Just bought an SRS SDA 3.1, what should I know and watch out for?

notbananas

I'm picking up an SRS SDA 3.1 (s/n "SRS 3.1T L1396R" and "SRS 3.1TL 1707L") tomorrow which I paid $325 for the pair from the original owner. Somebody forgot to tell me these puppies are 155lbs each when I looked up the specs! Time to call the moving company :-).
I have a home theater system with a Yamaha RX-A301 receiver which is a 9.2 speaker config currently using a Martin Logan Quest for the main speakers. I also have a McIntosh MC2500 power amp which is 500W per channel into any load (2, 4, 8 or 16 ohms) which I think should be enough for these speakers. This amp is supposed to have an automatic disconnect from the speakers if it detect any problems (should I trust it?).
I read through the manual (if all else fails, read the manual) for the 2.3 version (I couldn't find the 3.1 version) to familiarize myself with the hookup and placement.
What do I need to know based on the serial numbers? Is there anything that's unique about these speakers that I should be aware of other than what's in the manual?

BTW, I started in audio before stereo was invented. Yes, in the early '50s, so I'm not a newbie in the audio/video field. I just learned many hard lessons which I don't want to repeat with these speakers.

Mike Reeter

First of all, congrats on your new 3.1TL's. They weigh closer to a 100 lbs. than 155 lbs. (the weight of 2.3TL's) Make sure your amp (amps) are a "Common Ground" design before powering up the SDA's. The 3.1's are a 6 ohm. load, so they are fairly easy to drive.

The set-up and placement are the same as the 2.3 version you have read about. Place them at 6"-12" from the back wall for starters, a little closer to the wall will increase the Bass output, 3' for each corner is ideal also.

The serial numbers are very seldom close to each other, as in numerical order, so no worries there, as long as you have a LEFT and a RIGHT.

Did the Interconnect Cable come with the pair? The cable that connects the two speakers together is a MUST to achieve the SDA effect.

The 3.1TL's are over 20 yrs. old, many members here including myself believe that replacing the original caps/resisters (along with some other modifications) is the only to hear the true potential of these wonderful speakers, you will have to be the judge of that.

Good luck.

zane77

Congrats on your new find and welcome to the club. Read the stickies in the Vintage section of the forum. There are some extremely knowledgeable folks on this site that seem to eat, breathe and sleep these vintage speakers, Your going to have a lot of fun with these, enjoy!

oldmodman

You have just purchased the last set of speakers you will ever need.
Well, not really, there are always the other different SDA models. "Gotta collect them all".
And you got them for the lowest price I have ever heard of them going for. Congratulations.
As other have already said, to get the most enjoyment out of them you need to use the interconnect cable and play around with speaker placement. A few inches closer or farther from each other, and from the wall behind them can make a huge difference.
And after listening to them for a while consider doing some or all of the "Mods" that others have done.
I have a set of the 3.1tl as well a set of the non tl 2.3s. And I will be doing the complete mods on the 3.1's before I even consider doing anything electronics wise.

soundfreak1

+1 on the recap... Just finished recaping my RTA 12c's ( 70 hours on them sofar) and am simply thrilled with the results ( even though them will keep getting better thru about 300 hours) well worth the effort and cost. Congrats BTW

GlennDog

Congrats on your "steal of the month" . . .

Welcome to CP, Bananas!!

brgman

Great speakers,Fantastic speakers once you do the mods.
You'll get all the help you need here except for the $$.

F1nut

SDA SRS 3.1TL - Weight (each) 101 pounds.

boston1450

Welcome to CP & enjoy your new to you speakers

pglbook

Welcome to CP.
You got some great speakers at a fantastic price!
Enjoy them!
Polk SDAs are incredible speakers!

chandler9a

that MC 2500 is plenty to drive those Polks but I would confirm if it is common ground first. Maybe give Audio Classics a call.

As others may have mentioned, the first thing I would do is purchase the tweeter upgrades from Polk, part number RDO-198. Call customer service and tell them you are a club member to get a discount, $48 each I believe. After that, there are plenty of great mods to do little by little and IMO they are all worth it.

Congrats on the purchase of some great speakers and welcome to the Club!

drumminman

Congrats and welcome to CP! Mods rule - spend some time with them as they are and then start the upgrades.

nspindel

Hi there. A common ground amp certainly makes your life easier, but it is not necessarily a show stopper. You can't use the stock SDA cable if you don't have a common ground amp, or you can cook your amp, and probably do some damage to the speakers as well. But you can use an isolation transformer based interface that Polk used to sell called the AI-1, which one of our members DarqueKnight did some incredible work improving. Search for the 'Dreadnaught' on this site. I am pretty certain, but others will correct me if I'm wrong, that 3.1 TL's can use the AI-1. You should do the research regardless of your amp choice, because many of us have come to the conclusion that the AI-1 Dreadnaught offers sonic improvements compared to the straight SDA connection, and would advise you to use it regardless of whether your amp is common ground or not.

I've been up and down the SDA's over the last 24 years, never got as high as 3.1 TL's, but I've settled back down to the CRS+'s, which are the smallest in the SDA line. I can tell you that if I'd ever stumbled across your speakers at that price, I would have owned them.

As others have said, if you've bought them from the original owner and he's never done any improvements to them, you should seriously consider doing some. At a bare minimum, you should do the tweeter upgrade as others have mentioned. You don't even need access to the inside of the cabinets for that, you just swap them out. But you should seriously consider upgrading your crossover electronics, particularly the caps and resistors. The caps degrade over the course of time, and at ~25 years old, they are well past their intended lifespan. They can degrade to the point where the electrolytic leaks out, and the corrosive material can do damage to your circuit boards. The resistors are relatively inexpensive, and are a great upgrade to do while you're already into the crossover boards. There are much better components that can be acquired today, and good quality caps and resistors will give you a noticeable boost in sound quality. And if you're not well skilled with a soldering iron, one of our members has lots of happy customers on this forum, and can build them for you.

Make sure to ask lots of questions at every step of the way before you touch anything, as we have plenty of experts here who have been through the grind with these speakers for many years. And if you do head down the upgrade path, apologies in advance for the impact on your checkbook....

leftwinger57

Good luck w/ your new speakers. I still can't believe you have a Mac 2500.A 2300 would do me just fine.