home › Forums › General Discussion › Agony of choice U1 or M1 PX
- This topic has 31 replies, 5 voices, and was last updated 4 months ago by Jazzdude99.
February 5, 2023 at 10:40 am #1378
Very nice – and big congrats on working thru the issues!
Now time to enjoy them!
February 5, 2023 at 8:59 am #1377
These were the U1s and I believe these are the px panels. The previous owner updated them.
The amp I’m using is an Anthem P5. It’s rate at 325 wpc but I’m bianping so 650 wpc. It’s an absolute beast as it’s 625 wpc into 2 ohm.
I bought it specifically for ESL speakers, I have other speakers that are much harder to drive as they dip to less than 2ohm. Anthem claims “Statement P2 and P5 amplifiers are stable into any impedance down to a short circuit at full output”. So I’m surprised they struggled with the U1s.
February 5, 2023 at 7:32 am #1376
Thanks for the update, and yes all of us SLOG’ers are very interested.
Congrats on getting your U1’s fixed.
I totally forgot to mention about re-tensioning the membrane. I had to do that a few times with my pre-PX panels.
Enjoy your “new” speakers!
You might, at some point, consider updating the Toroid and crossover to the latest version. This will fill in a depression in the lower midrange response and make the speaker easier to drive. This has been mentioned in a few other threads here on SLOG.
February 5, 2023 at 7:13 am #1375
That’s great to hear! Is this the M1 or the U1?
What amp are you using?
February 5, 2023 at 6:32 am #1373
I’m not sure if anyone would interested at this point but it all worked out in the end.
I removed the panel, grill cloth, to inspect the Mylar and found that it was wrinkled in spots. Then heat gunned it to tighten them up. Once I put it all back together the sparking on bass had stopped but the distortion was still there. I switched the speaker cables and, yep you guessed it, the amp was blown in one channel. Luckily it’s a 5 channel amp. Rinse repeat on the other speaker and now they’re back in and playing amazing music.
I think this must happen a lot.
February 2, 2023 at 5:09 am #1371
I’m sorry to hear that – best bet at this point is to call the factory, the panels will need a rebuild.
February 1, 2023 at 7:56 pm #1369
I figured I would just continue this thread. I ended up buying them and hauled them all the way to my house. They sound great except for one thing. I can hear on some tracks a distortion in one speaker and sometimes a kind of slapping noise in the bass. The speakers also seem to spark when the bass is loud on both speakers but more on the one with distortion.
Any ideas on what this could be? Did I just buy a lemon? It’s my worst audio nightmare, saddled with worthless speakers that are near impossible to get rid of that take up half a room.
- This reply was modified 4 months ago by malthusian23.
January 28, 2023 at 2:55 pm #1355
Thanks for the tip John will do.
January 28, 2023 at 11:06 am #1354
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,
January 28, 2023 at 9:54 am #1353
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.
January 28, 2023 at 8:28 am #1347
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.
January 28, 2023 at 6:53 am #1346
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.
January 28, 2023 at 6:49 am #1343
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.
- This reply was modified 4 months, 1 week ago by John V.
January 28, 2023 at 5:37 am #1342
Unfortunately you can’t tell if it’s PX from its appearance.
January 27, 2023 at 7:13 pm #1341
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.
January 27, 2023 at 7:11 pm #1340
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
January 27, 2023 at 6:56 pm #1339
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?
January 27, 2023 at 6:51 pm #1338
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
January 27, 2023 at 4:29 pm #1335
Attached the same photo twice. Here’s a side on view.
- This reply was modified 4 months, 1 week ago by malthusian23.
January 27, 2023 at 4:27 pm #1332
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.
January 26, 2023 at 5:52 pm #1330
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???
January 26, 2023 at 7:39 pm #1331
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.
January 26, 2023 at 5:29 am #1325
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
January 26, 2023 at 5:06 pm #1329
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.
January 25, 2023 at 8:45 pm #1324
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?
January 22, 2023 at 10:56 am #1323
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
January 22, 2023 at 9:17 am #1322
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.
January 22, 2023 at 8:55 am #1321
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.
January 22, 2023 at 5:33 am #1320
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.
January 22, 2023 at 5:15 am #1319
The PX panels will be more efficient. I am not clear what the issue is about?
January 21, 2023 at 9:02 pm #1318
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?
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