circlework Posted June 1, 2012 Report Share Posted June 1, 2012 Hello all.I'm doing a resto on a pair of UK 2ax's and am trying to get a handle on the aproximate date of manufacture.Serial #'s... EAX005146 & EAX 005183. They have the later ceramic magneted woofer and foam seals between the mid and woofer baffle holes, instead of putty, where there is no evidence that putty sealant was ever used. The brass AR2ax nameplate is finished in black background (possibly anodised?) with the letter etching appearing to be either lacquered or painted gold. As far as I am aware, these UK versions were never sold in Australia, so they may have come as imigrant imports.A crossover question ... The mid range has an impedance equalisation network glued to its back, including what looks to be a 4uF electrolytic in parallel with the VC. Wanting to keep these units as original as possible, but wanting the best sonic reproduction as a priority, do I change out this capacitor when I change the other caps?Looking forward to your input.Thanks,Daryl. Link to comment Share on other sites More sharing options...
JKent Posted June 1, 2012 Report Share Posted June 1, 2012 Hi Daryl. Nice project! I'm not familiar with the UK version so I'll let others comment but here are 2 thoughts:Yes--replace any electrolytic caps with modern film caps. I'm just not familiar with the UK's xoI had a pair of AR7s and, like you, was convinced the logos were black anodized. They looked nice like that. Turns out it was tarnish. Solid brass that will polish up nicely.On a US-built 2ax there is that big block cap, which is a double, putting out 6uF and 4uF. There are no resistors.Are all 3 wires from your block cap connected to something?What I "suspect" is that the mid is a newer replacement and that the cap and resistors were added to a factory replacement mid to make it electrically and sonically match the original. One reason I think this is that your tweeter is front-wired but the mid is back-wired. Early 2ax's had front-wired mids and tweets while later ones had back-wired mids and tweets. OTOH, there is no front tab terminal for a mid, so...... who knows.I'm resisting making any snide remarks about Brit engineering Maybe the UK speakers were designed that way.Kent Link to comment Share on other sites More sharing options...
circlework Posted June 1, 2012 Author Report Share Posted June 1, 2012 *snip* Are all 3 wires from your block cap connected to something?Hi Kent, Thanks for the reply. Yes, the crossover traces out as per the standard 2ax cct diagram.*snip* I'm resisting making any snide remarks about Brit engineering Maybe the UK speakers were designed that way.Hmmm, now I'm really confused .... and your avatar is 'whom' from 'where'?? Daryl. Link to comment Share on other sites More sharing options...
JKent Posted June 1, 2012 Report Share Posted June 1, 2012 Hmmm, now I'm really confused .... and your avatar is 'whom' from 'where'?? HaHa! Cheeky devil! I hope one of our European members or someone else with knowledge of the English AR2ax will chime in here.Kent Link to comment Share on other sites More sharing options...
RoyC Posted June 1, 2012 Report Share Posted June 1, 2012 Daryl and Kent,The later US AR-2ax with the ceramic magnet woofer had a 3 ohm resistor in series with the mid. That arrangment was later replaced with a mid with higher dcr (9 ohms instead of 6 ohms).Assuming it is an original AR-2ax midrange, it appears the UK version did a bit more to compensate for the ceramic magnet woofer...or maybe the woofer and/or mid are not the same as the US versions. The back of the mid looks original in the photo. Kent, I don't believe any version of the 2ax had a front-wired mid.What are the values and arrangement of the resistors?Roy Link to comment Share on other sites More sharing options...
JKent Posted June 1, 2012 Report Share Posted June 1, 2012 Thanks Roy. I'm sure you're right about the 2ax mid. I was thinking of the AR-3.Kent Link to comment Share on other sites More sharing options...
circlework Posted June 2, 2012 Author Report Share Posted June 2, 2012 What are the values and arrangement of the resistors?RoyHi Roy and Kent. Thanks for the replys. The mid has 803109 & 1405 printed in green on the back of the magnet ass'y. There may be a digit/s hidden in front of the '8'. See cct below.Daryl. Link to comment Share on other sites More sharing options...
circlework Posted June 3, 2012 Author Report Share Posted June 3, 2012 After further investigation, the tarnish / black on the name plate is actually only under or in a film of lacquer, so that where the lacquer has been polished off, there is no black/tarnish and the brass is showing. I'd like to take a sample of the lacquer to see if it is actually pigmented black, but I'd have to take it from the front of the plate and as there is no lacquer on the sides or back, this is something I am very lothe to do. Also, there is absolutely no trace of red or black to the etched lettering.The further I go, the more questions arise.Cheers,Daryl. Link to comment Share on other sites More sharing options...
RoyC Posted June 3, 2012 Report Share Posted June 3, 2012 After further investigation, the tarnish / black on the name plate is actually only under or in a film of lacquer, so that where the lacquer has been polished off, there is no black/tarnish and the brass is showing. I'd like to take a sample of the lacquer to see if it is actually pigmented black, but I'd have to take it from the front of the plate and as there is no lacquer on the sides or back, this is something I am very lothe to do. Also, there is absolutely no trace of red or black to the etched lettering.The further I go, the more questions arise.Cheers,Daryl.Daryl.I have seen and refurbished many old AR badges. Yours are simply badly tarnished, and were likely in a very smokey environment for an extended period of time. There is no "black pigment" in the mix. :-)I use very fine steel wool to clean badges like yours. The entire surface may be rubbed with it, and the shiny brass will re-appear. There is no need to worry about the engraved portion, as sometimes the off-red lettering will also brighten up as you scrub the surface. This can later be filled with paint, if necessary, and the process repeated. The result will be a dramatic improvement from what you have now! Dipping the badge in a dilute mixture of polyurethane and mineral spirits when you are finished will inhibit tarnish from reforming.I believe the midrange drivers (and associated crossover modification) are original to your speakers. Other than possibly replacing capacitors in kind, I would not alter anything if they seem to be functioning satisfactorily.Roy Link to comment Share on other sites More sharing options...
circlework Posted June 5, 2012 Author Report Share Posted June 5, 2012 *snip* Other than possibly replacing capacitors in kind, I would not alter anything if they seem to be functioning satisfactorily.RoyThanks Roy. Guess I'll do the three amigos then ... woofer surrounds, clean pots and replace all the caps. At this stage I'm a little sus of the output level of the tweeters, but I'll see how they sound once I get them back together.Thanks to all for your help.Daryl. Link to comment Share on other sites More sharing options...
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