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Vintage Infinity Model differences

Discussion in 'Infinity Loudspeakers' started by Schiada788, Nov 15, 2018.

  1. Schiada788

    Schiada788 New Member

    Messages:
    3
    Can anyone shed light on the difference between early 80s A & B versions of the RS 3&4?
     
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  2. jimreeves

    jimreeves Poopy & Me Subscriber

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    4,446
    Location:
    New Port Richey, FL
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  3. goodolpg

    goodolpg Just an old fart trying to help. Subscriber

    This has been discussed before, as part of another thread. Not sure what thread of course.
    If I am remembering correctly, the main differences are the fuse location (exterior for one (b model), interior for the other (a model)) and color of the lettering (red for b model, blue for a model) on the dome mids and EMITs face plates.
     
    Last edited: Nov 16, 2018
  4. Schiada788

    Schiada788 New Member

    Messages:
    3
    Interesting site. They don't necessarily break out any differences between the 3a &3b, and 4a&4b. Sounds like they may be same other than “year model”. Same drivers and crossovers...?
     
  5. Brunt

    Brunt New Member

    Messages:
    46
    Location:
    San Diego
    Speaking from experience knowing owners of 3as and 3bs, and listening to two pairs of 3s (no a or b) from prospective sellers, the 3a and 3bs are almost identical. The 3s have a completely different cabinet and driver setup. 3s have polycone mid vs 3a/bs have polydome mid along with totally different cabinets.

    The crossovers are likely a little bit different between the a and b models as well, but then again infinity was well know to go through several crossover revisions during a single production run of speakers based on the parts available and the newest discovery of theirs to make things sound that teeny tiny bit better.
     
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  6. Tedrick

    Tedrick Infinity-phile Subscriber

    Messages:
    7,046
    Location:
    Gainesville, FL
    RS III a & b - the only difference is cosmetic. The print color and style on the Polydome and EMIT mounti6pkates is different. Otherwise, they are identical.

    RS 4 & 4b - there was no 4a. The 4b had an integral base that lifted the speaker up about 4 inches and tilted it back a few degrees; the 4 did not. They also shared the same cosmetic differences as the IIIa & b. Otherwise, they were identical.

    I've ownd IIb's, IIIb's, and 4b's at various times.
     

     

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  7. dcmaster

    dcmaster Infinity Lover

    Messages:
    112
    Location:
    germany, RLP
    Hi there,
    ok, I'm the website owner, but I'm not god :angel:. Some words to the 3 a/b. There are very differences between the versions A and B. Once there are different configurations of the chassis (all). The basses are once with curved membranes with bright dustcap (B) and straight membranes with dark dustcap (A). The colors of the labels on the polydomes and emits are once red (A) and gray / blue (B) and there are different type.

    In addition, the crossovers in the assembly are different. Version A has at the bass a capacity of 600μF and B of 1200μF. The crossover coils for the bass also are differnt. There are 40 mH (A) and 50 mH (B). You can see, there is a difference. The crossover parts for mid and high are the same in A and B.

    I hope I could shed some light on the models.

    Best wishes Klaus
     
    Last edited: Nov 16, 2018
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  8. uvafan420

    uvafan420 LiKe It LoUd

    Messages:
    309
    Great Site btw....
     
  9. Schiada788

    Schiada788 New Member

    Messages:
    3
    Klaus,

    Thanks for the info. I've had a set of 4b's driven by a bridged 2150/3150 nad combo since new in the early 80's. On a whim, I've been looking for a pair of 3b's,.... after 35+ years, (not that I'd give up the 4b's). I found a set of 3A's locally, but could not find any specific differences other than cosmetics on the drivers. My assumption was that it was simply a marketing model year change. Looks like my assumption was wrong. Technically, the differences you describe are above my pay grade, and may be above that which my 55 year old ears can actually hear. But, if I pick them up, maybe some crossover work would be in order during restoration.

    And yes, you have a great site. Informative and fun reading.
     
  10. Ross6860

    Ross6860 AK Subscriber Subscriber

    Messages:
    1,693
    Location:
    Ohio
    Just want to thank you for your website:beerchug:

    Dein Englisch ist viel besser als meine zwei Jahre Gymnasialdeutsch
     
  11. dcmaster

    dcmaster Infinity Lover

    Messages:
    112
    Location:
    germany, RLP
    Hi Schiada, why are the technical differences above your salary level? The purchase prices of the A and B are virtually the same. If something needs to be repaired or restored, there are no major differences.

    So do not go crazy. It's all easy to do. Basically, it does not matter if you buy yourself an A or B, because the sound actually have no difference, because they were technically designed the same.

    Klaus
     

     

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  12. dcmaster

    dcmaster Infinity Lover

    Messages:
    112
    Location:
    germany, RLP
    @ Ross6860, thank you. To my english. I never had learnd english in school. It resulted in learning by doing. Often that was forcible. And since the website, I had no choice, but at least I remain mentally fit. .... ok, I use often the google translator, but the grammar of google is often very bad. I interpret it as a belly sensation.

    Klaus
     
  13. TomBig58

    TomBig58 AK Subscriber Subscriber

    Messages:
    782
    Location:
    Chicago
    Thank you for your very informative website Klaus. I'm not complaining but why no information on the CS series?
     
  14. dcmaster

    dcmaster Infinity Lover

    Messages:
    112
    Location:
    germany, RLP
    Hi TomBig58,

    Because the CS series is not one of the classics for which I started the site. Since it's only about the series in which Arnie was still there and this only up to max. 1995th.

    Klaus
     
  15. swechsler

    swechsler Frog Whisperer

    Messages:
    5,226
    Location:
    7th row center
    Actually, I'm pretty sure the CS series was sold around the same time as the Kappa x.1 series (they both use EMIT-Rs); however, it was only available in North America.
     
  16. jazzmans

    jazzmans Super Member

    Messages:
    2,346
    Location:
    devils playground, NV
    I bet the Crescendo series never made it overseas, since they were custom built for Circuit City.

    That's ok, they fly under the radar. (unless you're trying to get fair $ for them, then good luck!)

    I also think they are at least the sonic equal of the vaunted Kappa .1 series, if not a touch better since they don't have the degrades over time Polydomes.

    I own 2 pair of 3009 and three pair of 3007 at the moment.


    once my damn arm heals enough to move them around, I think I'll do a side by side shootout with my 3009 vs my RS IIb.
     
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  17. TomBig58

    TomBig58 AK Subscriber Subscriber

    Messages:
    782
    Location:
    Chicago
    I don't know how I missed the replies about the CS series until now. Thanks for the info. I shopped (drooled) plenty at Circuit City back in the day. Now I know why there is not a lot of info on them. My refoamed CS3008 are besting the Kappa 6.1's but I have unresolved low end distortion problem with the refoamed 6.1's as explained in another thread.

    My infinity shootouts are a continuing operation as I recently picked up a pair of RSb large bookshelfs that I am currently A/B-ing with my trusty Qb's. Comparing THOSE two deserves a separate thread since they are made around the same time, are about the same size, but have different low/mid drivers and crossovers.
     
  18. swechsler

    swechsler Frog Whisperer

    Messages:
    5,226
    Location:
    7th row center
    I'll be interested in reading that; even though I don't own either, in the past I owned a pair of Qas and was very impressed, especially since I also had my first pair of Kappa 8s at the same time. I've read here that the Qb is actually better sounding than the RSb, but that was only one or two persons' opinions...
     
  19. TomBig58

    TomBig58 AK Subscriber Subscriber

    Messages:
    782
    Location:
    Chicago
    20181207_013341.jpg I'm finally refoaming the 2nd CS3008 tonight. I'm gonna take a lot of pics because there's not a lot of info on those. Been at it a few hrs with breaks. Man, the glue on those! Tedious. I'll take a family pic tonight then move them all out of the way for some set-up and compare. Maybe I'll play hooky from work tomorrow, heheh.

    Edit: Family pic as promised. It sure is busy there and I can only hook up two at a time right now. Qb's with RSb stacked, CS3008 and Kappa 6.1.

    The 08's are sweet. Soundstage comparison makes the Qb's almost sound like they are in the next room. Early returns have the Qb's nudging the RSb's.
     
    Last edited: Dec 7, 2018 at 1:59 AM

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