Monitor 7 recapping questions and Advice.

greyhnd

Hello folks. I purchased a pair of Monitor 7's a few months ago and one of the speakers has developed a problem. After approximately 15 minutes of use, the speaker begins to cut in and out then finally there is no sound at all. If I switch speaker cables the problem persists. The drivers appear to be in good shape and when the speaker produces sound it is excellent. I'm hoping a xover recap will fix the problem. One suggestion I received is to resolder the existing caps and see if that helps.

The 7's I have are the original version and AFAIK, there have been no upgrades done. I've read several threads here and at other forums and I'm confused about a couple things. There are so many different capacitor brands that I'm almost dizzy from trying to decide what I need. Some say use Dayton, some say Clarity, or Solen, etc. I'm truly lost as which I should purchase. My budget is limited, so top-of-line caps are out of the question, but I still want to use quality components.

Are there any rules of thumb that you experienced xover folks follow? A certain brand for the woofers another for the tweeters? There was a nice write up on the procedure by heiney9, but now I can't locate the darn thing. Does anyone use Erse caps? I'm hoping to tone down the tweeters a bit in the process, but I'm not sure which brand does what.

I hate being such a noob with such matters, but we all have to start somewhere. Any advice or suggestions will be appreciated. Thanks in advance.

Joe08867

If you look around the site you will see there is much debate about the subject.

My personal preference for Monitor series speakers is Sonicap or Clarity Caps. I have used Daytons and found them fatiguing. The two I suggested are much warmer.

Polk also makes a replacement tweeter for the Monitor series that is much smoother than the original. It is the RDO-194.

I have no personal experience with Erse so I can't say yes or no on that.

Robint

If these are the original Monitor 7 then they should have the Peerless tweeters which I find smooth. I bought Audience Auricaps 12uF caps. of ekbay for $12 a pop. These are well regarded caps. I too, am limited to how much I can spend on recapping my Polks These are for the tweeter. I'm ordering from Parts Express cheaper caps e.g. Dayton or Jantzen for the woofers adding up to 34uF.

Joe08867

We can answer this question of tweeter if you can describe what the tweeter looks like.

Is it All black with a small hole in the center of it? That would be the Peerless tweeter and if they are working I would keep them.

Is it Silver? This would be the SL1000 and they are the worst tweeter Polk Ever made. I don't believe they used them in the Monitor series but just in case I thought I would add them to the question.

Is it Black with a silver dome. This is the SL2000 and it is better than the SL1000 but not as good as the Peerless. I would switch them for the new Polk replacement.

I personally like using the same caps for the highs and lows. This is what I have done several times now. But a few here have done what Robint is doing with a real good cap for the highs and a cheaper replacement for the lows as they aren't quite as critical. I have not tried this so I don't know how it sounds.

cincycat13

My Monitor 7B XOs were done by the former owner and fellow forum member Ricardo. You got me curious so I pulled the passive today. They appear to be Dayton caps (although I saw no label) and resistors and sound really nice. I am sure they were done with budget in mind.

I also attached a picture to show the tweeters. These are the Peerless version. Have fun with the upgrade.

greyhnd

Joe08867 - The tweeter is the SL2000 you described, I think. The tweeter itself is black and the dome looks more translucent than silver, but I suppose it could pass for silver. I'll probably replace them in the future, but for now I'll leave them as is and hope a crossover upgrade will help. I hadn't planned to do anything but replace the caps, but now I wonder if I might be wise to replace the resistors as well.

greyhnd

Okay, I popped open the terminal cup and the xover assembly is different than what I was expecting. The board is white and attached to the terminal cup with two screws, It looks like the terminal cup is wound with copper wire all the way around. The 12uf cap is a big yellow one, the 34uf cap is a smaller blue cap and is standing "on end" instead of laying flat. There is also a wound copper resistor, at least I think that's what it is. I've lost the cable to my camera, so I'm not able to upload the pics I took right now.

After looking at the crossover, I'm not certain I'm smart enough to tear into it. Probably easier than I think, but the terminal cup being wound with copper makes me a bit worried. Has anyone done an upgrade with this type xover before?

cincycat13

greyhnd

The wound copper parts are the inductors. You will see one wrapped in black at the bottom right of my pic. You will leave them as they are. The terminal cup wrapped in copper is just the larger inductor.

You will desolder / replace the caps and resistors only. Have you looked at the schematic from stickies at the top of this section? I will check, but based on my picture I would think you will see 2 caps and 1 or 2 resistors for each XO. My guess would be one resistor and that Ricardo pulled replaced the polyswitch with a second resistor when he did the ones I show.

Joe08867

cincycat13 wrote: »

greyhnd

The wound copper parts are the inductors. You will see one wrapped in black at the bottom right of my pic. You will leave them as they are. The terminal cup wrapped in copper is just the larger inductor.

You will desolder / replace the caps and resistors only. Have you looked at the schematic from stickies at the top of this section? I will check, but based on my picture I would guess you will see 2 caps and 1 or 2 resistors for each XO.

Exactly what cincycat13 said. Leave the wound copper inductors alone and change the caps and resistors.

It really isn't that hard. But if your worried I think a couple guys around here still do this for club members for a nominal fee.

greyhnd

Okay, finally got some pics of the xover so you can see what I'm looking at. I think my question has already been answered, but here they are nonetheless. I think I can do this upgrade, it just looks a bit daunting at first inspection. I hate like hell to be so dense, but is the polyswitch what is labeled PS1 in the middle pic?

george daniel

yes on the poly--the mustard colored thing.

greyhnd

Thanks for clarifying that george. Much appreciated.

greyhnd

Decided to order my upgrade parts and went with Erse PulseX caps 33uf for the woofers and Clarity Cap PX Series 12uf for the tweeters. Not sure yet what to do about the resistors, but I'll probably replace them as well while I'm in the mood. Updates as the project continues.

The polyswitch, should I leave that alone, remove it altogether, or replace it with a fuse? It's been suggested to use a fuse, but I'm uncertain about doing that. Would a fuse holder connect to the polyswitch connectors on the pcb?

greyhnd

Here a couple pics of the XO removed from the terminal cup. What do others do to get enough room to do the soldering? Desolder the connection to the large inductor and the terminal wires? The terminal connections are held to the cup with nuts, so I thought about just taking them off that way. Not sure what size the nut is and there's not much room to get in there, but it would keep the number of solder joints down. I hope I'm not making this harder than what I need to.

greyhnd

I finished both crossovers over the weekend. Replaced the capacitors only just to see how much difference I could hear. So far, I think the Clarity Caps toned down the SL2000 tweets a good bit, not so "bright" as before. It also seems that the bass is a bit tighter and cleaner.


I still need to replace the resistors and either bypass or replace the polyswitch. Now that I got my feet wet I'm not so worried about doing the job myself. I appreciate everyone taking time to to offer advice. All of it was helpful in one way or another.

Joe08867

Glad your having fun and hearing the results.