AR-3 pots - why keep them?

[Sfffz]

Lucky, lucky me. I just came by an early pair of AR-3's, serial no's C-076xx and C-090xx.

I am also lucky enough, despite my technical illiteracy, to have re-capped AR-2ax's and AR-4x's. I bought the AR-2ax's as a young man at the 24 Thorndike Street factory in 1965. The AR-4x's I bought in 1970. My aging ears don't get much from the tweeters, so I merely took the AR-4x potentiometers out of the circuit. I was pleased with the results.

Now I'm thinking of doing the same for these beautiful AR-3's, replacing the dual capacitor and simply shorting out the pots. What do you think? Is it reasonable to just short out the pots? Which wires do the job?

I have the wonderful refurbishment PDF and the great schematics from John O'Hanlon and Tom Tyson. They may or may not keep me out of trouble. One cabinet is open and the circuit visible. Does anyone have recommendations for high quality replacements for the 0.4 mH and 0.06 mH capacitors?

David

[johnieo]

The AR-4x's I bought in 1970. My aging ears don't get much from the tweeters, so I merely took the AR-4x potentiometers out of the circuit. I was pleased with the results.

It is not recommended to remove the pots, but rather to connect terminals "1" and "B" with a shorting strap if you want to achieve max volume and are worried about corrosion between the movable wiper (Terminal "B") and the potentiometer winding. If you remove the 16-Ohm potentiometer, all the power goes through the tweeter; playing the speaker at high power now increases the risk of blowing the tweeter before aging ears have realized the problem. Examine the backside of the potentiometer and look for the outside two terminals numbered 1 an 2; B is the center terminal.

Now I'm thinking of doing the same for these beautiful AR-3's, replacing the dual capacitor and simply shorting out the pots. What do you think? Is it reasonable to just short out the pots? Which wires do the job?

Ditto as per AR-4x.

I have the wonderful refurbishment PDF and the great schematics from John O'Hanlon and Tom Tyson. They may or may not keep me out of trouble. One cabinet is open and the circuit visible. Does anyone have recommendations for high quality replacements for the 0.4 mH and 0.06 mH capacitors?

It is recommended to replace those old impregnated paper capacitors which by now have absorbed a lot of water vapor. Replace them with a good quality NON-POLAR electrolytic also designated "NPE" or "bipolar electrolytic" or "AC electrolytic" in the catalogs. 60-to-100 V is an adequate voltage rating. Depending on which of the four basic AR-3 schematics you have, you will need one 6-uF and one 24- or 30-uF capacitor for each Ar-3a cabinet. Audio supply houses such as Madisound and Parts Express carry this type of capacitor. DO NOT use the small polarized electrolyics that cost ten cents each; they will not work on alternating current!

The components you mention with values of "0.4- and 0.06-mH" are inductors. Do not replace them! They are air-core coils whose internal resistance is part of the crossover network's design.

Enjoy; they are both excellent examples of early AR speakers.

[Zilch]

It is not recommended to remove the pots, but rather to connect terminals "1" and "B" with a shorting strap if you want to achieve max volume and are worried about corrosion between the movable wiper (Terminal "B") and the potentiometer winding.

A shorting strap is not the recommended bypass approach, rather, removing the driver wire from "B" and connecting it to "1" leaving the potentiometer in place. As stated, if the potentiometer is turned down, it will indeed "short."

Bypassing the mid control is not advised, unless you like the sound of overly forward midrange. Consensus appears to be that some attenuation is preferred, which may be provided by two resistors equivalent to the desired setting, instead.

Best answer is to follow the recommendations in the PDF, i.e., rehab the pots, replace them in kind, or install L-pads plus resistors. "Hotrodding" vintage ARs to alter the system voicing using the stock drivers may lead to their early demise....

[johnieo]

Sorry, I meant to say remove the wire connected to "B" and connect it to "1" ... if you want the pots at full rotation. At your age, you may not be able to hear the difference in the last bit of rotation!

Cheers,

[Sfffz]

John and Zilch, thank you for your very informed guidance! I've order capacitors and now I think I'll take a crack at pot rehabilitation.

I've learned that these early 'sixties cabinets were probably never opened - until I opened one yesterday. That's good news. I know the drivers are original. The workmanship inside the case looks great. Bad news is that the high and midrange drivers produce no sound in the one speaker. Good news is that the other case is fine, all three drivers working. As an amateur bass trombonist and tubist, I appreciate hearing the extra bottom octave from these great twelve-inch woofers.

The potentiometers do not have the expected wire bale holding them down, but I'll see if I can open them up and brush away the corrosion with some 1600 grit micromesh (finer than 600 grit sandpaper and finer than brass polish).

Thanks, again,

David

[frankmarsi]

Lucky, lucky me. I just came by an early pair of AR-3's, serial no's C-076xx and C-090xx.

I am also lucky enough, despite my technical illiteracy, to have re-capped AR-2ax's and AR-4x's. I bought the AR-2ax's as a young man at the 24 Thorndike Street factory in 1965. The AR-4x's I bought in 1970. My aging ears don't get much from the tweeters, so I merely took the AR-4x potentiometers out of the circuit. I was pleased with the results.

Now I'm thinking of doing the same for these beautiful AR-3's, replacing the dual capacitor and simply shorting out the pots. What do you think? Is it reasonable to just short out the pots? Which wires do the job?

I have the wonderful refurbishment PDF and the great schematics from John O'Hanlon and Tom Tyson. They may or may not keep me out of trouble. One cabinet is open and the circuit visible. Does anyone have recommendations for high quality replacements for the 0.4 mH and 0.06 mH capacitors?

David

9-23-09

No lucky me!

If we all used trombones, maybe we’d be better off?

9-23-09

No lucky me!

If we all used trombones, maybe we’d be better off?

WOW! Thank God, to this planet, some 'new-blood' (you old thing, I am the same age), are welcome here!

At this site you are more than welcomed, I myself like others who won't agree cause they're too embarrassed as I am to be an old 'vampire', a 'dinosaur' looking for new/old blood as a vinegar substitute. The 'new wine' from California is 'so-so' lately.

Let's forget about you for right now, but 5 weeks ago I blew one newly re-foamed woofer and for some damn reason my S.A.E. 1800 is not working on the right side channel, it's 'mint' (old AR’s seem to need for my reasons anyway, a ‘parametric-equalizer’ and like a new to a you and me, it seems as though a 'pretty girl' is telling you to 'buzz-off' and

leave me alone’.

I'm starting to feel that my four LST's are too used to sounding like theatre speakers-why is that? Are my ‘mids’ getting old?

I recall that is I was told that's where they came from anyway.

Well, they’re actually from what I was told came out of a 42nd. Street theater/7th. Ave. theater here in NYC when they were

first 'de-commissioned' in 1987 after a life-time of service since 1972 of theater use and also at that time 42nd. Street was being ‘sold-out’ to ‘big-money’ in these old ‘United States’. Unfortunately we’re all in this ‘new country’ once more, WW2 and all of the 1950’s. ‘60s, ‘70s ‘80’s and 90’s are gone as that view-point goes. Too bad and how could’ve it had happened so quickly and stupidly enough?

When I got them on the street as 'ready for the dump’ or 'whatever' . I had to speak up on the '29th. St. and Madison Ave. studio was where my 2nd. Foto-studio was and inform the seemingly dumb and un-knowing young electricians that these speakers (looking humble and almost banged-up as they were), were worth something more and that I would be interested to take them off of their hands.

Speaking of the present, I now have six AR-LST's and I'm getting ready to stack not only 4 LST's, but six. Up to the ceiling Alice!

I got the amps and the wire , 20inch stands, and spades connectors. Anyone interested in a reply? I’m getting crazy here!

FM, -his own friend.

P.S. I’m so worn-out by my many AR speakers that I’m almost ready to leave Roy C. and Johnie’O’ in my will and use a kmart system. You too Dyna-Dan. Bret, Min, Soundminded, and all other from all of those 'other' sites'. you're not off the secret-list either, mybe I'll leave it all to you guys and anyone who ever answered to me, you can all fight amongst yourselfs?

P.S.1, I also state that there is nothing like to 'my great sounding 1972 AR-LST's and 're-fitted', not re-furbished, but 're-built' Phase linear Series Two amps.

All you Adcom-555 and 'what-ever-else', if, 'I' will say, 'other' 'high-end' amps, Mac or 'what-ever' amps can take a swim! You 'euro' guy amps can take a 'swim' also!

FM- ..................

[Sfffz]

9-23-09

Speaking of the present, I now have six AR-LST's and I'm getting ready to stack not only 4 LST's, but six. Up to the ceiling Alice!

Frank, you must have high ceilings!

My own good luck continues. I got my caps and I need to restore only one pair of pots. Five of six drivers are fine. There may be some compromises replacing one early AR3 midrange driver. If the project goes well, and if my wife doesn't shoot me, next project should be to find some nice LST's.

Folks, Thanks for the help!

David