Guest philM400 Posted November 8, 2009 Report Share Posted November 8, 2009 I've started refurbishing a pair of AR4x speakers that my father bought new along with a Fischer 500c. I thought this was in 1966 but the serial #'s on the back don't match this date. Maybe he bought the Fischer in 66 and the speakers at a later date, though that doesn't really make much sense to me. The #'s are FX44345 and FX44459. Can anyone help me place the date of these? The odd thing I've found on pulling the woofers is the wax capacitor has three wires coming out of it, a black green and blue. There were no values written anywhere. With an LC meter I've found the values to be 27.6uf between the black and blue and 24.3uf between the green and blue. Does anyone have a schematic for this configuration? The coil has 265 written on it. I'll attach a few photos of the parts. Thanks for any help! Phil Link to comment Share on other sites More sharing options...
Guest philM400 Posted November 8, 2009 Report Share Posted November 8, 2009 Here's a link to the photos that I've posted to photobucket. It may be easier to view them at full size there.AR4x with three wire wax capacitor photos Link to comment Share on other sites More sharing options...
RoyC Posted November 8, 2009 Report Share Posted November 8, 2009 Thanks for any help! PhilPhil,You certainly have interesting specimens. Your serial numbers should place them in the mid 60's.The typical AR-4x is usually equipped with a 20uf series tweeter cap and 200 or 225 turn (AR#4 or AR#5) woofer inductor. Your woofers are the earlier style, also used in the AR-4. The blue capacitor wire is typically the input wire...Where do the green and black wires terminate? Could it be that your speakers each contain a dual 20uf cap, only one side of which was used? What do the tweeters look like?The "265" on the inductor probably refers to the number of turns, but I have never seen a 4x with that coil. I'm wondering if they represent some kind of transition from the AR-4.Roy Link to comment Share on other sites More sharing options...
Guest philM400 Posted November 9, 2009 Report Share Posted November 9, 2009 Roy the green capacitor wire goes to the rheostat terminal marked 2 this is also connected to the yellow wire of the tweeter. The black capacitor wire goes to one end of the coil and also to the blue lead of the woofer. The tweeters look identical to all photos I've seen from the AR4x. The blue capacitor wire is going to an input terminal and the red side of the woofer. I'll take some photos of the tweeters and post them later. Link to comment Share on other sites More sharing options...
Guest philM400 Posted November 9, 2009 Report Share Posted November 9, 2009 After much searching for this peculiar AR4x setup I've only come across this one other thread. I'll attach his photo of the crossover wiring. I wish I had taken some photos of mine before I removed the rheostats for cleaning. three wire capacitor thread Link to comment Share on other sites More sharing options...
Guest philM400 Posted November 9, 2009 Report Share Posted November 9, 2009 I just photographed the tweeters and they are stamped with dates; one May 4th, 1969, the other May 5th, 1969 The speaker cone felt was coming away from the metal so I've glued it down with speaker glue. Link to comment Share on other sites More sharing options...
RoyC Posted November 9, 2009 Report Share Posted November 9, 2009 After much searching for this peculiar AR4x setup I've only come across this one other thread. I'll attach his photo of the crossover wiring. I wish I had taken some photos of mine before I removed the rheostats for cleaning. three wire capacitor threadThanks for the link...That one got past me.I see no reason to believe you have anything other than an early version of the 4x crossover. It is even possible the old style woofer necessitated a different crossover. It is slightly more sophisticated than that of the typical 4x, having the extra cap in parallel with the woofer. If you intend to replace the caps, I would use 2 new 20uf caps in each cabinet. It is likely the old 2-in-1 caps were 20uf on each side, and have drifted higher (as very old electrolytics often do). It would be fun to acquire a pair of the more common version and compare them. Roy Link to comment Share on other sites More sharing options...
RoyC Posted November 9, 2009 Report Share Posted November 9, 2009 I just photographed the tweeters and they are stamped with dates; one May 4th, 1969, the other May 5th, 1969 The speaker cone felt was coming away from the metal so I've glued it down with speaker glue.....thought your speakers were somewhat older than the dates on the tweeters indicate. Whatever, it is prudent to apply glue around the entire perimeter of the tweeter cones, as they are notorious for separating from the flange.Roy Link to comment Share on other sites More sharing options...
RoyC Posted November 9, 2009 Report Share Posted November 9, 2009 Don't forget to dismantle, and thoroughly clean the pots!Roy Link to comment Share on other sites More sharing options...
Zilch Posted November 9, 2009 Report Share Posted November 9, 2009 Yeah, they don't use "Search" over there, either.Also easily identified by the green tweeter wire being factory attached to the pot wiper, and formerly considered "user modified" here at CSP, (there are two examples of it in this forum, as I recall,) I documented the variant two years ago on AK:http://www.audiokarma.org/forums/showthrea...3113&page=2Further in the thread, the cross-hatch woofers in this pair were found to have different impedance and response characteristics from the more common AR4x -- they play higher and do not have as extended bass. I concluded that the 2nd order lowpass was required because they did not provide natural rolloff in the desired crossover region.AR designs of this era were more about shaping the response of the drivers themselves to provide the desired acoustic response; the filters were more commonly merely "touchup...." Link to comment Share on other sites More sharing options...
RoyC Posted November 9, 2009 Report Share Posted November 9, 2009 the cross-hatch woofers in this pair were found to have different impedance and response characteristics from the more common AR4x -- they play higher and do not have as extended bass. I concluded that the 2nd order lowpass was required because they did not have a natural rolloff in the desired crossover region.AR designs of this era were more about shaping the response of the drivers themselves to provide the desired acoustic response; the filters were merely "touchup...."Agreed...And a good reason to stay with the original crossover and associated component values. Thanks for the link, Zilch.Roy Link to comment Share on other sites More sharing options...
Guest philM400 Posted November 9, 2009 Report Share Posted November 9, 2009 Agreed...And a good reason to stay with the original crossover and associated component values. Thanks for the link, Zilch.RoyThank you Zilch for the AudioKarma link. I just finished reading it all. Truly amazing work! As Roy says I'll probably stay with the original crossover, maybe replace the old caps. These speakers have some sentimental value so I'd like to restore them as close to original as I can. The pots were pretty corroded but cleaned up ok and I've got them back together coated with some Permatex Dielectric Tune-Up Grease. Any other help or ideas are welcome. I'll post the results and some photos when I'm done. Link to comment Share on other sites More sharing options...
Zilch Posted November 9, 2009 Report Share Posted November 9, 2009 I just finished reading it all.I've acquired about a half-dozen more since then, so there'll be more kerfutzing in the future. [That's a dangerously subversive thread.... ] Link to comment Share on other sites More sharing options...
RoyC Posted November 10, 2009 Report Share Posted November 10, 2009 I just checked with CSP member, John O'Hanlon (Johnieo), who I assisted with the collection of data on 50+ AR-4x cabinets a couple of years ago.The serial numbers ranged from 55,xxx to 402,xxx, and all had the single 20uf cap crossover. The woofer inductors were the .88mh (200 1/2 turn) AR #4 coil until somewhere between 174,xxx and 212,xxx, where it appears they were changed to the 1.20mh (225 1/2 turn) #5 AR coil. I have sent John the data on the earlier 4x,xxx specimens described here and in the AK forum. Zilch, any data you can share as you "kerfutz" with the ones you have would be appreciated. Thanks.Roy Link to comment Share on other sites More sharing options...
RoyC Posted November 10, 2009 Report Share Posted November 10, 2009 I just photographed the tweeters and they are stamped with dates; one May 4th, 1969, the other May 5th, 1969 The speaker cone felt was coming away from the metal so I've glued it down with speaker glue.Phil,John's chart indicates your speakers were likely manufactured around 1966, as you originally surmised. His earliest serial number, 55,714, was manufactured in late '66. This would suggest that your tweeters were replaced with the 1969 units at some point.Roy Link to comment Share on other sites More sharing options...
Guest philM400 Posted November 10, 2009 Report Share Posted November 10, 2009 Phil,John's chart indicates your speakers were likely manufactured around 1966, as you originally surmised. His earliest serial number, 55,714, was manufactured in late '66. This would suggest that your tweeters were replaced with the 1969 units at some point.RoyThanks Roy! The memory isn't what it once was. Still I was pretty sure the purchase date was 66 and surprised to see the tweeters stamped 69. My father must have brought them back to the shop at some point, unknown to me. If I search around I may even be able to find the original receipt from 66. I know I came across it a some ten years ago. Link to comment Share on other sites More sharing options...
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