Help in refreshing Monitor 5B crossover?

soundfreak1

Drumminman other than listed in sig the 5jr+ are the first " complete mod" ive done on speakers. But after DAC the 12c's will be fully done as i will not ever sell them.

StuartB

jmwest1970 wrote: »

I've been silently following this thread because I have a pair of Monitor 5 speakers that I'd like to upgrade as well. If you can please post pics of the process as I've never done anything like this myself.

Thanks!

Well that makes two of us! I will post pics but there are also a couple other threads that have a lot of pictures and documentation. The is one started by heiney9 that is really thorough.....but I will post my process as well.

drumminman

soundfreak1 wrote: »

Drumminman other than listed in sig the 5jr+ are the first " complete mod" ive done on speakers. But after DAC the 12c's will be fully done as i will not ever sell them.

I still have to get RD0-194's (currently using the SL1000's they came with). I'm one of the few that don't hear the 13khz peak the original tweeters have. I'm wondering if the mods (all sonicaps mills on both upper and lower Xovers) have attenuated/ fixed that issue.

I agree, I can't imagine ever selling them. I've recently had a boatload of mods done to my main power amp, in effect tripling the current delivered. Even with a lower level Yamaha AVR as the pre (while the big rig is disassembled while I do mods to the living room :cool: ), the improvement is pretty amazing. The 12C's absolutely love high current power!

soundfreak1

When i first got the 12c's (using an. Avr) actually put tjem in the closet) not impressed but when i got the parasound they came alive and replaces every speaker i had at the time, ess's, epi's, jbl's and some b&w's just smoked them all. Then the dared came in and they loved the dared now with the gda700 DAC SYS. IS BASICLY COMPLETE. once the opamps ect. In the dac is done then the caps in the 12's im.done with this sys. LOL.the 194's did a lot more than eleminate the spike, just cleaned up the whole highend and helped the mids as well.

StuartB

OK, the upgrade is under way. I have everything disassembled. It is kind of a mixed bag. The passive radiator, the mid/woofer and the crossover are all dated January 1984. The tweeters are clearly the early Peerless (#7514xxxx). The mid/woofers are apparently the later MW6502. The crossovers have no tweeter protection switch, and just the tweeters are fused. The crossover has one 2.7 ohm resistor and on 12 uF capacitor on the tweeter and one 34 uF capacitor on the mid/woofer. The Polk Udio tags are on the bottom of the cadinet, not on the grill itself.

Everything seems to be stock and it sure does not look like any one has replaced components or even had the speakers out of the box.

So far everything has gone pretty well, thenonlynlittle snag I hit was that the wire connections to the tweeters were soldered to a degree, which made it a little tougher to get them off. I will need to clean them up before reconnecting.

I will post pictures later. I have been careful to label everything and have read up on posts from experienced members of this community.

I am waiting on a couple of the caps to be delivered. I know I will probably have some questions prior to desoldering/soldering the cross overs. Thanks for all the constructive input thus far, you have been a great help.

Anyone have any thoughts on the apparent mix of 5, 5A and 5B components that I seem to have, and is there any reason to consider a different resistor value given the tweeters that I have?

heiney9

Pics will help a LOT. Peerlees models (all I've seen) have (2) resistors in the tweeter path. Yours having just (1) 2.7ohm is suspect as to having the peerless tweets from the factory as is the MW6502 driver.

Are you SURE they are peerless? If they are, they are wrong for the rest of the parts as you have described them.

H9

P.s. Of course we all know Polk is the master or using up parts and cross-breeding models and parts.

StuartB

here are some pictures the first is of the tweeter.....I am pretty sure it is Peerless

Here is teh back of teh tweeter and you can faintly see the 7514xxx number

Then here is the MidWoofer

Here is the back of the passive radiator with the date on it

Here is the crossover

Here is the back cup with the fuse and 5B designation

Then here is a picture of the front of the cabinet, with the Polk Audio tag on the bottom of the cabinet and not on the grill itself.

These pictures correspond with the information I lissted earlier today. At this point are there any recommendations to use other componenets (Caps and Resistor) from what is in there and that I have in hand? I would rather do it right the first time than regret not correcting an error if there is one...

Please give me your thoughts and recommendations

heiney9

You've got quite the pair there :cheesygrin:

5A cabinets
5B x-overs and MW driver
peerless tweets that really don't fit with that x-over, however there were atleast 2 model peerless tweets used so who knows perhaps these were repaired and at the time they had no older x-0vers.

Is there a model number on the x-over anywhere?

I'd go with the RD0's since you have a later x-over, but you will have to very slightly modify the tweeter opening with a dremel like tool since the RD0194-1's are just slightly larger.

The x-over shown isn't for the peerless models (as I have ever seen).

H9

heiney9

2.7 ohm resistor and 12uF cap were used for models with the SL1000 and SL2000 tweeter.

Do both speakers have the exact same components? Serial numbers on the terminal cup? Either they were using up old parts (tweeters and cabinets) or they were assembled incorrectly or someone has replaced parts over the years. My guess is the x-over(s) have been replaced at some point.

I have also never seen a 5B with those style cabinets. 5B cabinets have a bevel around the edges (not square) and they don't have the Polk badge affixed to the outside of the cabinet.

H9

heiney9

Actually upon closer inspection of the baffle for the tweeter, it appears there is about 1/8" space all around the tweeter frame. Perhaps someone just put in peerless tweets. I have seen that cabinet style with the silver faced SL1000 tweeter which is the same dimensions as the SL2000 and RD0's.

That scenario would make much more sense. It looks as though the RD0194-1 replacement tweeter is a drop-in without modifications.

That would be best considering the x-over you have.

H9

StuartB

Yes, the two speakers are identical, SN 1733 and 1750 and all the manufacture dates are the same on the internal components. I called Polk Tech Support. Their thought was that someone probably replaced the SL tweeters with the Peerless tweeters. He did not have any concern about me replacing the crossover componenets part for part even with the Peerless tweeter.

Still looking for the collective wisdom of this board.

heiney9

All I can tell you is the x-overs ARE different for peerless models and SL tweeter models. If it were me I'd get the RD0194-1's since they are the correct tweeters. I have never heard a Polk Monitor series with the wrong tweeter vs. the correct tweeter so I can't offer any insight beyond making it correct. At this point you have no idea what you might be missing because you've only heard what you have.

If you want the wisdom of the board, that's my wisdom thought for you on this subject. Selling working Peerless tweets will help fund the RD0's.

H9

soundfreak1

Ive been watching this thread and havent chimed in cause you have had good advise from those whom have more knowledge than i but h9 cought something i didnt notice! The gap around the tweets is a dead giveaway. I have seen dozens of polks and have never seen a gap like that around a tweeter!!! I agree with him they are not the original tweets. Polk is just not that sloppy with thier tollerances. The fit around all drivers is always very close.in fact it can be a pain to get them out sometimes because they are so tight. Listen to him!!

StuartB

Is the RDO tweeter a direct drop in replacement for the Peerless tweeter....or I guess really the SL tweeter? I have seen where there was some discussion about expanding the cut out a little, but in terms of screw holes would it be a clean swap? I was going to add Hurricane nuts during the upgrade work but don't want to make a mess if I swap tweeters.

soundfreak1

If the original tweets were sl 2000 the rdo194's are a drop in perfect fit.btw i have a pair of the 194 in my 12c's and they sound fantastic far better than the 2000.

heiney9

StuartB wrote: »

Is the RDO tweeter a direct drop in replacement for the Peerless tweeter...

No it's not, but looking at your photo of the tweeter and which x-over you have, the peerless were added by someone. The RD0194-1 would be the correct tweeter in YOUR case.

I thought I said that very clearly already.:razz::cool:

heiney9

StuartB wrote: »

Is the RDO tweeter a direct drop in replacement for the Peerless tweeter....or I guess really the SL tweeter? I have seen where there was some discussion about expanding the cut out a little, but in terms of screw holes would it be a clean swap? I was going to add Hurricane nuts during the upgrade work but don't want to make a mess if I swap tweeters.

As I already said, look at how the peerless tweets are set in the baffle, they don't go all the way to the edges, that is pretty conclusive these came with SL1000 or SL2000 tweeters. The peerless are just a bit smaller.

H9

heiney9

You can clearly see here the tweeter bezel should completely fill in the baffle, tightly. This is an RD0194-1 in my 5B's which had SL2000 tweeters. No gaps around the bezel

soundfreak1

A pict. Is worth a thousand words

skrol

It is an interesting situation. My 5A's (1983) have Peerless while my 5B's (1984) have SL-2000. Physically the Peerless and the SL-2000 are not interchangeable.

My 5A crossovers have two resistors (2.7 and 2.5) in the tweeter circuit while my 5B have only one (2.5 ohm). The 5A cap values are 12uF and 27uF while the 5B caps are 12uF and 37uF.

StuartB

Could you tell me the physical difference between the Peerless and SL tweeter in terms of size and screw placement? My speakers clearly have only one set of screw holes in the tweeter cut out. There is the small gap around the tweeter physically, butif the two tweeters have different screw placement then I still question which tweeter is original to the speakers.

I appreciate all the input and advice, I would be lost without you guys.

heiney9

Look at my photo and your photo. The gap is minimal so the screw holes aren't an issue. We are talking about 1/8" or so. You are starting to stress over things that have no bearing. The RD0's will drop right in. If for some very very rare reason the holes have been stressed or slightly enlarged because of mis-alignment there is a very, very simple fix for that. But I'm 99% sure (based on others who have had your issue) it will not be a problem.

I will say it one more time..............THAT IS NOT THE STOCK TWEETER based on all the info you have presented.

H9

StuartB

I am not stressing over non-issues. I have never really done anything like this and my skills are marginal. I did a lot of reading to attempt to understand what I was getting into. I thought I was all set and was fortunate to have the better tweeters, and that if I could replace crossover components I would be in great shape.

Now it seems that the tweeters are not original and matched to the crossover. The recommended solution is to replace the tweeters, which makes sense to me. I am going to use hurricane nuts to secure the drivers, and my concern is that if the screwsnofnthe two tweeters do not align I may mess up the mounting in the MDF for the tweeters. It may seem elementary to you, but it is new territory for me.

It is also getting a little more expensive than I anticipated, especially if I add new tweeters. My current condition is such that I don't have a lot of disposable income.

Anyway, I am just trying to ask enough questions to minimize surprises. Not trying to be dense, but I would rather ask now as opposed to be sorry later, and I really want to make the right decisions on this.......I am sure it seems minuscule to many of the folks here, but again it is bigger deal to me.

I do appreciate the input.

heiney9

I hear ya and didn't mean to come off harsh, but you will be fine. It is a shame someone replaced the tweeters. Probably not the end of the world if you don't get the proper tweeter as the sound difference won't make or break your happiness with them.

The size difference of the tweeters, while noticeable, is minimal and has little impact on anything. The impact is a mis-matched x-over. There are easy fixes if the MDF is stressed or damaged so that shouldn't be a concern.

Since you are on a budget go for the Clarity Cap PX series for caps and Mills resistors and add the tweeters when you can. Like I said good condition Peerless can bring $50+ for a pair which will offset about 1/2 the cost of (2) RD0 tweeters.

On mine I also deleted the tweeter fuse and wired it directly as I don't have gear or play at levels that will damage the tweeters.

H9

pitdogg2

heiney9 wrote: »

Actually upon closer inspection of the baffle for the tweeter, it appears there is about 1/8" space all around the tweeter frame. Perhaps someone just put in peerless tweets. I have seen that cabinet style with the silver faced SL1000 tweeter which is the same dimensions as the SL2000 and RD0's.

H9

Brock,
I belive that the SL1000 tweeter is a tad smaller than a SL2000 tweeter. At least the screw holes do not match very well between the two.

StuartB

I went ahead and ordered the new RDO tweeters. I have everything else in hand, Mills resistors, Clarity PX for tweeter circuit and Solen for the MidWoofer. I will see how the tweeter lines up and go from there. MOrethan likely I will have some nice early Peerless tweeters for sale. I may look for input on how repair MDF if the screws don't line up (or I mess up the Hurricane nut installation). Now on to de-soldering the crossover components.

skrol

The tweeter mount plates Peerless and SL-1000 vs SL-2000 and RDO are different dimensions. You may need to rout out some of the MDF for the RDO to fit properly.

heiney9

skrol wrote: »

The tweeter mount plates Peerless and SL-1000 vs SL-2000 and RDO are different dimensions. You may need to rout out some of the MDF for the RDO to fit properly.

Look at his photo Stan, there is about 1/8" border around his peerless tweets.

His specific issue is starting to get murky here as you are generalizing. It *appears* someone installed peerless tweets in a model that came with SL1000 or SL2000 from the factory. All the evidence points to that.

IIRC, the peerlees bezel is slightly smaller than the SL1000, SL2000 and RD0, hence someone that has peerless tweets (stock) needs to do some minor routing of the baffle to allow the RD0's to fit, but the x-over is still wrong.

H9

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

heiney9

StuartB wrote: »

I went ahead and ordered the new RDO tweeters. I have everything else in hand, Mills resistors, Clarity PX for tweeter circuit and Solen for the MidWoofer. I will see how the tweeter lines up and go from there. MOrethan likely I will have some nice early Peerless tweeters for sale. I may look for input on how repair MDF if the screws don't line up (or I mess up the Hurricane nut installation). Now on to de-soldering the crossover components.

Great, I think everything should work out just fine. You will be very happy with the end result.

H9

pdxfj

When I refreshed my 5b's I used PX caps for everything and mills resistors. Also upgraded to the RDO tweets and I am very happy with the results. Don't have them hooked up at the moment, but they will go back into service soon.