Advent Loudspeakers (smaller advent)

[Doug G.]

The assumption has always been that green cone tweeters were different from orange cone tweeters merely by virtue of the cone color but that's not it.

Originally, Advent used green cones for the smaller Advent so the tweeters could be easily identified in the factory. An orange cone meant a 3" square magnet and a green cone meant a 2.5" square magnet. No danger of installing an incorrect tweeter in any given speaker.

In 1975, when they started installing the same tweeters (3" square magnet) in both the original Advents and the Smaller Advents (with the attending crossover change), they still had green cones left and I believe they used them up. That's why you see original (large) Advents with green tweeters from this period. It's also possible a green tweeter could end up in a Smaller Advent but with 3" square magnet. Hence, the confusion with tweeter color in Smaller Advents.

The point is that the magnet size on the tweeter is THE determinant in deciding on crossover components in Smaller Advents, not the cone color.

I'm sorry but I don't have the schematics. They should be available on the 'net. I know Pete Basel has documented a lot of Advent info.

Doug

 

[firealley]

Thanks Doug

 

[bamark]

Sorry, this may be a dumb question,(I'm new), but which wire in your photo goes to the bass speaker and which comes from the receiver output? Is it red to bass and green from output?

Not a dumb question. I'm a newbie also. I have to look at pictures to see how things work. The green wire goes to the woofer. The yellow wire goes to the tweeter. I know nothing was done to these xovers, because I know who owned them. Why Advent used a green and red wire to the (+) side of the woofer, I don't know. Someone else on this thread with more knowledge of the history of Advents can tell you. I will say they sound really good, and I did not use expensive replacement capacitors.

 

[classic carl]

I could be wrong but I believe there were 2 different green fried egg tweeters. The OLA is an 8 ohm speaker while the Smaller Advent is 4 ohm. Maybe the different crossover designs in the the 2 speakers were able to use the same tweeter. I don't know the answer to that. Anyone?

 

[drumbum]

Hi folks,

Does anyone have a good DIY that gives instructions on rebuilding the crossovers for a small advent speakers?
Any help would be appreciated .

You should pm member WickedSharp before buying poly caps for the smaller advents. He recently went through a couple changes with his pair.

 

[Doug G.]

I believe the voice coils are the same in all Masonite fried egg tweeters and the only difference between them is the magnet size.

Of course, it's difficult to be 100% sure without having many, many tweeters to measure.

Doug

 

[ra.ra]

Of course, it's difficult to be 100% sure without having many, many tweeters to measure.

This is all interesting, and probably should not be all that surprising, but this Advent tweeter identification issue is obviously a bit more complex - - - I originally thought the cone color was consistent with a particular magnet size, but evidently there are outliers that do not follow this simple ID pattern. Thx for the info.

 

[Doug G.]

If there had been no green cones left when Advent decided to use the same tweeter in both the original Advents (large) and Smaller Advents, it would be easy but I'm convinced they had some left over and didn't want to waste them. So there are some green tweeters with large magnets from 1975. I have a pair.

Another interesting thing, you can determine if you have an earlier Smaller Advent or later one just by the cabinet. I don't think you can get a large magnet tweeter in an earlier cabinet since the cutout was only large enough for a small magnet tweeter.

Doug

 

[firealley]

Thanks for the info Doug. It will definitely help me now and in the future.

 

[firealley]

You should pm member WickedSharp before buying poly caps for the smaller advents. He recently went through a couple changes with his pair.

Thanks I'll check with wickedSharp!

 

[classic carl]

I could be wrong but I believe there were 2 different green fried egg tweeters. The OLA is an 8 ohm speaker while the Smaller Advent is 4 ohm. Maybe the different crossover designs in the the 2 speakers were able to use the same tweeter. I don't know the answer to that. Anyone?

If there had been no green cones left when Advent decided to use the same tweeter in both the original Advents (large) and Smaller Advents, it would be easy but I'm convinced they had some left over and didn't want to waste them. So there are some green tweeters with large magnets from 1975. I have a pair.

Another interesting thing, you can determine if you have an earlier Smaller Advent or later one just by the cabinet. I don't think you can get a large magnet tweeter in an earlier cabinet since the cutout was only large enough for a small magnet tweeter.

Doug

Not to hijack this thread but I thought this info might help someone. The crossover photos below are from a pair of Advent/1 which was the successor to the Smaller Advent. It used the same tweeter as the New Large Advent and like the NLA, was 8 ohms. The Smaller Advent was 4 ohms. The cabinets were the same size. Notice that the two xovers shown are slightly different. The one on the right is not original.

The fried egg tweeters shown are from an OLA and an Advent/1. The OLA tweeter read 5.2 and the other one read 3.7 ohms. Does anyone have a resistance reading from a green fried egg?

Doug, do you know if there were 2 green fried eggs or was the resistance difference between the OLA and Smaller Advent determined by the crossover?

 

[ra.ra]

Hmmm.....I'm just looking back at some notes, but here's what I measured for two pairs of Smaller Advents:

s/n 46XXX - green tweets (1972)
tweeters: 1.1 and 1.2 ohms
woofers: both 3.8 ohms

s/n 214XXX - orange tweets (1975)
tweeters: both 2.9 ohms
woofers: 3.6 and 3.7 ohms

 

[classic carl]

Hmmm.....I'm just looking back at some notes, but here's what I measured for two pairs of Smaller Advents:

s/n 46XXX - green tweets (1972)
tweeters: 1.1 and 1.2 ohms
woofers: both 3.8 ohms

s/n 214XXX - orange tweets (1975)
tweeters: both 2.9 ohms
woofers: 3.6 and 3.7 ohms

Interesting. My DMM was a freebie from Harbor Freight, so I don't know how accurate it is. The orange tweet from the OLA above is dated 1973.

 

[Doug G.]

OK, I went back through some over 10 year old threads on Smaller Advents/Advents and found that, apparently, all the Masonite tweeters have a nominal DCR of 4 ohms, regardless of system impedence so the system impedence is determined by all components considered. The later fried egg tweeters, which are all orange and have no Masonite/are flush mounted, used in the New Advents have a higher DCR and Impedence. I believe Advent was trying to get the current draw lower since there were problems of people blowing OLA tweeters in the field. They were also ferro-fluid cooled.

There ARE two different green fried egg tweeters but it's only because Advent used up the green cones in later tweeters with a large magnet, I believe. I think the VC DCR/impedence will be the same in either one. I am waiting to be proven wrong The green fried egg tweeters in my 1975 Advent Loud Speakers (OLA) have large (3" square) magnets but the DCR is the same as all the orange fried eggs in my other OLAs.

Doug

 

[Doug G.]

ra.ra, the 1.1 and 1.2 ohm readings for those tweeters seem awfully low. Anybody else have an early pair (pre 1975) of Smaller Advents they can measure because you just never know.

Doug

 

[ra.ra]

ra.ra, the 1.1 and 1.2 ohm readings for those tweeters seem awfully low.

That was my thinking, too, when I posted the measurement notes I had made. If I get a chance, I will try to confirm these measurements and examine these tweeters again. They are currently sitting idle.

 

[Pete B]

1.1 and 1.2 don't pass a sanity check, did you measure them while connected to the XO?
The NLA tweeter actually has a lower DCR, I think they wanted more tweeter output in
the NLA. LA's are documented on my page including driver DCR:
http://baselaudiolab.com/ADVENT_LA_XO.html

 

[Pete B]

Have you all heard the story about the color of the tweeters? They were originally
bare paper grey and they cared about quality control. There was some variation
in the tweeter response that they determined was due to air leaks in the paper.
Henry's real goal was to design projection TV and he handed them some bulb
dye saying try this to seal the paper - that was the orange colored tweeter.
Are people aware that Henry designed the Large to fund his projection TV
obsession?

 

[Rasputin]

There is a measurable (and possibly sonic) difference between green and red, or more accurately, small and big magnet tweeters. I measured both at close range using a modified Neumann mic'd sound level meter. The green tweeter was about 1-2db lower in output in addition to rolling off sooner. It was 3db down at 14khz while the red tweeter did not roll until about 16khz. This would tend to corroborate the Stereophile review of the Smaller Advent with a green tweeter (presumably had the small magnet) from several years ago where the tweeter peaked then rolled prematurely at 13khz (the reviewer also commented that the high end sounded dull) whereas every other test I've read on the Original Large Advent from magazines at the time such as High Fidelity, Stereo Review, Stereophile, even Consumer Report did not show any such dip in the frequency response of the red tweeter. On the contrary, these reviews unanimously praised the smoothness of the speaker in that range. There is no way for me to know if this is an anomaly. One would think Advent would make sure the two measured and performed identically. Then again, maybe not.

 

[retox]

I am also in the process of recapping a pair of "orange tweeter" smaller advent speakers. The issue I have is I can't find any threads that state having 2 8mfd caps in each speaker. They are old caps and it's does not appear that they have been replaced. The glue, solder joints, and placement look to be original. Should I replace them with the same value Solen PB8 mfd caps and new 3 ohm resistors?