Monitor 10s?

bullet150

Hi all. A few months ago I picked up a pair of speakers at a garage sale. Paid 10 bucks for them as the owner didn't know If they worked, after looking at them I determained they where model 10s and they came with the original boxes although the cardboard was in rough shape. One speaker didn't work and all it needed was a new set of fuses. I'm not sure what sub model of 10s I have. On the back of the speaker cabinet there are 2 fuses. Any help on determining what sub model I have would be much appreciated as well as any suggestions on upgrades that could or should be done. Thanks in advance.

F1nut

Pictures

F1nut

NM, I saw your pics at AK. Early 10's, but not the very first.

bullet150

boston1450

So what size did you use for fuses ?

bullet150

boston1450 wrote: »

So what size did you use for fuses ?

It had .5 amp fuses in it, I replaced them all with 1 amp but I'm going to be picking up a 2.5 amp for the low end as I just noticed that diagram on the back appeared to call for it on the low end

boston1450

1 amp fast blow on top. You could go with a 2.5 or 3 amp fast blow on bottom. Great speakers & what a score. How do you like them ? Welcome to the forum btw

bullet150

boston1450 wrote: »

1 amp fast blow on top. You could go with a 2.5 or 3 amp fast blow on bottom. Great speakers & what a score. How do you like them ? Welcome to the forum btw

Thanks for the welcome. I like the sound alot. Although they are high up for a speaker so that could have an effect. I've got them sitting on my cheap pair of technics speakers right now since I don't have the stands you could get optionally for them. I also scored a pair of magnapen smgs from the early 80s I think 80-82, which I don't have space for in my current room but out of my 3 speakers I like the monitor 10s the best but placement could be a factor in that

boston1450

Have you tested them for air leaks. Push in on the passive/hold in.if drivers stay out 3-5 seconds your good.... If you haven't done this yet. It may be a good idea to put a small bead of Loctite Powergrab glue on EACH side of the magnets. To help prevent magnet shifting... upgrading them crossovers will definitely bring them to better level. There are many here that can answer most ?s to walk thru if needed. Enjoy your new speakers

mhardy6647

These guyses know these loudspeakers

So -- they are 10s and not 10As; I'd missed the tag & got it wrong previously. My 7As have two fuses and cosmetically (so to speak) are extermely similar to these 10s.

Someplace Else, the OP @bullet150 mentioned stands. The early Polkstands for the 7 and 10 were identical.

Fair amount of "Polkstand" chatter 'round here. This thread should be helpful/useful/interesting.
https://forum.polkaudio.com/discussion/comment/2357316

boston1450

So are they Model 7's "VS" Monitor 7 ab(or)c models ? The same as his Model 10's

boston1450

Nm I screwed up

mhardy6647

boston1450 wrote: »

So are they Model 7's "VS" Monitor 7 ab(or)c models ? The same as his Model 10's

Tags on mine say 7A. The boxes just say 7 -- but I bought them as demos, so who knows?

DSC_5417 by Mark Hardy, on Flickr

The original 7 had an eight inch uncoated paper PR; the 7A has a 10" coated PR. AFAIK, there was not an intermediate version -- but who knows what's floatin' around out there in the world (especially at this late date)?

bullet150

Thank you all for the comments and support. I am getting ready to start the "restoration" on my monitor 10s. Any tips or tricks? I plan on either upgrading or having the crossover upgraded, removing the fuses and adding resistors into the circuit per recommendation. I also want to attempt to either reglue or jb weld the magnets to keep them in place but am not sure if it would be worth it as it was mentioned it may not be possible to remove the speakers due to the mortite, any comments or suggestions will be helpful. To my ears there is nothing wrong with the speakers but would like to "restore" them as I am going to be moving into my own place soon and they will be a centerpiece of my living space. Thanks again.

windstriker

A couple other options would be upgrading the tweeters to modern ones. That may depend on what original tweeter are installed. Using dyna mat on the woofer and pr baskets may help as well.

bullet150

Thank you for the reply @windstriker. The original tweeter is the peerless tweeter. Also I am not that familiar with what dynamat is.

windstriker

Dynamat is sound deadening material that is used alot in cars to reduce vibrations. It will help keep the baskets for ringing.

bullet150

@windstriker thanks for the info and the reply.

delkal

Your tweeters have a material like plumbers putty sealing them in (drawing a blank on the name right now). The woofers probably have this too. All of the early Polk used this as a seal and not a removable gasket.

While the putty probably did a better job keeping the speaker airtight it gets hard over 30-40 years and it can be a PITA to get the speakers out. Your best bet if you try and open them up is to remove the crossover and try and push the tweeter and drivers out. Be careful. Then you will have to clean everything up and find a suitable replacement when you put them back together.

pitdogg2

mortite

bullet150

@delkal @pitdogg2 thank you for the reply. That will definitely help me in removing them if I do so

bullet150

Also this will he my first time doing a speaker rebuild so I'm most likely rusty on how to do everything but am always willing to give things a shot so any help is very much appreciated.

pkquat

The sealing material appears to be mortite. I believe it should feel hard by now, and you should be able to break bits off from the outside. If this is the case you have a good chance of being able to remove the speakers. I would double check with members here on the best methods. I have not done it personally, but others have removed them with no damage to the speakers or the cabinets. If the sealing material is soft and rubbery or very hard like epoxy then someone may have used silicone or liquid nails. That would be more difficult.

You have the peerless tweeters. There is no need to replace them unless one is not working. In that case used from ebay is your best source. Check with us first since there are a few variations of the peerless tweeter.

The speaker wire to the fuses likely has corrosion. You also have the option of not using the midwoofer fuse, and a few bypass the tweeter fuse as well. I am not sure if you need to add extra resistance for fuses or not. I thought only the polyswitches added noticeable resistance to a circuit, but I could be wrong.

The speakers and crossover are all likely soldered together. The tweeters are for sure. Do not try and de-solder the tweeters. This often des-olders the tweeters voice coil too or does other damage if not done properly. Cut the wires with enough length to add some type of connector. The same goes for the mid woofers. You may decide to use the original wiring, or choose new wire. There should be a spot to connect new wires to the midwoofers with a spade connector. In that case snip off the original wire as short as possible. For the tweeters you will probably want to connect the new wire to the original wire. For new speaker cabinet wire, I recommend the tin coated supra wire from https://www.madisoundspeakerstore.com/speaker-wire/ .

Sonicap or Clarity Caps are recommend and Mills or Mundorf resistors. Sonicap should have or can make the exact values for you.

@westmassguy , Dave at DHS speaker service can rebuild crossovers and do some critical soldering if you feel that job is too big.

Lastly I believe you can mod these crossovers to match the original RTA 12's so the speakers will become left and right hand versions. This will help the imaging with them. Others may know the specifics of that mod. I did a quick search and could not find it.

bullet150

@pkquat thank you for the response and the info and insight.

bullet150

@pkquat. I pulled the grill off of my right speaker(as this is the one that doesn't have a chunk of the wood missing from the grill frame) and the only mortite material I can see is from some of the extra screw holes on the drivers. There is none around the outside metal of the driver that I can see. When using my finger nail to feel the material in the extra screw holes it pushed in and left an indent in it. Does this mean the material is not mortite? Or maybe it hasn't hardened? Is there supposed to be any around the outer edges of the drivers? Will attempt to pull the grill off of the left speaker. Also anyone have suggestions on either making new grills/frames for the grills. Mine have the weird velcro esq interlocking material on the grill and speaker cab. Was thinking I could put the frame in vice and use wood glue to put the piece back in and clamp it together and then maybe put a nail or to in it if possible.

pitdogg2

Mortite should only be under the flat of the basket. Your's are on the face of the bezel so a slim thin plastic pry bar like thing could assist. As could say small cord like string to use to pull around the rim to slice though the mortite. It can also tear part of the particle board face off so be very careful.

ken brydson

pitdogg2 wrote: »

Mortite should only be under the flat of the basket. Your's are on the face of the bezel so a slim thin plastic pry bar like thing could assist. As could say small cord like string to use to pull around the rim to slice though the mortite. It can also tear part of the particle board face off so be very careful.

Maybe dental floss?

bullet150

@pitdogg2 @KennethSwauger. Thank you for the reply and the helpful advice. Assuming the main parts of the restoration are the crossover and either glue or jb weld to the magnets, would it be necessary or make sense to pull the passive radiator / tweeter off If possible.

Gardenstater

If it were me I could see trying the longest, thinnest, narrowest, most flexible putty knife I could find, with the end sharpened on a whetstone. Bevel it on one side and place the beveled side against the speaker baffle, so the putty knife doesn't tend to cut into the particle board. Mark it with a line, the depth of the speaker basket flange, so you don't get overzealous and have an idea of when you've gone deep enough, then carefully work around the entire circumference of the non tweeter drivers. If it's the tweeter you want to remove, well that's a tough one because of the recess in the particle board.

pitdogg2

I've cut PVC pipe with dental floss
If you can find some that is not that plastic glide stuff sure would give it a try as well. The glide stuff stretches too easy imo. Well it's really up to you but if i was going through the trouble of recapping a crossover I'd want to glue the interior or check the interior for any air leaks and so forth and then glue up the sides if need be. You can only do that through the passives hole. I'd prolly leave the tweeter alone unless it pushes out fairly easy from behind. Gasket tape or armacell would for new gasket no more mortite.

pkquat

It sounds like it is indeed mortite from yours and the others responses. Unfortunately I do not have direct experience with it. For similar type situations I have used old school waxed dental floss that is made up of many small fiber strands if you can find it. I have also used plastic putty knives because they can be very flexible and easy to shape. Often multiple small ones work better. Squeegee applicators can also work in some situations.
https://www.amazon.com/TECKWRAP-Plastic-Squeegee-Scraper-Applicator/dp/B01DY6SUYO.
In worst cases, I have painstakingly worked at getting material out with pick tools and dental picks from a hobby store.

I would recommend trying to remove all the drivers including the tweeter. As mentioned, using gasket tape or armacell to seal the drivers works better and allows drivers to be easily removed if needed.