A Real SL 2000 Hack. Replace stock (burnt voice coils) with "silk diaphragm dome ".

VSAT88

Went shopping for some glue. Think I have it covered now. I have not tried any of it yet but I will post back when I do. I found all of this and much more at Hobby Lobby. They have lots of neat stuff. Even a section of model rockets ! My favorite as a child. Never recall a lunch with a recovery though.

VSAT88

So far after listening to them off and on for a few days I would say at this point that I am unsure if it was really worth the effort. So far they lack any crisp sparkle that one may expect from a nice tweeter. However they are still better than no tweeter. I have heard from others and have had some limited experience myself with a break in period. I have read up to 150 hours...I guess it still remains to be seen if they will do better farther in. I will say this, I have been punishing them a bit and no failure yet..

westmassguy

VSAT88 wrote: »

So far after listening to them off and on for a few days I would say at this point that I am unsure if it was really worth the effort. So far they lack any crisp sparkle that one may expect from a nice tweeter. However they are still better than no tweeter. I have heard from others and have had some limited experience myself with a break in period. I have read up to 150 hours...I guess it still remains to be seen if they will do better farther in. I will say this, I have been punishing them a bit and no failure yet..

I received my two replacement domes, but haven't had the time to install them yet.
Your observations don't sound promising, although anything is better than the original SL2000 domes I suppose.

drumminman

Nothing ventured, etc.

VSAT88

westmassguy wrote: »

VSAT88 wrote: »

So far after listening to them off and on for a few days I would say at this point that I am unsure if it was really worth the effort. So far they lack any crisp sparkle that one may expect from a nice tweeter. However they are still better than no tweeter. I have heard from others and have had some limited experience myself with a break in period. I have read up to 150 hours...I guess it still remains to be seen if they will do better farther in. I will say this, I have been punishing them a bit and no failure yet..

I received my two replacement domes, but haven't had the time to install them yet.
Your observations don't sound promising, although anything is better than the original SL2000 domes I suppose.

Cant wait to see what you have to say after you do yours !

VSAT88

drumminman wrote: »

Nothing ventured, etc.

Exactly !!

westmassguy

I did note there's more membrane than silk. You can see through it. Not a true Silk Dome. I ordered another type, that's densely woven, see how they compare.

VSAT88

westmassguy wrote: »

I did note there's more membrane than silk. You can see through it. Not a true Silk Dome. I ordered another type, that's densely woven, see how they compare.

That's the reason I was wondering about glue. It seemed like a "plastic" membrane to me and very little "silk" if any...Hope we can find a good combination for the old magnet assembly and new dome. I think we are on the right track trying different combinations..

VSAT88

Anyone else tried this yet ? I want to know what you all have to say about the parts you bought and the sound that came out !

westmassguy

So I received the 2nd order of Silk Domes: http://www.ebay.com/itm/231540997837?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
Unlike the first ones, which were more Membrane than Silk, these are all Silk, with a light, shinny sealant applied to the outside. They are dead ringers for the RDO-194/198 Domes. I've had the RDO-194/198s apart, and the underside of the dome has a rubberized coating. The replacement domes have no coating, just the plain silk.
I took some purely static measurements for all the tweeters I have on hand.
Peerless: 7.56 DCR, 3.14mh
SL1000: 6.17 DCR, .646mh
SL2000: 6.01 DCR, .504mh
RDO-194: 6.7 DCR, .558mh
RDO-198: 5.55 DCR, .400mh
New Silk Dome/SL2000: 6.03 DCR, .828mh
The Replacement Domes are similar to the SL1000/2000 DCR, but have a slightly heavier coil.
The OPs SL2000 dome apparently came off rather easily. I was not so lucky. My sample had the glue from h e l l. I eventually had to use a sharpened, fine 1/4" wood chisel to remove it. To say it was a PITA to remove, would be an understatement. Getting the old dome off without damaging the grove in the plastic bezel required a lot of patience. Once everything was removed, the new dome fit perfectly in the grove. Since the back of the new dome was untreated silk, I used Aleen's tacky glue. Once it dried thoroughly, a began reassembly. This was also a PITA, because my sample needed alignment. It took many attempts to properly center the coil in the air gap. There was just enough play in the mounting holes on the bezel to find the center, and then tighten the hex screws. I use a pencil eraser to gently press down on the rolled edge of the new dome, listening for coil rubbing.
I had intended to do some rudimentary measurements with my trusty Rat Shack Digital SPL Meter. Unfortunately the RS meter's tolerances are quite lax, so any measurements would have been useless. I don't have a calibrated microphone or one of the many computer programs that will generate an accurate frequency response graph. I had to rely on my 57 yo ears.
I installed the tweeter in my left SDA-2ATL. The Right speaker has the RDO-198 Tweeter. This is an important detail, because the TL modification consists of a contour network added to the crossover. My unaltered Monitor 7s are packed away at the moment, and would have been the better choice for the listening test.
I fired up my system, and played some familiar tracks. The image was dead center, which is good, because that means the overall SPL of the new dome is similar to the replacement RDOs. The overall sound was very good. Vocals were consistent between the two. I did note some extra "sparkle" in the treble region with certain instruments.
This could be inherent in the new dome, or could be due to the contour networks slight rise in output as frequencies increase. I did not experience any listening fatigue over the course of the test, which is also good.
Would I do this again? No. I would rather spend the money on the RDOs. I do plan to do a second SL2000, so I'll have a matched set I can use for some other project.
It could be worthwhile for someone who has the skills, manual dexterity, and patience.
The replacement domes are certainly cheap enough to save you quite a few bucks.
My time is money however.

drumminman

Nice work.

voltz

Nice job! Sometimes projects like that are fun, sometimes there not but its kind of cool to know you were able to do it.

westmassguy

Thanks drummin, and Darryl. As I said, not worth it to me, but others may want to give it a go

westmassguy

I did the second SL2000. This time it was easy peasy. The Silicone sealer on the coil wires peals off with your thumb. I cleaned up the groves with a jewelers screwdriver to remove any remaining Silicone. I then removed the plastic bezel, and hit it with a hair dryer set on hi, for about a minute. From the underside, I pushed the old dome/coil, and it pealed right off. This left the old solvent glue bead intact, and perfectly flat. I screwed the bezel back in place, and de-soldered the old coil wires with a solder sucker. Be very careful and very quick, as too much heat will melt the plastic. I used a small, fine artists brush to apply Aleen's tacky glue on top of the old solvent glue, placed the new dome in place, smoothed out the edge, then removed it. Aleen's tacky glue can be used as a contact cement. I smoothed out the glue bead on the bezel, and on the lip of the new dome. I let it set for about a minute or two, then placed the dome back in place. Alignment was easy this time around, and the tacky glue bonded enough to check for any voice coil rubbing. I smoothed the lip of the new dome several times, and applied heat from the hair dryer set on low, to speed up the drying process. This part was the most time consuming, making sure the bond was uniform, the coil stayed in alignment, and the bumps where the lead wires come out are sealed. If is do this again, I'll put a notch where the lead wire are to make it smoother. The new Dome's lead wires are much thicker than the old coil wires.
I let it set for about an hour, then threaded the coil wires through the rivets. I used surgical clamps underneath to keep the wires taught while I soldered. I dressed the coil wires with some black glue I use for dust caps.
I plan to dig out my unmodified Monitor 7s, and do some real listening tests comparing the new domes with the SL2000s and RDO-194s.

westmassguy

Thanks nbrowser. I wanted to dress them up a bit, so I cleaned the faces with 409 then isopropyl alcohol. Found a bottle cap that fit over the dome, and shot a few coats of Krylon Satin Black. Came out pretty nice.

Faustin

Look great, but I am thinking you have way too much time on your hands!

ken brydson

westmassguy wrote: »

Thanks nbrowser. I wanted to dress them up a bit, so I cleaned the faces with 409 then isopropyl alcohol. Found a bottle cap that fit over the dome, and shot a few coats of Krylon Satin Black. Came out pretty nice.

Where did you find the paint?

westmassguy

Faustin wrote: »

Look great, but I am thinking you have way too much time on your hands!

Just the opposite, this a diversion from the rest of my workload

westmassguy

ken brydson wrote: »

westmassguy wrote: »

Thanks nbrowser. I wanted to dress them up a bit, so I cleaned the faces with 409 then isopropyl alcohol. Found a bottle cap that fit over the dome, and shot a few coats of Krylon Satin Black. Came out pretty nice.

Where did you find the paint?

It's Krylon Satin Black. You can find it everywhere.

ken brydson

westmassguy wrote: »

ken brydson wrote: »

westmassguy wrote: »

Thanks nbrowser. I wanted to dress them up a bit, so I cleaned the faces with 409 then isopropyl alcohol. Found a bottle cap that fit over the dome, and shot a few coats of Krylon Satin Black. Came out pretty nice.

Where did you find the paint?

It's Krylon Satin Black. You can find it everywhere.

I have no response ...

VSAT88

Wow, awesome. I have to try again now Westmassguy !

Nightfall

westmassguy wrote: »

It's Krylon Satin Black. You can find it everywhere.

http://forum.polkaudio.com/discussion/29186/where-to-buy-black-paint/p1

westmassguy

I dug out my untouched, all original Monitor 7Cs last night, for some comparative listening tests.
I chose an album I'm very familiar with, Fleetwood Mac, Rumors, Re-mastered 2 CD Set. The 7s were setup on original Polk stands, toed in slightly. First up, was the original SL2000s. They sounded decent, but the treble harshness became very apparent very quickly. Next, I changed the left tweeter with the rebuilt unit. The sound of the rebuilt tweeter was very laid back compared to the SL2000. The stereo image did not shift in either direction, so again, the overall SPL of the rebuilt tweeter is similar to the SL2000. The right speaker was almost raspy compared to the rebuilt.
Next I changed the right SL2000 with an RDO-194 Tweeter. The Stereo image remained dead center. There was a difference between the two, but much less so when compared to the SL2000. For the last test, the other rebuilt Tweeter was installed in the right speaker. The sound quality was very good. I did not experience any listening fatigue, or notice any harshness. The overall sound was very balanced, and the rebuilt Tweeters blended well with the Woofers. I'd say it's a win, however, if pressed, I would give the nod to the RDO-194s, if for no other reason, than they were designed by Polk as improved, direct replacements. Keep in mind, the SL2000s and the RDO-194 were fully broken in, where-as the rebuilt tweeters only had a few hours on them.
Would I do this again, most likely not. Would I recommend others try it? Yes, with several caveats. You must possess fine motor skills, patience, and be very competent with your soldering skills. You should also have good magnifying glasses, and a soldering station with a fine tip. The plastic bezel will melt very quickly if you're not careful.
I don't consider myself an audiophile, rather a music lover, so I'm not going to attempt to use esoteric terms to describe the differences between the three Tweeters.
I did listen to a few other CDs, but not every type of music, so take what I said with a grain of salt. I don't listen to Classical Music, or Monks chanting.
The rebuilt Tweeters are much better than the SL2000s, and comparable to, but different than the RDO-194s.
If you have the skills, and a few hours to kill, try it. The domes are $10.00, and if you like the sound, you saved yourself $90.00

Faustin

Thanks for the nice write up / comparison Dave. Doing things like that are time consuming.

voltz

Nice review and comparison of those tweeters and I'm glad you got to enjoy the 7's again and listen to some good music! You have to stop and smell the roses sometimes too, can't just work on the rose bed all the time

westmassguy

Faustin wrote: »

Thanks for the nice write up / comparison Dave. Doing things like that are time consuming.

Welcome Bruce.

westmassguy

voltz wrote: »

Nice review and comparison of those tweeters and I'm glad you got to enjoy the 7's again and listen to some good music! You have to stop and smell the roses sometimes too, can't just work on the rose bed all the time

You got that right Brother. Took my mind off everything else on my plate, for a little while.

VSAT88

Made the order for the new improved "real silk" domes westmassguy. Thanks for the write up and link ! It should make my next victims easier to hack !

leftwinger57

Hey Dave I saw that you did a comparison test w/ your 7s. Mine still have the Peerless so no joy there and I replaced my silver domes on my 2Bs w/ 194s. Any comparison between the 2 sets. You guys were right all along because the way older silver domes were sounding tired, scratchy and no comparison w/ the new 194s. Also they kinda can't be called silver domes any more, because mine kinda tarnished to a gold patina. lol

OldmanSRS

Where does one buy the RDO-194's. I've been MIA from here for a couple of years and many brain cells ago.

Thanks,
Greg