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Utah Heritage HS1-C

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  • chrisn
    replied
    Originally posted by michaelp View Post
    Well, the drivers still work. I bypassed the pot, and the mid and tweeter sound fine.
    If I want to replace the pot with a fixed resistance, maybe I need to measure the minimum resistance of the pot in the other speaker. I don't know what the minimum resistance would be.

    Inner dimensions of the box are 13 5/8 x 24 1/4 x 12 3/8 (I calculate a box volume of 2.37 cubic feet, assuming I didn't make a mistake). The port is 4" in diameter, and the length of the tube is 1 3/8".
    I'd try blocking the port or lengthening it, see if anything else is preferable. As far as replacing the pots, if you don't have measurement gear, a bunch of resistors and time can help you dial that in.

    DJG linked to another thread further up, which itself has 2 links to applicable designs if you're thinking of modifying those Utahs

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  • Steve Lee
    commented on 's reply
    Min Resistance will be zero or very near zero - max will probably be 8 ohms but measure the functional pot in the good cabinet to find out what it is by disconnecting one of the wires connected to it first.

  • michaelp
    replied
    Well, the drivers still work. I bypassed the pot, and the mid and tweeter sound fine.
    If I want to replace the pot with a fixed resistance, maybe I need to measure the minimum resistance of the pot in the other speaker. I don't know what the minimum resistance would be.

    Inner dimensions of the box are 13 5/8 x 24 1/4 x 12 3/8 (I calculate a box volume of 2.37 cubic feet, assuming I didn't make a mistake). The port is 4" in diameter, and the length of the tube is 1 3/8".

    Leave a comment:


  • fpitas
    commented on 's reply
    I figured it was the cheapest way they could do it. These aren't exactly white van, but they're nosing into that territory.

  • fpitas
    commented on 's reply
    Those do look nice. I can appreciate the vintage look, at least. Some internal bracing and decent drivers would turn them into nice looking and sounding speakers.

  • billfitzmaurice
    replied
    Originally posted by Steve Lee View Post
    That may have been the design intent, Bill - I mean everybody needs a knob to turn in the audiophile realm . . .
    I doubt that it was intentional, more likely a matter of not knowing any better. Utah wasn't exactly of the same caliber as Altec, EV or JBL. I've seen more pictures of their input boards using the same AFU arrangement. It's a miracle that they all didn't catch fire, using 2 watt pots.

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  • djg
    replied
    https://techtalk.parts-express.com/f...-3-way-rebuild

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  • michaelp
    replied
    Well, I do sometimes have a sense of nostalgia for speakers and gear. I make guitars out of cigar boxes and cookie tins, and play some vintage guitar amps, so I can appreciate some lo-fi coloring of the sound in some situations. The one speaker that does work is nothing special on first listen...not a lot of low bass for a 12" woofer, and the highs are not very crisp. If I get the other speaker working, I'd like to spend a little time listening, but I would consider modding these in the future. The boxes are pretty sturdy and have a nice veneer.
    I'll open the box up again soon and try to get some measurements...the outside of the box is 15x14x26. Looking at that photo, I think the mid speaker is 5", so that port must be almost that big, and the tube is not at all long...so I think you are right that it is tuned pretty high.
    I will check and make sure the drivers are still working.
    Click image for larger version

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  • michaelp
    commented on 's reply
    Yes, I have a multi-meter.

  • michaelp
    commented on 's reply
    Yes, I guess that is a next logical step. The edge of the pot actually looks a bit charred, and does not turn, so I'm pretty sure it is bad.

  • Chris Roemer
    replied
    If you tell us the internal dims of the box, and the length and i.d. of that port tube, we can tell you what freq. the box is tuned to (looks high to me!).

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  • fpitas
    replied
    Unless you just like the nostalgia, your best bet is to replace the drivers with something modern. Driver technology has advanced enormously since those were made. Of course I'll admit I don't "get" nostalgia for its own sake, and that may be a big factor here. In which case, ignore me

    Leave a comment:


  • chrisn
    replied
    Got Utah 12" 3 ways at the thrift years ago for $2.52. Mine have an 8" sealed back midrange with horrendous measured distortion anywhere below 2000 hz, which is kinda useless, but the woofer and tweeter are nice. I would try bypassing the Lpad/resistor thing and see if all the drivers are good. Anymore pics of the speakers?

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  • Chris Roemer
    replied
    Do you have access to a DMM (HFT used to GIVE them away!) ?

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  • rpb
    replied
    If you momentarily connect a 1.5v battery to each driver, you should hear it make some crackling type noise. On woofers, you will see the cone move. Find out if the drivers work at all before digging in too deep.

    A 4uf cap will pass only high frequencies. On my speakers, it is more common for me to use 8uf or so.

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