Restored(?) 1982 RTA 11's
pickoid
Posts: 31
Here's a thread I started on these speakers over a year ago:
Some new Monitor 11's...
I finally got around to re-veneering the cabinets. They were in a pretty sorry shape. Moisture had really done a number on the stands and most of the corners. The original walnut vinyl veneer looked dull and cheap, and had suffered its share of scratches and scrapes. I didn't want to spend a lot of cash on this project, so I decided to use the Parts Express self-adhesive vinyl veneer. I figured that it would probably be at least as good as the original vinyl. I chose the "red maple" pattern, but if I had it to do over I would probably try the teak or the walnut pattern.
I had to remove the old trim pieces off the front of the cabs (underneath the grilles). They got destroyed in the process - they were glued and screwed to the front of the cabs. I cut some new trim pieces out of poplar to replace them. The old pieces were rounded to match the side profiles of the grilles, and the new ones are not. I don't think it looks too bad with the square edges.
I used a heat gun to remove the old vinyl. Then I patched up the swollen and/or missing corners with bondo. I sanded the MDF with 100, 220 and 320 grit, applying a couple of coats of sanding sealer to get as smooth a surface as I could.
The actual veneering process was pretty difficult. I had a hard time at the edges of the cabinets, and it's probably not going to be a very durable finish. I tried a couple of different techniques at the edges, and neither worked too well. But I think they look decent. I'm not too ashamed of them. They look good from a couple of feet away, at least.
As the old thread states, two of the original MW6600x drivers were frozen. I bought a couple of replacement MW6600x's, but one of them was damaged in shipping. I eventually just gave up and got a couple of new MW6503 drivers from Polk. I used the new drivers in the "outer" or woofer position in each cab. The inner driver in each cab is an original MW6600x - with thoroughly JB-Welded magnets of course.
I also re-did the grill fabric, which had lots of pulls and a couple of holes. I painted the integrated stands and the back of cabs flat black.
These speakers sound pretty darn good. These are the only vintage big Polks I have heard. The Peerless tweeters are very nice, and the bass is nice and tight.
So, there you have it. They aren't original in any way, but at least they live to play again another day. The next logical step would be re-capping the crossovers. For now, I've sunk enough money and time into these.
Some new Monitor 11's...
I finally got around to re-veneering the cabinets. They were in a pretty sorry shape. Moisture had really done a number on the stands and most of the corners. The original walnut vinyl veneer looked dull and cheap, and had suffered its share of scratches and scrapes. I didn't want to spend a lot of cash on this project, so I decided to use the Parts Express self-adhesive vinyl veneer. I figured that it would probably be at least as good as the original vinyl. I chose the "red maple" pattern, but if I had it to do over I would probably try the teak or the walnut pattern.
I had to remove the old trim pieces off the front of the cabs (underneath the grilles). They got destroyed in the process - they were glued and screwed to the front of the cabs. I cut some new trim pieces out of poplar to replace them. The old pieces were rounded to match the side profiles of the grilles, and the new ones are not. I don't think it looks too bad with the square edges.
I used a heat gun to remove the old vinyl. Then I patched up the swollen and/or missing corners with bondo. I sanded the MDF with 100, 220 and 320 grit, applying a couple of coats of sanding sealer to get as smooth a surface as I could.
The actual veneering process was pretty difficult. I had a hard time at the edges of the cabinets, and it's probably not going to be a very durable finish. I tried a couple of different techniques at the edges, and neither worked too well. But I think they look decent. I'm not too ashamed of them. They look good from a couple of feet away, at least.
As the old thread states, two of the original MW6600x drivers were frozen. I bought a couple of replacement MW6600x's, but one of them was damaged in shipping. I eventually just gave up and got a couple of new MW6503 drivers from Polk. I used the new drivers in the "outer" or woofer position in each cab. The inner driver in each cab is an original MW6600x - with thoroughly JB-Welded magnets of course.
I also re-did the grill fabric, which had lots of pulls and a couple of holes. I painted the integrated stands and the back of cabs flat black.
These speakers sound pretty darn good. These are the only vintage big Polks I have heard. The Peerless tweeters are very nice, and the bass is nice and tight.
So, there you have it. They aren't original in any way, but at least they live to play again another day. The next logical step would be re-capping the crossovers. For now, I've sunk enough money and time into these.
Post edited by pickoid on
Comments
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Forgot to mention that I've run these with a 125 wpc Kenwood Basic M1D amp and a 200 wpc Yamaha M-70 amp. These speakers can suck up some power. I think 100 wpc would be a minimum. They're also approximately a 4 ohm load (manual says 4.5 ohm), so you have to be careful of that too. Not a speaker for wimpy amps.
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They look pretty good to me - my pair of SDA-2's could use some attention as well. I noticed the fuse above the speaker inputs, was that factory or did you add it? I'm looking at getting some type of passive protection for mine and have thought of adding a fuse...
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Gavin.Wright wrote: »They look pretty good to me - my pair of SDA-2's could use some attention as well. I noticed the fuse above the speaker inputs, was that factory or did you add it? I'm looking at getting some type of passive protection for mine and have thought of adding a fuse...
Fuse holders are definitely original to the crossovers. 3/4 amp. One of them had a 3-amp fuse or some such thing when I got them. Lucky it wasn't wrapped in tinfoil. -
So, now you have a pair of great sounding AND great looking speakers! Very nice!
I was fortunate enough to acquire a pair in very good condition, but I've only been able to spend a limited amount of time listening to them. One day I'll get it all set up right... It's threads like these that motivate me! -
Nice Job! Enjoy
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Great work on bringing some fairly rare birds back to life!Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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Pickoid - Could you post some pics of the "stands" since we don't see them often and I'd like to get some dimensional information if you don't mind. Great work.CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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Could you post some pics of the "stands"
You mean the risers?Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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The original walnut vinyl veneer
Are you sure that was vinyl? I'm pretty sure they only came with wood veneer.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Yes, he called them "stands" so that's how I referred to them.
Ok, if he doesn't get you that info, I will. Off the top of my head, they are 2" tall. I'd have to measure the rest.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Ok, if he doesn't get you that info, I will. Off the top of my head, they are 2" tall. I'd have to measure the rest.
TY F1Nut. Just figured he could provide some tangible pictures and measurements since he has them in his hands. If you do, even better since your far more accurate in my travels than most folks.CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint. -
Are you sure that was vinyl? I'm pretty sure they only came with wood veneer.
LOL. Yep, it was vinyl. See pic. -
Pickoid - Could you post some pics of the "stands" since we don't see them often and I'd like to get some dimensional information if you don't mind. Great work.
My risers are about as much bondo as MDF at this point. I could have just rebuilt them, but I had plenty of bondo, so I figured I'd just square up the corners where the MDF had swelled. See photo below.
Dimensions are 13" wide, 9.75" deep, 2" tall.
They are just screwed into the bottom of the cabs with 4 wood screws (with countersunk holes). I added the nylon feet. -
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Are you sure that was vinyl? I'm pretty sure they only came with wood veneer.
Jesse - I'm pretty sure mine are vinyl, too. Wish they were wood veneer... -
Gavin.Wright wrote: »They look pretty good to me - my pair of SDA-2's could use some attention as well. I noticed the fuse above the speaker inputs, was that factory or did you add it? I'm looking at getting some type of passive protection for mine and have thought of adding a fuse...
Gavin,
Those fuses are what Polk used prior to polyswitches. The fuse covers only the tweeters, just like the polyswitch. No real need to have it, as long as you're careful with what amplification you use, and your volume levels.Ludicrous gibs! -
Those 11's look good.
Gavin, the fuse was only for the tweeter section like the poly's are in your crossover. -
nadams and Joe08867 - thanks for the info, i thought the fuse would be wired in series with the positive speaker input but I guess not. Thanks
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I don't think anyone ever did that except maybe EV for there PA speakers but that was more a lightbulb that would protect the whole system.
I think a fuse would blow to easy with the bass signal coming through them. -
Resurrecting this thread... I just couldn't resist the opportunity to waste more time and money on these speakers, so I set about to upgrade the crossovers. I decided to swap out all the caps and resistors in the network. I used Mills resistors and Parts Express Dayton 5% caps for everything. I also replaced all the internal wiring with 16 ga. A couple of "before and after" pics of the crossovers are attached.
This was kind of a big undertaking for me. It's only the second time that I worked on any speaker crossovers, and the only time I've done it on anything I wanted to keep. My soldering skills are improving, I think. I hope I didn't create any problems to come back and bite me down the road.
I also did a complete T-nut retrofit on the cabs, with stainless steel "Allen-head" machine screws to mount the drivers and crossovers. I damped the speaker and passive radiator baskets with cheap sound deadening sheet material. I couldn't really tell any difference this made on the mid-woofer baskets, but it made a big difference in the "ringy-ness" of the passive baskets. I replaced all the speaker gaskets with the stick-on stuff that Parts Express sells (might not be the best material, but I had it on hand). I re-used the tweeter gaskets because they seemed to be in pretty good shape. All of this definitely improved the air-tightness of the cabinets. I can tell a big difference when I push a passive radiator and observe how long it takes the drivers to move back in.
After wiring everything up and checking continuity and resistance, I connected them to a "sacrificial" amp and crossed my fingers. To my relief, they sounded good and the amp didn't smoke. Believe me, it was a concern. After an hour or so of listening, I was convinced that all was well. Tonight they will get moved to the listening room and hooked up to my Yamaha M-70 amp for some more break-in and listening.
I'm hoping that I hear an improvement in the highs. There was a little perceived harshness in the high-end on the left channel speaker on some material (seemed to show up on piano the most, go figure). The issue was not solved by swapping the tweeters, and I also eliminated the source/preamp/amp chain because the issue followed the speaker. This led me to suspect the crossover network in that speaker. Based on what I could tell from listening last night, I'm very hopeful the problem is sorted.
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Parts list for a single crossover was:
2x 47uF caps, replacing 45uF originals
2x 0.47uF cap, replacing one 0.47uF and one 0.5uF original
1x 4.3uF cap, replacing 4.4uF original
2x 4.5ohm resistors -
A word of advice, that clear jacketed speaker cable is infamous for turning green from oxidation. Consider using something else.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Parts list for a single crossover was:
2x 47uF caps, replacing 45uF originals
2x 0.47uF cap, replacing one 0.47uF and one 0.5uF original
1x 4.3uF cap, replacing 4.4uF original
2x 4.5ohm resistors
Very nice restoration! I'm sure those speakers are worth the effort."Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer -
I spent a few hours listening to them last night - holy smokes. It was worth it. Highs are smoother, bass is tighter. I was listening to the new Pink Floyd/Meddle remaster, and "Echoes" was downright frightening. I also played a few of those Telarc Cincinnati Pops CDs - amazing dynamic range. These speakers just soak up power without a hint of distress. I'm impressed.
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I walked into to a local hifi shop several months back and saw a pair of these in the back corner. I asked, "what are those?" The older gentlemen replied, "ah, those are nothing" as he was trying to sell me on a pair of Paradigm Signature S3 bookshelf speakers. As I was auditioning the Paradigm Signature's (paradigms top of the line speaker series) I asked if we could listen to the old polks with the same setup as the paradigms. The dude hooked them up and BOTH of our eyes were wide open with jaws dropped. The guy looked really confused and said, "wow, those sound better than most of the speakers we have in here. I might take them home myself." I think he might have to because he looked dead serious. That was when I knew I would like the SDA's so I picked up a pair of 2B's.
What's crazy is that the 2B's didn't sound anything like the 10's when I auditioned them. The 10's destroyed them top to bottom, but the 2B's needed some work (although when I bought they had did have the replacement RD0-194 tweeters). I also listened to the 10's through some newer NAD separates.
Anyway, great looking speakers and phenomenal work! -
typo in last post: replace "10's" with "11's"
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Nice Job !Carver C-1, M-500 MKII, Yamaha HTR-5835, Polk RTA 12BM's (M-for mod'd).
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Just finding your post. I recently acquired pair of 11's myself and plan recap and hopefully re-veneer. That original vinyl is not very good looking on mine.
Some of your cap values look different from layout in sticky. Hope I did't order wrong size caps. Will soon find out - as soon as I can stop listening long enough :biggrin: -
I'm in the process of tweaking my Model 11 Polks as well. While you were inside the speakers, did you notice dark foam baffling glued to the inner chamber underneath one of the mid drivers? Both of my speakers, which look like they've never been opened up, have this below the 'inside' driver. Since these are mirrored pairs with specified left and right speakers, by 'inside' I mean to say the driver closest to center. The baffling has broken down due to old age and one has fallen down to the bottom of the cabinet where all of the white baffling is located under the passive radiator.
Does anyone have experience replacing these? I'm wondering whet function they serve. My guess it that they partially seal off one of the upper chambers, but I'm not certain. How important is it to find the same material as a replacement?
Here's a picture of the foam baffle on its own:
