Does it make sense that my 3's sound so different then my 3a's?

[samberger0357]

Cause they do.  My 3's date to '64, restored(not by me) with Russian oil caps, new ohmite pots, redoped woofers. The 3a's date to early 70's, restored(not by me) with caps that are electrolytic in the low 
section , a mix of polyprops in the mid section --
large Axon with a Wima MKP bypass -- and an Erse polyprop for the
tweeter, and refoamed woofers. 

One of the 3's has had some additional work and wiring after I had some issues(amp caused) with the woofer, and later the mid. The highs are a little less then the other. It doesn't really bother me much, and I have a separate channel treble control on my amp that allows me to make up for the small discrepancy.  I love these speakers and they deliver a beautiful presentation, particularly with small chamber music and jazz. 

The 3a's are much more lively, and the bass is more pronounced. I know that most folks prefer the cloth woofer, and it does have a personality all it's own, but on mine the later, foam woofer of the 3a's go deeper. And the highs on the 3a's are sharp and clear, sparkling. Crisp. The 3a just sounds much more modern, for lack of a better term. They were restored more recently and it's possible that the caps are still being broken in, and perhaps that will lead to a little less crispness going forward. 

It's really something how different these speakers sound from each other. I suppose it's why I liked stacking them. They really complimented each other. That said, I'm preferring to use a smaller amp these days(McIntosh 1700) that sounds great with both pairs of speakers, but wouldn't have close the juice needed to drive both pairs simultaneously. 

I also have my 3's horizontal, about 24" off the ground, while my 3a's are on replica AR stands about 11" off the ground. No doubt, that could explain, at least partially, the bass difference. But I've used my 3's on the same stands and while the bass does go deeper as they're closer to the floor, it's still, seemingly, not as pronounced as the 3a's and their foam woofers.

I suppose we can all theorize as to why they sound different, and that would be great. I'm always interested in others opinions and experience.  I just thought it was interesting enough to document here. 

[Liangshan Marsh]

Hi Sam!

Later have a time I will hook up the AR3s and 3a serial C-8xxx via Dynakit ST 70+ Pas3 for test and hope some one may judge it, which one is better.. because my ears were not accurate..

Edited: Adding video clip..

Due to the original, old age of tweeter, midrange, XO on both the AR3s and AR3a that might not meet the equally original working condition of both and not properly test equipment so these video clips are non-purpose about the comparing.., just for reference only, Thanks for watching.

 

[samberger0357]

Thanks Liangshan. 

 

Just to clarify, I should've said that the title to my post is more or less rhetorical, in that I'm sure it "makes sense" that the speakers sound different. I mean, they're different speakers! And to be sure, I like that about them. 

And certainly, I'm not attempting for others to determine which is better, although if they want to pass along preferences that's cool. I'm simply trying to articulate my own experience, and some surprise, as to how different they do sound. I wonder back when the 3a went to a foam woofer, if the sound was much different to a '64 3(were they still using oil caps in the 3's at that point?)?

Anyway, I'll look forward to hearing your speakers Lliangshan, especially with the ST70, as I would love to add an affordable tube amp for the speakers, especially the 3's. There is a set of Dynaco MKIII's in my area being advertised on CL that I've inquired about. Still waiting to hear back from the seller. 

[fedeleluigi]

There have already been some topics about today's differences between AR3 and 3a sound .

 

http://www.classicspeakerpages.net/IP.Board/index.php?/topic/8815-difference-in-sound-between-ar3-and-ar3a/#comment-107669

 

http://www.classicspeakerpages.net/IP.Board/index.php?/topic/9195-stopped-for-toilet-paper-found-a-pair-of-ar3s/&do=findComment&comment=111657

 

It's very  strange that you can listen to evident differences in bass frequencies but when comparing loudspeakers they should be exactly placed in the same position otherwise the differences you note could only depend on speaker positioning.

 

Although old reviews that compared perfect functioning loudspeakers said that the differences between AR3 and AR3a were subtle, today, after about 50 years,  things are different.

 

Today, AR3s  often have problems especially with midranges (low midrange output) whereas AR3as very often have problems with tweeters (low tweeter output).

 

Luigi

[ar_pro]

This is a very interesting topic, involving a direct comparison of what were certainly AR's two most iconic speakers.

As noted in some of the original testing & observations of the AR-3a, the most significant difference appeared to be an improvement in HF dispersion over the AR-3.

And Luigi makes an excellent point - any comparison now will need to deal with the variables brought on by the drivers' age, especially the foam-supported phenolic domes. This could certainly be why you notice a difference between the two AR-3 systems.

Sam - the Mark III is a really nice, virtually bulletproof tube amp that sounds a lot more powerful than its 60-watt rating. I've heard them in systems with the AR-2ax as well as the AR-3, and it's a very musical combination. In the '80s, I owned a single Dyna Mark II that had been left out in the rain, but the transformers were still good, and once the PC board had been cleaned & re-populated, the metal chassis re-plated, and new tubes installed it sounded great - nearly as good as a classic Harman/Kardon or Mac. And the Mark III is even quieter & more powerful than the II. Just be careful of those high voltages if you ever open it up - keep one hand in your pocket!

 

[samberger0357]

2 hours ago, fedeleluigi said:

There have already been some topics about today's differences between AR3 and 3a sound .

 

Thank you Luigi.

 

1 hour ago, ar_pro said:

Sam - the Mark III is a really nice, virtually bulletproof tube amp that sounds a lot more powerful than its 60-watt rating. I've heard them in systems with the AR-2ax as well as the AR-3, and it's a very musical combination.

 Yes, I've read pretty much on the subject and those you've cited are very interesting

 

2 hours ago, fedeleluigi said:

It's very  strange that you can listen to evident differences in bass frequencies but when comparing loudspeakers they should be exactly placed in the same position otherwise the differences you note could only depend on speaker positioning.

Well that's part of the reason I started the thread. I have compared the speakers positioning the same and still detect a lower bass response from the 3a's then the 3's. Not drastic, and the 3's do provide very satisfying, realistic bass, but it's there. I wonder if it might have to do with redoping the cloth surrounds vs. new foam surrounds. It would seem that doping the cloth is less an exact science then simply adding new surrounds. I may very well be wrong, but it is my assumption. When doping, you could use too little or too much, which is not possible when just using new, replacement surrounds. 

 

I

1 hour ago, ar_pro said:

the Mark III is a really nice, virtually bulletproof tube amp that sounds a lot more powerful than its 60-watt rating. I've heard them in systems with the AR-2ax as well as the AR-3, and it's a very musical combination. 

That's what I've heard. Hope to have a pair at some point. 

[fedeleluigi]

9 hours ago, samberger0357 said:

I wonder if it might have to do with redoping the cloth surrounds vs. new foam surrounds. It would seem that doping the cloth is less an exact science then simply adding new surrounds. I may very well be wrong, but it is my assumption. When doping, you could use too little or too much, which is not possible when just using new, replacement surrounds. 

Yes, a not correct dope for the woofer cloth surrounds, but also a wrong foam surround for the ferrite woofer can change the Thiele and Small parameters of the woofer itself and consequently its performance in the same enclosure volume.

I would have carefully tried a solvent like toluene in the hope that it could refresh and revive the old dope instead of using a dope of "unknown characteristics".

Talking of this subject, does anybody know what AR exactly used to dope cloth surrounds?

Luigi

 

 

[samberger0357]

The 3 woofers were redoped with the stuff that vintage-ar makes/sells on Ebay. I assume you know of it but if not do a search.My understanding is that it's pretty much the same as original.  My concern would not be with the solvent, but how much was used. 

The foam surround was done by Carl of Carl's Custom Loudspeakers. Again, do a search if you're not familiar. 

FWIW, here is the restoration thread on Audiokarma for the speakers I now own:

http://audiokarma.org/forums/index.php?threads/ar3s-so-pretty-i-couldnt-resist.642340/page-4

 

 

[RoyC]

The AR-3 and AR-3a are different speakers, and were never meant to sound the same. The two models share a cabinet of the same internal volume, and only the early 3a has essentially the same woofer as the 3. Everything else is different...drivers, crossovers, even amounts of cabinet stuffing. (Consumer Reports magazine actually preferred the AR-3 and the AR-2ax to the AR-3a back in the day...so there were definite differences between the 3 and 3a when they were new).

Making a meaningful comparison between any two pair of these two models today is pretty hard to do. Version, degree of sometimes significant wear/degradation of individual drivers, and the quality of repairs are huge variables. I work with these speakers all the time, and differences can often be heard between restored specimens of the same model.

The cloth surround of the early woofer is actually the very least of these variables. We conducted many measurements when we were putting together the 3a restoration guide, and subsequent to that I worked with these woofers a great deal when developing the solution mentioned above. The fact of the matter is these woofers seldom require re-treatment. When they do, a light application of the toluene/butyl solution is usually all that is needed. The original sealant is still present in the cloth, so it is not wise to add much of anything to the surface that can add mass or potentially decrease compliance.

On the other hand, different iterations of the later woofer, and worn/replaced spiders can result in noticeable differences in bass response. Foam surround replacement type and workmanship can also result in performance variations.

Roy

[samberger0357]

51 minutes ago, RoyC said:

The fact of the matter is these woofers seldom require re-treatment. When they do, a light application of the toluene/butyl solution is usually all that is needed. The original sealant is still present in the cloth, so it is not wise to add much of anything to the surface that can add mass or potentially decrease compliance.

Thanks Roy. I'm hoping that the redoping that was done to the 3's was done correctly, and hasn't affected negatively the woofer performance. I suppose there is not much I can do about it at this point.

[RoyC]

7 hours ago, samberger0357 said:

Thanks Roy. I'm hoping that the redoping that was done to the 3's was done correctly, and hasn't affected negatively the woofer performance. I suppose there is not much I can do about it at this point.

The treatment sold by Vintage AR is my stuff, and is not likely to be the cause of the differences you describe between the early and later woofers. It is deliberately made to be thin and remains a bit tacky to prevent the usual issues associated with "re-doping" a cloth surround. If you believe you may have applied too much, you can easily remove it with toluene or xylene. Goo Gone will also work fairly well. Contact me if you need further guidance.

The earlier woofer tends to have a more damped response than the later version, and the way it is implemented in the AR-3 may account for some of the difference you hear. The amount and type of cabinet stuffing, and room placement, are also two potentially significant variables to consider. Having just re-read your comments at the top of this thread, I can say with confidence that "breaking in" caps are never going to be the cause of the differences you describe...much less anything else of consequence.

Roy

[samberger0357]

Hi Roy,

 

Thanks again for the advice. If you look a couple posts of mine back, you'll find a link to a Audiokarma thread that I provided on the restoration, not ny me, of the 3's that I eventually came to own. I believe you had some participation in the restoration as well. I wasn't the one who redoped the woofers so I don't know if the amount used was correct or not. I'm really not concerned because the bass response from the speakers is fine imo. But it is not as pronounced as the 3a's, which brought about my original comments. You have helped to clarify that the differences could be looked at as normal. So thank you!

[RoyC]

7 hours ago, samberger0357 said:

Hi Roy,

 

Thanks again for the advice. If you look a couple posts of mine back, you'll find a link to a Audiokarma thread that I provided on the restoration, not ny me, of the 3's that I eventually came to own. I believe you had some participation in the restoration as well. I wasn't the one who redoped the woofers so I don't know if the amount used was correct or not. I'm really not concerned because the bass response from the speakers is fine imo. But it is not as pronounced as the 3a's, which brought about my original comments. You have helped to clarify that the differences could be looked at as normal. So thank you!

I remember the project (and your mids). They are beauties!

I'm going to go out on a limb and suggest the amount of stuffing in your cabinets may account for a fair amount of the difference you are hearing. The AR-3 and early 3a had much more stuffing packed into their cabinets than the later 3a with the foam surround woofer (32 to 36oz vs 20oz).

Roy

[samberger0357]

15 minutes ago, RoyC said:

I remember the project (and your mids). They are beauties!

I'm going to go out on a limb and suggest the amount of stuffing in your cabinets may account for a fair amount of the difference you are hearing. The AR-3 and early 3a had much more stuffing packed into their cabinets than the later 3a with the foam surround woofer (32 to 36oz vs 20oz).

Roy

They are indeed! After almost 2 years  I still can't stop looking at them. 

The stuffing is an excellent thought. Would certainly make sense. 

I've been playing with positioning of my 3's, and now have them closer to the back wall, about 1-2" from it, and that has helped the situation even more. 

 

Thanks again for your valued input. 

[Sonnar]

My AR 3 sounds very clean , sparkling and have a more " open " sound than AR 3a . In the video I drive it with QSC but things are even better with the 1.5 Kw Crown Macro Tech 2402 . I recapped the x-overs with polypropilene german-made Mundorf caps ( very expensive ). Adriano

20170220_191854.mp4

[samberger0357]

32 minutes ago, Sonnar said:

My AR 3 sounds very clean , sparkling and have a more " open " sound than AR 3a . In the video I drive it with QSC but things are even better with the 1.5 Kw Crown Macro Tech 2402 . I recapped the x-overs with polypropilene german-made Mundorf caps ( very expensive ). Adriano

20170220_191854.mp4

Interesting. That's different from what I hear. Just the opposite, really.  I prefer my 3's, but find them more laid back, and a little darker overall then my 3a's. As Roy has indicated, there could be any number of reasons for this, so I'm not concerned. Your's sound excellent, btw. 

[Sonnar]

Serial numbers of mine are C 61229 / C 61224 , probably close to the end of production. Mids are very neutral , female voices , horns , piano,  but AR 3a mids are slightly more in evidence , while the  level of high frequencies in  AR 3's tweeter is really more audible and sparkling than 3a's . In fact, orginal frequency response by AR shows a rool off of 6 db in AR 3a's tweeter response while AR 3's tweeter is absolutely flat to 20 Khz . 

[samberger0357]

My 3's have serial numbers in the 30xxx area, and date to 1964.  And as yours the mids are neutral, the overall presentation more natural. I know Roy does not put much credence in differences in caps, but I do feel that the NOS oil caps used in the 3's vs. the new polyprops and electrolytics used in the 3a play some role in the differences that I'm hearing. And of course as Roy pointed out there may very well be significant enough differences in the stuffing used in both speakers to influence the sound as well. 

[Sonnar]

Roy is right. Caps doesn 't have influence on sound. I use polypropilene because of its precision and because they last for a very long time. I left the same original damping material inside ( rock wool ? Fiberglass? It's yellow ) and new mortite around woofers for a perfect seal. 

[RoyC]

9 hours ago, samberger0357 said:

 I know Roy does not put much credence in differences in caps, but I do feel that the NOS oil caps used in the 3's vs. the new polyprops and electrolytics used in the 3a play some role in the differences that I'm hearing.

Again, I seriously doubt it in this case...

If you were to remove your AR-3 mids and put a music source to them as they sit on the bench in front of you, the difference you would hear between the one I repaired for you and the untouched one would likely surprise you. It is not just a matter of the repaired mid being more sensitive/louder, it is the difference in extension into higher and lower frequencies. These differences often exist in AR-3 and AR-3a tweeters as well. I've had dozens of these drivers lined up in a row, and the response variation is always all over the place, yet they are fully "functional". To believe these differences, even if they are small, are somehow superseded by extremely fractional differences in capacitor performance (or alleged brand-related characteristics) is simply not practical.

The level controls will also compensate somewhat for differences in capacitor series resistance, yet the old pots can also vary quite a bit. They routinely vary from just below 15 ohms to just over 16 ohms. When this occurs there is a difference between series and parallel resistance, albeit small, at each pot setting. This not only affects output, but (very slightly) the crossover point. It is not a big deal, but it is huge compared to any differences between properly functioning capacitors.

It should also be noted that, unlike the 3a, there are no capacitors in the AR-3 woofer circuit.

Roy