Questions about recently acquired Polk Audio SDA SRS 2 speakers
POLK3429
Posts: 26
Recently acquired a set of Polk Audio SDA SRS 2 speakers and had a couple questions. Here is some info on the speakers
* They have the pin/pin connection, did not come with an interconnect cable, so I just bought one on ebay
* One serial number is in the 800's and the top/bottom caps are pieces of solid wood glued together. The laminated caps still look new - no cracks, warping, etc.
* The other serial number is in the 1600's and the caps are veneered
Was this model was sold from about 1986 to 1988? A "late 80's" confirmation is good enough for me.
Is there any significance/meaning to the serial numbers? No idea how many pairs they manufactured per year at the time, and therefore no idea how long it takes to go from 800's to 1600's ........ or if I should even care.
Anyone else have a pair of these SDA SRS 2's where the wood caps mismatch (one laminated & one veneered)? I did have a quick glance of at least one person replacing the caps - love the concept, but do not have the time.
* They have the pin/pin connection, did not come with an interconnect cable, so I just bought one on ebay
* One serial number is in the 800's and the top/bottom caps are pieces of solid wood glued together. The laminated caps still look new - no cracks, warping, etc.
* The other serial number is in the 1600's and the caps are veneered
Was this model was sold from about 1986 to 1988? A "late 80's" confirmation is good enough for me.
Is there any significance/meaning to the serial numbers? No idea how many pairs they manufactured per year at the time, and therefore no idea how long it takes to go from 800's to 1600's ........ or if I should even care.
Anyone else have a pair of these SDA SRS 2's where the wood caps mismatch (one laminated & one veneered)? I did have a quick glance of at least one person replacing the caps - love the concept, but do not have the time.
Comments
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I'm assuming you mean pin-blade interconnect? Pics would help.
Gustard X26 Pro DAC
Belles 21A Pre modded with Mundorf Supreme caps
B&K M200 Sonata monoblocks refreshed and upgraded
Polk SDA 1C's modded / 1000Va Dreadnaught
Wireworld Silver Eclipse IC's and speaker cables
Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)
There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus -
Yes pictures because there are two completely different SDA SRS 2 speakers. One built of the SDA 1b and one off the SDA 1c not to mention they used very different drivers.
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The interconnect is blade/blade - sorry for that brain lapse.
The attached picture is what I have:
- 2 x SL2000 H.E.
- 4 x MW6509 Mid L.E.
- 1x SW150 passive radiator
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I own a pair of them.
I replaced the tweeters with replacement RD-0194's.
You're in for a treat!!Most people just listen to music and watch movies. I EXPERIENCE them.
“Anger is an acid that can do more harm to the vessel in which it is stored than to anything on which it is poured.”
--Mark Twain.
“If at first you don't succeed, then skydiving definitely isn't for you.” - Steven Wright -
The SDA Handbook is always the go to:



George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Thanks for that info @Gardenstater! I did not know that a handbook existed, but after reading your post, I found this nugget (see picture). Is this the handbook that you reference?

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Yes that is the bible
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The B/b SRS 2 is more expensive to update the caps and the mw6509 drivers are as rare as hens teeth. The mw6509 was only used in the SDA 1b and the model you have. Probably the shortest run driver of them all.
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The B/b SRS 2 is more expensive to update the caps and the mw6509 drivers are as rare as hens teeth. The mw6509 was only used in the SDA 1b and the model you have. Probably the shortest run driver of them all.
Thanks for the info. That is not ideal news about the MW6509 being rare, but I bought them without doing much research.
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I am enjoying these so far just as-is. The bass response is impressive for a 40 year old speaker.
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While I think the 2.3tl is the true SDA sweet spot…….I think the SRS 2’s are special as well.
BDTI plan for the future. - F1Nut -
All I've heard had a huge sound stage.
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The B/b SRS 2 is more expensive to update the caps and the mw6509 drivers are as rare as hens teeth. The mw6509 was only used in the SDA 1b and the model you have. Probably the shortest run driver of them all.
I'd expect the SRS 2.3 "Donut drivers" to be even more rare. -
You need some?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 -
Me? No, thanks. Those were 6513...right?
Probably should have looked into the 6510/6511s that were on eBay recently, though. I have spares of one or the other, I don't remember which.
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Yes and very rare, but I have some.Those were 6513...right?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 -
All I've heard had a huge sound stage.
These SDA SRS 2's do seem to have a large sound stage. The seller claimed they were unmodified, and I have not disassembled yet to verify. I am sure everyone has songs they use, but Neil Diamond's 'Soolaimon' has percussion events that happen outside both the left & right speakers on these SDA SRS 2's.
I just picked up a 2nd pair of SDA's, a pair of SDA 1c's that have been modified, but the Neil Diamond 'Soolaimon' song does not have the SDA effect. I can pinpoint the sound as coming from the speakers (almost no sound stage) - which is very disappointing. I will probably need to disassemble the 1c's to trouble shoot, and start a separate thread. -
I bought my SDA SRS 2's blade/blade September 1987. Andreas Vollenweider "Caverna Magica" sounds good. Speakers are original, no mods, nothing.
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When you finally get around to replacing the capacitors, the SDA inductor, and the tweeters, you're gonna be AMAZED. While you're in there, lift the fiber packing back up where it belongs, instead of drooping down into the bassive radiator area. Fresh resistors, other exotic mods optional.brewingwithms wrote: »I bought my SDA SRS 2's blade/blade September 1987. Andreas Vollenweider "Caverna Magica" sounds good. Speakers are original, no mods, nothing.
I was, when I did that to my SDA 1Bs--same guts except for one resistor, smaller cabinet, smaller bassive radiator.
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Passive radiatorPolitical 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 -
You got me interested now. Where do I buy these parts? All the other mods have diminishing returns? I just read the bible, very informative.
When you finally get around to replacing the capacitors, the SDA inductor, and the tweeters, you're gonna be AMAZED. While you're in there, lift the fiber packing back up where it belongs, instead of drooping down into the bassive radiator area. Fresh resistors, other exotic mods optional.brewingwithms wrote: »I bought my SDA SRS 2's blade/blade September 1987. Andreas Vollenweider "Caverna Magica" sounds good. Speakers are original, no mods, nothing.
I was, when I did that to my SDA 1Bs--same guts except for one resistor, smaller cabinet, smaller bassive radiator.
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There's a hundred vendors for capacitors and resistors. Folks on this forum have their favorites. ERSE--or what used to be ERSE but is now something else--seems to be a preferred source for inductors, although again, there are other sources.
When it was me, I bought 1% tolerance Dayton capacitors from Parts Express for the high-frequencies, 5% Dayton for the low-frequency section, and four bigass 91uF 3% tolerance ERSE PulseX capacitors for the SDA. None of those caps are on the "approved" list on this web site, and yet I'm completely thrilled with them. ANY film cap is going to be better than the worn-out, ancient electrolytic caps in there now. Hell, even FRESH electrolytics would be better than the original electrolytics.
IF (big IF) you have a decent amplifier, you can eliminate the polyswitch "tweeter protection". Some folks replace it with a low-value resistor, 1/4 or 1/2 ohm. I just bypassed it with a jumper wire, which increases treble volume slightly--much needed on my 1Bs, and I suspect on your SDA 2s as well.
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Passive radiator

I prefer Bassive radiator, as that is also the frequency range it provides.
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brewingwithms wrote: »
You got me interested now. Where do I buy these parts? All the other mods have diminishing returns? I just read the bible, very informative.
When you finally get around to replacing the capacitors, the SDA inductor, and the tweeters, you're gonna be AMAZED. While you're in there, lift the fiber packing back up where it belongs, instead of drooping down into the bassive radiator area. Fresh resistors, other exotic mods optional.brewingwithms wrote: »I bought my SDA SRS 2's blade/blade September 1987. Andreas Vollenweider "Caverna Magica" sounds good. Speakers are original, no mods, nothing.
I was, when I did that to my SDA 1Bs--same guts except for one resistor, smaller cabinet, smaller bassive radiator.
Sonic Craft and Parts Connexion carry the better components. There's also HiFi Collective in the UK. They carry a lot of components that no one else does. My latest order from them is on the way
Some reading for you. Dayton is not mentioned, but the Bennic XPP is the exact same thing.
https://www.humblehomemadehifi.com/Cap.htmlPolitical 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 -
brewingwithms wrote: »
You got me interested now. Where do I buy these parts? All the other mods have diminishing returns? I just read the bible, very informative.
When you finally get around to replacing the capacitors, the SDA inductor, and the tweeters, you're gonna be AMAZED. While you're in there, lift the fiber packing back up where it belongs, instead of drooping down into the bassive radiator area. Fresh resistors, other exotic mods optional.brewingwithms wrote: »I bought my SDA SRS 2's blade/blade September 1987. Andreas Vollenweider "Caverna Magica" sounds good. Speakers are original, no mods, nothing.
I was, when I did that to my SDA 1Bs--same guts except for one resistor, smaller cabinet, smaller bassive radiator.
Sonic Craft and Parts Connexion carry the better components. There's also HiFi Collective in the UK. They carry a lot of components that no one else does. My latest order from them is on the way
Some reading for you. Dayton is not mentioned, but the Bennic XPP is the exact same thing.
https://www.humblehomemadehifi.com/Cap.html
What are you working on?
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Something Van Halen-related.
What are you working on?
Sonic Craft and Parts Connexion carry the better components. There's also HiFi Collective in the UK. They carry a lot of components that no one else does. My latest order from them is on the waybrewingwithms wrote: »You got me interested now. Where do I buy these parts? All the other mods have diminishing returns? I just read the bible, very informative.
Some reading for you. Dayton is not mentioned, but the Bennic XPP is the exact same thing.
https://www.humblehomemadehifi.com/Cap.html
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