LS70 upgrading?

bd1886

Hey you guys, It's been a while since I've been on these forums and just popping in to ask a few questions from those of you who know this speak?

This GW find is what got me into audio (vintage audio specifically). About a year and a half ago I hooked these up and haven't looked back as these seem to be a great balance for both theater and old school 2 channel listening. I've since tried JBL L100's,JBL GHE 1000v's, ADS 810's,L710's,L910's, BA 150's,several Dahlquist models....and others. All these speakers have been at least very good to some actually being nicer than the LS70's (for one reason or another). Still....the footprint size,performance level,looks (shape) and the "Polk sound" have left these LS70's being my speakers that I use the most! (The sound stage for such a small footprint speaker can't help leave me impressed.)

My priorities are because of this...I have a small run of wall space and a custom,low slung,audio stand that is getting close to completion. After some custom treatment to these speaks, the late '50's Danish look of the whole thing will be incredible and match well with our living room look. I'll end up keeping the best speakers (from what I have) and these look like they will be staying too....until my listening space changes dramatically

What I've heard with comparisons to it's siblings suggests that these have a little room for improvement using some mods that kick there level of performance up a bit. What are the best things to do with these? I enjoy 'em,love the looks with this series, and after I finish them with walnut,throw on some mellow amber skirt lighting,carpet post elevated Wilkison Sandstone base,internals all they can be....there going to stick for a long,long time. (I'll post pics.)

Gear I'll be running them with my just completed 15 receiver collection:

Theater: Modern Onkyo AVR

Two Channel (in rotation):
1. Sansui G-9000
2. Sanyo JCX 2900K
3. Sansui 9090db
4. Pioneer SX-1010
5. Pioneer SX-1250
6. Marantz 2325
7. The early 70's "littlest brother" (to each brand of these) "Where performance quality just starts to compete with big bro".

Is there a best approach with crossovers,capping,stuffing,etc....? Appreciate it and know several of you guys know both Polk....and older gear.

bd1886

I've been working real hard learning and wheeling and dealing to get these receivers.....or I normally couldn't have afforded so many nice ones in such a short period of time. (Please forgive me my pride in that list.) The learning has been a blast and settling in to enjoying it....with some maxed out LS70's. Bump

gwg_97

Almost everyone on this site has a long list of gear. Its all part of the fun. The crossover upgrade is very, very easy on the LS70s. Just one cap and one resistor. I used Sonicap and mills. Difference was not huge but certainly noticeable; however, I only have about 20 hours on them since the upgrade and the amp I am using is pretty low end. See below and have fun.

BTW, the LS70 schematic is in the vintage speakers forum. I should also note that I did the crossovers without disconnecting the drivers.

gwg_97

DSkip wrote: »

Spike them and dynamat the drivers. Those are both cheap fixes. You could look into crossover upgrades (new caps) and I bet that would really help these. If you end up wanting to do some mods to the crossovers and are a little skiddish of damaging them, I've got an extra pair of crossovers for sale.

I really don't see the point of any upgrades past those. Maybe some treatment on the back wall of the cabinet like black hole but other than that, there isn't much to do. Your best bet is the spiking; that made a noticeable improvement in mine.

Hmmm, did the spikes tighten up the bass a bit? I find that they are little bass heavy for me as is.

chris0626

DSkip wrote: »

...I did dynamat my drivers...

What exactly do you mean by this? I have a pair of LS70's as well.

bd1886

Right on....this is exactly what I needed to get these moving forward! I have some huge old bronze lamp phinals that will be perfect carpet spikes and now to round up parts. I'll post pics once I get it all done. Thanks Gents!

gwg_97

DSkip wrote: »

Helped throughout the entire range. I did dynamat my drivers, but I'm not sure how much it really helped to be honest.

Did the crossover upgrades help the tweeters any? That's become my biggest complaint with the LS series; it seems like something is lacking in the tweeters.

Thanks! While I didn't have a lot of time with them (stock) before the upgrade, I'd say it was a definite improvement (improvement in overall clarity). I'm guessing it will only get better with some time on those caps.

gwg_97

I forgot to mention that I needed to add a couple of 1" stand-offs to the pcb/binding post cup so that the backside of the binding posts could clear that large cap. No big deal.

jakeo25

LS70 crossover schematic on Vintage Speakers forum is broken. Does anyone have a PDF or JPG?