TimmyTonga Posted August 28, 2016 Report Share Posted August 28, 2016 Picked these up; a bit scruffy round the edges, but nothing terminal. Advertised as tweeter not working, but it actually works fine - it's just the pot that doesn't. Woofers dated 1971, cloth surrounds. But what about this.. I was definitely the first person inside the cabs; I can attest the glue was original. Inside - If one Googles '4x' one image comes up (among many others) that has the same blanked-out hole as these, but no explanation. Also, the cabs are, as you see, a kind of orangey colour - would anyone like to hazard as to what colour they might have been originally? Link to comment Share on other sites More sharing options...
RoyC Posted August 28, 2016 Report Share Posted August 28, 2016 Those are typical AR-4x's in every way except for the covered holes. The Sprague caps and #5 inductors show they have the last iteration of the 4x crossover. Another forum member posted a photo of a pair of 4x's with a similar appearance awhile back. I believe those specimens were in the UK as well. Obviously there was some experimentation with a port of some type along the way. If the cabinet holes are original to these specimens, it would not be a stretch to assume AR experimented with an aperiodic port similar to the Dynaco A25. As it stands, 4x's of this era were not completely sealed given some apparently deliberate air leakage through the alnico magnet/dust cover arrangement, and lightly treated surrounds. Roy Link to comment Share on other sites More sharing options...
JKent Posted August 28, 2016 Report Share Posted August 28, 2016 I wonder what's behind those covers, since they're domed. Can you stick a camera in there? Link to comment Share on other sites More sharing options...
TimmyTonga Posted August 28, 2016 Author Report Share Posted August 28, 2016 I will when they get back from my friend who is tarting up the cabinets. Link to comment Share on other sites More sharing options...
RobHolt Posted August 28, 2016 Report Share Posted August 28, 2016 Hurry up, I'm intrigued Link to comment Share on other sites More sharing options...
TimmyTonga Posted August 28, 2016 Author Report Share Posted August 28, 2016 It's going to be Friday now, as I'm out of town until then ¯\_("/)_/¯ Gimme a steer on the colour someone......teak? what finishes did they come in? Link to comment Share on other sites More sharing options...
ra.ra Posted August 28, 2016 Report Share Posted August 28, 2016 Those cabinets will "tart up" very nicely - - a little hard to tell, but it looks like the typical American walnut to me. Grilles are also not too bad - - - maybe try to clean them up a little and find yourself some metal badges. I did expect, however, to see the England address on the paper tags. Roy is correct that a similar situation was posted here before (see thread attached), but this pair had some sort of passive element in that third baffle cut-out. I believe that it's intent, origin, and performance qualities were never adequately defined or determined, but in your case with the solid patch stapled in, it's a moot issue, and you can just proceed as if that "third hole" does not exist. Those caps might still be within original spec (20uF, 10%), but those pots require a full inspection and cleaning (or replacement). Just a suggestion, but I'd recommend maybe you contact member mangoman in the UK and see what he has learned since about his pair, even though yours do not have the third (phantom?) driver. Maybe you'll find another AR friend just a couple villages away from you. Link to comment Share on other sites More sharing options...
TimmyTonga Posted August 29, 2016 Author Report Share Posted August 29, 2016 Thanks for digging that thread out ra.ra - very interesting to see not one but two pairs with similar cut-outs have previously surfaced. Regarding general condition, one of the pots is desperate, and I may have to replace with L-pads unless, of course, it is fine in the max position, which is where I would expect it to end up : ) Also, much correspondence on this board regarding the difficulty of correctly ascertaining the value of NPEs with a multimeter, and indeed all, NPEs I measure, even new, seem to read at least 10% over. So I have kind of adopted a policy of replacing NPEs come what may, especially values where reasonable-quality film caps can be had quite cheaply. Given the paucity of 4xs over here I may have to settle for replica badges from Vintage AR........ Colour - I have read other threads on here where members express a preference for a certain red tinge to their walnut, and but these MSTs are called walnut; which are a very 'english' kind of walnut with no red in at all. This flooring, on the other hand; is called American walnut, which looks more like my speakers. So maybe that's what I should be going for, except why would English-made speakers be given an American walnut finish? Unless the lack of a UK address on the back means they were for some reason imported? Also, why is one speaker certificate marked with a large +, and the other a large o? Link to comment Share on other sites More sharing options...
DavidDru Posted August 29, 2016 Report Share Posted August 29, 2016 timmy, post a photo of the sides and tops so we can see the cabs better. Link to comment Share on other sites More sharing options...
michiganpat Posted August 30, 2016 Report Share Posted August 30, 2016 On 8/28/2016 at 0:14 PM, RoyC said: Those are typical AR-4x's in every way except for the covered holes. The Sprague caps and #5 inductors show they have the last iteration of the 4x crossover. Another forum member posted a photo of a pair of 4x's with a similar appearance awhile back. I believe those specimens were in the UK as well. Obviously there was some experimentation with a port of some type along the way. If the cabinet holes are original to these specimens, it would not be a stretch to assume AR experimented with an aperiodic port similar to the Dynaco A25. As it stands, 4x's of this era were not completely sealed given some apparently deliberate air leakage through the alnico magnet/dust cover arrangement, and lightly treated surrounds. Roy Whew, you've been a bit sparse on here and Audiokarma, RoyC, I was starting to get a little worried..... Link to comment Share on other sites More sharing options...
RoyC Posted August 31, 2016 Report Share Posted August 31, 2016 23 hours ago, michiganpat said: Whew, you've been a bit sparse on here and Audiokarma, RoyC, I was starting to get a little worried..... Hey Pat, I still visit on a regular basis, despite a fair amount of traveling this summer. Admittedly, I've (mostly) lost interest in the AK forum these days. Thanks for your concern. Roy Link to comment Share on other sites More sharing options...
TimmyTonga Posted September 2, 2016 Author Report Share Posted September 2, 2016 So here is an inside photo, of sorts; the appearance of a 'dome' on the front of the cover is a trick of the light; the cover is stapled into a shallow recess, created to take black goo much like the tweeter I presume, so that the mystery unit would sit reasonably flush with the baffle. What you have on the underside is four captive nuts, only two are shown here (one just a hole); obviously the one visible in the top left-hand corner is that of the tweeter. Any discussion over colour is rendered superfluous by the fact that while I was away the restorer finished his work. Anyway; it all looks very nice and I will post pictures when the units are finished. He has retained something of their red glow. Link to comment Share on other sites More sharing options...
TimmyTonga Posted September 3, 2016 Author Report Share Posted September 3, 2016 Two questions - the cloth surrounds on these 4x woofers; looking a bit dry and tired. Is it as well to leave it be, or does it look like it needs some sealant? Secondly, when replacing the glue on grilles with velcro for the first time, what is the favoured method of attachment of said velcro? Staple gun? Thanks as always for any guidance Tim Link to comment Share on other sites More sharing options...
JKent Posted September 3, 2016 Report Share Posted September 3, 2016 Hey Tim AR woofers sound much better than they look I'd leave them alone. The AR-4x is not a completely sealed system, more of an "aperiodic" design, hence the porous dust caps. I would defer to Roy's judgment if he says otherwise but I think they are fine. I would glue & staple the Velcro to the speaker baffle and the wooden grille frame. If your grille is Masonite (I haven't seen that on 4x's) then even 1/4" staples would be too long. -Kent Link to comment Share on other sites More sharing options...
TimmyTonga Posted September 3, 2016 Author Report Share Posted September 3, 2016 Many thanks JK. Minimum intervention is big with me. regards/Tim Link to comment Share on other sites More sharing options...
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