments here about it; this fellow likes the LA with BSC better than his Celestion SL6si's (post #97):
http://www.classicspeakerpages.net/IP.Bo...amp;#entry74537

Here is part of my collection:
http://baselaudiolab.com/PLB_SPKR_PICS.html

There is a loaner BSC line level box if Art is interested in trying it.

There is a discussion concerning grille cloth here:
http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=2954

Advent used a very coarse weave (16 ct) that looks a bit more like burlap than anything. Sources are given in that thread but I was unable to find it back when I redid a pair so I used 28ct Irish Linen that looks excellent. I would not go finer than 28ct and the original is probably better.

Advent capacitor replacement:
http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=2790

Buddha
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Re: Art Dudley's Article on the Advent Restoration

Further discussion from restoration-types at Audio Asylum:

Link.

Pete B
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Re: Art Dudley's Article on the Advent Restoration


Quote:
Further discussion from restoration-types at Audio Asylum:

Link.

Quite the fuss over there, I don't see this as any sort of perfectionist restoration, rather just an example of what you can do with a $15 find from a tag sale. The woofers are a drop in replacement and I have confirmed the in system T&S parameters but not the upper range FR of the woofer. The cone looks to be exactly the same, and others claim that it does not require any crossover changes.

Gerald Crum
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Re: Art Dudley's Article on the Advent Restoration

I am a good bit surprised that no one has commented on the crossover network requiring some work. If the speakers are as old as the tweeters, the caps are probably well over the hill and need replacement. Further, if the crossover is as old as the tweeters it's likely to be the first version with the 4 ohm series resistor and the 16 uF bypass cap.

Simply replacing the woofer surrounds (with the wrong ones, it appears) and then making judgements is not really fair to the speakers.

This isn't quite as bad as Peter Brueninger's review of the Smaller Advents which had replacement woofers of some generic sort; but it isn't a representation of what the Advent was like when new.

I see you've appointed yourself as the world's expert on Advents - Gee! I thought I was

I don't think the BSC is necessary if you get the crossover right. I'm using the third version with film caps, but an added 0.5 ohm resistor in series with the 16 uF cap, before the bypass cap, to compensate for the lower ESR of the film caps. In-room measurements at my listening position with a 61 band RTA show no sign of the baffle step.

Lots of good info in your post.

Jerry

Pete B
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Re: Art Dudley's Article on the Advent Restoration

As I said, I don't think this was meant to be any sort of perfectionist restoration.

If you want the worlds expert title you can have it. How many pairs of LA's do you have? I have more than I want to mention and I don't even use them in any main system here.

spkrdtr
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Re: Art Dudley's Article on the Advent Restoration

Pete's BSC circuit worked in my NLA test case.
Check out post #133 here:
http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=2692&st=120

Pete B
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Re: Art Dudley's Article on the Advent Restoration


Quote:
Pete's BSC circuit worked in my NLA test case.
Check out post #133 here:
http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=2692&st=120

Thanks for posting this measurement Carl!

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