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AR-2ax Speaker - what kind of wood veneer? Pine?

Well, I had assumed you had your drivers out of circuit first rodeo or not. With a DMM set to 200 ohms, pots should read +15 to ZERO at center to -15 end to end.
 
Bill S said:
Well, I had assumed you had your drivers out of circuit first rodeo or not. With a DMM set to 200 ohms, pots should read +15 to ZERO at center to -15 end to end.
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Yes. Of course. I had clipped the wires going to the capacitor, and clipped the wires going to the pots, and removed them all. But I hadn’t yet stripped the 2 wires going to each driver. So I measured at the driver terminals, and at the brass connector stubs for the tweeter. Continuity, primarily. But that gave me incorrect readings for actual dc resistance. So as I had already said I would, I measured again. This time for accurate DCR.

Nope. Not my first or 100th rodeo. Coil measures 15.5 ohms end-to-end. Wiper to coil measures 0.3 ohms to 15.3 ohms per rotation. At center position, wiper to either coil end measures 7.7 ohms. Just like it should. No?

And your skepticism here is based on….what?
 
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Only skeptical because you were so insistent your high readings for tweeters and mids were correct. I'm trying to help and you spoke to me like I'm stupid. I never said hot rod your speakers. Lots of folks with tons more exp with AR speakers than you have know the issues and solutions to keep them as original as possible. I have a pair of 2ax I restored doing primary duty in my garage for the last dozen years and I've restored a few pairs of AR3s for my friend. I do know a little.

I had pots that looked good but still didn't work well. Out of circuit with a probe on each of the 2contacts you should get zero at ctr, +15 ohms on one side and -15 ohms on the other side. Proper procedure is disassble and polish wiper to a shiney surface with 320-600 grit and finish up with a pencil ereaser. Coat wiper and coil with dielectric grease and reassemble. You do you though.
 
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I do what works. I don’t get your +15, -15 ohms. There is only short circuit and 15.0 ohms resistance at terminal ends. (This is the pot out of circuit.)
4A2A4421-7D27-4937-8156-9EAF466FDC5F.jpeg





I also don’t like The Classic Speaker Page’s schematic for the AR 2ax. It’s a cartoon with wire colors. It doesn’t help the reader know what’s going on with the circuit. Perhaps that’s why you’re confused about the resistance of the potentiometers?

EB1236F3-810A-46F5-B86B-29374BFAF4EF.jpeg
 
The “real” schematic is as follows. The pot is used in classic voltage divider mode. Tweeter circuit and mid circuit are identical, except 6 uF cap instead of 4 uF for the midrange driver:

(I think many “assume” the pot is used as a variable resistor *in series* with the mid or tweeter voice coil. It’s not.)
ABE821F4-6F48-4D0A-81EF-40437E1443C1.jpeg

And at full volume:
A1A13221-DE39-4C0C-B538-C2B995745496.jpeg

At “0” Volume:
02A5C2DE-72A4-4098-A111-E085C9073D61.jpeg
 
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Here is one of the best diagrams of the original AR 2ax
file.php
 
I did notice some of the blue-green corrosion on your pots- if they were mine I would clean them and apply die-electric grease. I have done multiple older pots on AR speakers, Good luck!
 
r_brumett61 said:
I did notice some of the blue-green corrosion on your pots- if they were mine I would clean them and apply die-electric grease. I have done multiple older pots on AR speakers, Good luck!
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No corrosion anywhere on the pots. All shiny brass or black metal, inside and out. Where do you think you see corrosion? In which pic?
 
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r_brumett61 said:
Here is one of the best diagrams of the original AR 2ax
file.php
Click to expand...

Nice! Thank you. Mine don’t have that 2 ohm resistor in the mid driver circuit. This looks like someone’s version of the original schematic, from the notes. A modified version. When I was shopping for capacitors, I noticed that 4 and 6.2 uF, 250 v, 5% metal films were common. I chose 2 and 4 uF caps. These specs don’t match the originals, so this must be someone’s version of the original. Guess I’ll have to check polarity of the mids and tweets, to see if the reversed polarity of the woofer is original, or a mod.
 
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The pic you show:
F072A6D0-3EC0-4CF8-9E5D-503ED5AFE607.jpeg

Was before I cleaned the pots using electrical contact cleaner. You can even see a piece of trash on the resistance coil; that white spec. Also, what “appears” to be corrosion is just an artifact of using the flash on my phone.

Better pics, each pot. After cleaning. (You can see the cadmium plating and shiny cut sides of the wiper and wiper arm, and wiper contacts:
17550DF0-A88F-4C38-8492-AEFEA0F8B1B4.jpeg

027EBA22-7417-4BA3-9D53-8014AFE62E55.jpeg
 
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Damn, clean or not clean???
You can easily disassemble those pots to clean them properly, and if you didn't then they are not really cleaned and lubricated properly in my opinion!
They need a bit more attention I think? :dunno:
 
doctorolds said:
Damn, clean or not clean???
You can easily disassemble those pots to clean them properly, and if you didn't then they are not really cleaned and lubricated properly in my opinion!
They need a bit more attention I think? :dunno:
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Thanks! Am I selling these to you? I don’t remember….:dunno:

They’re clean. Guess I’ll have to pop them open and take pics. Just to satisfy the OCD folks in here…

And as a good rule of thumb, if you find corrosion on the electrical connectors, on the outside of the pots, you’ll find corrosion inside as well… But if you don’t find corrosion, likely you’ll have none inside.

Another thing is heat. If these speakers have been abused, the pots may get warm, which can make them susceptible to corrosion. I don’t see any signs of abuse with these speakers. Even the woofer surrounds are nearly perfect.

As found:
FE608FC6-6136-4657-B15C-99201D146EA5.jpeg


Closer views:

0EC1F877-AFBB-46F5-AE85-C12028A8D93E.jpeg

4CEA3949-D679-4D1A-B6C1-B16CF18E5BB2.jpeg
 
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No sir, I'm not buying them. I cannot see inside of them and am unable to determine the condition. Since they are very simple to take apart and clean, I personally would do it to be sure.

Your speakers, so do as you see fit. Only a little push on my part to encourage you to go a step further. Best of luck!
 
doctorolds said:
No sir, I'm not buying them. I cannot see inside of them and am unable to determine the condition. Since they are very simple to take apart and clean, I personally would do it to be sure.

Your speakers, so do as you see fit. Only a little push on my part to encourage you to go a step further. Best of luck!
Click to expand...


So…. How clean must they be to work more perfectly than perfect? How clean must they be to last another 50 years?

Should I burn them in before remounting in the cabs? Maybe apply 120 vac for 2 seconds?

Which will attract and hold more dust in the cabs? A little lightweight synthetic oil on the shafts, or plenty of silicone dielectric grease?
 
I'd personally hot rod them by installing caps that are almost 50% lower in uF value than the originals.
 
I’ve got plenty of Dynaudio woofers, dome midranges, and tweeters, NIB when I bought them in 1986…. Perhaps go to an aperiodic damped cabinet…. Still have 6 Variovents.

Or, find some Cerwin Vega take-out drivers!!

Nope. I’ll keep the phenolic dome tweets, etc.
 
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