Help in refreshing Monitor 5B crossover?

pitdogg2

heiney9 wrote:

P.s. I might be mistaken on the SL1000 being the exact same dimensions as the SL2000 and RD0, I honestly can't recall.

They're not the SL1000 is smaller. I'd bet that they came with SL2000. I tired to use Larry's brackets on the SL1000 and they are off about 1/8".

heiney9

Good to know on the dimensions. It would be unusual for that cabinet style to have SL2000's, but not impossible. Also most times that early cabinet style has a (2) fuse terminal cup, but again these could be a transition model as the proof is in the x-over and MW6502. Real early M5's with that cabinet style usually have the peerless tweeter paired with the MW6500.

Again, that x-over is NOT for a peerless model, so I still think the RD0's will drop right in based on his photo and the gap I can see and also be a better electrical match for the x-over he has.

H9

heiney9

Early M5's the Mid woof and Passive radiator baffle cut out overlap and the driver baskets touch. Later M5's have a gap between the baffle cut out of the mid woof and passive.

Perhaps the OP could post a pic or confirm which he has. That is more conclusive proof of which model he has.

H9

StuartB

OK, first crossover is desoldered and the old componenets are removed. I ended up clipping the caps and resistors off the board first and then desoldered. It seemed that this was the easier way to get the leads out. Not sure if that is recommended or not. Man they do not give you much room on a couple of those connections with the wires connected. I did not completely unwire the crossover from the mounting plate, just separated from the spacers, and bent the two sections apart from each other.

.

I think that is what H9 did in his pictures as well. Am I OK in doing it that way? I will probably lay out the new parts and figure out the sequence to install this evening.

If my speakers had a Jan 1984 manufacture date, would that lead you the believe that they started life with SL1000 or SL2000 tweeters?

Any recommendations on fitting and soldering the new caps?

StuartB

QUOTE=heiney9;1796177]Early M5's the Mid woof and Passive radiator baffle cut out overlap and the driver baskets touch. Later M5's have a gap between the baffle cut out of the mid woof and passive.

Perhaps the OP could post a pic or confirm which he has. That is more conclusive proof of which model he has.

H9[/QUOTE]
The drivers touch on mine

[

heiney9

Do one x-over at a time so if you get confused you still have one to look at for reference.

H9

heiney9

StuartB wrote: »

QUOTE=heiney9;1796177]Early M5's the Mid woof and Passive radiator baffle cut out overlap and the driver baskets touch. Later M5's have a gap between the baffle cut out of the mid woof and passive.

Perhaps the OP could post a pic or confirm which he has. That is more conclusive proof of which model he has.

H9

The drivers touch on mine

[[/QUOTE]

Those are early cabinets, a mystery of sorts. But you are on the right track.

H9

heiney9

You can clearly see on my 5B's the drivers have spece between them. Hard to see but the edge of the cabinets are beveled and the Polk logo is attached to the grill




H9

heiney9

This shows 3-5-85 on the Passive which is original and these are 5B's with a tweeter fuse. The drivers are maked from 1991 because the originals were blown.



H9

heiney9

Here is my x-over when done.

12uF
34uF
2.7 ohm

You can see the date tag on the pcb a February 28, 1985. What does your x-over say if there is still a sticker?

pitdogg2

heiney9 wrote: »

Do one x-over at a time so if you get confused you still have one to look at for reference.

H9

and do not cut the cap or resistor wires after install until you know it will work the way you put it together. just in case you need to reinstall differently

heiney9

pitdogg2 wrote: »

and do not cut the cap or resistor wires after install until you know it will work the way you put it together. just in case you need to reinstall differently

Exactly, test the modded one to ensure it works before moving onto the other one in case you need it as a reference.

StuartB

heiney9 wrote: »

Here is my x-over when done.

12uF
34uF
2.7 ohm

You can see the date tag on the pcb a February 28, 1985. What does your x-over say if there is still a sticker?

Both of mine are date January 1984, the dates are a little smeared. BUt the dates on both crossoveres, both MW drivers and both radiators all line up with Janaury 1984. The Tweeter is the outlier.

THree questions:
1) did you have to strip additional insulation on the Carilty cap leads to fit it on the board?
2) dumb question, but is there a way to test the rebuilt cross over without hooking everything back up in the cabinet?
3) was there a specific reason why you did not use a touch of hot glue on the new components?

heiney9

StuartB wrote: »

Both of mine are date January 1984, the dates are a little smeared. BUt the dates on both crossoveres, both MW drivers and both radiators all line up with Janaury 1984. The Tweeter is the outlier.

THree questions:
1) did you have to strip additional insulation on the Carilty cap leads to fit it on the board?
2) dumb question, but is there a way to test the rebuilt cross over without hooking everything back up in the cabinet?
3) was there a specific reason why you did not use a touch of hot glue on the new components?

1) I can't remember, but that would be the way to do it.
2) Not that I'm aware of. If you are confident you did everything correct don't worry. This is very, very straight forward. Hard to screw up as far hooking it up wrong. Maybe a poor solder joint if you aren't used to soldering, but as far as connections go, a piece of cake.
3) I pulled them snug to the foam on the board from the previous caps. Didn't think hot glue was necessary as they were secure.

StuartB

I finished the first crossover this morning. It went pretty well.

I have a general question. I connected the rebuilt cross over to a power source and connected the speakers on an open table. I got sound out of both speakers but it sounded really thin since the speakers were not mounted.....if I get sound out of both drivers is that a pretty good indication that the rewiring and reconnection of crossover elements was successful?

heiney9

Looking good! If I might make one minor suggestion don't put the foam under the resistor. At high volumes there is a chance it could heat up and a small gap between the resistor and pcb aids in cooling. Not at all a big concern and certainly don't disassemble, but more for general knowledge in the future. If you can remove the foam w/o disassemble, try it. If not, let it be as in this type of circuit and the size of the resistor being 12W when a 2W is called for, it won't be an issue.

H9

skrol

It does look good. With those big caps, you might have difficulty fitting the crossover through the hole in the cabinet. I had to remove the PC board from the terminal cup (wires still attached) and feed it through the hole then attach the board to the cup from inside the cabinet.
Stan

StuartB

skrol wrote: »

It does look good. With those big caps, you might have difficulty fitting the crossover through the hole in the cabinet. I had to remove the PC board from the terminal cup (wires still attached) and feed it through the hole then attach the board to the cup from inside the cabinet.
Stan

Just checks, it will fit (barely) in one piece. I will make sure the second one is as compact as it can be.

I also tried to pull the foam from under the new resistor...not going to happen, so I will store the recommendation for the next project.

Two additional questions.

1) if I temporarily attached the cross overs to speakers and amp and get sound through both drivers, is that a fair test that the upgrade is initially successful? The sound was poor since the speakers were not mounted, but I did get mucin through both speakers connected to the new crossover.

2) what is the thinking on using a small amount of hot glue to stabilize the new capacitors and resistor to the board. Mine are relatively snug on the original foam, but I was thinking I would use a small dab of hot glue to further couple the components to the circuit board.

Today I will have the second crossover completed. I will be waiting on the hurricane nuts and the new tweeters, and I will be able to wrap up this project. If by chance the bolt pattern is the same on the Peerless and RDO tweeters I will be able to compare the two sets of drivers.

I also use JB Weld to glue the magnets on all drivers.mit was interesting to see the metalized epoxy interact with the magnets...I wasn't expecting that.

As always,thanks for the input.

heiney9

1) a fair test, yes

2) caps can transmit vibration so in order to minimize vibrations they make sure the caps are very secure. Hot glue makes the most sense because if you used other types of adhesive the caps would be impossible to remove.

Have fun listening. Caps and tweets will take about 200-300 hours to fully break in. First they will sound good and then they will sound like a$$ then they will slowly settle in. So don't be hasty after the first few listens.

H9

StuartB

Soldering checkpoint. I am sitting here second guessing my ability to solder effectively.

I used copper braiding to desolder and remove most of the old solder. When I placed the new components I used flux and good quality solder. The connecteions appear to be good and I get signal to the speakers. Anything else I should check or be aware of. I have read about cold solder joints, and I assumed that if that occurred there would be no signal. Am I just obsessing over nothing, or is there any way to further check my work prior to reassembling the speaker?

transmaster

From the Horse's mouth:cool:

Polk SL1000, SL2000 Tweeter vs SL2500


http://reconingspeakers.com/2010/12/polk-sl1000-sl2000-tweeter-vs-sl2500/

StuartB

OK, I have both cross overs completed.

I think they turned out pretty well for a first timer. I briefly connected each to an amplifier and drivers, and got sound from each circuit....so I am calling them good and not obsessing over the quality of my soldering.

I used a hot glue gun to sparringly tag each capacitor to the board.

I did not hot glue the resistor.

I also used JB Weld to glue both midwoofer and tweeter magnets to prevent future slippage.

So now I am waiting for hurricane nuts and screws and sound damping material, and then the new tweeters from Polk.

I have Armaflex ready to be used for new gaskets for each driver and the mounting plates.

Is it recommented to use a little bit of epoxy to mount the hurricane nuts?

I did not replace binding posts and I did not bypass the tweeter fuses. Other than that I have tried to accomplish most of the recommended upgrades discussed in this forum.

Still open to any questions or recommendations before I start reassembling the speakers later this week.

I have had a lot of fun doing the work so far. I do not have great expectations of immediate improvements but my comfort level with doing this sort of work has gone up tremendously.

THanks again for teh help thus far.

jmwest1970

Thanks for the pics! They look great. I'm a little more stoked to upgrade mine when the funds allow.

transmaster

When I rebuilt the XO's on my Monitor 10B's I took heiney9, and others advice on the cap's I installed SonicCap Gen1 for the high side, and I used a Axon True cap's for the low side. The Axon True Cap is made by Solen. I checked them out in a couple of forums dedicated to crossovers. The consensus was the Axon's where a little better then the parent Solen's.

Except for the Soni Cap Gen 1's I purchased the rest of the parts from Parts ConneXion. (http://www.partsconnexion.com/index.html)

Solen 33uf 400VDC PB Series, is $14.79 each
Axon True Cap 33uF / 250VDC, , is $6.51 each

Not much difference in price but getting the Axon cap's did save me enough money to more then defray the cost of the SoniCap's.

As heiney9 has observed as things burn in the sound improves. I don't know how many hours I have on the refurbished 10B's but in the last week or so the sound is astonishingly better. It didn't seem like the bass was right, a little snappish and not at all smooth. Now however as I listen to the compilation CD Bombay Sapphire, Pure Chill Out Distilled by Buddha-Bar. there are at least 23 releases in the magical Buddha Bar series . Everything is clear as a bell, with bass guitar, and percussion I can feel through my fingers on this keyboard. All of this out of a 23 year old set of speakers. I have the original tweeters, with all of the testimonials on how much better the replacement sounds I think I am going to call Polk up and order a pair.

StuartB

Nice recommendation on the Axon capacitors. I think I paid $12.75 for 35uf Solens from Madisound. I probably would have gone with Axon had I known about them. I am anxious to get everything back together and start breaking them in. Which tweeters are currently in your 10's?

pitdogg2

StuartB wrote: »

2) what is the thinking on using a small amount of hot glue to stabilize the new capacitors and resistor to the board. Mine are relatively snug on the original foam, but I was thinking I would use a small dab of hot glue to further couple the components to the circuit board.


As always,thanks for the input.

I wouldn't put ANY hot melt glue on the resistor's.....

StuartB

pitdogg2 wrote: »

I wouldn't put ANY hot melt glue on the resistor's.....

Good I didn't, in addition H9 recommended that I remove the original foam under the resistor to allow for additional cooling.....alas it was too late and the resistors were snugly installed against the foam. I tried to slip out the foam but it would not budge.

Tha

StuartB

OK, I am in the home stretch. I replaced the original seals with Armaflex. It was very pliable and easy to use.

I dampened the passive radiator and mid/woofer baskets with Sonic Barrier from Parts-Express. It is similar to Dynamat, but much less expensive. I also used JB Weld to the magnets on the speakers as a preventative measure.

Not the most elegant application, but effective in damping the backets, and of course it will be hidden once assembled. In the picture you can see the Sonic Barrier, the Armaflex gasket and the JB Weld. Once the Sonic Barrier was installed I let them heat up in the sun for maybe 30 minutes and made sure the seal was good

Then I installed Hurricane Nuts to all screw locations. This really went easier than I anticipated. THe MDF did not crack or split at all. I used a 13/64 bit to expand the screw holes, then got the nuts started and attached to a screw, applied a little JB Weld and then tightened the screw to pull the nut into the MDF. The only potential snag will be that in some of teh cut outs the huriricane nut juts out past the cut out...this could make the crossover fit tighter than it already will be.

All I am waiting for now are the new RDO tweeters. Once they are here I will see how they fit, adjust the cut out if necessary, drill and install the hurricane nuts for the tweeter, and then put it all back together.

After that I will have a pair of perfect Danish Peerless tweeters for sale.

StuartB

Well, crap. The new RDO tweeters came today and they are not the same size. It looks like it is Dremel time.......I was hoping not to have to mess with the tweeter cut out on the cabinet. Here are side by side pictures of RDO and Peerless tweeters.

heiney9

Did you try them in the openings? Only reason I ask is because in your photo there is about 1/8" gap between the peerless bezel and the cutout and if you are just comparing the tweets physically side by side and not checking to see if they fit in the cutout, then you might be mistaken.

I ask because you say they are not the same size and nothing about them not fitting in the cut out.

It does appear the RD0 is more than 1/8" larger than the Peerless.

H9