LS90 Tweaks and upgrades

thsmith

I have googled polkaudio.com for LS90 threads. Not a lot of info on tweaks and upgrading the crossover.

I get dynamating the MW and spiking the cabinets and will be doing those things.

I am curious if anyone has upgraded the caps and resisters and how did they like the upgrade ?

These are some special speakers for sure. A bit picky on placement but find the right spot and you are rewarded.

Anyway, thanks in advance on anything else I should consider and especially feedback on crossover.

55LS70

I upgraded to sonicaps on my LS70's and what an upgrade it was. They sounded better than new. I should mention that I also replaced the drivers and tweeters at the same time, but nevertheless, they sounded better than new. The cap upgrade was well worth the effort. Good luck.

thsmith

Thanks 55LS70. Sonicaps is what I used in my 1Cs and plan to use in the LS90s.

ken brydson

My 90's were already done with Dayton caps, Mills resistors and Jantzen air core inductors when I bought them last year. Love 'em! I can probably pull the c/o's and take photos if you need them...

ohskigod

good to see the LS90's get a little appreciation here. Not mentioned enough in my eyes.

I traded mine for LSi15's and while I like the LSi a little better, there is something about the ls90 I miss.

I think it was the combination of great fidelity and overall bad **** volume this speaker had. I threw ALOT at it, and it NEVER faltered. great for my home theater but when they served as a party speaker? wow were they loud and clean without being too bright.

westmassguy

thsmith wrote: »

I have googled polkaudio.com for LS90 threads. Not a lot of info on tweaks and upgrading the crossover.

I get dynamating the MW and spiking the cabinets and will be doing those things.

I am curious if anyone has upgraded the caps and resisters and how did they like the upgrade ?

These are some special speakers for sure. A bit picky on placement but find the right spot and you are rewarded.

Anyway, thanks in advance on anything else I should consider and especially feedback on crossover.

I did a pair for a customer of mine. Although he bought the LS90s as a pair, the crossovers were different. One was the original and the other was revised. Long story short, replaced the mylars with Sonicaps, Resistors with Mills, and changed one Inductor so they matched. He was floored when he got them back.

55LS70

I should have mentioned earlier that when I replaced the drivers and tweeters in my LS70's I noticed a definite high pitched hiss when I started using them again. It was noticeable enough to end any doubt of something being wrong. Polk installed, what appears to be, a 10 cent cap in there and after about ten years of use, it was shot. When I installed the sonicaps, they were not only replacing worn out caps but a considerable improvement over what the OEM caps were when they were new. I think the entire upgrade cost me about $45. It was like a component change. Again, good luck.

thsmith

Awesome responses. The 90s sound amazing but figured the caps could use replacing/upgrading.

I had them in my HT setup but like them alot better in my office for music.

I cant wait to pick up my AMP 1 and get some real power to them but I am impressed how well they sound with the Pioneer SX-980.

I will post some pics once I get started.

Ken, if you are up for it I would love some pics of your XO.

ken brydson

Here's some pic's. Like I said, I didn't do the job. Have no idea what the originals looked like...

thsmith

Thanks Ken, I am hoping to open mine this weekend.

thsmith

Opened up one of the LS90s and removed all drivers, tweeter and crossover.

I think mine are original not revised because I have the electrolytic 10mf cap. What is suprising is the schematic for original has .8 ohm resister as well as the circuit board print but there is a 2 ohm resister in place. The revised schematic shows a 1 ohm.

I am a little lost on what to do, go with 2 or .8 ohm?

This I better open up other crossover and see what it has.

thsmith

DSkip wrote: »

I'm interested to see how you like them after the mods. I've done everything except xovers on my 70's. By chance, did you pick up the pair from Jim?

Not sure if Stubby's name is Jim or not. He lives south of KC.

thsmith

thsmith wrote: »

Opened up one of the LS90s and removed all drivers, tweeter and crossover.

I think mine are original not revised because I have the electrolytic 10mf cap. What is suprising is the schematic for original has .8 ohm resister as well as the circuit board print but there is a 2 ohm resister in place. The revised schematic shows a 1 ohm.

I am a little lost on what to do, go with 2 or .8 ohm?

This I better open up other crossover and see what it has.

OK, it just got wierd. The other crossover has a 1 ohm resister and the circuit board print under the resister has .8 ohms.

Thoughts on what to go with ? I am thinking .8 ohms 5w mills.

thsmith

Is it normal to have this green pad between top 2 and bottom 2 mws?

thsmith

DSkip wrote: »

I'm interested to see how you like them after the mods. I've done everything except xovers on my 70's. By chance, did you pick up the pair from Jim?

Do you by chance know what the thread is for the spikes on these ? I have mine out and going to HD tomorrow to figure it out.

ken brydson

They didn't come with spikes. Likely aftermarket.... Looking into spiking mine.

thsmith

mine has these silver flat buttons that screw in the bottom and look OEM.

cletusjones

Mine have those so that makes two!

thsmith wrote: »

Is it normal to have this green pad between top 2 and bottom 2 mws?

thsmith

Good to know, thanks Cletus

thsmith

looks like the MWs came from different plants.

Conradicles

Interesting...my cs350ls also has a 2 ohm resistor in there but the schematic does not.

thsmith

Conradicles wrote: »

Interesting...my cs350ls also has a 2 ohm resistor in there but the schematic does not.

Maybe Polk ran out and used what was close. I am going back with .8 ohm.

westmassguy

thsmith wrote: »

Maybe Polk ran out and used what was close. I am going back with .8 ohm.

The .8 ohm was used in the original design, and the 1.0 ohm in the revised design. The L3 inductor is also different between the two. Yours are marked RE0905-1 which are the originals. Go with the .8 ohm Mills, unless you want to upgrade them to the revised model. That would require changing both L3 inductors in addition to the Resistors. Either way, the LS90s are great speakers.
Don't worry about the color of the basket frames, they may have been built months apart, and used woofers from different production runs.

thsmith

DSkip wrote: »

The silver platters are nailed in. You have to pry them out. Then you are going to have to drill some holes for the spikes. Make sure you get some that have the socket with them. Choose whatever size you want. That green pad is normal. Its a divider between the upper/lower crossed drivers.

Thanks, mine has screw in feet that are 1/4 - 20

westmassguy wrote: »

The .8 ohm was used in the original design, and the 1.0 ohm in the revised design. The L3 inductor is also different between the two. Yours are marked RE0905-1 which are the originals. Go with the .8 ohm Mills, unless you want to upgrade them to the revised model. That would require changing both L3 inductors in addition to the Resistors. Either way, the LS90s are great speakers.
Don't worry about the color of the basket frames, they may have been built months apart, and used woofers from different production runs.

Thanks, .8 ohms is what I plan to order.

thsmith

DSkip wrote: »

It's amazing how many different ways they did things on one single speaker. I wish mine had been screw-in. Would've made spiking them that much easier.

Turning out to be tough to find some decent spikes

stubby

thsmith wrote: »

Not sure if Stubby's name is Jim or not. He lives south of KC.

Good to see the 90's are getting a makeover! And it is not Jim, locals call me Paul. LOL

thsmith

Hey Paul, yeah they are getting some attention. After all said and done you need to come take a listen.

thsmith

I ordered these, may be a little small but we will see.

http://www.avoutlet.com/index.php?dispatch=products.view&product_id=1575

ken brydson

thsmith wrote: »

I ordered these, may be a little small but we will see.

http://www.avoutlet.com/index.php?dispatch=products.view&product_id=1575

Let me know how they work out. Need to spike mine as well.

thsmith

Will do Ken, I am hopeful as I do like the look.

I ordered Dynamat extreme, caps and resistors today. Hopefully this weekend I can reassemble and listen.

I feel so disappointed with my Monitor 5As after having the LS90s in my office. I guess they will have to be next because I know they should sound better than they currently do.

thsmith

Looks like I should have caps, resistors, spikes and dynamat extreme by the weekend.

WAHOOO !