Looking for (2) MW-6501 Woofers for SDA-2 NEWBIE ALERT

Tronman

I picked up some SDA-2's from Craigslist and it appears the gentlemen hooked up the polarity backwards as he had broken the speaker terminals off and installed the plate upside down and obviously had no idea which terminal was + or - . My Guess is he hooked up one of the speakers with reverse polarity and blew 1 tweeter and 2 of the MW-6501's. I had an extra tweeter but have been unable to locate some MW-6501 to finish repairing them. Any help or information on location the drivers would be great.
To let everyone know I have installed some Focal HP6M115 in there place to make sure everything is working correctly and they actually don't sound to bad ;-) - So you can see the dire situation I am in. This is only my second post I am a NEWBIE so go easy on me.

Thanks to all in advance I have been reading the forums for a looooong time and have acquired vast amounts of information from everyone.

I am also in the process of upgrading my SDA-1C's (My new pride and joys and main project) These are in need of the following:
1. Refinish End Caps
2. Upgrading crossovers with Sonicaps and Mills Resistors
3. Build new side panels
4. Dynamat the Woofers and Radiators
5. JB Weld the woofer magnets
6. Already have standoffs for the speakers (DAYTON AUDIO DSS4-G GOLD SPEAKER SPIKE SET 4 PCS P/N 240-718)
7. Already upgraded to RDO194 Tweeters
8. Replacing Speaker binding posts - on order

I am also going to try to make new end caps with either Oak or Mahogany and do a complete restore - this will be a first for me doing the end caps all the rest I have done on other projects.

I am also looking for some Larry Rings if he is still making them :-).

Thanks all.

Tim

gimpod

Try calling Polk (Number at top of page) I think they still sell the MW6501 drivers according to this link Current Production Drivers Vintage Support

BTW: Hooking up SDA's with reverse polarity will not blow tweeter's & drivers, One of two things most likely happened, They were hooked to an under powered amp/receiver that was over driven or hooked up to a non-common ground amp with SDA IC plugged into both speakers.

Tronman

I called them yesterday and asked them if they carried any of the MW-65xx drivers in stock as I've read here they had some models back in production and the answer was NO we carry no MW-65xx drivers at all in stock. MMMmmmmm maybe I'll try one more time. If anyone knows for sure they carry something of the older models it would be nice to know. I will try and give them a call tomorrow and let you know.

Tronman

That's funny I clinked on your link for the vintage drivers still supported and that was the same info I was referring to when I called them - that information was THE reason I called but I did notice that post was in 2011??

Tronman

BTW: Hooking up SDA's with reverse polarity will not blow tweeter's & drivers, One of two things most likely happened, They were hooked to an under powered amp/receiver that was over driven or hooked up to a non-common ground amp with SDA IC plugged into both speakers.

I would have to go for the under powered amp as the gentlemen I picked them up from could barely figure out his own receiver and it was not even close to something that might even have a chance to power them. I do believe the words "Blew up my stereo" came out of his mouth while talking to him. Well I can't complain I got them from him for $80.00 :-) and I am listening to them right now with my focal temporary woofer in one.

BKphoto

I'm parting out a pair of SDA 2A's...I dont have a place for them and I'm using the passives on my RTA 12's...

Let me know...

pitdogg2

SDA2a's do not use MW6501 they should have 2 mw6510.....

keep an eye on ebay they come up often

Tronman

The SDA's I have are Early SDA-2A (2) Sl-2000 and (3) Drivers MW-6501 (2nd Generation I think there called) or in other schematics they reference SDA-2. There was a thread in here about 2 guys discussing SDA-2A and one was referring to the one with 1 tweeter (3rd Generation) and the other talking about the previous SDA-2A (2nd Generation) and they were confusing the crap out of each other - in the end they concluded they were both right :-). If you look at the schematics on the forum it is listed as a SDA-2. Needless to say I am still looking for (2) MW-6501. I called Polk today and talked to them and they are not making the MW-6501 but told me the replacement is the MW-6503's (I know it is not a direct replacement but that is what she told me). They do have the following in stock right now:
As of 2/20/2014
Model Qty Price
MW-6502 279 $48.00
MW-6509 ? $48.00
MW-6510 209 $48.00
MW-6511 108 $48.00

The 6509 I did not ask quantity since the other 3 were over 100.

If the SDA-2A you are parting out have the MW-6501 I would be very happy to take those off your Hands :-)

gimpod

Tronman wrote: »

The SDA's I have are Early SDA-2A (2) Sl-2000 and (3) Drivers MW-6501 (2nd Generation I think there called) or in other schematics they reference SDA-2. There was a thread in here about 2 guys discussing SDA-2A and one was referring to the one with 1 tweeter (3rd Generation) and the other talking about the previous SDA-2A (2nd Generation) and they were confusing the crap out of each other - in the end they concluded they were both right :-). If you look at the schematics on the forum it is listed as a SDA-2.

You have 2nd gen (1983 - 1984) SDA 2's, Polk made two versions of the SDA 2's the early ones with the dual SL-1000 tweeter (a transitional model) followed by the ones like yours with the SL-2000's. As far as I know Polk NEVER made SDA 2A's with two tweeters and three drivers. Also the 3rd gen SDA's dropped the dimensional tweeter entirely. I'll bet the date on the back of the MW-6501's say 1984 maybe early 1985, this and the fact that they have two tweeters and three drivers makes them just SDA 2's not SDA 2A's.

Check this link out SDA Speaker Identification

pitdogg2

Gimpod is so right on this they are SDA2 plain and simple no suffix attached.

Tronman

This is what I found and where I found it :-)

http://www.polkaudio.com/forums/showthread.php?146764-how-do-Polk-SDA-1B-compare-to-SDA-2B/page2

The above link has the pictures in it if my attachment doesn't work

1. http://vr3mods.com/uploads/SDA_Handbook_2011_Rev2.pdf
http://vr3mods.com/uploads/SDA_Handbook_2011_Rev2.pdf
1. My list of drivers clearly states 2 - sl2000 tweets for the 2A. The sentence on page 7 is a bit confusing. After reading the paragraph over a couple times it does seem to indicate a single tweeter. My copy must have a typo when it lists the drivers for the 2A's, which was subsequently corrected in the dl version.

So yes, lets' put this to bed because who cares, if he has a single tweeter, then he has a single tweeter. I do know of 2A's which were early runs having 2 tweeters, perhaps they were mis-identified. We ALL know Polk and transitional models can be hard to classify. That's the best evidence you're going to get, unless it comes from Communist China.

H9

Tronman

If you have the MW-6501's let me know I will definitely take 2 of them off your hands. :-)

Tronman

BKphoto wrote: »

I'm parting out a pair of SDA 2A's...I dont have a place for them and I'm using the passives on my RTA 12's...

Let me know...

If you have the MW-6501's let me know I will definitely take 2 of them off your hands. :-)

Still learning how to post things

westmassguy

H9 was basing his information on the first Handbook, which had errors, as does the second version. I transitional 2A would be hard to imagine since the crossovers were re-designed for the 3rd generation, and there would be no way to even connect the sub-bass woofer, or the dimensional tweeter the 2s had.

On3s&Z3r0s

I've got three MW-6501's, and would be willing to part with two or all three if you want the extra as a spare. They are stamped Aug/Sept 1984. I think you've got enough posts to PM, so if you're interested, just hit me up or let me know on this thread and I'll PM you.

Tronman

On3s&Z3r0s wrote: »

I've got three MW-6501's, and would be willing to part with two or all three if you want the extra as a spare. They are stamped Aug/Sept 1984. I think you've got enough posts to PM, so if you're interested, just hit me up or let me know on this thread and I'll PM you.

Great ! I'd like to take all three :-), I think having a spare would be a great idea since they will be my next project once I am done with the SDA-1C's. I will try to PM you - haven't tried it yet so if you don't get something shoot me one. Thanks

Tronman

westmassguy wrote: »

H9 was basing his information on the first Handbook, which had errors, as does the second version. I transitional 2A would be hard to imagine since the crossovers were re-designed for the 3rd generation, and there would be no way to even connect the sub-bass woofer, or the dimensional tweeter the 2s had.

I agree with you now that I think about it. I have looked over the schematics and noticed no schematics for the SDA-2A with that configuration. The only one that matches it is the SDA-2 schematic. I find it hard to believe with all the schematics listed in the forum that this schematic would be missed. Thanks for clearing that up - so I am currently sitting here listening to my SDA-2's :-)

On3s&Z3r0s

I replied to your PM... here's some pics so you'll know what you're getting. Thanks and welcome aboard!

On3s&Z3r0s

When I was taking those pics I noticed one of the magnets had a couple of chips in it and looked slightly off center so I decided to check it out to make sure it wasn't frozen / rubbing. I popped it into the spot for the MW6503 in a SDA-2B cabinet. Damn if that didn't make me a bit nostalgic for the SDA-2's I had for a time. Nothing against the SDA-2B's of course, but I always preferred the bass that came out of the three MW6501 drivers to what I've gotten so far from the MW6503/6511 combo.

Tronman, you'll have to keep us posted on the upgrades you make to the 1C's and 2's. If there was one recommendation I would make on potential upgrades to the 2's, since you've already got the RD0-194's for the 1C's I'd try them in the 2's with and without the dimensional (outside) tweeter connected. I'd definitely try that before you invest in four new 194's for the 2's. You'll find plenty of discussion on the forum about the dimensional tweeter and whether to leave it connected or disconnect. Could save you some bones if you decide you're likely to be running without the dimensional.

westmassguy

On3s&Z3r0s wrote: »

When I was taking those pics I noticed one of the magnets had a couple of chips in it and looked slightly off center so I decided to check it out to make sure it wasn't frozen / rubbing. I popped it into the spot for the MW6503 in a SDA-2B cabinet. Damn if that didn't make me a bit nostalgic for the SDA-2's I had for a time. Nothing against the SDA-2B's of course, but I always preferred the bass that came out of the three MW6501 drivers to what I've gotten so far from the MW6503/6511 combo.

Have you changed the "Full Compliment Sub Bass" Inductor on your 2Bs?

On3s&Z3r0s

westmassguy wrote: »

Have you changed the "Full Compliment Sub Bass" Inductor on your 2Bs?

Actually... I just got both some Solen perfect lay inductors (not the hepta-litz variety) and a pair of Erse SuperQ's that I had them dewind to 16mH. I'll be putting the Solen's in and starting the burn-in this weekend. I have high hopes based on all the inductor replacement threads I've seen so far.

westmassguy

On3s&Z3r0s wrote: »

Actually... I just got both some Solen perfect lay inductors (not the hepta-litz variety) and a pair of Erse SuperQ's that I had them dewind to 16mH. I'll be putting the Solen's in and starting the burn-in this weekend. I have high hopes based on all the inductor replacement threads I've seen so far.

I've installed the Erse SuperQs in both my SDAs, and many of my customers. The difference can be astounding. The one big caveat, is the impedance of the speaker will drop. I don't know the DCR on the Solens, but the Erse are quite low, compared to the original.

On3s&Z3r0s

westmassguy wrote: »

I've installed the Erse SuperQs in both my SDAs, and many of my customers. The difference can be astounding. The one big caveat, is the impedance of the speaker will drop. I don't know the DCR on the Solens, but the Erse are quite low, compared to the original.

That was a concern, so I'm starting with the Solens. Their DCR is less than 2ohms but a little bit higher than 1.5 depending on who's doing the measuring I think. Those SuperQs can be right around 1ohm! If the Solens don't fry my amp, then I'll give the SuperQs a try. I've got a B&K 200.2 so I think I should be safe.

Apologies to Tronman for the threadjack, but at least this should give him an idea of how far down the rabbit hole goes.

westmassguy

On3s&Z3r0s wrote: »

That was a concern, so I'm starting with the Solens. Their DCR is less than 2ohms but a little bit higher than 1.5 depending on who's doing the measuring I think. Those SuperQs can be right around 1ohm! If the Solens don't fry my amp, then I'll give the SuperQs a try. I've got a B&K 200.2 so I think I should be safe.

Apologies to Tronman for the threadjack, but at least this should give him an idea of how far down the rabbit hole goes.

Actually, the 16 gauge, 18mh Erse is around .5 ohms when unwound to 16mh. The existing Polk 16mh is about 2.5 IIRC.

On3s&Z3r0s

westmassguy wrote: »

Actually, the 16 gauge, 18mh Erse is around .5 ohms when unwound to 16mh. The existing Polk 16mh is about 2.5 IIRC.

Wow... that is low. The first guys to plug those in as replacements are braver than me. But I guess in the audio modding hobby sometimes you just rolls the dice and takes your chances.

westmassguy

On3s&Z3r0s wrote: »

Wow... that is low. The first guys to plug those in as replacements are braver than me. But I guess in the audio modding hobby sometimes you just rolls the dice and takes your chances.

My Carver can handle even 2 ohm loads, so not a problem. Your 2Bs would drop from 6 ohm nominal to 4 ohm nominal.

BKphoto

That pic is wrong,

SDA 2A has 2 drivers and one tweeter...I've seen several mistakes in the specs of older speakers...

On3s&Z3r0s

BKphoto wrote: »

That pic is wrong,

SDA 2A has 2 drivers and one tweeter...I've seen several mistakes in the specs of older speakers...

There have definitely been some rare birds and one-offs that have cropped up for identification on the boards, but it does seem extremely unlikely that there is anything other than MW-6501's in the speakers Tronman has. It's kind of like a game of telephone with the specs on the speaker models from before the mid-80's. The original manual or specs on them may have been wrong, or that information could have been transcribed wrong at some later time.

The manual that came with the SDA-2's I had (bought from the original owner) said they were supposed to have 3 x MW-7500's in each cabinet. I had those apart enough to know for sure they were MW-6501's all around.

Tronman

On3s&Z3r0s wrote: »

When I was taking those pics I noticed one of the magnets had a couple of chips in it and looked slightly off center so I decided to check it out to make sure it wasn't frozen / rubbing. I popped it into the spot for the MW6503 in a SDA-2B cabinet. Damn if that didn't make me a bit nostalgic for the SDA-2's I had for a time. Nothing against the SDA-2B's of course, but I always preferred the bass that came out of the three MW6501 drivers to what I've gotten so far from the MW6503/6511 combo.

Tronman, you'll have to keep us posted on the upgrades you make to the 1C's and 2's. If there was one recommendation I would make on potential upgrades to the 2's, since you've already got the RD0-194's for the 1C's I'd try them in the 2's with and without the dimensional (outside) tweeter connected. I'd definitely try that before you invest in four new 194's for the 2's. You'll find plenty of discussion on the forum about the dimensional tweeter and whether to leave it connected or disconnect. Could save you some bones if you decide you're likely to be running without the dimensional.

Right now I have only the stereo tweeter hooked up :-) powered by my Carver TFM-35. I had to take all the drivers out and test them when I got them home to see what was actually not working to my surprise it was only one tweeter and 2 Drivers. I was actually expecting a lot worse.
I had two bad Sl-2000's one from the SDA-2's and one from the SDA-1C's, when I took them both apart to look at the voice coils they looked great but zero continuity. So I brought them to work where I have a microscope and found on both tweeters the voice coil wire was broken right were it goes through the dome of the tweeters. i have a guess as to why it happened - metal fatigue after 30 years of vibrating. Any way I was able to solder the tweeter wires back together, easier when you have a real nice soldering station and a microscope :-) plus I work with stuff like that all the time at work. It was fun to see if I could do it. So I will be using those as spares as I am unsure of the longevity of a soldered tweeter wire.
Just wondering if any body else had noticed that with the blown tweeters??

Tronman

Since you've already got the RD0-194's for the 1C's I'd try them in the 2's with and without the dimensional (outside) tweeter connected. I'd definitely try that before you invest in four new 194's for the 2's. You'll find plenty of discussion on the forum about the dimensional tweeter and whether to leave it connected or disconnect. Could save you some bones if you decide you're likely to be running without the dimensional.[/QUOTE]

Agree with you 100% on testing before I order some - that is a great idea since I already have them out of the 1C's :-) Working on stripping the End Caps to refinish them. Looks like I have a stain I am going to have to use some wood bleach to remove. Much better then it was but will stick out like a sore thumb once I put the finish on them. Any input besides wood bleach to remove the stain from the wood would be great.

On3s&Z3r0s

Tronman wrote: »

...
I had two bad Sl-2000's one from the SDA-2's and one from the SDA-1C's, when I took them both apart to look at the voice coils they looked great but zero continuity. So I brought them to work where I have a microscope and found on both tweeters the voice coil wire was broken right were it goes through the dome of the tweeters. i have a guess as to why it happened - metal fatigue after 30 years of vibrating. Any way I was able to solder the tweeter wires back together, easier when you have a real nice soldering station and a microscope :-) plus I work with stuff like that all the time at work. It was fun to see if I could do it. So I will be using those as spares as I am unsure of the longevity of a soldered tweeter wire.
Just wondering if any body else had noticed that with the blown tweeters??

I've heard stories of folks disassembling and repairing blown tweeters this way and frozen MWs by resetting and re-epoxying the magnets. Both are well beyond the scope of my equipment, knowledge and dexterity. But I think there have been other posts reporting tweeters failing that way.

Tronman wrote: »

...
Working on stripping the End Caps to refinish them. Looks like I have a stain I am going to have to use some wood bleach to remove. Much better then it was but will stick out like a sore thumb once I put the finish on them. Any input besides wood bleach to remove the stain from the wood would be great.

I think F1nut is the resident expert on refinishing end caps. I have some to do also and was planning on using a wood bleach containing Oxalic acid when I get around to it. I used that one summer to bleach some water damage out of the walls on my dad's D-log cabin. If it worked there, it should work to kill the plant ring on a little veneer!