Watkins woofer white paper

Discussion in 'Infinity Loudspeakers' started by geoff727, Jan 18, 2010.

  1. geoff727

    geoff727 Well-Known Member

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    Does anyone have (or at least know of the existance of) a technical white paper for the Watkins woofers? If you have one, would you be willing to share it with me?

    Thanks.
     
  2. goat67

    goat67 AK Subscriber Subscriber

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  3. kmanusa

    kmanusa AK Subscriber Subscriber

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  4. geoff727

    geoff727 Well-Known Member

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    I have seen both of those sources, thanks. I remember seeing a thread on that white paper on this forum, from a while ago. But, neither a link to it nor the actual text was posted. I was hoping someone would have it.
     
  5. jimreeves

    jimreeves Poopy & Me Subscriber

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  6. rs1b

    rs1b Member

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    Watkins Woofer

    What would you like to know about the Watkins woofer. I have had many years experience . Ask away.
     
  7. geoff727

    geoff727 Well-Known Member

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  8. geoff727

    geoff727 Well-Known Member

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    P.M. sent. Thanks.
     
  9. jimreeves

    jimreeves Poopy & Me Subscriber

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    Maybe Army will revive his interest in posting it as a sticky in the Infinity forum.:)
     
  10. jimreeves

    jimreeves Poopy & Me Subscriber

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    Rs1b, I'd like some background on the changes to the 12" dual drive woofer over its lifespan. My QLS's have the clear poly woofers although I'd bet they started life with the paper cones. I see Bill Watkins is using a gray cone now. Any other changes besides the cone? Are there sonic differences?

    Jim
     
  11. cdfac

    cdfac AK Subscriber Subscriber

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    OOC, what do you guys want to know exactly? i can tell you from talking to Bill that there were no real changes to motor structure of the Watkins at any point for the Quantums and Reference Standard series. the possible exceptions would be the Ren and Omega varieties, and also the big IRS I/III/V's. in my experience, upgrading to the brand new black poly cone from the very old black-coated paper cone yielded only a subtle extra tightness in the bass, which one would probably expect, but it wasn't so noticeable that i can't be sure i wasn't imagining things. still, that was reportedly the main motivation in manufacturers moving away from paper cone woofers anyway.

    IIRC, Bill mentioned that he designed his new woofers to perform exactly like the old ones, since making subjective "improvements" to the design could reduce drop-in ability.

    "RS1b" can probably tell you more of the technical nitty-gritty, as he's made several very informative posts before.
     
  12. Kencat

    Kencat Super Member

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  13. cdfac

    cdfac AK Subscriber Subscriber

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    interesting about the magnet and VC sizes. i stand corrected. both different versions of the paper cones seemed to at least have the same magnet size that the new poly has. however, i wasn't looking at the spider and VC that closely. yes, very interesting... :scratch2:
     
  14. Kencat

    Kencat Super Member

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    Leads to another question of how to identify the different magnet/VC versions. You'ld have to be careful buying one replacement.
     
  15. jimreeves

    jimreeves Poopy & Me Subscriber

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    Thanks Kencat, I hadn't seen that thread and it brings up a interesting point regarding crossover differences. When I bought my QLS's the crossovers used 1400mfd and 1600mfd caps in the watkins circuit. The crossovers were hacked by a previous owner so I rebuilt them to the schematic from infinity.de, thanks to cdfac's supply of the 1100mfd and 1400mfd caps from a scavenged set.
    Makes me wonder now how they would've performed with the older circuit.
     
  16. jimreeves

    jimreeves Poopy & Me Subscriber

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    My 12" watkins woofers are undergoing a refoam now. I'm pretty sure mine have 1.5" diameter voicecoils and I presume they have the smaller magnets although I'm not sure how to tell? Should both sizes have the same part number stamped on them? Is there a visual clue to look for?
     
  17. Kencat

    Kencat Super Member

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    This note is on the QLS-1 page on Infinity-classics.de site, you may or may not have noticed: "Comment: There are QLS-1 where the midbass coupler is nearer the woofer, maybe a newer revision." The pictures there show these different versions. What other differences exist.....would be interesting to have details. Certainly looks like one difference is poly vs paper cones.

    The 1100/1400 caps (schematics from Infinity-classics) is quite different from 1400/1600. If those original cans looked like the old single large caps of the era it's unlikely they were altered even though the xover was modified. Where would someone have gotten them from?

    Anyone here have a xover schematic showing the 1400/1600 mfd set for QLS-1's?
     
    Last edited: Jan 22, 2010
  18. jimreeves

    jimreeves Poopy & Me Subscriber

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    Do you mean 1400/1600? No schematic I've ever seen other than the 2/78 and 7/98 versions you just mentioned.

    My right-hand cabinet had the 1400/1600 coke cans in it, while the left-had cabinet had a bunch of 350mfd and 150mfd polyesters lined up to equal the 1400/1600 values, IIRC. At least I think they're polyesters? Black with red ends?

    I haven't run accross any non-polarized large cans of the type anywhere else.
     
    Last edited: Jan 22, 2010
  19. jimreeves

    jimreeves Poopy & Me Subscriber

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  20. Kencat

    Kencat Super Member

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    DOH!

    yeah, 1400/1600 was in my head but I wrote the other. I'll edit my post.

    Better get another coffee :sigh:
     

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