Newly acquired AR-78LS

[patrickw]

As I said in my other thread...

I have a newly acquired pair of AR-78LS. There seems to be scant information on these. Though I did see the linked review that was posted in an old thread. 

As I said, I had forgotten I was going to get these speakers as well, so I was a little surprised when I saw how big (and heavy) they were. When I got them home I was not blown away. I was surprised that the surrounds were intact, and aside from the finish needing some renewal they are in great shape. 

But in the last week I hooked them up to a Fisher 400 and I have been pleasantly surprised by these. They have very nice sound, very natural. Not too bright and very nice bass. They also seem to improve the more I run them. From what I understand that can happen with older capacitors as they start to get the current flowing again, they can reform. At first I was certain I would sell these. But now.... hmmm. I may just have to hold on to them.

Does anyone have experience with these? I know the caps are old, do they need to be replaced? I saw an AK thread where someone mentioned doing an LSi upgrade to a pair of 98LS speakers. Is that something that can be performed on these? What are people's thoughts?

Stay tuned for the photos...

 

[patrickw]

Photos...

 

[DavidR]

I had never heard of them either. Below is some info on them - last line (and scroll to the right)

MODEL

INTRO

DISC

SERIAL NO

WOOFER

LOWER MID

MID

TYPE

TWEETER

TYPE

FREQ RESP (Approximate)

SPL

XOVER

POWER        (Min-Max)

OHMS    (Min-Nom)

SIZE

WT

PRICE Each, unless noted

DATE

MODEL

AR-94s

1982

1983

-

8"

-

8"

Cone

1.25"

Cone

44-22k

87 db

350/2000hz

15-125 w

5-6 ohms

31x14x11

43.0 lbs

$230.00

AR-94s

AR-98LS

1982

1985

-

12"

-

8"/1.5"

Cone/Dome

.75"

Dome

39-32k, +/- 3db

87 db

200/1100/5500hz

15-250 w

3-4 ohms

29.5x15.5x10

63.0 lbs

$450.00

AR-98LS

AR-9LS

1982

1985

-

10"/12"

-

8"

Cone/Dome

.75"

Dome

28-32k, +/- 3db

87 db

200/2300/5500hz

25-400 w

3.2-4

52x18.5x14.5

118.0 lbs

$750.00

AR-9LS

AR-18B

1983

1985

-

8"

-

-

-

1.25"

Dome

62-22k, +/- 3db

88 db

2000hz

10-100 w

8 ohms

17x11x6

17.0 lbs

$252.00

AR-18B

AR-28B

1983

1985

-

8"

-

-

-

1.25"

Dome

52-22k, +/- 3db

88 db

5000hz

10-100 w

8 ohms

20x11x7

21.0 lbs

$330.00

AR-28B

AR-58B

1983

1985

-

12"

-

4"

Cone

.75"

Dome

39-32k, +/- 3db

87 db

600/4500hz

20-175 w

3.6-4

27x15x11

49.0 lbs

$700.00

AR-58B

AR-78LS

1983

1985

-

12"

-

1.5"

-

.75"

Dome

39-32k, +/- 3db

87 db

400/5000hz

25-200 w

3.6-4

27x15x12

60.0 lbs

$900.00

AR-78LS

[DavidR]

Very nice BTW

[ra.ra]

And also see this page from the Library literature. With the 12" woofer, 1.5" midrange, and 3/4" tweeter, it appears the AR-78LS could be a distant descendant of the AR-3a. Those look very nice, congrats.

http://www.classicspeakerpages.net/library/acoustic_research/post-classic_series_1981-19/post-classic_series_brochur/ar_ls_b_series_brochure/ar_ls_b_series_brochure_pg5.html

[Stimpy]

Wow, free AR-78LS speakers.  I could get used to a problem like that.  And glad to hear that you're liking them so far.  My recently acquired AR-58S speakers surprised me as well.  Dynamic, with a smooth, even frequency response.  Very good speakers.  Also, here's a AR-78LS crossover schematic, if needed.

 

[patrickw]

 

3 hours ago, DavidR said:

Very nice BTW

 

Thanks, I am really happy with them. Like I said, they seem to keep improving sound wise, becoming more nuanced and natural. 

[patrickw]

2 hours ago, ra.ra said:

And also see this page from the Library literature. With the 12" woofer, 1.5" midrange, and 3/4" tweeter, it appears the AR-78LS could be a distant descendant of the AR-3a. Those look very nice, congrats.

http://www.classicspeakerpages.net/library/acoustic_research/post-classic_series_1981-19/post-classic_series_brochur/ar_ls_b_series_brochure/ar_ls_b_series_brochure_pg5.html

Funnily enough that is exactly what the guy who was selling the 3A's told me, that I was getting the original 3A plus the updated version of the 3A. I don't have my 3As running yet (they work, but there are a few weak points to be detailed in another thread when I get to them...), so I am really enjoying the sound of these. 

 

[ra.ra]

1 minute ago, patrickw said:

....that is exactly what the guy who was selling the 3A's told me....

I have every reason to suspect this guy might have been a straight shooter, but sellers throughout history are known to make extravagant claims - - some people call it "the art of the deal". Nonetheless, despite this mid and tweet being streamlined into a single unit, there are a few uncanny resemblances with the 3a, at least with regards to the driver count and their relative sizes, and I suspect you've got a very fine loudspeaker in your stable. Without scrutinizing the performance specs and crossover configurations, I don't think it's far-fetched to see the evolution from the AR-3a to the AR-91 to the AR-58s and then to the AR-78LS and so on.  

[patrickw]

2 hours ago, Stimpy said:

Wow, free AR-78LS speakers.  I could get used to a problem like that.  And glad to hear that you're liking them so far.  My recently acquired AR-58S speakers surprised me as well.  Dynamic, with a smooth, even frequency response.  Very good speakers.  Also, here's a AR-78LS crossover schematic, if needed.

 

 

Yes, in one sense they were free. 

Or you could say that I bought these at their for original 1983 prices of $900 and received a free pair of 3As that need a little work. 

Thanks for the schematic. Has anyone re-capped these? The other thing I am noticing is that the speaker terminals are not the best. Has anyone had experience replacing those on this era of AR speakers? Are there recommended products to update the terminals? Ideally I would like terminal binding posts that could accept banana plugs. 

Thanks!

-Patrick

 

 

[patrickw]

5 minutes ago, ra.ra said:

I have every reason to suspect this guy might have been a straight shooter, but sellers throughout history are known to make extravagant claims - - some people call it "the art of the deal". Nonetheless, despite this mid and tweet being streamlined into a single unit, there are a few uncanny resemblances with the 3a, at least with regards to the driver count and their relative sizes, and I suspect you've got a very fine loudspeaker in your stable. Without scrutinizing the performance specs and crossover configurations, I don't think it's far-fetched to see the evolution from the AR-3a to the AR-91 to the AR-58s and then to the AR-78LS and so on.  

Indeed. I am pretty happy with the speakers and I do think it is a very fine loudspeaker.

I did not mean to imply that I felt I was hoodwinked. More I was like you, a bit skeptical when I was told of the claim that the speaker was an update of the 3A. As a large three-way speaker I could see the basis for making that assumption.

But honestly I was not expecting much from these speakers, knowing they came from the later era of AR, and especially since the first time I hooked them up I was not blown away. But they keep sounding better. And the more I poke around and turn over rocks looking for info, the more I see that these were well engineered, top of the line loudspeakers. They truly sound sweet. 

[DavidR]

10 hours ago, patrickw said:

I was not expecting much from these speakers, knowing they came from the later era of AR, and especially since the first time I hooked them up I was not blown away.

They were made in the Teledyne years. Many of AR's top speakers were made under them - the 9 Series. If you asked me what happened to AR I'd have to guess it was poor marketing and a higher priced product than competitors. It's a shame. Put some fresh capacitors in them and they will sound even better.

[Stimpy]

13 hours ago, patrickw said:

Yes, in one sense they were free. 

Or you could say that I bought these at their for original 1983 prices of $900 and received a free pair of 3As that need a little work. 

Thanks for the schematic. Has anyone re-capped these? The other thing I am noticing is that the speaker terminals are not the best. Has anyone had experience replacing those on this era of AR speakers? Are there recommended products to update the terminals? Ideally I would like terminal binding posts that could accept banana plugs. 

Thanks!

-Patrick

 

 

I used these Parts Express binding posts, when I recapped my AR-90's.  They were the same length and thread pitch, as the originals.  They worked perfectly for me.

As to recap's, that's a debatable subject.  But, for my two-cents, I do it, and like the differences in sound, from fresh caps.  I usually use polypropylene caps for at least the series values, then usually NPE's (Mundorf E-Caps or Bennics) for the shunt/parallel values.  For my 90's, I used decent Mundorf poly's (EVO Oil).  For my 58S AR's, I'm using ClarityCap ESA's for the 2 series caps, and Bennic NPE's for the shunts.  The ESA's were on sale, and the final cost was around $65 for all of the 58S caps.  I hope to finish the 58S recap this weekend.  The 90's have been recapped, but I'm refinishing the cabinets too, and that might push that project into the Spring.

Good luck.

[patrickw]

6 hours ago, Stimpy said:

I usually use polypropylene caps for at least the series values, then usually NPE's (Mundorf E-Caps or Bennics) for the shunt/parallel values. 

Sorry for the questions of noob, but in your schematic that you posted would the 3uF, 5uF and 24uF be the series values, while the 60uF and 12uF be the shunt/parallel values? I would not want to buy the wrong caps.

I am attaching a photo of the terminals. I think I would have to look for binding posts that might work as a replacement for the whole unit.

 

[lARrybody]

I always replace those spring loaded clips with these from Parts Express.

 

https://www.parts-express.com/parts-express-gold-plated-banana-5-way-speaker-wire-binding-post-terminal--260-302

[ra.ra]

Yes, patrickw, you are reading the schematic correctly.

There are a few members here that have used a very good simple dual-post terminal from parts express that works very well, and this is the solution I used for a pair of AR-18s speakers.

 

[patrickw]

50 minutes ago, larrybody said:

I always replace those spring loaded clips with these from Parts Express

 

https://www.parts-express.com/parts-express-gold-plated-banana-5-way-speaker-wire-binding-post-terminal--260-302

Those look great. Thank you!

 

46 minutes ago, ra.ra said:

Yes, patrickw, you are reading the schematic correctly.

There are a few members here that have used a very good simple dual-post terminal from parts express that works very well, and this is the solution I used for a pair of AR-18s speakers.

 

 

Thanks for the info on the schematic, ra.ra. I love your classic solution for the binding posts!

[ra.ra]

1 minute ago, patrickw said:

Those look great.

He posted a few minutes before me, but I was thinking of Larry's solution when I made my first comment about the terminals - - this PE product is an excellent, inexpensive, replacement part which accepts multiple wiring options.

We'll be interested to hear how your 3a project develops, but this model (AR-78LS) doesn't show up very often so it makes for an interesting thread.     

[patrickw]

4 minutes ago, ra.ra said:

He posted a few minutes before me, but I was thinking of Larry's solution when I made my first comment about the terminals - - this PE product is an excellent, inexpensive, replacement part which accepts multiple wiring options.

We'll be interested to hear how your 3a project develops, but this model (AR-78LS) doesn't show up very often so it makes for an interesting thread.     

 

I appreciate both of you chiming in. I am going to order those terminals from PE for when I decide to do the recap on the AR-78LS. 

Stay tuned for the 3A thread. I have the photos, I just have not opened them up yet. 

 

 

[DavidDru]

I bet those are good.

So are we always going to say any 3 way with a 12" woofer from AR is a descendant of the AR3?  At this point in the chain I am not sure what the 3 or 3a would have to do with a 3-way 12" design.  

[ra.ra]

6 hours ago, DavidDru said:

So are we always going to say any 3 way with a 12" woofer from AR is a descendant of the AR3? 

Hi David - - my brief comment on the evolution of AR's 12" 3-ways was mostly based on driver size and arrangement - - the 78LS uses the p/n 003 woofer, a 1-1/2" dome mid, and a 3/4" dome tweeter - - not unlike its ancestors. A very good discussion of the 78LS is found in the thread shown here, including a 1984 High Fidelity review. 

Read the thread, and if you do not agree that the 78LS is part of this lineage, that's fine, but then make your argument.

But the answer your question is no - -  I don't think anyone is trying to make the case that the AR TSW 610 (12" woofer three-way) has much in common with the AR-3 lineage.

 

[DavidDru]

My comment was just that, a thought out loud comment and general question.  Not pointed specifically at your feedback on these specific speakers ra ra.  It's just interesting  to me that so many other later models from AR are looked upon this way, where in general most are just 3-way designs like many other brands.  I would guess it would depend on how different the drivers were at this point.  The enclosure is different.  Crossovers are different etc

Maybe I am wondering if it's a fair thing to do and wondering if it's only because it's the same brand.  Thought I would throw out the question and get people thinking and responding.

[ra.ra]

1 hour ago, DavidDru said:

Not pointed specifically at your feedback...

Yes, I understand David, and perhaps I hastily worded my response a bit defensively - - - not intentional at all. I simply thought maybe you were seeing something that I could not, and was therefore interested in your observations. I agree with your points that, for various reasons, each of these models included differences with internal components, cabinet styling and even mid/tweet driver designations, but I think it is not a stretch to see these multiple models as an evolving product line which shared several unifying principles.

We're just talking here about AR's 12" three-ways, and while this analogy of mine may indeed be a bit of a stretch, compare this product line-up with the auto industry approach. If we can accept the notion that there is some flowing connection between the AR-3 and the A-78LS over the course of more than 25 years - - with certain revisions more significant than others - - at least Acoustic Research typically opted to change the product model name/number at least a half dozen times over this period in order to differentiate. With automobiles, generally the variations within a model are defined by product year and options "packages". In both style and performance, there is not all that much similarity between a 1953 Corvette and a 2017 Corvette, but a strong and lasting "brand" has been developed by keeping the original model name. At least the 'Vette over 64 years has remained the quintessential American sports car , but I would suggest that perhaps there is a stronger consistency of product in the AR speaker lineage with all of its model number changes than there is in the Chevrolet two-seater that has retained its original name for more than half a century.  

I am no kind of marketing guy whatsoever, but in our consumer society, it is interesting to think about brand loyalty, buyer's trends, and product line evolution, and then view these things through the lens of revisionist history.       

[DavidDru]

The car analogy is a good one.  One would wonder what would have happened if AR had kept the model number going and just made changes to it over the years like they seemed to do for a while with various models (3 -3A, 2-2a-2ax etc).  At some point they either felt the design changed enough to call it something else, or the marketing people finally got their way.

No doubt, the 3 and 3a were the industry standard for write some time and I am sure other speakers manufacturers probably tired of being compared any time they came out with a 3-way design of similar proportions.   

[nfmisso]

Just to add my $0.02 - which maybe worth less than two cents. 

I see the AR 12" 3 way lineage as: 

AR3 -> AR3a -> AR10pi/AR11 -> AR58s "bookshelf speakers"

and the AR91 (and AR91.5) branching of to floor standing vertical speakers -> AR78LS/LSi which is the end of the line.

The AR58B due to it's cost reduction does not fit into the lineage, and the TSW stuff are totally different.

The later AR303 is a nice resurrection.

My current collection (operating): pair of AR91 & a pair of AR91.5; (need work) pair of AR9 and AR93.

Nigel