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Fisher XP-7b - recap!

Discussion in 'Fisher' started by loudnoises, Mar 19, 2017.

  1. loudnoises

    loudnoises Escalates Quickly Subscriber

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    well i've finally gotten my hands on my father's XP-7Bs. These are the speakers i grew up with, and amazingly enough all the surrounds are still good.

    But the crossovers need work. i know this because one of the caps fell out a few decades ago... Searches have gotten me nowhere, anyone have a schematic for these? Otherwise i'll have em apart this week so i can order up new caps.
    2017-03-19 21.22.09.jpg
     
  2. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Pull the other speakers crossover and order double the number (for both). The crossovers aren't anything a caveman couldn't handle.
     
  3. fred soop

    fred soop Super Member

    Messages:
    1,703
    The XP-7 series is similar to the XP-9.

    XP-9 has 3 midrange units and a 5 ohm resistor substituting for a 4th midrange. They are in a series/parallel circuit with an inductor in series with the entire string and another inductor from the first inductor to ground. All of this then has a 25 µF capacitor and 2.2 Ω resistor in series.

    The single dome tweeter has a 4 µF and 3.75 Ω in series. Of course, there is an inductor in series with the woofer.
     
  4. loudnoises

    loudnoises Escalates Quickly Subscriber

    Messages:
    870
    Location:
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    Have it opened and oh yeah, that's where the missing cap goes!

    pics incoming, 4 caps, 4 resistors and 3 coils, plus the -/0/+ switch for the tweeter. Paper cone and rubber surround.

    2017-03-24 21.20.26.jpg

    Even the cone has a part number.
    2017-03-24 21.22.02.jpg
    2017-03-24 21.21.15.jpg 6uf, 16uf, 25uf, 50uf.
     
  5. loudnoises

    loudnoises Escalates Quickly Subscriber

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    The grey/blue resistors are 12ohm 3w, the brown are 8ohm 3w.

    Can the numbers on the woofer be "decoded"?
     
  6. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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  7. loudnoises

    loudnoises Escalates Quickly Subscriber

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    it seems the 7b was only made in 70/71. they were paired with a pioneer fron 69/70, so maybe these were early with older drivers? No that's backwards... the xp-7 was a 3-way with i believe the same woofer, made from 67 on i think.

    Rola. no bells there... :dunno:
     
  8. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    The ROLA Co. was an OEM speaker Co. by the time the 7B was produced, quality was on the way down as EMERSON had bought FISHER and shut down the Milroy speaker plant. . Bill Hecht was no longer supplying drivers to FISHER. So they went with different manufacturers apparently. CTS, ROLA, etc. My 56B's have ROLA Drivers for the Woofers.
     
  9. Tim D

    Tim D AK Subscriber Subscriber

    Messages:
    543
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    I
    I did a thread last year for recapping 7b's. I'll look it up and post the link tomorrow. The thread included a schematic that I hand drew from scratch. I now have 2 pair.
     
  10. Tim D

    Tim D AK Subscriber Subscriber

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    Here's the link to the thread about recapping a Fisher 7B.

    http://audiokarma.org/forums/index....tore-need-x-over-diagram.722323/#post-9764877

    These 7B's have well built cabinets and they put some thought into the parts and layout of the crossover board. They aren't going to win any awards for the sound, but they are decent sounding. Definitely a nice to have speaker.

    The original pair that I did in that thread is still waiting to have the cabinet and grill redone, but they are electrically complete. I recently picked up a second pair off CL that are in near pristine condition from the original owner. I haven't touched those yet, but they are beautiful.
     
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  11. Tim D

    Tim D AK Subscriber Subscriber

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    Oh and I have a user manual for the Fisher 7B that I recently picked up. I'll scan it and find a place to upload it. I believe we have a library section or some such that can hold it.
     
  12. loudnoises

    loudnoises Escalates Quickly Subscriber

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    Thanks for the links.

    Step one for these is just getting them up and singing. I ordered some inexpensive electrolytics from PE, combining gets me spot on the values for the caps, which in mine are the same richey lytics' i've seen in wharfdales and a few others. Literally falling out of the crossover.

    I barely remember the sound of these, and the tweeters aren't getting any rave reviews, so we'll see what happens. For a few bucks i can't go wrong, the nostalgia factor at least.
     
  13. loudnoises

    loudnoises Escalates Quickly Subscriber

    Messages:
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    Well caps came in, pretty easy swap. The second crossover tho oh boy. Both narrow inductors fell off the board, one snapped a lead. Hot glue to the rescue!

    Interestingly enough, some of the caps seem to be Fisher re-branded richey caps. too late for a listen, it'll have to wait till tomorrow.
     
  14. loudnoises

    loudnoises Escalates Quickly Subscriber

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    One set of tweeters wouldn't fire, but it just required a bit o' cleaning. many terminals, much corrosion.

    So far they sound pretty good. all drivers working, caps still burning in. Keeping volume low for a bit, want to see if i shake loose any corrosion on the voice coils. Low volume they're pretty warm, better than i expected from these tweeters after reading reviews. Need to let them play for a bit and see if the high end clears up a bit. Low end is detailed, but not in your face.

    I wonder how much of this design was geared to quadrophonic setups.
     
  15. loudnoises

    loudnoises Escalates Quickly Subscriber

    Messages:
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    Alright, a couple days and a dozen hours of "burn-in" I'm enjoying the sound. They've got a big wide sound, fills the space well. Plenty of bass if you ask for it, vocals and voices sound very good. very easy to listen to. They remind me of a console-like sound. Won't be bumping anything out of the main setup, but good enough sounding i wont mind keeping them.

    The tweeters... yeah. 3" paper cones aren't really the best. Running them with the tweeter circuit on "+" and a boost on the treble control gets them up to usable balance with the rest of the speaker. They meter just fine, so i wonder if maybe the paper cones have gotten soft?
    Poking online for potential swaps. 2 3" holes and 8ohm goal is pretty dang easy to work with. If the Vifa ring radiators had a wider dispersion i think they'd be a great sounding match.

    Well they ain't broke anymore, so I'm probably going to just use them for a bit and see what comes along.

    Thanks for the help all, Tim D, that schematic is exactly what is needed for reconnecting that convoluted crossover..
     
  16. Tim D

    Tim D AK Subscriber Subscriber

    Messages:
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    Location:
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    You are welcome loudnoises.

    So, maybe some of the Fisher experts will chime in, but I've read on more than one thread that Avery Fisher voiced most of the early speakers himself (and maybe the 7B's too?). He tended to roll them off, so that might be what you are hearing. They definitely aren't bright speakers. If you ask, you might find some suggestions to change parts in the crossover to make them a bit brighter, but I'd be careful because it would make the tweeters easier to blow. I.e. You might want to put a fuse in the tweeter circult.

    I just picked up some rough Fisher tube equipment. Once I get them refurbed (which will take a long while), I'm going to try them with my 7B's and see how they sound.
     
  17. loudnoises

    loudnoises Escalates Quickly Subscriber

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    I've a theory on the "rolled off" high end.

    It's not that he preferred rolled off sound, it's that the sound wasn't there to roll off. Listening to Beatles albums, i don't notice a thing missing. baseball games, talk radio, all the period appropriate stuff sounds great and balanced, without any boosting. Kinda makes sense as many sources of the day had limited high end capabilities anyways. The speakers will do it with an eq bump, and with the tweeters only running at full with the selector in the "+" position, maybe there was an anticipation of unpleasantness to avoid?

    Sunday morning ramblings. Now i need to fix the receiver...
     

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