Mon 5 Jr: scratchy tweeter and split passive bass

Berkeley

I hope I'm in the sub-forum. I can't imagine I'm old enough for my speakers to be "vintage!" I've got Monitor 5 Jr speakers with serial numbers 5A136XXX. One tweeter sounds scratchy, so I assume it's blown. I also see that one of my passive woofers is badly split. I've been in contact with Helen at Polk, and she pointed me here. I see part numbers for the tweeter and mid still available, but no passive bass parts.

1) How do I test the speakers to find the actual source of the problem? Specifically, one tweeter sounds bad. Is it as simple as testing Ohms with a multimeter? If I replace one, should I replace both?

2) Obviously, the split bass is bad, but do I replace or repair? Again, I see no part number for a replacement.

BTW, external fuses look good, but I can meter them tonight to make sure.

I love the little 5Jrs, so I hope I can get them going again!

nadams

Those are some nice 5jr+'s you have there. And yes, they are the 5jr+. They were the only 5jr's with any type of passive radiator. The radiator you're looking for is the SW6528, according to http://clubpolk.polkaudio.com/service/models/modelpartslist.php3?model=monitor

Call Helen back and you should be able to pick up one of those. As for the tweeter problem, swap the tweeters between the two speakers and see if the problem follows. That would rule out any problem with the crossovers or the amp itself.

I have the standard 5jr's (w/o the bass radiator), and I love 'em! Enjoy!

Berkeley

OK, the 5/5jr/5jr+ is starting to make sense. I'm still a little confused because the vintage info on the polkaudio.com site does not list a speaker with my physical dimensions. My 5jr+s must be early models, and are not specifically listed. They're 10.5" wide. In any case, thanks.

I'll run some tests tonight and try to narrow down the problem.

nadams

You may actually have the standard Monitor 5's, which are listed as 10" wide. I just checked my standard 5jr's, and they're 9" wide. Also, the Polk website is not always the most accurate, as there were many revisions within a model run.

When you're doing the tweeter swap, make note of which model tweeter it is. That can tell you a lot about what speaker you have. also get the model off of the woofer (the active driver, not the passive) if you can. Then we can compare to the parts list for the Monitor series and see what exactly you have.

Also, when you go to purchase anything, mention that you're a Club Polk member and you'll get a discount

Berkeley

I swapped tweeters, and I still get the same crappy sound. The left speaker seems especially bad, the side I thought was blown. Bad crossover?

BTW, the receiver is a Denon DRA-425R. Not great, but not junk either.

I'm more confused than ever about the speaker model, too. The driver is marked MW6500, dated 1/10/83. The Parts list shows the MW6500 for only the 5jr, but I have the passive radiator of the 5/5jr+. Maybe the driver is marked as the MW6500 "family" but is actually a 6502. The tweeters are marked 55145082 and 55144882.

VR3

Swap the speakers, see if it follows the speaker making the problem now.

If it does, Denon... If it dont...

Crossover (that is, the replacement tweeter didnt fix it)

DId the 5jr use a polyswitch? if so...could that be it?

Berkeley

Swapped cables at the speakers, and the problem moved to the other speaker. Now I'll test to rule out a bad wire or poor connection at the receiver. Perhaps it's time to start shopping for a new video-compatible receiver, and add additional speakers.

Would I be able to test for a bad receiver, or would a local stereo shop have to do that? We've got a high-end shop that's been around forever, Audio Ecstasy.

Now I suspect they're Monitor 5 speakers. :rolleyes: (I must sound like a total lamer.) I don't know where at what point the "junior" got stuck in my head, but it's been a while. I dug out the original boxes burried at the back of the attic. They say "Monitor 5" and are stamped with the correct serial numbers. Apparently, they're a "NEW STYLE" too!

F1nut

If need be, you can get replacment tweeters from Polk, but you can not get any of the PR's. Best bet would be to shop ePay for another set to use for spare parts.

nadams

Nuts... I thought that Polk had the PRs, too. That's too bad.

Berkeley- Now switch the speaker wires at the receiver. If the sound moves again, then you can bet that a channel on the receiver is going out. How old is this receiver? It may just need to have the volume controls cleaned out. I'm too lazy to look the receiver up right now, so that may not even be possible.

Have fun, and let us know how you make out...

nadams

Berkeley

This from Helen:

Good-morning Mr.Johnston,
Unfortunately we no longer have the SW6528 Passive Sub-woofers available. However there is a Company called Madisound at www.madisound.com (608-831-3433) that may have a 6.5" Passive that would work in your M5 Jr's.

I swapped wires at the receiver, and the problem moved again, indicating a problem in the Denon. I also tried B speakers, and the problem remained. Just when I thought I had narrowed down the problem, I swapped wires at both ends. Now the problem seems to have greatly diminished, even gone away.

At this point, however, I think questions about the speakers themselves have been answered. I need to replace (repair?) the split PR. Bad receiver test/repair and questions about a new A/V receiver should be posted elsewhere. Is there an appropriate sub-forum here to discuss what to buy next?

nadams

Sure is... look for the "electronics" section . It's always nice to see a newcomer who cares about where to post, and using proper spelling grammar. It really helps us help you.

Any yes, you need to either repair or replace the PR. With that slit in the surround, all the air that's supposed to be in the cabinet is getting out when the active driver moves, which completely defeats the purpose of the sealed cabinet, PR design. I would suggest replacement over repair... see if you can find a pair on eBay.. if not, go with the madisound PRs, but I would buy two and replace them both at the same time in case of any sonic differences between the original Polk PRs and the Madisound's.

Berkeley

d00d my sp3krs is blown what d0 i d0 i dont hav3 ne $ plz hlp!!!!!

I need to thank everyone here, too. I left myself wide open with my earlier "Denon... not junk" comment. Tempting, I'm sure, but thanks for not taking the bait!

I should just get two Seas SP21R H9901 and be done. This image show that my PR is ~8" dia, so that probably means I've got Monitor 5 speakers. Helen recomended 6" for 5jr, and that's too small for me.

Thanks again!

F1nut

Berkeley,

Just want you need,

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=71572&item=5753567120&rd=1

No affiliation

BobMcG

Welcome Berkeley,

You can't always tell by what's marked on old Polk boxes as to the exact model that was contained within. I've seen, had and have a lot of their boxes. They often only have the prefix of the model number on them. IE: SDA-2B; SDA-1; Montior-7 etc. When in fact it was the SDA-2Bs; SDA-1Cs and the Monitor-7Cs that came inside. It looks as though the boxes could be used for any of the speakers for that model family without being changed.

Just a note: The Monitor 5Bs were 21.5"H x 10.5"W X 8.5"D and have an 8" Passive Radiator.