Monitor 5b's x-over upgrade w/pics

heiney9 · April 2010

Great!

I have a lot going on this weekend but I'm determined to wrestle with my 1C's and get them done.

The dac mod has me just floored!! Just freakin' floored!! Can't wait to get the 1C's done. I would tackle it tonight, but I have a newly modded dac to listen to.

H9

comfortablycurt · April 2010

The hardest part in this mod really was removing the gaskets from the passive radiators. The gaskets on the MW's and the tweeters basically peeled right off...but I had to go around the entire edge of the PR's and scrape the gasket off with a little flat head screwdriver. It left a little residue...but most of it cleaned up with the corner of a rag dipped in a little rubbing alcohol. If you've gotta do that though...be very careful. I don't think the rubber surrounds would get along too well with the alcohol.

That probably wasn't even really necessary, but I wanted a nice clean surface for the mortite to seal to.

This is fairly time consuming though. And it's that kind of work where there's not really anything you can do to make it go faster. I definitely wouldn't be looking forward to mortiting a pair of 1.2TL's!

I'll also add, that upon further inspection...the MW's don't really seem to be staying extended much longer than they were before. An extra second or so maybe...but I'm not even sure of that. As others have mentioned though, I think the benefits of this mod are really more due to the better coupling between driver/baffle. After all, you don't want these speakers to be completely air tight, they still need to be able to breathe. My point here, is that even if your speakers are air tight, and pass the PR Press Test, this mod is still going to give you big improvements. If I did the PR Press Test on my 7A's before the Mortite mod, the MW's stayed extended for 30+seconds, so air tightness wasn't the issue really. Also, like I said above, the 2A's don't really seem to be much more air tight than they were before, but the results are staggering. The cheap paper gaskets that Polk used have just worn out over time. Even though they may still be keeping an air tight seal, they aren't coupling the drivers to the baffles as well as they could, which is robbing you of sound quality.

heiney9 · December 2010

I can re-up the photo's of the Mortite procedure. I moved them into a separate folder in Photobucket so the pics in post #171 are no longer there.

TNHNDYMAN · January 2011

heiney9

just read this thread w/ interest today because I am considering modding some Monitor 10B's. Could you repost the pics of the Mortite procedure or provide a link to them. I think I understand what you did but would appreciate some visual help. TIA

bamark · March 2011

TNHNDYMAN wrote: »

heiney9

just read this thread w/ interest today because I am considering modding some Monitor 10B's. Could you repost the pics of the Mortite procedure or provide a link to them. I think I understand what you did but would appreciate some visual help. TIA

Ditto for me.

Also, now that it's been awhile, are you still happy with the Solens (LP) and Clarity (HP) caps?

heiney9 · March 2011

bamark wrote: »

Ditto for me.

Also, now that it's been awhile, are you still happy with the Solens (LP) and Clarity (HP) caps?

Extremely pleased, you could go all Clarity caps. I didn't on the low pass simply because the Solen was already in place and I didn't want the extra expense of replacing both Solen caps.

The highs just seem smoother and more natural with the Clarity cap vs. the Solen.

Great bang-for-the-buck and highly recommended.

H9

bamark · March 2011

heiney9 wrote: »

Extremely pleased, you could go all Clarity caps. I didn't on the low pass simply because the Solen was already in place and I didn't want the extra expense of replacing both Solen caps.

The highs just seem smoother and more natural with the Clarity cap vs. the Solen.

Great bang-for-the-buck and highly recommended.

H9

I noticed in the picture previously, you had a different type of dome tweeter.
Mine are "Silver Domes" (SL-2000?). Will that affect the type of cap I need?

Mark

Joe08867 · March 2011

bamark, the answer is no. He is using the Polk Replacement tweeter. So all the parts listed in the original crossover will work with your SL2000 or the new RDO-194.

heiney9 · March 2011

bamark wrote: »

I noticed in the picture previously, you had a different type of dome tweeter.
Mine are "Silver Domes" (SL-2000?). Will that affect the type of cap I need?

Mark

I am using the RD0194-1 replacement silk dome tweeters. They are much smoother and more natural sounding than the sl2000 (silver dome, mylar) tweeters. My 5B's previously had the sl2000 tweeters but I hated them, even more after I refreshed the x-overs.

It's your call, but the $100 is well worth it to replace the sl2000 tweeters. The RD0194-1 tweeter is a Polk manufactured part and is a drop in replacement.

H9

bamark · March 2011

heiney9 wrote: »

I am using the RD0194-1 replacement silk dome tweeters. They are much smoother and more natural sounding than the sl2000 (silver dome, mylar) tweeters. My 5B's previously had the sl2000 tweeters but I hated them, even more after I refreshed the x-overs.

It's your call, but the $100 is well worth it to replace the sl2000 tweeters. The RD0194-1 tweeter is a Polk manufactured part and is a drop in replacement.

H9

Appreciate the input. I'll take this in stages, as it's newbie territory for me.
I color printed your recap procedures, and have been reading the process and familiarizing myself with the pictures. Maybe I can contribute a little more in the way of additional pics. I would imagine there are lots of guys lurking around, who may be interested.
Good information on this thread.

Thanks

Mark

bamark · March 2011

H9, I pulled the xover on one of the 5b's and it matches the photo you took of the single you bought for parts (picture 10).

This leads me to new questions regarding replacement caps.

http://www.polkaudio.com/forums/showthread.php?t=73470

I started reading this particular thread due to the discussion of whether or not removing a poly switch should be done.

I ran across your post on that thread:

"Hey guys,

I notice in many of the Monitor series that use the sl2000 there is 2.0 ohm resistor if they are fused and a 2.7 ohm resistor is they use a polyswitch. I believe the polyswitch does alter the circuit in a small way. With the right cables and equipment I don't doubt a subtle difference can be heard. I'm going to experiment with my (fused) 5B's with a 2.7 and 3.5 ohm just to take a bit of the fowardness away. I have the RD0194-1's and they aren't harsh or grainy it just seems they are a bit "loud" in the upper vocal range. I hope to have the upper vocals blend a little better.

Let us know what you find out.

H9

P.s I installed a 2.0 ohm resistor per what was already on the board as stock."

I also see that the capacitors on my x-over are 12uf 50v and 34 uf 50v.
Can I assume that I can replace those using the same values that you used -
12 uf 400 VDC and 34 uf 400 VDC?.

As for the resistor, assuming I remove that poly switch (after reading DK's post concerning pre-trip and post-trip values - I figure these have also been tripped) should the 2.0 ohm resistor be increased to 2.7 or even 3.0 ohms?
DK evidently talked to Polk about this:

When I consulted with Polk prior to doing my first SDA modification, I was advised to remove or short the polyswitches if and only if I was using quality amplification and if I was not in the habit of overdriving my amplifier. There was no advisement on a requirement for resistance compensation due to the removal of the polyswitch.

I should add that I'll be using the Pioneer SX-650 for this setup. I'm also going to have it re-capped in the near future. It should have enough power for 6 ohm speakers, and I won't be driving them hard.

That thread is also particularly interesting because it touches the subject of brightness in the tweeter. Maybe removing that switch reduces some of that brightness.

So H9, given the above information, would it still be ok to use the following for my 5's:
Original 12uf 50v - replace with Solen or Clarity 12uf 400VDC, 5% tolerance
Original 34uf 50v - replace with Solen 34uf 400 VDC, 5% tolerance
Remove Poly switch
Original 2ohm 10% 5W resistor - replace with 2ohm 12W resistor (or should this be increased?

Thanks and sorry to beat this thread some more. I just want to do it right the first time.

Mark

ben62670 · March 2011

Stay away from the Solen in the 12uf.

bamark · March 2011

ben62670 wrote: »

Stay away from the Solen in the 12uf.

Hey Ben, yea, Heiney9 said the same thing. Clarity PX 12uf are $8.30, Clarity SA 12uf are $15.40. Solen 12uf are $7.03.

I'm looking at a maximum difference of $16.74 for the SA's, and $2.54 for the PX. Also suggested I upgrade to the RD0194-1's for about $100.
I think he ended up using the SA's. I read the specs for both (SA vs PX), and I'm not sure what the difference in sound would be.

ben62670 · March 2011

SonicCaps are $20.45 each, and are tried and true.

bamark · March 2011

ben62670 wrote: »

SonicCaps are $20.45 each, and are tried and true.

OK, what about the Poly switch; leave it in and use the 2 ohm resistor, or take it out.

thanks

Mark

bspeis108 · April 2011

Is there anyone who lives in NY, anywhere near queens who has done this xover mod on the monitor 5's? I'm about to put RDO194's in to replace the sl2000's and would love some help with replacing caps on my xover.

please email me at bspeis24@yahoo.com if you would be willing to help.

thanks!

gwg_97 · April 2011

Just opened up one of my 5Bs (no fuse version) to replace a damaged PR and saw that the crossover was very different from the one in heiney9's photos. Unless I'm going completely blind (which may be the case), all my caps and resistors were standing up on end and the caps appeared to have no leads coming out of the end sticking up off the board (top end). Sorry no camera at the time. Anyway not much space to add those big Clarity caps (or any other new cap for that matter). Anyone run into this?

heiney9 · July 2011

I finally opened my package from Larry (TOOLFANFORLIFE) and I started to install the rings and tweeter brackets he machined for the drivers in my 5B's. I would have had one speaker done tonight but to do it right I need some washers so the bolt heads don't puncture the basket holes on the driver and passive radiator. Too late to hit the hardware store.

This is a practice run for when I also do my SDA 1C's. Only area that will trip you up is the nasty glue on the inside of the cabinet most likely will interfere with the bracket for the PR. A small flash light, carpenters knife and a very small bladed screw driver will allow you for pry, shape and cut the glue out.

I have pics and I'll post them soon. I have the brackets in place and the drivers in place. I was only able to tighten the tweeters because those didn't need washers between the bolts and the basket frame.

I'll revisit tomorrow night with a step by step and pics.

H9

heiney9 · July 2011

As promised here's the write up and pics on adding Larry's driver rings and tweeter brackets to my 5B's. I decided to start a new thread, but here's the link.

http://www.polkaudio.com/forums/showthread.php?t=121653

H9

gaspipe · August 2011

I know this thread is old, but to answer this, I used clarity caps and mills 2 ohm resistor both ways with/without the switch in my 5B's (no fuse). I could not hear a definitive difference, so I put the poly switch back in after fooling with them over a couple weeks. Mayhap my ears are too old :frown:

Interesting thing is my 5B XO's were funky - one had a 34uF cap, the other a 35uF cap. I bought these new ~20 years ago, and they had never been out of my hands.

bamark wrote: »

OK, what about the Poly switch; leave it in and use the 2 ohm resistor, or take it out.

dorokusai · August 2011

gaspipe wrote: »

I know this thread is old, but to answer this, I used clarity caps and mills 2 ohm resistor both ways with/without the switch in my 5B's (no fuse). I could not hear a definitive difference, so I put the poly switch back in after fooling with them over a couple weeks. Mayhap my ears are too old :frown:

Interesting thing is my 5B XO's were funky - one had a 34uF cap, the other a 35uF cap. I bought these new ~20 years ago, and they had never been out of my hands.

That's not really surprising given the years produced.

Monitor 5b's x-over upgrade w/pics

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