AR3/AR3a guidance needed

[mrbruce4]

 

Recently had an opportunity to buy a pair of AR3s from their second owner.  This owner has had them since the 70s and simply wanted to get rid of them, and also threw in 6 inch tall AR stands.  Serial nos. are C43341 (speaker #1) and C43394 (speaker #2).  Woofers and tweeters appear identical but the midranges are different, as are the crossovers.  Drivers produce sound with leads connected to the fronts of mids and tweeters.  Woofers are also responsive.  Cabinets and grills are in excellent condition, with the exception of a dark spot on the top of one.

I've looked through the Restoration guide which is full of great info.  Both tweeters seem to be the AR3 version but midranges seem to be style A.13 (speaker #1) and A.11 (speaker #2)  Crossover for speaker #1 has the additional 6 mfd capacitor (apparently for the AR3a), while speaker #2 has the AR3 crossover.  Neither speaker has any indication that it was ever opened before I removed the woofers.

I had ordered 24 and 6 mfd polypropolene capacitors (1 each for each speaker) before I opened speaker #1 (with the apparent 3a crossover), tonight. It now appears I will need to get one more 6 mfd but welcome advice.  I ordered the capacitors based on the close serial numbers and the crossover schematics for the serial numbers (i.e. both well below 70228).

I expected, and hoped, for the refurbishment to be easier than this.  I have put in new caps for AR4x and AR2ax in the past, but have not owned AR3s previously.

The guidance I would like is regarding whether I need to do anything beyond the new capacitors, and cleaning the pots, for these 2 to sound similar.  I would like these to sound the same and am less concerned about them being identical.

Thanks

Bruce   Tucson, AZ

 

 

 

 

 

 

 

 

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[ra.ra]

HI Bruce, those look like fantastic speakers.

My guess at what's going on is pretty much explained by this document which outlines the history of the AR-3 crossover. Based on your serial numbers, I suspect both speakers originally had the single coil x-o shown in Part C. At some point the midrange in speaker 1 went bad and was replaced with an AR-3a midrange (due to lack of original AR-3 mids) and the two crossover revisions shown in Part D: addition of 6uF cap and a second coil, as confirmed by your pics. Looking at the variety of drivers shown in the 3a restoration manual, I think your speaker #2 mid is the A.9 version; and the mid in #1 appears to be the A.13 or A.14 variety. 

Replacing caps is probably a very good idea, but you should not neglect making the effort to examine, evaluate, and restore or replace the variable level controls for the mids and tweeters. This is every bit as important as having accurate caps for the proper HF performance.

One thing of interest is the addition of the triangular corner panels and the Velcro tabs, to facilitate future grille removal, I presume. It is quite possible that this was done at the same time that the mid in speaker 1 was replaced, since these corner pieces were not original features. They appear to have been installed very well, but I am curious whether this results in the grille fabric sitting further forward than originally intended? 

[stupidhead]

39 minutes ago, ra.ra said:

 

One thing of interest is the addition of the triangular corner panels and the Velcro tabs, to facilitate future grille removal, I presume. It is quite possible that this was done at the same time that the mid in speaker 1 was replaced, since these corner pieces were not original features. They appear to have been installed very well, but I am curious whether this results in the grille fabric sitting further forward than originally intended? 

 

Good guidance/info from Robert, and I too am interested in the Velcro tabs and the resulting depth of the grille.

Geoff

[mrbruce4]

Ra.Ra -  Really appreciate your thoughts.  Certainly possible a midrange had to be replaced, but both cabinets looked truly undisturbed.  If someone did have to have a midrange replaced (possibly even by the factory?), they did a very good job of matching the putty and paint on the baffle.  After I bought them, I called the previous owner to ask how long he had owned them and whether he had done anything to them.  They were such a giveaway price ($80) that he would have no reason to shade the truth.  He said he got them in mid 70s, while in Indiana, and brought them to AZ in early 80s.  He said he had not done anything to them other than listen since he owned them.  When I first saw them, they were in his workshop garage and he said that is where he always listened to them!  Selling them because they were retiring and selling the house and travel in their RV. 

Our low humidity may have helped minimize pot corrosion.  I have already removed and cleaned the pots in the #2 speaker.  Both looked quite clean with very little corrosion.  (Much less than what I have found in 4x and 2ax sets that I have come across in Tucson.)

Since I ordered caps from PE before I knew about the additional 6 mfd cap, I'm thinking about just buying a NPE cap locally, rather than pay PE more for shipping than for a single cap.  Thoughts from anyone would be appreciated, as it relates to difference in sound of an NPE vs. a Solens.  (Please note that I toss around terms pretty easily but am not much of a tech.)  What I know was learned from years of reading CSP and AK!

Thanks in advance.

[mrbruce4]

Forgot to answer about the grills.  When they are in place the grills are as close to flush with the cabinet face, as a visual look would find.

Original grill fabric is in near perfect condition.  I don't see any snags, etc.  Personally don't like the look of the stuff.  Prefer the linen look, but recognize the original appeals to some.  If I keep these, I may make new grill frames, save the originals, and put cloth on the new frames.

[genek]

What kind of fabric is on the grills? Is it the original waffle weave, or the later linen?

[stupidhead]

$80.....wow.

as for sonic difference in cap brands, it is a Pandora's box question and you can get all sorts of responses. The most important thing is replacing with new if old are found to be out of spec, which yours likely are. If there is any real difference in sound it is marginal. I tend to use Solens mid grade as a rule, but less expensive caps are fine as well.

 

[mrbruce4]

Genek - Attaching a photoof grill cloth.

Stupidhead - Thanks for the comment on caps.  Believe I will just buy an NPE locally for the "extra" cap requirement.

JKent - Thanks for the email.  I'll be monitoring responses closely.

[RoyC]

1 hour ago, mrbruce4 said:

Ra.Ra -  Really appreciate your thoughts.  Certainly possible a midrange had to be replaced, but both cabinets looked truly undisturbed.  If someone did have to have a midrange replaced (possibly even by the factory?), they did a very good job of matching the putty and paint on the baffle.

Ra.ra's assessment is right on the money. Your AR-3's were manufactured in the mid-60's and were originally identical based on the serial numbers alone. The converted back to front-wired midrange driver was built in the mid 70's, and was used in the LST, AR-11, 10pi and last 3a. The original AR-3 mid had not been available for quite some when this repair was required. The added crossover components are also later AR parts, which suggests the speaker was sent to the factory or the AR repair center,  AB Tech Services, for repair at that time. The screw through the center of the added #4 inductor shows it is definitely an added repair part.

The replacement mid was matched with the appropriate crossover changes, but new replacement capacitor types will initially be the least of your concerns if you hear differences. Besides having different construction and sonic characteristics, the original AR-3 mid has been showing signs of degradation these days. In fact, the 2 speakers, though close,  probably did not sound precisely the same after the mid was replaced.

Roy

[ra.ra]

2 hours ago, mrbruce4 said:

Original grill fabric is in near perfect condition........Personally don't like the look of the stuff.  Prefer the linen look....

That grille does appear to be in exceptional condition, and like yourself, I very much like the linen and walnut combination look of the classic AR's. However, the weave and texture of the AR-3 fabric really does account for its unique appearance, and over time, I think you may begin to appreciate its distinctive visual characteristics, particularly if you have the correct badges to give it the "full Cleveland".

2 hours ago, mrbruce4 said:

.....such a giveaway price ($80) .....He said he got them in mid 70s, while in Indiana,

Not a bad price at all, but since I also acquired my first AR's while living in Indiana in the early 70's, I would have tried to talk the guy down to $75 to cash in on a friendly Hoosier discount. 

25 minutes ago, RoyC said:

Besides having different construction and sonic characteristics, the original AR-3 mid has been showing signs of degradation these days.

This is such an important point that you might even want to begin long-term planning to eventually replace the original mid in speaker #2 as its performance continues to diminish. This process, of course, would require the addition of the 6uF cap and 0.4 mh coil into speaker 2 at that point. 

Regarding new cap, there's no reason a locally purchased 6uF NPE won't work fine, but since you're already using new poly types, it might be nice to complete the mid circuit with poly caps. But yes, paying add't shipping for a single cap order is ridiculous , so perhaps someone here has an unused spare cap in their parts bin that could be mailed in a simple envelope. I'll try to look through my stash in the next day or so.

[mrbruce4]

RoyC and Ra.Ra - I greatly appreciate your institutional knowledge, insights and things for me to consider.  I will go back through threads and start looking for an approach that replaces the other midrange (based on Roy's expectation of the older midrange eventually requiring replacement.

Surprisingly, "AR Inc." badges, 1" square, were screwed into the rear of each cabinet.  No "3" badges were there though.