Blown tweeter on (very) old Polk speaker (Monitor 10?)

Michael Marley

Hi. I am having a problem with a very old Polk speaker, that I think is a Monitor 10, based on the image here. The speaker doesn't have any model name or number anywhere on it. (I have yet to figure out how to open the cabinet.) Here are two images of the speaker I am talking about:

http://michaelmarley.com/misc/images/speaker.jpg
http://michaelmarley.com/misc/images/tweeter.jpg

My mom says that she bought this speaker (and another one, of course) back in the early 80s, perhaps 83 or 84. Up until recently, they had been hooked up to a partially blown Denon amplifier of the same vintage that had been damaged in an electrical storm. (This is a completely different story, but yes the amplifier was surge-protected.) Recently, I hooked the speakers up to a new amplifier, but I quickly discovered that one lacked very severely in high-frequency response. After removing the front cover, I found that the tweeter was not functioning. I was wondering if it might be possible to get a replacement tweeter, and if so, how I might go about doing it. Thanks!

concealer404

That seems to be an SL2000 tweeter. Polk does sell replacements, but the new ones are RDO194s, and you'd want to replace them in both speakers. They ARE an upgrade, though.

If you just want another SL2000, check the For Sale section here, there's usually a few floating around on the cheap.

Welcome! Stick around.

Michael Marley

Thanks! You are quite fast! I looked in the For Sale section, and found some SL2000s here, but they don't look the same?

F1nut

The tweeter in your picture is an SL1000. You can try to find a used one here or eBay. Otherwise, two new RD0194-1's from Polk is the answer and a major upgrade from your present tweeters.

Michael Marley

Yeah, I had just figured that out. Would an SL2000 fit in the same place as an SL1000? I can't seem to find any RD0194s.

F1nut

You don't want the SL2000 and really, you don't want the ones you have.

Call Polk at 1-800-377-7655 and ask for Customer Service.

Michael Marley

OK, but would an SL2000 fit in the same spot? I am trying not to break the bank, here.

danger boy

the SL2000 would fit the same spot.. but as F1Nut said.. you need to order the RD0-194 from polk audio.. you will not find it on Ebay for sale. only through Polk can you get the correct replacement.

tell Polk customer service you are a club Polk member for a discount. well worth it too.

if you install an SL2000 (not recommended) you are doing yourself and your speakers (monitor 10's) a disservice.

concealer404

F1nut wrote: »

The tweeter in your picture is an SL1000. You can try to find a used one here or eBay. Otherwise, two new RD0194-1's from Polk is the answer and a major upgrade from your present tweeters.

Whoops. My bad. Sorry bout that.

kcoc321

No sorry the SL2000 WILL NOT fit in a SL1000 opening directly, without modification of your speaker.

The SL1000 faceplate is 77mm high x 114mm wide and the SL2000 faceplate is 85mm high x 117mm wide, so you would need to router out the speaker alittle bit. You would also need to router out the speaker to fit the RDO-194.

Since it has not been asked, did you check the fuse on the back?
It is for the tweeter protection, and if blown, would keep the tweeter from working.
Just besure to replace with the same size and type. I would also open up the xover plate on the back and look at the electrical components. You could have a fried resistor or capasitor from the energy strike.
Look for 'black' or burnt looking on the white rectangular little boxes (resistors) or maybe brown 'ooze' (technical term..hehe) coming from the capasitors (cylinerical pale yellow, maybe).
Any of those issues would effect the tweeter functioning as well.

Michael Marley

I hadn't checked the fuse... I thought it was for protection of the entire speaker, so I figured since it was working at all it must be good. However, I just checked it, and the fuse is not blown. I also removed the cover on the back, and nothing inside looks burned or otherwise failed. I also unscrewed the tweeter did a continuity test with the multimeter using the terminals on the back. It registered very low resistance. This seems to indicate that the tweeter is not actually blown?

kcoc321

The fuse still could be bad, even if it looks okay. Try swapping fuses from the good speaker to the bad. See if the problem 'follows' the fuse from the 'bad' speaker.

If it is measuring any resistance then at least it has continuity, but what value is "low resistance" I just checked one of my SL1000's and it reads 6.9ohms.

Also, it is okay to hook up the tweeter direct, but ONLY using low volumes. That may help you trouble shoot furthur.

gdb

Since the plate opening is smaller than the 2000/RDO194 tweeters, I wonder if a Peerless might be an exact fit? Would the Xover support the use of Peerless tweeters? If so, that would be another possibility and would sound very good !

Michael Marley

The fuse was indeed the problem. I switched the fuses in the speakers, and the problem followed the fuse. Now I shall run to RadioShack before I get snowed in.

kcoc321

HEHE...while I was being so verbose, You fixed it......great...

For the future:
the Peerless tweeter would require a modification to the xover.
It takes an additional resister, but I don't remember the value for a Mon10 xover.

I know on the Mon7's it varies, (been watching what ppl have) from 4.7-6.7ohm, since I have considered that for my Mon7's. (with SL1000's) I have not documented what other differences there where to account for the differences. Unfortunately, there is not a "official" wiring diagram using the Peerless tweeter. Actually, I just looked at some from Mon7a's that Cambri had and they had a total of 5.2ohm. (2.5+2.7)

And the Mon10's HF wiring is different than the other 'original' Monitor's HF wiring, so that could be different as well.

'Cambri' has some Mon 10a's with tweeters, so you can PM him (IF you are considering this route) and maybe he will check his, or maybe he will chime in.