SDA Question?

[MoonDog]

Good Morning,

How do you tell the difference between SDA 2A's and SDA 2B's?

I own a set of Polks. The Instruction Manual clearly states "SDA 2A" and the back of the speaker "SDA 2".

Dimensions-12"D x 15" W x 40"H.

Thank You. Your expertise is appreciated.

[ND13]

2Bs have only 1 tweeter and 2 mids and a passive.

Welcome to Club Polk!! :)

[BobMcG]

Here's a few pics starting with the original SDA-2

[BobMcG]

Next was the SDA-2A

[BobMcG]

Then there was an "in-between" model, an early version of the SDA-2B. Notice the base is different from the 2A and the final 2B.

[BobMcG]

And the final version of 2B

[ND13]

Well damnit, after all these months of being told I have 2Bs, I must have the 2As that you just pictured in post #4. Mine have that base. I've been told so many different things about these speakers, it's driving me nuts.

Bob, the serial numbers on my 2somethings are 11491 and 12373 so can you help me out and tell me what I have, please?

The serial number labels are a bit different, too. the right speaker is a black label with white lettering and the left speaker is silver label with black lettering.
Other than the difference in the labels, they look the same, same vinyl, same cabinet, same everything else and they sound great.

[nadams]

Noel- do you know what drivers they have?

[fenderlady]

Anyone heard all three iterations of the 2's? Which one sounds the best of them if you have?

[BobMcG]

Well damnit, after all these months of being told I have 2Bs, I must have the 2As that you just pictured in post #4. Mine have that base. I've been told so many different things about these speakers, it's driving me nuts.

Bob, the serial numbers on my 2somethings are 11491 and 12373 so can you help me out and tell me what I have, please?

The serial number labels are a bit different, too. the right speaker is a black label with white lettering and the left speaker is silver label with black lettering.
Other than the difference in the labels, they look the same, same vinyl, same cabinet, same everything else and they sound great.

Noel,

The serial numbers are correct for 2As and the 2As were the last of the 2s to be offered with vinyl or real wood. The 2Bs weren't offered in vinyl.

Not listed to be compatable with the use of an AI-1, the 2As do have one plus going for them as they are efficiency rated at 92dB SPL/W/M. There are 2Bs that can use an AI-1 but the 2Bs are rated 89.7 dB SPL/W/M.

[ND13]

Thanks Bob!!!! :) :)

[Emlyn]

Noel,

The serial numbers are correct for 2As and the 2As were the last of the 2s to be offered with vinyl or real wood. The 2Bs weren't offered in vinyl.

There was a brief crossover period when Polk made a 2B studio version in black ash vinyl with a blade/blade interconnect. I know this because I have a pair like this still. I was confused about what they were, but checking the mid-woofers confirmed that they are 2B's. I bought these from a guy in Baltimore. These Frankenpolks didn't get far once they left the factory. :D

Check the midwoofers. 2B's had one 6503 and one 6511 driver each. 2A's had two 6510 drivers. Boxes and speaker cabinets were not marked 2A or 2B at this time because it wasn't adopted as a naming convention back then. The boxes may have been marked "improved" in some cases. Manuals were not reprinted to say "2B" speakers, but an addendum sheet may or may not have been included.

[BobMcG]

Emlyn,

It seems within the Polk lines there are indeed a few Franken speakers made at the crossover points. There were early 2Bs and 1cs with B/B connectors.

The 2bs were offered in a black ash studio version but I forgot this was vinyl. To clear things up I should say that the walnut and oak was real wood and you could no longer get a similar look in vinyl.

You're right, Polk didn't make a habit of marking the cabinets themselves with the A or B or such monikers. They did it on the boxes and placed addemdum sheets in the owner's manuals. (For the most part at least.)

[F1nut]

Polk continued to offer the Studio 2B in black ash vinyl with the pin/blade IC until the SDA production ceased.

[candyliquor35m]

That means my p/b walnut studio 2b's are real wood. I always assumed they were vinyl. yahoooo!

[F1nut]

Well, no. Any SDA "Studio" version meant vinyl clad.

[ND13]

I guess I'll need to pull the drivers and get the numbers. Rich had provided me with a paper that he had written down all the drivers and the years they were produced, I'll see if I can find it first. Mine are walnut vinyl with blade/blade IC.

Wait....Bob said that the serial #s are for 2As, so nevermind :o :)

[schwarcw]

My SDA-2 drivers were all MW6600X. Jesse replied to a posting I made indicating the MW6600Xs were interchangeable with the MW 6501s, which is what is on the schematic.

carl

[fenderlady]

My SDA-2 drivers are all MW7500's

Kristi

[F1nut]

MW7500's aren't even listed as a Polk part number.

[fenderlady]

That is what it says in the owners manual. I have not had the speakers apart yet, so I can't speak to what is imprinted on them.

[F1nut]

After looking a little more I came to realize Polk doesn't list the parts for the original SDA 2 with the SL1000's, so you may be correct. Pull a driver and let us know.

[ND13]

From what I can find:

2Bs have 1 MW6503, 1 MW6511 and a SW121
2As have 1 MW6510, 1 MW6510 and a SW121
2s have 2xMW6501, 1 MW6501 and a SW120
All have SL2000s

The only SDA I could find with a SL1000 tweeter were the SDA 1s.

Of course that really doesn't mean **** since we've all seen exceptions in the interim models and I guess anything is possible with the SDAs. You might just have an extremely rare set.

I thought the only Polks with MW7XXX drivers were some of the later models/series of speakers with 7" drivers, but can't find anything with MW7500. The closest I can find is a MW7005.

Hope this helps and doesn't confuse the situation even more. :)

Edit- I was just looking through a pdf file for the manual to a RTA12C and for some sttrange reasom it listed the drivers as MW7500s, but the parts list list them as 6500s, so go figure Something else strange about that file is that the S series speakers are in it for some reason.

http://www.polkaudio.com/downloads/m.../12CManual.pdf

[reeltrouble1]

I have this mental image of Stu, making up this crazed numbering system with smoke all around him and Hedy popping a cold one putting drivers where they fit.

Must of been one hell of a ride.

Everytime I think I have a handle on this a curve gets thrown in.

RT1