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Upgrading Polk Monitor 10A sl-1000 tweeter to rdo-194-1

H

hrtattckcity

AK Subscriber
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I just updated my Polk 10a's from the sl-1000 tweeter to the rdo-194, it was not as simple as I thought it would be so I thought I would post the process here.

-the sl-1000 is smaller than the rdo-194 and the recess needs to be enlarged for the rfi-194 to sit properly in the cabinet. I laser cut a thin plywood template, based on the profile of the rdo-194 + 1/32" on all sides for tolerance. The router bit I used had no offset between the bearing and the cutting edge. (I used the Yonico 14176q Template Trim Hinge Mortising Router Bit 3/4" Wide x 1/4" High 1/4" Shank) This was my first time using a router, and it worked very well. I set the depth of the router just a hair deeper than the existing recess to make sure the entire surface was even. If anyone is interested in the CAD drawing of the profile, let me know.

-the mounting hole pattern is different on the sl-1000 than on the rdo-194, so if you have already installed hurricane nuts, removing them is a bit of a pain. I threaded a machine screw into the hurricane nut so that the head of the screw was protruding out of the front of the cabinet and tapped it with a hammer until it came loose. I did get a bit of chip out on the inside of the cabinet in a few locations, but not significant enough that it created any problems installing the new hurricane nuts. Existing holes needed to be patched with epoxy and new holes redrilled for the rdo-194. Drilling the new holes is not as precise as it would be as it was going through some filler, not just particle board.

-the rdo-194 does not ship with foam gaskets. I think the intention is to reuse the ones from the sl-2000? for which the rdo-194 is the drop-in replacement. I handcut some out of spare packing foam I had around, as I was worried any of the gasket tape I had was too thick. I used a few small daps of Alene's tacky glue to hold the foam in place while installing the tweeter.

Otherwise, all went well.

I've had these 10A's for a while, last year I re-veneered them with some flat sawn maple.
 

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Good choice I installed the RDO-194’s on my 10B’s, much better sound. As for gasket material just go down to the auto parts store you can get rolls of it for real cheap, You can get the real nice rubber gasket material. The factory gaskets on my 10B’s were not foam but more like automotive gasket material. The advantage of this type of gasket material is it seals better and you never will run into the problem of the speaker being “glued” to the opening thanks to broken down foam.
 
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transmaster said:
Good choice I installed the RDO-194’s on my 10B’s, much better sound. I am a little puzzled my 10B’s also came with SL2000 tweeters and the RDO-194’s just dropped right into the same holes. As for gasket material just go down to the auto parts store you can get rolls of it for real cheap, You can get the real nice rubber gasket material. The factory gaskets on my 10B’s were not foam but more like automotive gasket material. The advantage of this type of gasket material is it seals better and you never will run into the problem of the speaker being “glued” to the opening thanks to broken down foam.
Click to expand...

Rdo-194’s are a direct drop-in for the sl-2000, but I had the sl-1000 in my 10a’s.
 
hrtattckcity said:
Rdo-194’s are a direct drop-in for the sl-2000, but I had the sl-1000 in my 10a’s.
Click to expand...
I caught the fact you had SL1000’s instead of SL2000’s after I posted. There is a slow argument going at the Polk Audio forum as to which is better the Peerless, or the RDO-194. All I know is they are better then the SL2000.

Rebuilding a set of 10B crossovers I purchased off of eBay. I had already done so on the ones installed but this pair were to clean and a great price. As I reported else where there is a phasing problem with the left side 10B. These crossovers will be rebuild as 10A’s the only difference is the late A model was fused and the B model had the bogus Polyfuse. R1 is a 2.5 ohm 5 watt on the “A”, and 2.0 ohm 5 watt on the “B”. The 1/2 ohm difference was the Polyfuse.
 
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I have been educating myself over at the Audioholics DIY forums about crossovers and capacitors. As you may know the word Audioholics is the favorite curse word in the Audiophile community. I am learning, and I am not surprised, there is just as much voodoo BS in the crossover capacitor world as everywhere else in the audiophile world. The bottom line is a capacitor that is within necessary spec's and stays that way over a lot of years is all you need. I am still going to go with the Mundorf MCap EVO's which at Sonic Craft have an excellent price, about the same as the Dayton Premiums. I normally would not replace the sand cast wirewound resistors but I need to accommodate the larger size of the the MCaps, and the Vishay Miller 12 watt resistors are smaller and have untrimmed leads. The PCB pillars are old brittle and are breaking. easy to replace but I found out these are the same pillars used on Westbend kitchen appliances, I can do a whole lot better.
 
I'm watching with interest here. I have 10Bs with SL-1000s and had read the RDO-194 are a good upgrade. Great job fitting them. I love my router. The veneer is gorgeous. I want to start with a crossover rebuild go from there.
 
As I said above the RDO-194 is superior to the SL-1000, 2000, the argument is about if it better then the Peerless Tweeter. The one thing I don’t know is if it is better is than SL-2500 that was in the Monitor 10 Series II, the final version of the Monitor 10.

The discussions about the Monitor 10B's crossovers at the DIY Audio forum say the biggest impediment to the sound is the Polyswitch it is supposed to be about 1/2 an Ohm in resistance but it is usually much higher which screws up the high pass side of the crossover.
 
transmaster said:
As I said above the RDO-194 is superior to the SL-1000, 2000, the argument is about if it better then the Peerless Tweeter. The one thing I don’t know is if it is better is than SL-2500 that was in the Monitor 10 Series II, the final version of the Monitor 10.

The discussions about the Monitor 10B's crossovers at the DIY Audio forum say the biggest impediment to the sound is the Polyswitch it is supposed to be about 1/2 an Ohm in resistance but it is usually much higher which screws up the high pass side of the crossover.
Click to expand...

The RDO194 was not designed to be a replacement for the SL1000. There is no proper replacement for it. The RDO194 was designed to replace the SL2000 only. You may like the end result, but perimeter wise they are not a match.

The polyswitch is a thermal reset device. It does not affect the sound quality. If it has been tripped too many times it becomes hypersensitive and trips at lower thresholds. If it is not replaced it will eventually not reset at all. The reason many remove it and replace with a .5 ohm resistor has nothing to do with sound quality, it's because with top notch gear the polyswitch is not needed.
 
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Mr Creosote said:
I'm watching with interest here. I have 10Bs with SL-1000s and had read the RDO-194 are a good upgrade. Great job fitting them. I love my router. The veneer is gorgeous. I want to start with a crossover rebuild go from there.
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Thanks Mr Creosote,
I started with a crossover and veneer upgrade—after one other similar project on a pair of infinity QB’s. I used relatively cheap Solen and Audyn caps—not as high end as many here go. The existing capacitors looked as if they had melted and started leaking out of the end of the cylinder. I am generally pretty wary of biased confirmation of upgrades—but since the capacitor upgrade they seem to sound better and better as time goes by.
 

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transmaster said:
These discussions are very fragmented going back more then 10 years. Here is a good posting that you can start to link.into other areas.
http://www.audioholics.com/diy-audio/upgrade-speaker-crossover-polk-audio
Click to expand...

Thanks, I actually had that bookmark. The tweets F1 linked look interesting and appear to have great specs. Now I've seen a few different looking Monitor 10b crossovers. With and without fuses. Mine have fuses. That means no polyswitch? Here's what I have. Who is the resident Polk guru on here? I don't want to risk hijacking the thread so, We now return control of your television set to you.
IMG_0250.jpg IMG_0249.jpg
 
Mr Creosote said:
Thanks, I actually had that bookmark. The tweets F1 linked look interesting and appear to have great specs. Now I've seen a few different looking Monitor 10b crossovers. With and without fuses. Mine have fuses. That means no polyswitch? Here's what I have. Who is the resident Polk guru on here? I don't want to risk hijacking the thread so, We now return control of your television set to you.

You have an early model 10B, that does not have the Polyswitch. You can see from the date tab the crossover pictured was assembled
Click to expand...
 
What fun I have another Logitech keyboard wearing out.

Your Crossover is was assembled in early 1984 has the fuse and not the Polyswitch. It is interesting that you have a 36 uF cap on the low side the schematic shows a 34 uf, but 36 uf is within the 10% tolerance of the circuit. I was reading about the NPE's and they have a habit of having a rough sound, whatever they mean by that. They do have the advantage for the manufacture of being cheap. look at R1 that is the resistor the outside resistor on the upper right side of the photo is should be a 2.5 Ohm 5 watt.
 
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