Agony of choice U1 or M1 PX

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    • #1355
      malthusian23
      Participant

      Thanks for the tip John will do.

    • #1354
      John V
      Participant

      Should you decide to go ahead with the purchase, I would check to see if there is a ballast weight attached to the box that holds the backplate. Early U1 frames, such as mine, did not have this and the speaker is nose heavy and can be prone to tipping w/o the backplate installed.
      The first picture I posted shows the result of this imbalance when a tube trap fell over striking the frame with the backplate removed causing it fall over and hit the wooden arm of a loveseat. The core was returned to SL for repair, which was done for a reasonable cost and timeframe. Actually, the total shipping cost was much greater than the repair cost.
      Anyhow, I purchased 1/2′ steel plate and glued it to the rear wall of the box of both speakers to prevent a future recurrence. I would recommend doing the same if no ballast weight is present.

      Good luck with the purchase,
      John

    • #1353
      malthusian23
      Participant

      Ok, so it’s not that unusual to increase the size of the panels I guess. They do look pretty bad I must admit though on the ones I’m looking at. Those staples are ugly. Maybe I’ll look at doing something similar.

    • #1347
      John V
      Participant

      I upgraded my U790 panels to U890 bass focus in 2018.
      As the panels are taller than the original frames, as they are with the U1’s your contemplating purchasing, I had SL make a set of extensions so the speaker looked finished. The extensions came to me unfinished so I could have them painted to match the color of the existing frames by a local auto body shop. To the rear of the frame, rectangular pieces of kydex/lexan were added to match the existing mounting flange and finish the look.
      See the attached pix. and diagram to see how it was done.

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    • #1346
      malthusian23
      Participant

      Oh man, that is heart breaking seeing that. I hope turned out all right.

      I did shine a light on them when I was there and could clearly see that lattice structure you refer to.

      Ok, now I’m a bit more stoked. They’re not official U1PX but they’re darned close and a lot less risky than I thought.

      Thanks
      Owen

    • #1343
      John V
      Participant

      Those look like a custom height panel, most likely made when the previous owner upgraded to a PX panel. SL has made custom width panels in the past so I’m sure they’ve also done custom heights.
      As to determining if the panel is a PX panel, the earlier panels had no lattice structure between the vertical and horizontal ribs. The lattice greatly strengthened the panel.
      Use a bright flashlight and shine it into the panel, you’ll be able to see whether or not the lattice is present.
      See the pix. I attached to get an idea of how it looks.
      And yes, that is a damaged panel, a story for another time.

      John

      • This reply was modified 1 day, 7 hours ago by John V.
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    • #1342
      Jazzdude99
      Participant

      Unfortunately you can’t tell if it’s PX from its appearance.

      Andy

    • #1341
      malthusian23
      Participant

      Do they look like px to you? I don’t know how you would tell. If they were changed I would assume they upgraded to PX. Unfortunately the original owner is available to answer questions.

    • #1340
      ernestov
      Participant

      It is not uncommon for SL owners to swap panels. The seller may have removed the original panels and replaced them with PX panels. If so, it will be difficult to trace the source of the PX panels

    • #1339
      malthusian23
      Participant

      745 maybe. The 845 would be too big I think. And likely an older version.

      I think it’s clear though that they aren’t original panels. Would you guys say px?

    • #1338
      Jazzdude99
      Participant

      Could it be an 845 panel in a U1 frame? Doesn’t look very tidy as it projects the unfinished edge beyond the frame. Definitely 90 degree

    • #1335
      malthusian23
      Participant

      Attached the same photo twice. Here’s a side on view.

      • This reply was modified 1 day, 21 hours ago by malthusian23.
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    • #1332
      malthusian23
      Participant

      Ok, the plot thickens. I’ve been looking at older models and this one is weird. I’ve attached photos of the U1. Look at how the panel extends above the frame. Also the height is 91”, and what I’ve seen is the U1 was 82” high. Also the panel seems to taper at the top.

      Anyone have a clue as to what these actually are? They say U1 but I think they may have been modded with new panels at some point.

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    • #1330
      Jazzdude99
      Participant

      You might want to call the factory – if there’s an issue with the back plate I would suspect the bias supply which is an easy swap as opposed to the step up transformer.

      Sounds like it’s the same person selling both speakers???

      Good luck

      Andy

      • #1331
        malthusian23
        Participant

        They are both being sold by the same person. He’s more of a record store but stumbled on two pairs of full size SLs to sell at the same time, poor guy.

        I’m really torn between them and so may not buy either, they both sound high risk to me not being someone with excellent soldering or electrical troubleshooting skills.

    • #1325
      Jazzdude99
      Participant

      Malthusian23 – you are spoilt for choice there for sure!

      With the PX panels you are unlikely to need to send them back for a rebuild. With non-PX it’s just a question of time. The PX solution was a game changer for SL reliability.

      They are a pain to ship – so given that I would get the M1 PX – are they 90 or 45 degree?

      ***Ernestov – could you share further details info pictures for the alternate metal frames please?

      Cheers and best wishes

      Andy

      • #1329
        malthusian23
        Participant

        The M1 PX look to me to be 45 degree. I can compare the two and the U1 seem to have much more of an arc than the M1 PX.

        The issue with the M1 is that apparently the power supply has an issue on one of the speakers. I believe it’s the step up circuit.

        So not great options, and maybe why they’re both for sale I suppose. He declined to let me swap the panels from one to the other unfortunately to get the best of both worlds.

    • #1324
      malthusian23
      Participant

      Could you expand on the idea that I need to buy PX panels? I get that they are more reliable and likely better in terms of performance but are the pre PX panels a total right off? Do they have a particular failure mode I need to be aware of?

    • #1323
      ernestov
      Participant

      You need to buy the PX panels. If you like the look of the U1 I know a shop that builds better metal frames than the ones used in the Ultimate series

    • #1322
      malthusian23
      Participant

      Ok thanks. I don’t think they’re bass focus panels.

      I’m kind of assuming the seller will let me switch. If not which would you choose between U1 and M1 PX? Are the older panels (circa 2000) considered a bit of a gamble reliability wise? The U1 panels sound ok, not popping or fizzing.

    • #1321
      John V
      Participant

      Are the PX panels also Bass Focus?
      It is possible to transfer the cores from the M1 to U1, but I would verify that both sets of cores are the same size as there have been minor size differences over the years as the stator construction evolved. You might want to check with the factory to further verify fitment.

      GLWS,
      John

    • #1320
      malthusian23
      Participant

      Not really an issue I suppose. I can buy U1 or M1 PX. Which should I buy? Just looking for some opinions. They’re the same price.

    • #1319
      ernestov
      Participant

      The PX panels will be more efficient. I am not clear what the issue is about?

    • #1318
      malthusian23
      Participant

      Hi All,
      First post so hello there.

      After waiting for ages for a pair of SLs to come up for sale I have the weird situation of finding a pair of U1s without PX and a pair of Millenium 1s wit( PX.

      Given the choice which way would you go? Is it crazy to consider transferring the M1 panels into the U1?

      Thanks

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