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Flathead38

Just picked up my first pair of Polk speakers and am excited to get them up and running. From my research here I have determind that they are SDA1's from 1982 as they have the 3 prong RTA 12 type interconnect cable. Paid $120 for them without grills or the interconnect cable. I will be taking them apart to refinish the cabinets and would like some input as to what else should be done to them. I have been reading here of all of the upgrades and it is a bit too much info to digest at once. I would like to budget myself and do the upgrades as funds become available. If you had to prioritize your upgrades in what order would you do them?
Also what are your thoughts about powering these with a Harman Kardon receiver with an output of about 100w?

TennMan

Welcome to the forum! Your first step should be getting an interconnect cable for them so you can get the best out of them. Without the IC you will not get any SDA. Once you have the IC in place you should listen to them for a awhile them to determine what work needs to be done to them next.

Flathead38

Can an interconnect cable be made up for this particular set up? I could image finding one of the 3 prong RTA 12 type cables is going to be difficult.

TennMan

Flathead38 wrote: »

Can an interconnect cable be made up for this particular set up? I could image finding one of the 3 prong RTA 12 type cables is going to be difficult.

I'm sure it can be made but I'm not familiar enough with that model to make recommendations on how to do it. I'm sure someone will be along shortly that can help you.

PolkieMan

I too am at a loss to answer your question about making the cable.
Make sure that your power is common ground once you hookup the cable.
The SDA Handbook will help get you started.
http://vr3mods.com/uploads/SDA_Handbook_2011_Rev2.pdf
Once you get them all hooked up with the cable then you can check
that each driver is functional, the empty paper towel tube works well.

Flathead38

Am I to guess that it is used as a stethoscope to listen to the drivers?

drumminman

Flathead38 wrote: »

Am I to guess that it is used as a stethoscope to listen to the drivers?

Yep, one end next to your ear and the other over the driver in question.

westmassguy

Welcome to CP. The three prong sockets and plugs should be replaced, with SpeakOn Plugs and Sockets, and you favorite 10 or 12 gauge speaker cable.
These are the Sockets: http://www.parts-express.com/neutrik-nl4mp-speakon-connector-4-pole-panel-mount--092-052
These are the plugs: http://www.parts-express.com/neutrik-nl2fx-speakon-connector-2-pole-cable-mount--092-198
You only need two conductors between the two speakers. The plugs I listed are 2 pole, while the socket is 4 pole. The 4 pole sockets are better constructed than the 2 pole version. The 2 pole plug will fit the 4 pole socket.
Installing them will require removal of the old connector, and enlarging the existing hole. Basic soldering skills will be required, unless you have the proper crimping tool for spade type quick disconnects. The SpeakON sockets take a 3/16" female spade, and the connection to the crossover should be a 1/8" female spade.
Once you get that finished, then you can properly check all the drivers.

Flathead38

Thank you for the info. Going to return the Radio Shack 3 prong XRL microphone jacks and 15 gauge wire I just purchased!

westmassguy

Flathead38 wrote: »

Thank you for the info. Going to return the Radio Shack 3 prong XRL microphone jacks and 15 gauge wire I just purchased!

You're more than welcome. When you receive the SpeakON Parts, make note of the polarity. The Plug's internal contacts are marked + & -, so both plugs must be wired the same. There's usually a mark or stripe on the speaker wire.
The sockets will have 4 contacts. You'll be using the +1 and -1 spades on the back. I'm not sure what color the original wires are on the old connector. Just make sure to connect the same color wire to the same spades on the SpeakON. The other end which connect to the crossovers, must be reversed on one. If this is not done, your amp will not like it.
You also asked about your Harmon Kardon Receiver, but didn't list the model. Any receiver or amp used with the SDA-1s MUST have a Common Ground, and MUST be able to handle 4 ohm speakers. You can contact the manufacturer, or do your own test for the common ground. A good Volt/Ohm meter can be used. Test the resistance between the two negative terminals on the back of the receiver. If it's below 1 ohm you should be fine. 100 watts/channel is not going to shake the walls. At best, you'll be able to listen to them at low to moderate levels if it's compatible. If it's an AVR type Receiver, they're not recommended, since all channels share the same power supply. Even in two channel operation, most AVRs will not have sufficient power available.

leftwinger57

Flathead, I had the original i/c for what's call 1987 SDA 2Bs. Once I got these speakers home I had no idea to the lenghts that one can make a great speaker sound even better.It's to bad I'm not familiar w/ your set so I could help more but follow what Westmassguy said and get the Neutrik base modules and what I call sleeves. 1 important thing always get more wire than you think your going to need because 1 for possible mistakes,2. for rearrangement of your gear 3. cleaning and 4. moving. When I did mine more definition was heard and like I said for something like $16 w/ shipping and the wire it's an easy mod plus your missing what those speakers are meant to do.I'll list my sig so you can see the extent of what I did and there are even more technical mods like doing x-overs ,binding posts and internal wire which I have not done.Welcome to the club,ask away and there is so much info both w/ tutorials and just threads it will take you months to get through it all it's that comprehensive.

Mr. Bubbles

welcome to the forum. Am not familiar with any of the 1st gen stuff (I assume that is what you have due to the 3 pin interconnect) other than just listening to them but I am sure you will enjoy the ride. Many great mods and a lot of very knowledgeable folks here to help you spend your money....Um I mean.... preform those mods. Congrats on the purchase.

Flathead38

Thanks to all for the information. The Citation receiver has no designation. The owners manual only states Citation Receiver. It was manufactured only in 1977-78. It is also dual powered, I haven't figured that one out as of yet!
I probably with complete the interconnect cable and while I have them open, replace the binding posts. What should I remove to do this work, the passive driver?
Another question for the experienced ones, the wooden stands on the bottom need replacing, not a difficult job by any means, but what about the thought of removing the stands and adding outriggers and spikes to elevate and stabilize the speakers. They will be on wood floors.
Thanks again.

westmassguy

Replacing the Binding Posts on that model is a PITA, unless you're upgrading the crossovers at the same time. The lower half of the crossover is mounted to the back of the Binding Post Cup. Unless the Binding Posts are broken, I'd leave that one till you're ready to upgrade the crossovers. Access to the cable connections and everything else is more or less through the Passive Radiator.
The raised base should be tossed, and spikes installed. You can spend a lot, or not so much on spikes.
These are the spikes and pucks I use for my 2As, which have a similar footprint:
http://www.ebay.com/itm/380442488663?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
http://www.ebay.com/itm/380442486449?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
You'll be hard pressed to find solid copper spikes for this price, for a set of eight.