AR-2ax woofers: which one?

[pmsummer]

I'm in the process of a utility restoration of some AR-2ax speakers. They were sold as "refoamed". The first speaker I began work on (new caps, cleaned the pots) did indeed have a refoamed woofer (six-hole basket with lip, square magnet).

When I began work on the second one, I discovered that the grill had never been removed. I carefully removed it and discovered a cloth-surround woofer (with round magnet and felt ring around the dust-cap). The surround needs to be re-coated, but that's no problem.

The serial #s don't match, but they are close (within a few hundred seems like). The pots and caps all match. All four pots have the red plastic shaft with the white mark on the top... no knob.

But my question, O Wise Ones, is which woofer was "better" (if either), the round magnet/cloth-surround/flat basket, or the square magnet/foam-surround/lipped basket woofer? Am I just being anal-retentive/compulsive?

Thanks in advance!

P.S. They're sounding good running through a MAC-4100!

[frankmarsi]

Hi, I don't know too much about the AR-2's woofers, I dwell with the 12 inchers, but I can warn you that you'll be recieving a truck load of answers before the day in through, henceforth I will learn also, thanks.

FM

[pmsummer]

The info/discussion in the library about these speakers seems to say that the later woofer was smoother. I saw a single woofer on the internet and grabbed it. So in the next few days, I'll install it and report back. At least they'll be matched!

[charger3834]

>I'm in the process of a utility restoration of some AR-2ax

>speakers. They were sold as "refoamed". The first

>speaker I began work on (new caps, cleaned the pots) did

>indeed have a refoamed woofer (six-hole basket with lip,

>square magnet).

>

>When I began work on the second one, I discovered that the

>grill had never been removed. I carefully removed it and

>discovered a cloth-surround woofer (with round magnet and felt

>ring around the dust-cap).

The surround needs to be re-coated,

>but that's no problem.

I don't know about that, as long as it slowly returns when "push tested" it's fine.

>The serial #s don't match, but they are close (within a few

>hundred seems like). The pots and caps all match. All four

>pots have the red plastic shaft with the white mark on the

>top... no knob.

Great attention to detail, I love it. From the details you provided, I think you have a pair from right around the transition period in 1970. Could you provide the actual serial numbers of each ? In addition, what tweeter is in each ? What numbers are on each coil ?

>

>But my question, O Wise Ones, is which woofer was

>"better" (if either), the round

>magnet/cloth-surround/flat basket, or the square

>magnet/foam-surround/lipped basket woofer? Am I just being

>anal-retentive/compulsive?

Not at all, this is important research ! Those woofers are actually pretty similar in response. The foam version is a bit smoother in the lower midrange/upper bass.

>

>P.S. They're sounding good running through a MAC-4100!

I bet they are :-)

[pmsummer]

Brad,

Thanks for the response.

The one with the foam surround is AX-80985

The one with the cloth surround is AX-84014

When I push in the cloth surround, it seems to want to deform and stay that way. I'll look more closely, but I actually found a foam surround woofer for an AR-2ax for $20 (at that web auction site), so it's on its way to me.

So... the one with the almost 4,000 digit earlier number has the newer woofer. Replacement for a blown driver early in it's life?

The tweets are "mahagony" colored (see attched pic). I'll pull them if the serial # will really help, but I'm listening to Vivaldi at the moment.

1567.txt

[charger3834]

These are without a doubt "old style/pre 1970" AR-2ax's. More accuratly, they date to around 1968. The correct woofer for both is the cloth surround woofer. If it were me I would get two cloth surround woofers. Although an oversised 6-bolt foam woofer or a 4 bolt foam woofer with 4 to 6 bolt adapter ring will work, the best way to ensure that the target "Q" is achieved would be to use the cloth woofers.

If AR replaced the woofer, it is safe to say that all other variables are controlled i.e. stuffing quantity, crossovers etc.

The whole system operates with crossovers of 2000 HZ and 7500 HZ respectively. It uses the "number 5" inductor coil.

Don't get hung up on the differences between the foam and cloth woofers. They are both very good. The later 3/4" tweeter has better dispersion than that of the earlier 1-3/8" phenolic-resin dome, however there is no reason to switch that either.

You have great speakers, enjoy them.

[pmsummer]

Cool! Thanks again.

1968? That's about the time I first heard some ARs (3a), but these are my first pair.

I'll replace the cloth woof with the foam one... and then keep my eyes peeled for another cloth one! Then I'll go back to all cloth. The foam woofers will then go on the market to help someone else.

The cabs are in "decent", but not great shape. Couple of dinged corners, some deep scratches, and a couple of veneer chips along the back. But they're responding well to the #0000 steel wool and tung oil/beeswax treatment.

The coils "looked" the same, but I'll double check 'em. The cloth one had never been disturbed, but the foam one showed signs of a lot of digging around inside (the "toilet paper" barrier was just sort of wadded up). The caps were the same, but the ones in the foam box were loose...torn away from the masonite.

I really like the sound of 'em. When I get the cabs where I want 'em, they may come out into the main room to alternate with the Cornwalls.

You've been very helpful. I appreciate it.

[Shacky]

I have a pair of 1965 older model 2AX that I love. I have a beat later model pair that I'm getting some new drivers to complete. Been reading a lot about the new vs. old woofer and tweeter. I am no where near an expert but thought I'd throw my $0.02 in.

While the later style woofer was said to be smoother in the mid bass I'm thinking I may also have read somewhere that the later model was stiffer and rolled off much lower that the early model. This was not a problem with later model crossover which was much lower the early model.

Therefore there may be a problem using later model woofer in older cab/corssover set up. It may not be reproducing everything in the 1400 - 2000 Hz (new vs. old cutoff).

Please someone with more knowledge than I confirm or correct this!

[charger3834]

>The coils "looked" the same, but I'll double check

>'em.

No need, they are almost certainly both #5 1.187 mh coils. The number 7 coil came later. That is associated with versions made in 1970 and beyond.

By the way, all AR-2ax's regardless of vintage had the 4 and 6 mfd capacitors. Having said this, the 1970 and newer versions operate with crossovers of 1400 HZ and 5000 HZ. This gives the newer speaker a more "open" personality. Crossover frequencies were altered with the coil change and different driver inpeadances.

You have to keep in mind that there are actually several versions of the new, post 1970 10" foam woofer. You need one of the earliest versions with the oversized 6-bolt frame to fit your cabinets. The 1971 and newer, small frame, four bolt version, will not fit without an adapter ring.

The 2ax was in production from 1964-1976 and there were subtle changes along the way. This is the case with most AR models. The changes in 1970 were quite significant and we forum members like to divide them in to two groups, "old" and "new" versions. There is very little variation in the "old" models. The post 1970 models show a lot more subtle variation through the years.

Glad I could help,

Brad

[charger3834]

>

>While the later style woofer was said to be smoother in the

>mid bass I'm thinking I may also have read somewhere that the

>later model was stiffer and rolled off much lower that the

>early model. This was not a problem with later model

>crossover which was much lower the early model.

>Therefore there may be a problem using later model woofer in

>older cab/corssover set up. It may not be reproducing

>everything in the 1400 - 2000 Hz (new vs. old cutoff).

Shacky, I am impressed by your comment, although I can neither confirm or refute it. I would say that your assumption is very reasonable and a distinct possibility. I think you meant to say that the new cone is less stiff, which it is.

The new cone which was molded by AR's new "low vaccume process," starts rolling off before 1400 HZ, however in the "new" AR-2ax system, its interaction with the 3.5" CTS-built midrange gives it very flat power response right through the crossover region.

[charger3834]

A couple of late 60's 2ax woofers on ebay.

Item number: 230025363688

[pmsummer]

>A couple of late 60's 2ax woofers on ebay.

>

>Item number: 230025363688

Thanks for the heads up.

I found a single 6-bolt foam-surround woofer yesterday on ebay (see pic), so I bought it (being as it matched what I had in one speaker perfectly).

But now, for purity's sake, I'll be watching for a single cloth-surround 10" in the future.

Thanks again for all the insight. I feel like I know something now!

Peace,

P.M.

[pmsummer]

>A couple of late 60's 2ax woofers on ebay.

>

>Item number: 230025363688

Well, I actually did grab those early woofers.

So, I'll soon be listing on AK (or later on ebay), a pair of early-later model woofers (foam surrounds with six-bolt frames...no adapters), as well as probably an early cloth-surround woofer.

I was impatient (surprise) and bought dome oyster jute burlap on Saturday and recovered the grills. I couldn't stand looking at those horribly nicotine-stained grills any long, and for $2 a speaker, I wasn't worried the cost of the new cloth. LOOKS very nice, and I can't hear any muting/muffling of the sound (but these 56 year-old ears do "roll off" at about 15K, I think), although the weave is considerably less open looking than the original material. Carl is sending me some samples of his cloth for my final covering, but these will do nicely for the time being (and are suitable for showing off).

Thanks, folks! You guys are AR-right!

;-)

[charger3834]

>Thanks, folks! You guys are AR-right!

>

>;-)

Good one. Glad to hear you are happy.

[pmsummer]

Cloth surround woofer installed (1968 vintage), burlap grill cloth installed (temporary? maybe). Cabinet oiled-up. Sounds great (especially piano works).

http://www.classicspeakerpages.net/dc/user_files/1578.gif

[charger3834]

Looks pretty good :-)

[Shacky]

Brad,

Was the large Woofer crossover changed between the old and new models? I know the 4 and 6 uf caps stayed the same but thought the resistance of the new tweet and mid changed thos crossover points. I think I remember John O saying the early models had #7 copper coils and newer #5 (or vice versa).

Jim

[RoyC]

Jim,

The #5 coil, which was originally used with the 2ax woofer, was changed to the #7 coil about the time the woofer with the wide flange was replaced. This was probably in 1971 sometime.

In the mid 70's the alnico magnet woofer was changed to a ceramic magnet version, and the tweeter dcr was raised from 6 ohms to 9 ohms.

It was one of my spare 9 ohm mids and Brad's slightly earlier (burned out) midrange, with an attached 3 ohm resistor, that led to that discovery. The #7 coil remained, as well as the original 4uf and 6uf caps.

Roy

[RoyC]

>In the mid 70's the alnico magnet woofer was changed to a

>ceramic magnet version, and the tweeter dcr was raised from 6

>ohms to 9 ohms.

Correction...that should have been "mid dcr was raised...")

Roy

[charger3834]

So Jim, Just to recap what Roy said....In 1970 the cast frame, cloth surround woofer with the cylindrical alnico magnet was dropped. The stamped-steel, foam surround woofer with the alnico "slug" magnet replaced it. Early versions had an oversized, 6 bolt frame matching the size of the original woofer. The tweeter was of course changed at the same time, however the 3.5" mid remains the same. The capacitors also remain the same. This is the basic distinction between the "old" and the "new" 2ax.

The number 5 coil is mostly associated with the old 2ax and the number 7 coil is mostly associated with the new 2ax.

From some of Roy's work it appears that the number 5 coil survived the 1970 change and was changed out later in 1970 or 1971. This is around the same time as the introduction of the smaller frame 4 bolt 10" woofer.

Much later in 1974, a ceramic-ferrite magnet replaced the earlier alnico "slug." This woofer had different midrange characteristics and this is when you see added resistance to the mids. Initially sand-cast resistors were added, then later in 1974 a new 3.5" mid arrives that measures 9 ohms as opposed to 6.5 ohms. The two mids look identical.

Is all this clear as mud ?

[Shacky]

This helps a lot. I have a mix match pair I picked up a few months ago. Both later models. Serial numbers are consecutive but one is a written serial number and looks like it's a service replacement - the entre speaker. One is wood facing, with 4 screww woofer and 4-6 screw adapter ring. The replacement cab is MDF facing, 4 screw woofer and 4 screw openning. I was wondering if there's a diference between the mids in these two. No resistors on mids. Have picked up parts to complete the set - one mid. one woofer, and one tweet not working. It was not a pot problem - cleaned and replaced.

Jim

[onplane]

Jim,

On that non-working tweeter, can you get any reading on an ohm meter?

PS: there is also a very simple test with an ohm meter to deterimine if the pots are really working without opening the speaker box.

Regards,

Jerry

[charger3834]

The mids are probably the same 6.5 ohm versions unless one serial number is well over 200000 and that woofer has the flat, square ceramic ferrite magnet. In this case, you will have either a 9 ohm mid or a 6.5 ohm mid with attached resistors.