New (to me) LS50s

jason32835

Whoops, I posted in the main Speaker Forum, I realize now I should have posted here!

I picked up a pair of LS50s last night on Craigslist for $85. When I got them home I realized they have a couple of issues. The main problem is that one speaker is missing all the low end. I tried the simple things like switching sides and double checking my wires, no help.

I took out the drivers and they look good as new, I even swapped speakers for one of them (the bottoms) and the problem didn't move. I'm thinking the issue is with the crossover? I thought about switching the crossover to the other speaker to test it? Are there any other ways to test the crossover? I found the schematic in the sticky, but I don't know what to check for this issue (You've guessed I'm a noob by now).

I will post some pics tonight, but everything looks good as new inside.

Thanks for any help!

[Deleted User]

Hello jason,
Probably the first thing to do is to remove the two mid-bass drivers from the nonworking speakers and, at a low volume, try playing each one by directly powering it from your receiver. Each driver should produce sound when given a small amount of power, resist the temptation to increase the playing volume if you don't hear anything. This will determine if you have a driver problem or a crossover problem.
Let us know what you find.
Regards, Ken

jason32835

OK great, I will do that tonight. Thanks a bunch.

[Deleted User]

No problem...

jason32835

Ok, took the drivers out and hooked directly to my receiver. They played with no problem.

Here are some photos for fun...

Where to go from here?

jason32835

Well.. an update, I put the drivers back in and now they sound great!! I didn't notice the polarity when I was taking them out, I wonder if one of them was backwards? That would tend to screw things up pretty well.

Anyway, I am in business and that was easy! Just need to figure out how to get some bubbly vinyl off the trim and what to replace it with next.

20hz

to kenneth swauger are those drivers in series or parallel ?
I am thinking maybe they are in series and if one is intermitant when it opens it turns them both off ?
I got a pair of the ls50's I will probebly take them to my gave " they sound great " .
I bought them new and was surprised being a audio video speaker they were not magnetically sheilded so a quick call to polk customer service they sell bucking magnets for like ?5? each fixed the problem yes I had a CRT tv than , but thanks customer service great prices great know how plus I got a discount for being a forumn member !!

jason32835

I really love them. They are a little beat up on the outside, but look brand inside. Hopefully they will continue to sound correct, but if not I will check out the wiring.

Does anyone suggest upgrading the crossovers on these? Any suggestions on where to buy the components?

[Deleted User]

Hello 20hz,
They are connected in parallel. I'm not sure what caused the initial problem, but it looks as though it has been solved. I believe the LS series was the first speaker series that had the influence of Mark Suskind in the overall sonic development.
Enjoy, Ken

skrol

Glad to hear that you got them working. I used to lust after that series in the cherry finish. If it does it again, look for bad solder connections on the crossover or a loose short (ie inductor). I had a couple bad connections on the ones in my RTA-11TL's from the factory.

jason32835

Great, I will watch out for those as well. Thank you.

ken brydson

Welcome to the LS club. Full 7.1 set here. Bought my 50's new back in 1996 and ran them as my mains until I recently scored some 90's. The 50's are now pulling surround duty. I've got a scanned manual I can email you if you're interested.

jason32835

Wow.. that is some surround setup!

That would be great, I'd love to have that. I'll PM my email.

ken brydson

Modest setup by a lot of peoples standards. LS90 mains, CS 350LS center, LS/fx's on the sides, LS50's in the rear. Backed up by an SVS 25-31PC+ sub. To ME it's badass... I'll send you the manual shortly.

55LS70

Jason, congrats on your score. I bought my LS70's in '95 and after upgrading the crossover caps and replacing the drivers and tweeters (I have to admit I abused them a little and they needed replacing) they sound better than they ever did. The crossover upgrade I think cost me about $45 and made a massive improvement. Again, good score and enjoy.

jason32835

Thank you and sounds like a good thing for me to try. Is there a guide that would help through the crossover upgrade??

Goldenboy72206

I would love to have a pair of ls90

55LS70

Jason,

At the top of this Forum's "Vintage Speakers" section is a thread that has some Polk Speaker schematics. That's where I found my LS70 schematic and they do indeed have the schematic for your LS50's. It will tell you the capacitor and transistor values you'll need to get. I used Sonic Craft to obtain the ones I needed and had excellent results. There are no doubt other venues that offer these items that probably would provide just as good if not better results. Do a thread search through this forum as there are a couple out that depict replacing caps and transistors. Good Luck.