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

Tony M

xschop wrote: »

I'll share my findings since this can be done with a common supplement. Back in my research days, Retinol or Retinoic acid has a very close molecular weight to dibutyl pthalate.

It's fat-soluable and importantly,
It sticks to proteins too ( silk e.g.)

It indeed does clear up frequencies and transitions in these uncoated domes. Also I took them back out after a few hours and the tight weave silks didn't allow the compound to penetrate back into the back-sides. Not sure it matters if it does. Each dome took just a couple micrograms to coat.

The sound is excellent and indeed improved...
Coated on left, uncoated right... Just brushed on with small artists brush evenly with no excess until perfect sheen achieved...

Does this coating dry to a flexible film?

xschop

I don't believe it will. It's been in 100 plus temps the last few days and it is still a light oily sheen. It is an anti-oxidant, so check back with me next year.

You can try the Dibutyl Pthalate from Sigma Aldrich. Their smallest bottle with probably do a few hundred domes.

It will polymerize to a rubbery plasticizer.

Tony M

Thank you for that info.

xschop

Tony M wrote: »

Thank you for that info.

Thank you too for your info.
On that one SL-2000 magnet that fell apart, could you Mic the ID of the magnet?

xschop

I got the wider mount holes programmed and the wider diameter rear inset and depth programmed for the SL2Ks....

VSAT88

Looking good !

Tony M

Here you go;

26.79mm

1.0545 inches

xschop

Ok thanks again. This matches the Version2 plates I have. If these SL2k/RDO's were ever to become obsolete, I've found a matching ceramic magnet and could machine the pole-piece and attachment plate as well.

BlueBirdMusic

Tomy M, xschop, VSAT88

Interesting stuff from you THREE

xschop

BlueBirdMusic wrote: »

Tomy M, xschop, VSAT88

Interesting stuff from you THREE

You forgot WMG. He put in a lot of footwork and had some good results too.

VSAT88

Yep, westmassguy is a good one. He has helped me and many many others here on site as well. I will say that I definitely appreciate him and his incite. His ideas about the SDA 2b are copy and pasted in a word .doc right on my desktop.

BlueBirdMusic

westmassguy, Tony M, xschop, VSAT88

Interesting stuff from you FOUR!

Sorry about that guys especially to Dave.

I would say Dave has helped more people on this site than anyone. He was the first person that I contacted and he helped me immediately.

westmassguy

BlueBirdMusic wrote: »

westmassguy, Tony M, xschop, VSAT88

Interesting stuff from you FOUR!

Sorry about that guys especially to Dave.

I would say Dave has helped more people on this site than anyone. He was the first person that I contacted and he helped me immediately.

Appreciate the compliment, but there are many members here who forgot what I know, and have helped me in the background. Never underestimate the senior members.

RandyCroissant

I think the alloy face plates look slick! nice job XSChop would love to see them with the Polk logo around the throat or really anywhere on them. To me that would bring it all together.

xschop

RandyCroissant wrote: »

I think the alloy face plates look slick! nice job XSChop would love to see them with the Polk logo around the throat or really anywhere on them. To me that would bring it all together.

The end-user is welcome to do any extra curricular activity one chooses. One member will be anodizing them I hear. Laser-etching would be most economical method I believe, but sky's the limit.

Tony M

I finally got the right length screws for these silks;

8-32...1/4". They seem to work.

I just thought of something. I'll take a new screw and screw it into that one magnet that I broke the glue bond on. I'll have to get an 1/8" thick something ( to take the place of the new silk diaphragms )and then place the bezel, 1/8" something and screw the new screws down as far as I can. If the length pushes the plate up from the magnet...I'll have to go shorter.

I do like the black screw color.

VSAT88

Those bolts look great and the speaker looks original. That is great work !

Tony M

All thanks and credit goes to the man who researched the size dome and its coil needed and found a source to buy some. I just followed his path.

A bit of modification to the new dome screw holes and face plate backs and drilling out the old clip rivets are the tedious parts.

One could leave the former lead wire grooves open but I still want to fill them in. I thought of taping on each side of the groove, caulking and then squeegeeing the excess off, leaving a nice smooth filled groove after removing the messy tape. also taping the opening of the dome hole and doing the same there. The face plate would be removed to do the circle opening. I think it would create that little horn flange attribute.

Too bad these replacement domes come from China.

These new domes do fit perfectly don't they.

I haven't done the extreme tightening of the screw length test yet.
Maybe this week.

These 8-32 x 1/4" do tighten down pretty tight. But all it takes is ONE screw to break that bond of metal pole top plate from the magnet. I know...

xschop

Looks good. The countersunk screws don't work on the factory frames as you discovered.
Before I tossed my old 5B sl2k plates, I ground the old Silicon out and filled them in with Bondo. After careful sanding and black Fusion plastic paint, they looked great. Was alot of work to still have that throat step though.

Tony M

Bondo...that's probably the BEST way to fill these grooves. I have zero experience with Bondo in my many years of owning cars.

I don't want to sand and paint my bezels just yet. If I can get away with caulking just those areas I mentioned, I'll be ok with it.

Lowe's home improvement didn't have the screws I wanted or thought I wanted. I wanted something fast to secure those face-plates down. I hated the look of those countersink head screws sticking up and knew I had to get the right pan-heads.

I think I'll have 4 more sets to do later this year. I too just ordered some more diaphragms. They say "Due to arrive by Oct. 20th"... We'll see.

Tony M

Update;

I just saw in an email they sent, shipping will be BETWEEN Sept. 24th and Oct. 20th.

I missed the Sept. date somehow. like I said...we'll see.

vmaxer

Awesome work you are doing.

Tony M

Thanks.

It's been fun.

xschop

Tony M wrote: »

Update;

I just saw in an email they sent, shipping will be BETWEEN Sept. 24th and Oct. 20th.

I missed the Sept. date somehow. like I said...we'll see.

Same boat here. Luckily I have another extra set I can mod up from last batch.
My stainless countersunk M4x0.7x8mm showed up. I will have to trim 1.5mm off threads for full seating and thread grip without "popping the top" as you warned about.

Tony M

I've yet to test my 1/4" screw thread length on my bad magnet.

Darn squirrels!

xschop

Tony M wrote: »

I've yet to test my 1/4" screw thread length on my bad magnet.

Darn squirrels!

I ground these stainless socket heads down to 0.25" total length and they hit the spot....

Tony M

I like how those sit flush. Great job! I also like the SS screws. I could always order some knowing what I do now.

When I was in Lowe's the other day, I looked again for 1/4" anything and didn't see anything in 8-32.

So I must've really searched thoroughly before.

I DID measure ( with my new Caliper ) my screws' thread length which is 1/4" and then with it bottomed out on a magnet. I was setting up a face-plate taping session last night and thought, I CAN do the above and the remaining threads will give me the absolute MAXIMUM before disaster.






So 1/4" - 3/32" leaves what? That's the thickness danger point cliff's edge.

I have to eat dinner right now...

1/16" for the new dome's plate.

I can't measure the Polk's face-plate thickness where it counts in all this. Well, maybe I can...

Tony M

So I think the Polk's flange needs to be a touch more than 1/16" thick or greater at the mounting area screw opening to be safe. 1/16" thick is too close! It MUST be thicker!

I'm going to re-read this thread and see if one of you mentioned how thick the plate is for these SL-2000s.

Tony M

Well, I didn't see the thickness mentioned anywhere but it sure was fun reading this thread over again.

Here's what I did last night.

I taped over the wires just because. I'm going to tape the other 2 corners with a little square piece of tape too. So it will sit flush.











Putting caulking in the grooves and bezel has me a little trepid. Never done this before so we'll see how one turns out first.

VSAT88

xschop wrote: »

Tony M wrote: »

I've yet to test my 1/4" screw thread length on my bad magnet.

Darn squirrels!

I ground these stainless socket heads down to 0.25" total length and they hit the spot....

Everyone is going to want those brother. They look fantastic !