RoyC

Wow, that was fast! Thank You!! Roy

I agree, the 40uf cap would be consistent with the others like the AR-11 and '3a Limited. I speculated on the 50uf based on the 150uf woofer cap and the assumption of a #9 woofer coil. John O. and I have been comparing notes on this. The seller told us both that he couldn't read all of the caps but stated 4 values, the 4th being another 10uF. We are thinking that the seller mistakenly stated the very different looking (compared to the others) 10uf cap twice, and that the 4th is still a mystery...but who knows. Given the probable use of an AR-11 type tweeter and the 20uf cap in the mix, I guess we can now safely assume that the "Improved" is not the same as the original AR-3a regardless of the pot elimination. The cabinets went for $88 not including shipping. Lets hope the new owner checks in here at some point. Roy

I received a reply to my inquiry..The values of 3 of the 4 caps are 150uF, 20uF and 10uF. The 4th couldn't be read. I'd be willing to bet that one is a 50uF cap (aka original AR-3a midrange circuit). The 10uF cap and extra inductor indicates that part of the crossover may be similar to the AR-11's tweeter section.

Hi Minh! Besides the pot elimination, it appears that the crossover is somewhat different than the original 3a. At the very least they appear to have an extra cap and inductor. I sent the guy an email asking if he could read the cap values, but received no response. Roy C.

Thanks Tom...Were the "European" versions ever sold in Canada by any chance? I've seen some sold on Ebay that were located there, not to mention a number of them here in NY. Roy

I just came upon grills for AR-2xa's. There is no mention of this model in the library. Can we assume they were sold about the same time as the 4xa, following the 4x and 2ax era? The grills are slightly too large to fit the 2ax cabinet. Anyone have info on this model?...Tom, Steve? Roy

Hey Pete, The AR#9 inductor (2.85mh) was used with this woofer in the '3a and by my measurement with an inexpensive LCR meter its .9+ ohms. Some of us have found that an AR#7 inductor (1.9mh) was used with the cloth surround woofer in some early '3a's and that measures .7+ ohms. Roy

>2. AR had 10-inch woofers and 12-inch woofers. If some parts >supplier insists on foolishly and inaccurately referring to an >AR 12-inch woofer as an "11-inch" woofer, then there is the >all-too-real possibility of a less experienced hobbyist >ordering the wrong driver for their speaker. Although I initially felt compelled to apologize for referring to our beloved woofer in a less than 12" way, I feel a point made by Mluong303 on another thread needs to be reiterated. A conventional 12" foam surround will not work with this woofer. I just conducted a survey of major foam surround replacement websites and found that it is almost universally referred to as an AR 11 inch woofer and they sell their kits accordingly. With AR speakers changing hands faster than Christmas fruitcakes on Ebay, and this website increasingly mentioned as a place to find out how to repair or restore your purchase, maybe its a good thing that this issue is brought up from time to time. If this website is really worried about misleading the "less experienced hobbyist" then maybe historical nomenclature is not as important as finding the right repair kit. There are many more folks replacing foam surrounds than replacing the strangest shaped 12" woofer on the planet! At what point does "insider arrogance" become more misleading than "outsider ignorance"?

I'm guilty, I know better and I apologize! I have referred to it as such only when in discussions about "replacement drivers". There is no other "12 inch" woofer on the market that I'm aware of that will fit into that small 10 1/2" hole and a 10 incher will fall through :-)! With that said, your point is well taken! I'm all for the original woofer anyway. As a long time lurker on this board my comment about Tom's valuable insight extends to you as well, Steve. Thanks, Roy

Thanks Tom! You sure explained the "tweaking"! Most of us are definitely groping in the dark without the historical insight you provide. I still much prefer the original woofers and consider the Tonegen a solution of last resort in the AR-3a. Regardless of the similar specs, in my opinion, it really doesn't have the tangible deep bass of old. I think that accounts for the lack of warmth you mentioned. It also muddies the upper mid/lower bass when matched with the old mid and tweeter. It seems to be better, however, with the newer (AR-11 on) drivers of higher sensitivity. If you send an unfiltered recorded signal through a 1970 version and a Tonegen on the bench, they sound like different drivers! Roy

I purchased an Advent 350 Receiver (rare bird!) and some Dynaco stuff from Sound Values in those days. Of course I sold it all and regret it. I agree, the AR9's are wonderful speakers! Many believe its the pinnacle of AR as we knew it...I had just found it interesting, and not surprising, that the AR9 owner posted that he went back to his original re-foamed woofers after being disappointed with the AR9 replacement woofers. AR was probably tweaking as needed all along....hang on to those original drivers. Roy

I agree lower sensitivity shouldn't be an issue these days. Matching the newer woofer to the old drivers is an issue. Maybe the current AR replacement woofer works better with some of the later models than the AR3a...although there was at least one AR9 owner on this board who was not impressed and went back to the old one. As the competition heated up and power handling and sensitivity became more important, the designs changed accordingly. By the time of the AR11, the tweeter was completely different with ferro fluid, the midrange was tweaked to match the new tweeter, and the woofer was becoming "stiffer". We now have the "one (odd) size fits all" woofer as the only "authentic" alternative for all the models that used it.. In spite of its reputation as power hungry speakers, the vast majority of the AR1/AR3/AR3a era speakers were used with low power amps by today's standards, and not typically played at very loud volumes. They sound great (as did many of that era's acoustic suspension speakers) at low to moderate volumes, and is a big favorite of tube amp owners accordingly....Maybe that original "floppy" woofer would not stand up to the home theater and bass thumping high power applications that drives the "subwoofer" market of today. In a world of brute force amps and a sea of "subwoofers" its probably not necessary to accomodate us. You would think, however, that one of the many manufacturers out there would make a variety of replacement drivers to make some very nice acoustic suspension cabinets sound good again. Roy

I have a number of these woofers from different eras. They are all similar electrically (2.8ohms+/- and .75mh+/-) and identical in dimensions. In 69 or 70(?) it was redesigned from the cloth surround, old style magnet, and damping ring (used in the AR1/AR3/ earlyAR3a/) to the current day foam surround, magnet and cone. The suspension seems to have gotten stiffer, and the sensitivity higher, over the years. Tonegen in Japan built the only replacement drivers currently available. Tonegen also built the NHT1259 and the full 12" AR303 (6ohm) woofer...and is no longer operating as Tonegen, if at all... ABTech, Simply Speakers are both selling the same replacement woofer. Not an easy driver to replace...and probably not wise given the collector status these old speakers have achieved. Roy

They all sound like worthy possibilities for those who are willing to try and don't mind altering the original arrangement. The main thing for me is that our discussion is taking into account what it takes to maintain the original character of the sound. I have a "project" pair of 3a's with the pots hanging out the back as we speak. Maybe thats the solution, easily accessible, "hanging" pots! I just checked out the MCM pots....$25 to $30 each ($100+ for the required 4)!! Youch! That certainly would be at the bottom of my list of solutions. Roy

You're right John, Parts Express, Layne (assuming they are still in business) and most others, offer l-pads, not potentiometers or rheostats (which seem to overlap in definition). The original AR3a potentiometers measure 1 and 5/16" in diameter which may make the MCM offering at 1 5/8" too wide. I just measured a couple of them to make sure...not sure how you got your measurements. The one pictured above is smaller and only $1.50 and therefore worth a try. I've ordered some to take a look at. The 15 watt rating should not be a problem as the "AR3a Limited" crossover discussed at length here recently uses 15 watt 8 ohm l-pads (yes, l-pads, not pots). I've used that crossover for almost 7 years with no problems other than some minor dead spots developing in one of the four. John, have you tried the resistor substitution you posted awhile back for fixed levels? I believe you had the right solution. Roy

They look promising! The original pots are 1 3/8" in diameter..They should fit. It certainly doesn't look like the typical "l-pad" sold by Parts Express, etc. (which we really don't want even if they do fit). How much $ and how do we get a hold of these to conduct a little research? Roy

I'm not sure they make 'em anymore. If you can get restorable pots and use automotive dielectric grease (battery cable, spark plug cable stuff) to coat the innards after a thorough cleaning, the restoration will last a long while. I have a 35 year old pair that have been working flawlessly with no dead spots for 2 years after restoration. They were a mess when I got them and failed the first attempt at fixing them. I got better at it. Modern l-pads get scratchy too...they are simply disposable, cheap and easy to replace. Another thing to remember is that you will need to get small replacements if you intend to use the same holes for the shafts. Some folks on this board are having trouble getting Layne to respond. I believe he was selling simple L-pads...don't know the impedance. There is a guy on EBAY by the name of Vintage AR (I think his name is Larry) who may be worth talking to. He also sells AR replacements but discloses that they are l-pads...again no mention of impedance. Keep us posted on the outcome of your inquiries. Roy

They are pots. If you were to measure them in action you would find: 1)Between terminals "1" and "B" is the series resistance 2)Between terminals "B" and "2" is the parallel resistance 3)The sum of 1) and 2) is 15 ohms 4)Between terminals "1" and "2" is always 15 ohms. If you were to put an ohm in series with the tweeter and 14 ohms in parallel and you were to put 3.25 ohms in series with the mid and 11.75 in parallel, you would be close to what many folks consider to be the "optimum" pot settings. This would be equivalent to the "dot" midrange pot setting, and the "increase" tweeter pot setting... By-passing or using l-pads could change the impedance which would affect the crossover points (usually lower) and therefore the sound. It may also endanger the tweeter which only has a 6mfd cap between it and oblivion. With all that said its best to try to replace the pots with originals. I believe dogmeninreno has refurbs for sale on this board. Roy