restoring AR 4Xa (not 4X)

[axoneill]

Hi - I have a set of both AR 4Xs and 4Xas - I previously restored the 4Xs and assumed the parts were the same for both - should have checked before ordering! Anyway, the tweeters are bad in the 4Xas, and they are not interchangable with the 4Xs, the outside diameter is 3.5 inches vs 4.5 inches, and they have the hair thin wires on the face, rather than the rear terminals, anyone out there know a source for replacement tweeters for the 4Xas?

I bought the tweeter replacements for the 4Xs off Mid West Speaker Repair and they work fine. The 4X also has the old wax caps and the 4Xas have the polypro types. The 4X has an Lpad and the 4Xa just a high/low switch in the rear.

From the AR history looks like the 4X was 1965-73 and the 4Xa was the end of the run - 1973-74.

[JKent]

According to the 1975 lit,

http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_brochures/acoustic_research_loudspeak.pdf

the 4xa is an improved version of the 4x and uses the same tweeter as the AR-6: a 32mm (1-1/4") cone. Crossover is 1600Hz. The tweeter in the AR-7 is described as the same "type" as the AR-6. Maybe that will help some. If you do a google search on AR-6 tweeters you'll find some discussion but doesn't seem too promising.

Maybe Roy can offer some advice--he was looking into finding a replacement last year.

btw, the 4x used pots--not L-pads. L-Pads do make good replacements though. Did you replace the wax caps?

How are the tweets in the 4x's working out? I could be wrong, but I suspect that the tweets Midwest Speaker and Vintage AR are selling as AR4x replacements, at about $25 each, are these:

http://www.parts-express.com/wizards/searchResults.cfm?FTR=phenolic+ring+tweeter&search_type=main&WebPage_ID=3&searchFilter=phenolic+ring+tweeter&x=0&y=0

Kent

[RoyC]

Maybe Roy can offer some advice--he was looking into finding a replacement last year.

Various versions of this tweeter were used in other AR models, such as AR-6, 7, 8, 93, 94, 18B, and others, into the 80's. Any used version is still the best bet as a replacement. There are no acceptable new drop-in replacements that I am aware of. We have experimented with some promising replacement candidates, but nothing that does not require modifying cabinet holes and/or crossovers.

Roy

[michiganpat]

Various versions of this tweeter were used in other AR models, such as AR-6, 7, 8, 93, 94, 18B, and others, into the 80's. Any used version is still the best bet as a replacement. There are no acceptable new drop-in replacements that I am aware of. We have experimented with some promising replacement candidates, but nothing that does not require modifying cabinet holes and/or crossovers.

Roy

I personally prefer the newer tweeter that came out in the 17/18 ADD models...they've been very robust for me, and are nice and airy....

if "restomodding", I wonder how the dayton 1 1/8" dome would work. I've heard they sound pretty good, and have a low Fs, so it should handle a low crossover point.