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The Original New Large Advent Crossover.


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#1 Robint

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Posted 02 April 2012 - 12:30 AM

Hi, new member and first post. Recently I found 4 NLA's at a thrift for $5 each. Of course they need to be refoamed! So I pulled the woofers and checked the capacitors before ordering new. To my surprise they were 12uF capacitors and not the 13uF caps in the Audiokarma Advent thread. On further investigation both resistors are 1 Ohm 10% 5W. There was also a difference in the foam stuffing.

The serial # are:-
A3 00104 4 pieces of foam.
A3 00195 5 pieces of foam.
A3 00237 5 pieces of foam.
A3 00244 4 pieces of foam.

So the question do I leave them as is, or do I rebuild with the later crossover settings?

Sorry for the poor quality picture.

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  • NLA 002.JPG
  • NLA 002.JPG


#2 Doug G.

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Posted 02 April 2012 - 01:48 AM

First, if they all work except for the surrounds, you STOLE those speakers. Congratulations!

Of course, it's up to you and I'm sure other will disagree but I would restore each one to the way it originally was manufactured.

It won't make that much difference anyway since Advent undoubtedly used capacitors with a tolerance that resulted in overlap with 12uF caps. even if they were marked 13uF.

And welcome.

Doug

#3 Doug G.

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Posted 02 April 2012 - 02:19 AM

Oh, and another point of interest is that, apparently, Advent made changes during production of the New Advents too which I don't think we've discussed before and I don't think any of us knew or mentioned. Of course, the production changes made in the original Advents are well documented.

Your four are all pretty early New Advents with those serial numbers because the New Advent sequence started with A300000. The A3 is not a model number or anything. The "A" just designates the full size Advent with a walnut cabinet. The "3" is actually just the first number of the serial number.

So, they orignally put 12uF caps. in them and two 1 ohm resistors and later changed to 13uF caps. and one 1 ohm resistor and one 1.5 ohm resistor. Actually pretty minor changes as I bet there are very few listeners who could ever tell the difference in sound between the different configurations.

Doug

#4 Robint

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Posted 02 April 2012 - 02:34 AM

I assumed the A3 was the model number because these are in a much bolder and darker type the the following numbers. The thing that confuses me is the difference in foam batting. Did they listen to each speaker and decide that this one needs extra batting?

Robin

#5 Doug G.

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Posted 02 April 2012 - 11:35 PM

Some of the things Advent did remain a mystery and those are evidently two of the things.

I imagine they made the first two characters bold just to easily be able to tell them from original Advents at a glance, especially with the utility versions which are almost identical at a glance.

Because, officially, at that point in time, the model was still "The Advent Loudspeaker" as seen on the back plate, even though they probably should have put "The New Advent Loudspeaker" there.

The foam batting is a poser because it seems unlikely they would have listened to each speaker to determine how much to put into each one. You never know though.

How are the pieces arranged? Is there just a missing piece behind the woofer? Are the pieces otherwise identical in the different versions or are the pieces larger or different in the 4 piece versions?

Another possibility is somebody got into them earlier and removed a piece of foam in the 4 piece ones.

Doug

#6 Robint

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Posted 03 April 2012 - 02:04 AM

All the pieces are identical in size. Once i pulled the woofers I pulled the foam and placed it on the woofer, It was only later I noticed that 2 of the stacks were shorter. I looked around but found no more foam. Why would anyone remove 1 piece of foam from two of the speakers and leave the others alone? These 4 speakers had to be bought at the same time,

Robin

#7 Mystery

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Posted 19 April 2012 - 07:46 PM

Both of my NLA Utility have 4 pieces of foam.
3 right under the woofer below the crossover and 1 goes almost to the tweeter above the crossover.

#8 Robint

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Posted 25 April 2012 - 03:10 PM

Well I refoamed all 4 NLA's with surrounds from Rick Cobb, very happy with the result. Replaced the 12uF cap in one pair with 2 6uF Axon caps and 1 Ohm 10W precision resistors. The new resistors are much longer than the original, so had to use a short pigtail to reach the switch. The other pair remained original and I have been comparing the the sound from each pair. I have the caps. and resistors ready to do the second set. Will give them a couple of weeks to settle down before making a final descision. As of yet I can find no discernable difference. As to the foam issue, I was wrong, each speaker had 5 pieces of foam. I did not remove 1 piece of foam behind the tweeter. The other piece of foam was folded over in the top of ther speaker.
Found out how to attach pictures!

RobinNLA's 001.JPG NLA's 002.JPG NLA's 003.JPG

#9 Mystery

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Posted 25 April 2012 - 03:30 PM

Link to pictures?
I'm still thinking whether or not to upgrade crossover on mine.
Mine look exactly like these.

Posted Image

#10 Carlspeak

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Posted 25 April 2012 - 03:39 PM

Chances are the important, functional properties of the 13 uF cap have drifted. Most folks do a recap at a minimum during the refoam process while the woofer and foams are out of the cabinet.
Erse has the 13 uF caps. They aren't expensive.
What's holding you back?
IT'S ALL ABOUT THE MUSIC!

Carl
Carl's Custom Loudspeakers

#11 Mystery

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Posted 25 April 2012 - 07:35 PM

Thanks for comment Carl.
I just had these NLA's for less than a month and not sure if I want to keep them.
I'm starting to like their sound so hopefully I'll keep them and definitely re-cap. :)

I like the sound from NLA's as it is and replacing caps may or may not drastically improve sound.
Caps are not that expensive and resistors are even cheaper.
Erse charges $14 for s/h. I think that is too much for few pieces of caps.
Other sites like partsexpress charge less than $4 shipping.
I have Polk Monitors as well that I'm planning on capping and need to order caps/resistors together to avoid multiple shipping fees and get all of them done at once.

#12 BUCKS

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Posted 16 November 2012 - 03:10 AM

Hello, new member here and first post. Recently picked up a pair of NLA'S, found them on Craigs List. They are in the original boxes and packing material and the cabinets are mint. The foam is dry and cracked so I have already ordered new foam from Rick Cobb, should be here tommorrow. On one of the speakers the tweeter only works with the switch in the extended position. I have read elsewhere on this forum that the resisters are probably blown in that situation. So I want to rebuild the crossovers. I have looked on the Erse site and they have the correct caps and resistors except for the voltage rating. The 13uF caps they sell are rated at 250V and the 1 and 1.5 ohm resistors that they recomend are rated at 25 watts. My question is will the higher voltage and wattage ratings make a difference? If I need to stay with the original ratings where can I get them?

Thanks,

Randy

#13 JKent

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Posted 16 November 2012 - 04:57 AM

Welcome Randy
You should always go for a higher voltage rating for caps. It's perfectly fine, even desirable, to replace a 50 volt non-polarized electrolytic with a 100, 250, 600 or higher voltage film cap.
The resistors should be the same wattage as the originals except in cases where the originals were 5 watts--I would bump those up to 10 or 12. 10w seems to be standard. The problem with 25 watt resistors is they are just too big physically.
According to Pete's page http://baselaudiolab...VENT_LA_XO.html you need a 1.5 ohm and 1.0 ohm resistor, both 10w.
These Mundorfs are nice: http://www.madisound...undorf-10-watt/ and you can get your caps from them (Madisound) too. Try their "Surplus" caps. You can get a 10uF for 60 cents and a 2.7uF for 30 cents. A total of 12.7 is close enough, or add the 0.33uF GE cap for another 40 cents.
Parts express also has the parts you need.
Just remember: If you put capacitors in parallel you add the capacitance, so a 10uF + a 2.7uF will give you 12.7uF.
BUT combining resistors is WAY more complicated. My advice: don't do it. You can google the formulas for parallel and series resistors but just buy the correct values.

Kent
J. Kent Hollingsworth




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