Monitor 7B Tweeter and driver question

JohnLocke88

Hey guys. I just picked up a set of Monitor 7Bs on the cheap. Problem: one of the tweeters is blown (I believe). One of the tweeters (the working one) has a dimple in the center (which I believe is normal?) but also has some brown residue around the edges. Is there a way to clean this, or just leave it be?

The tweeter that is not working has a 'hole' where the dimple is on the other. On this one, you can actually see inside to the white cone beneath it. Is this fixable or is this thing f*kst?


I think these are the "peerless" tweeters that everyone is always talking about. However, I'm wondering, I have $35 in the speakers, is it worth spending the additional $x.xx for the one tweeter, or should I just part them out and be done with them and start over.

When I got to the lady's house (hooray craigslist). One of the tweeters clearly looked like it had issues with the tweeter. However, having just spend an hour and a half trying to find her house, I wasn't in the mood to drive another hour back empty handed.

So, thoughts, comments?

Also, She had a dog and the MW and passive have some dog hair stuck to them. Cleaning tips?

Thanks all in advanced.

-Jon

heiney9

Pics?

JohnLocke88

heiney9 wrote: »

Pics?

i've tried tyo get one that shows thehole, but its so small that my crappy camera cant get a focused close up of it.

heiney9

How about just a shot of the speaker with the grill off. Just to verify what tweets you have. Unless you're 100% sure they are peerless

hearingimpared

Use Windex applied to a soft cotton towel to clean the MWs.

comfortablycurt

Here's an upclose pic of the Peerless tweet...




There were two versions of the Peerless tweets. The one in that picture is the American Peerless Tweeter, which had the hole in the dome. This supposedly relieves the tension on the dome, and makes them a little smoother sounding. There are also the Denmark Peerless tweeters, which look the same, minus the hole in the dome.

As far as cleaning the tweeters...you might want to try brushing them off VERY lightly with a dry q-tip...but I wouldn't do much more than that.

Cleaning the MW's and the PR's is different though.

The best way to clean them is with Windex...believe it or not. Works like a charm. Get a lint free cloth, and spray about 8-9 squirts of Windex on the cloth per driver...wipe them off in a circular pattern. Be careful not to apply too much pressure to the drivers.

Depending on how dirty they are, you may need to apply it a few times.


Congrats on the speakers. The M7's are some fantastic sounding speakers...especially the ones with Peerless tweets. If you've only got $35 in them, I'd say it'd be very worth it to replace the blown tweeter with another Peerless tweet.

JohnLocke88

comfortablycurt wrote: »

Here's an upclose pic of the Peerless tweet...




There were two versions of the Peerless tweets. The one in that picture is the American Peerless Tweeter, which had the hole in the dome. This supposedly relieves the tension on the dome, and makes them a little smoother sounding. There are also the Denmark Peerless tweeters, which look the same, minus the hole in the dome.

As far as cleaning the tweeters...you might want to try brushing them off VERY lightly with a dry q-tip...but I wouldn't do much more than that.

Cleaning the MW's and the PR's is different though.

The best way to clean them is with Windex...believe it or not. Works like a charm. Get a lint free cloth, and spray about 8-9 squirts of Windex on the cloth per driver...wipe them off in a circular pattern. Be careful not to apply too much pressure to the drivers.

Depending on how dirty they are, you may need to apply it a few times.


Congrats on the speakers. The M7's are some fantastic sounding speakers...especially the ones with Peerless tweets. If you've only got $35 in them, I'd say it'd be very worth it to replace the blown tweeter with another Peerless tweet.

Those are them. I remembered because they have the 45 degree slant on the 'wings.'

I am curious though now, maybe the other one does have a 'hole' and it's not just a dimple. I'll check. Is there something else that may be causing the tweeter to not be making any sound. I checked the leads on the back of the tweeter plate, they're connected fine with solder.

Thanks for the windex idea. I'm going to do that now.

comfortablycurt

JohnLocke88 wrote: »

Those are them. I remembered because they have the 45 degree slant on the 'wings.'

I am curious though now, maybe the other one does have a 'hole' and it's not just a dimple. I'll check. Is there something else that may be causing the tweeter to not be making any sound. I checked the leads on the back of the tweeter plate, they're connected fine with solder.

Thanks for the windex idea. I'm going to do that now.

Going out on a limb here...but is there a fuse in the back near the binding posts? I don't believe many of the 7B's were fused, like the 7A's were, but it's worth a shot.

The fuses were used as the tweeter protection circuit in a lot of the earlier Monitor Series speakers. If they are fused, check to see if the fuse is blown. If the fuse is blown, that would be interrupting the signal path to the tweeter, and would prevent them from functioning.


Just FYI, the drivers in the Monitors have a somewhat tacky/sticky feel to them...that's normal. Clean them up, but don't try to get all of the stickiness off of them. They're supposed to be like that.




On an unrelated note...do you know how to check them for proper air tightness?

Push in on the passive radiator and hold it in...the mid-woofer should extend completely, and move back very slowly over a period of 10 seconds or so. If it moves back real fast, you're leaking air from the cabinets, which will decrease the bass output quite a bit, and muddle up the mid-range.

stubby

My 7B's are fused.

comfortablycurt

Another thought...

You could also swap the questionable tweeter over into the other speaker. If the tweeter doesn't work in the other speaker...it's blown. If it does work, the problem could be in the crossover.

jtgranby

comfortablycurt wrote: »

Another thought...

You could also swap the questionable tweeter over into the other speaker. If the tweeter doesn't work in the other speaker...it's blown. If it does work, the problem could be in the crossover.

I would swap the fuses first.

Jim

JohnLocke88

Hmmm... Yes there are fuses. I checked them. One is a straight wire. Not broken, the other is a squiggly wire. Still one peice of wire though. Is this blown?

I tried swapping the fuses. When I take the fuse from the non working tweeter and put in the one that works, the working one cuts in and out.... the non working one still doesn't work even with the 'working' fuse. Should I try replacing the fuses? If so, just a hardware store would have these?

The pressure seems good. I push in on the PR and the MW comes back in totally in about 12 seconds on both.

Thanks for the heads up about the 'sticky' feel. I knew about that already, but that must make cleaning a bit annoying in a dusty environment.

Don't have the tools with me (assuming I need a soldering iron) to swap the tweeters. May run to home depot and get one in a few hours when my car gets done getting fixed.

Thanks again for the help.

Pictures to come.

rayslifecycle

Good Luck With Your Repair

Easily worth the upgrade and more - there are a lot of threads on here that show crossover upgrades and I believe (assuming it doesn't work and if you can't find another peerless) that you can replace the tweeters with the RDO-194 replacement from Polk - also say that you are a forum member for the discounted price. about 48bucks ea. I think....recommend doing both at the same time.

The distance from the wall really affects the amount of bass these speakers put out - so if it sounds "Boomy" pull them away - and if it sounds thin - push them closer to the wall.......in my room they sound best about 11 inches out.

rAy

heiney9

The only way to know 100% if a fuse is working is to use a VOM. A visual is not good enough. It sounds like fuse issues. Look at the ratings on the fuse and go to the hardware store and get (2) fresh fuses. I bet that solves your problem.

H9

heiney9

The RD0194-1 is not a direct replacement. The tweeter cut out needs to be carefully enlarged and the x-over is not designed to be used with the RD0's although there would probably only be a slight difference in sound.

If you decide to go that route you'll need to replace both tweeters with RD0's and I highly suggest you look at the x-over schematic for the 7's that use the sl2000 tweeter and re-work the x-over with those exact parts.

If you find one of the peerless tweets dead your other option is to find a used uit on ebay.

H9

JohnLocke88

heiney9 wrote: »

The only way to know 100% if a fuse is working is to use a VOM. A visual is not good enough. It sounds like fuse issues. Look at the ratings on the fuse and go to the hardware store and get (2) fresh fuses. I bet that solves your problem.

H9

On my way out the door now to the hardware store. Called Polk. Said they're 1 amp AGC 'quick blow' fuses.

heiney9 wrote: »

The RD0194-1 is not a direct replacement. The tweeter cut out needs to be carefully enlarged and the x-over is not designed to be used with the RD0's although there would probably only be a slight difference in sound.

If you decide to go that route you'll need to replace both tweeters with RD0's and I highly suggest you look at the x-over schematic for the 7's that use the sl2000 tweeter and re-work the x-over with those exact parts.

If you find one of the peerless tweets dead your other option is to find a used uit on ebay.

H9

The RDO 194 is the replacement for the SL2000 right?

comfortablycurt

The hardware store will have the fuses. They cost basically nothing, so you might as well just replace both of them. They can wear out over time anyway and degrade the signal a little bit. If one of them was cutting out, it may even fix your problem with the dead tweeter.

Sounds like your air pressures all good on them.:)


The RD0's aren't a direct replacement for the Peerless tweets, as Brock mentioned. The RD0's are a replacement for the SL-2000.

To use the RD0's, the cutout would have to be enlarged a little bit, and the crossover would have to be reworked. IIRC, the SL-2000 based 7's used a 2 ohm resistor on the high frequencies...the Peerless based 7's used 2.7 ohm and 4.5 ohm resistors wired in series.

Personally, I much prefer the Peerless tweets to the RD0-194's anyway. I'd try to find a replacement Peerless if the tweeter ends up being bad. They pop up on ebay fairly frequently. If you posted a WTB ad here, I'm sure someone has a spare sitting around.

I'm betting your problem can be traced back to the fuse though. Good luck.:)

JohnLocke88

comfortablycurt wrote: »

The hardware store will have the fuses. They cost basically nothing, so you might as well just replace both of them. They can wear out over time anyway and degrade the signal a little bit. If one of them was cutting out, it may even fix your problem with the dead tweeter.

Sounds like your air pressures all good on them.:)


The RD0's aren't a direct replacement for the Peerless tweets, as Brock mentioned. The RD0's are a replacement for the SL-2000.

To use the RD0's, the cutout would have to be enlarged a little bit, and the crossover would have to be reworked. IIRC, the SL-2000 based 7's used a 2 ohm resistor on the high frequencies...the Peerless based 7's used 2.7 ohm and 4.5 ohm resistors wired in series.

Personally, I much prefer the Peerless tweets to the RD0-194's anyway. I'd try to find a replacement Peerless if the tweeter ends up being bad. They pop up on ebay fairly frequently. If you posted a WTB ad here, I'm sure someone has a spare sitting around.

I'm betting your problem can be traced back to the fuse though. Good luck.:)

Thank you one and all. New fuses $1.31 at Crown Ace. New working tweeter. Priceless

Excuse while I listen to my Heart CD, then Peter Frampton...

Thanks again all! I'll post a picture of my new 'speaker stands.'

EDIT: There's also dog hair all over the grille covers. Any reason why simply hosing them off (off of the speakers of course) and letting them dry would be inadviseable?

Face

JohnLocke88 wrote: »

Excuse while I listen to my Heart CD

Maybe you should put those old fuses back in...

doctor r

I strongly recommend to upgrade the crossovers. It will make those wonderful 7Bs sound even better. I have owned my since they were new in 78 and I followed the great directions with pictures avaliable here and with my very basic soldering skills was able to perform the parts change in under three hours. They now live in my bedroom system.:)

JohnLocke88

Thanks for the tip Doc.

Although the tweeter is now working, it's still distorted. At first I just thought it was the recording, but when I use the test tone level calibrator on my 705 Onkyo, the distortion is obvious. I think I'm going to try to hunt down another tweeter on the FM or on CL. If anyone know's someone that's trying to sell, shoot me a PM.

comfortablycurt

As far as cleaning the grills go...I don't know if hosing them off would be a good idea. I wouldn't imagine that would be too good for the MDF frames. You might want to try a brush type vacuum attachment.


You might want to try swapping the tweeters around to see if the distorted sound follows the tweeter. There's a possibility that it's something in the crossover. It sounds like it's most likely a tweeter issue though...it's always nice to rule other options out though before you spend money on the wrong thing.;)

I'm planning on upgrading the crossovers in my 7A's sometime next year possibly. I'm anticipating big improvements. I'd listen to them in the stock form for a while before you upgrade them though, if you even plan to upgrade the XO's. That way you can get more of a feel of what's been improved.

heiney9

JohnLocke88 wrote: »

Thanks for the tip Doc.

Although the tweeter is now working, it's still distorted. At first I just thought it was the recording, but when I use the test tone level calibrator on my 705 Onkyo, the distortion is obvious. I think I'm going to try to hunt down another tweeter on the FM or on CL. If anyone know's someone that's trying to sell, shoot me a PM.

Be sure to trouble shoot the noisy tweet. Many times the resistor(s) in the high pass part of the x-over are easily cooked. Replace with like rated Mills non-inductive 12Watt resistors. Probably cheaper than sourcing a peerless tweet.

JohnLocke88

I'll be trying to swap out the tweeters as the next step ( I think it's the most logical.) This way I'll know if the tweeter is tweatked, or if it's something else.

I'm going to a friend's house tomorrow after work to borrow his soldering iron. I'll update you guys with the results.

comfortablycurt

Just swap the two tweeters around...that's the logical next step.

If the distortion stays with the tweeter...then the problem is the tweeter. If it stays with the cabinet that currently has the distorted tweeter, it's most likely in the crossover.

gdb

Peerless are great tweeters and I'd find a used replacement if I were you. One thing you might check for is if the prongs of the fuse holders have any corrosion on them, a little scrub with Scotchbrite and Deoxit will ensure good electrical transfer. As for cleaning the grille cloth, contrary to common belief, the frames and cabinets are constructed of particle board NOT MDF and as such, they will swell up like a dry sponge if exposed to any significant amount of water. If you've got a wet-vac you could put some rug doctor upholstery solution in a spray bottle, spray an area and immediately vacuum it out. Be careful, I have a big wet-vac that would snatch the cloth right off the frame without reducing the vacuum suction first!!:eek: Good luck !!

http://images.google.com/imgres?imgurl=http://www.germes-online.com/direct/dbimage/50333644/Particle_Board.jpg&imgrefurl=http://www.germes-online.com/catalog/13/668/263129/sell_particle_board.html&usg=__cWF0mrOG1jKYGeATm0-0uiOZcBY=&h=360&w=360&sz=37&hl=en&start=1&tbnid=q50ws8_Ig-LWBM:&tbnh=121&tbnw=121&prev=/images%3Fq%3Dparticle%2Bboard%26gbv%3D2%26hl%3Den


http://www.bajajecotec.com/cache/mdf2.jpg

JohnLocke88

gdb wrote: »

Peerless are great tweeters and I'd find a used replacement if I were you. One thing you might check for is if the prongs of the fuse holders have any corrosion on them, a little scrub with Scotchbrite and Deoxit will ensure good electrical transfer. As for cleaning the grille cloth, contrary to common belief, the frames and cabinets are constructed of particle board NOT MDF and as such, they will swell up like a dry sponge if exposed to any significant amount of water. If you've got a wet-vac you could put some rug doctor upholstery solution in a spray bottle, spray an area and immediately vacuum it out. Be careful, I have a big wet-vac that would snatch the cloth right off the frame without reducing the vacuum suction first!!:eek: Good luck !!

http://images.google.com/imgres?imgurl=http://www.germes-online.com/direct/dbimage/50333644/Particle_Board.jpg&imgrefurl=http://www.germes-online.com/catalog/13/668/263129/sell_particle_board.html&usg=__cWF0mrOG1jKYGeATm0-0uiOZcBY=&h=360&w=360&sz=37&hl=en&start=1&tbnid=q50ws8_Ig-LWBM:&tbnh=121&tbnw=121&prev=/images%3Fq%3Dparticle%2Bboard%26gbv%3D2%26hl%3Den


http://www.bajajecotec.com/cache/mdf2.jpg

I was just wondering about that. Just because we've gone from, not working at all (oxidized fuse holder contact, corroded fuse contact) to sorta working (oxidized fuse holder contact, new fuse contact)... I'll try this before I pull the tweeter.

comfortablycurt

gdb wrote: »

Peerless are great tweeters and I'd find a used replacement if I were you. One thing you might check for is if the prongs of the fuse holders have any corrosion on them, a little scrub with Scotchbrite and Deoxit will ensure good electrical transfer. As for cleaning the grille cloth, contrary to common belief, the frames and cabinets are constructed of particle board NOT MDF and as such, they will swell up like a dry sponge if exposed to any significant amount of water. If you've got a wet-vac you could put some rug doctor upholstery solution in a spray bottle, spray an area and immediately vacuum it out. Be careful, I have a big wet-vac that would snatch the cloth right off the frame without reducing the vacuum suction first!!:eek: Good luck !!

http://images.google.com/imgres?imgurl=http://www.germes-online.com/direct/dbimage/50333644/Particle_Board.jpg&imgrefurl=http://www.germes-online.com/catalog/13/668/263129/sell_particle_board.html&usg=__cWF0mrOG1jKYGeATm0-0uiOZcBY=&h=360&w=360&sz=37&hl=en&start=1&tbnid=q50ws8_Ig-LWBM:&tbnh=121&tbnw=121&prev=/images%3Fq%3Dparticle%2Bboard%26gbv%3D2%26hl%3Den


http://www.bajajecotec.com/cache/mdf2.jpg

That's a good suggestion. Sometimes a little oxidation can go a long way.


As far as the dog hair goes, you might want to pick up one of those pet hair rollers, if you don't have one already.

rayslifecycle

heiney9 wrote: »

The RD0194-1 is not a direct replacement.
H9

Oooops - sorry - my bad

heiney9

JohnLocke88 wrote: »

I was just wondering about that. Just because we've gone from, not working at all (oxidized fuse holder contact, corroded fuse contact) to sorta working (oxidized fuse holder contact, new fuse contact)... I'll try this before I pull the tweeter.

I cleaned mine with Caig products. One day when I have time, I'm bypassing the fuse all together. I don;t listen at loud enough levels or with under powered gear to make the fuses necessary.

H9

comfortablycurt

heiney9 wrote: »

One day when I have time, I'm bypassing the fuse all together. I don;t listen at loud enough levels or with under powered gear to make the fuses necessary.

H9

That's one of the things on my list too. I'm planning on hot rodding my 7A's eventually...upgraded XO's, mortite, dynamat, better binding posts...the whole works. I'm gonna bypass the fuses when I do that. I don't listen at completely ear shattering levels, so I don't really think I need the extra protection.