SDA SRS 2 need CPR and ICU life support

Schurkey

proffitt wrote: »

does anyone have an opinion on a used ATI model AT-1502 amplifier? Decent or junk? For a $500 budget?

First Guess: The ATI is a fine choice provided you confirm that it is common-grounded, and it's in serviceable condition.

Never seen one in real life; can't find specs on the ATI web site. Brochure looks good, though.

PolkieMan

What about this?

http://shop.emotiva.com/collections/amplifiers/products/xpa2

proffitt wrote: »

Hi All. I'll get new pics up soon. One speaker electronically complete. reinstall next and I don't think my low crossover is going to fit back in without the passive radiator hitting it. Think I'll have to remove the two largest caps and mount in the cabinet on the vertical brace like I saw a pic somewhere that someone did. With all your help the mods we relatively easy.

I'm thinking of temporarily leaving one speaker unmodded. You might recall, I've never listened to these speakers before. I'd kind of like to hear the difference. And then mod the other one. That brings me to the need of an external amp.

I'm buying my first external dedicated amplifier for these newly modded SDA SRS 2 set. And I dont think my Onkyo TX-SR505 has the muscle to handle the job. I also have to figure out if it has pre-outs that i can run to an amp, allow that amp to drive the SRS2 set in stereo for music listening... and then for HT, that set would be the fronts and the Onkyo would drive the rest of the surrounds, center, etc. in the HT set up. Does that sound like a good plan?

So along those lines, does anyone have an opinion on a used ATI model AT-1502 amplifier? Decent or junk? For a $500 budget?

Thanks for input.

Schurkey

PolkieMan wrote: »

What about this?

http://shop.emotiva.com/collections/amplifiers/products/xpa2

I'd much rather buy a used-but-usable American/North American/Free World amplifier than a brand-new Communist Chinese unit.

rsxman

Schurkey wrote: »

I'd much rather buy a used-but-usable American/North American/Free World amplifier than a brand-new Communist Chinese unit.

huh....ya....a lot of high end amps are made in china....but i get what you mean....a usa made amp thats older does have a certain amount of pride that goes with it

proffitt

Schurkey... Your pointing out of the Emotiva made me look into that brand closer. Sounds like it gets good reviews. So I looked around at other emotiva models too. Found one in town used that seems a good deal too. So here's my question... And it revolves around how much power to get over the hump from good to great with the SDA SRS 2 set. One amp would give me 200 watts per channel for 3 channels. And cost me $450. Another bonus is that it gives me a third channel for the center channel. The other amp is 300 watts x 2 channels. Doesn't give me the center channel coverage. And cost is $680. So my question is does 300 watts give the SRS 2 so much more performance than the 200 watts? Will the 200 leave me wishing I had gone with 300? Or does the 200 watts get it over that hump?

Schurkey

proffitt wrote: »

Schurkey... Your pointing out of the Emotiva made me look into that brand closer.

Credit goes to PolkieMan, not me.

proffitt wrote: »

Sounds like it gets good reviews. So I looked around at other emotiva models too. Found one in town used that seems a good deal too. So here's my question... And it revolves around how much power to get over the hump from good to great with the SDA SRS 2 set. One amp would give me 200 watts per channel for 3 channels. And cost me $450. Another bonus is that it gives me a third channel for the center channel. The other amp is 300 watts x 2 channels. Doesn't give me the center channel coverage. And cost is $680. So my question is does 300 watts give the SRS 2 so much more performance than the 200 watts? Will the 200 leave me wishing I had gone with 300? Or does the 200 watts get it over that hump?

The mistake is thinking there's some magic "hump" that has to be gotten over in order to get "from good to great" sound.

Polk speakers were advertised as "easy to drive" provided they had common-ground amps with suitable current (amperage) capacity to deal with the 4- or 6-ohm nominal load.

My 1Bs spent the first six years of their lives being powered by a 120-watt **** receiver. The only time I had problems was after the receiver started to go flaky, and even then only at higher volume.

How loud do you plan to play the peaks? How big is your room? That's how many watts you need. More realistically, that's how many volts you need, with enough current capacity to assure that the voltage isn't affected by the low-ish speaker impedance.

In particular regarding Emotiva; I avoid supporting Communists wherever practical. At least you're thinking of buying it used. Better to avoid it altogether, there are still Free World alternatives.

proffitt

Polkieman... sorry for the miscredit. Thank you too.
Hey Schurkey... thanks for even more great input. I appreciate it. I too feel your pain on supporting the communist economies. I guess i should feel it more. But if its used.....

I hear you about there not being that "magic hump". I guess the better way to ask it would have been... would 100 more watts above 200, give me the same enjoyment adder, as the first 200 watts. There's got to be a leveling off of power that at some point the SRS 2 has peaked... it could take more, but it doesn't really sound better, just louder.

My plan for the room is 75% HT, and 25% 2 channel music. The rom is 15 ft wide and 40 ft long. Its an open home theatre that the back is open into the basement den/bar area. The system would go on the 15 ft wall. Carpeted, finished, furniture, etc.

Loud yes, but not oppressive, but i do like to feel my movies, and the music is from Zeppelin, Floyd, Stones, to Big Head Todd, Toad, and Nickelback.

I'm thinking I'll want to enjoy the 3rd channel, and that 200 watts is probably plenty. But I have no reference. 300 is alot more than 200 and I wonder if i would appreciate that extra power if I went with the 300... appreciate it enough to not to have the 3 channel for center.

Mystery

proffitt wrote: »

...And I dont think my Onkyo TX-SR505 has the muscle to handle the job.

I had TX-SR505 until few weeks ago powering RTA-12C and I could never go past 75% volume as it would be very loud and start shaking walls. So yes it can power it fine unless you are using them in very large room.
However, it's always better to get high current dedicated amplifier that can work below 4 ohms not only for power handling but also for cleaner sound than average HT A/V receivers.

Schurkey

proffitt wrote: »

I'm thinking I'll want to enjoy the 3rd channel, and that 200 watts is probably plenty. But I have no reference. 300 is alot more than 200 and I wonder if i would appreciate that extra power if I went with the 300... appreciate it enough to not to have the 3 channel for center.

You're using the wrong scale.

Stop thinking in terms of watts, start thinking in terms of dBW.

http://www.rapidtables.com/electric/dBW.htm

200 watts = 23.01 dbw

300 watts = 24.77 dbw

Not much difference at all.

proffitt

Wow, great info again guys. This group just keeps on giving.

Finally something i have a reference on and can relate to. Thanks Mystery for noting the same AVR and commenting.
And Schurkey, you make a great point and if the dBW is that similar, I'm going with the 200w x 3 channels and have room to throw in my center channel in there too. And saves me nearly $250. Thanks all!!!

Oh, by the way, i finished all the electrical / electronic mods last night on the first speaker. And got the crossovers on that cabinet remounted. I'm going to photo document the other one as it goes, and post here, with parts list and any gotchas.

Thanks to you all, I finally "got it" and moved through it. It wasn't that difficult, and its remaining very fun. I've still never heard a POLK SDA SRS of any kind. So I'm going at this completely blind...but very anxious for the outcome.

You should see how the wood turned out (you will soon stay tuned in). I think it was F1Nut that inspired me to keep it near original, and i did, walnut with Red Mahogany stain, warm with just a hint of red. They are gorgeous.

Mystery

Schurkey wrote: »

You're using the wrong scale.

Stop thinking in terms of watts, start thinking in terms of dBW.

http://www.rapidtables.com/electric/dBW.htm

200 watts = 23.01 dbw

300 watts = 24.77 dbw

Not much difference at all.

+1.

3db difference is as louder as our ears can detect volume change.
So it's a very slight change and that needs twice the power.

Basically, you'll never even use over 10-100 watts unless you are covering your ears and turning the volume knob just for testing.

I was temporarily deaf from Polk S4 when I switched input on the Onkyo TX-SR505 from aux input ( that was playing music from my phone and I had to turn the volume past 54) to DVD input that had way high output and S4 just blasted past bearable levels. :eek:

F1nut

Your pointing out of the Emotiva made me look into that brand closer. Sounds like it gets good reviews. So I looked around at other emotiva models too.

You're their ideal customer, the one that has never owned an amp before.

proffitt

UPDATE: The first one is finished. Take a look.

Whew. That was certainly a labor of love, but i think it'll be worth it.
When I first got them, the wife unit couldn't even believe I was bringing those nasty things in the house. But a full overhaul and she saw them last night and was floored. They still can't visit the living room, and are banished to the basement, but that's fully because of their size. I'll tell you what... the first one took a long while, but the second one is going very quickly.

With the second one, I'm photo documenting and capturing everything and going to post here a "Layman's How-to". Coming soon.

But the anxiety to hear these things has inspired me to go ahead and finish off the theater room in my unfinished basement, and has gotten spousal approval as well. For that too... I love my SDA SRS's, (and I've still never heard them).

Two of my four new tweeters arrived damaged. The connector posts were broken off and rattling around in the bottom of the box. The "thread" filament looks too small to solder. I mean, it doesn't even look like wire, but very small thread. Any suggestions on DIY fix? Or back to Polk?

drgalexo

Beautiful job prof, I would send the damaged ones back to Polk.

tommyt21

Great work!

Mystery

Looks like CPR and ICU saved them. :biggrin:
Good work!

TNHNDYMAN

Lookin good Profit

helipilotdoug

Very Nice!! All your hard work is well worth it

bikezappa

It lives again!

proffitt

OK... so starts the modifications to the second speaker. Of course I did all the wood and fabric panels at the same time. The wood and panels are waiting to be installed, and those are all pretty self explanatory especially from the previous posts.

So I want to start here, and document for others, the mods, with pictures, with thanks to many here for enlightening me.

First... I removed the drivers, tweeters, and PRs. Removed the binding post cup and the Interconnect (IC) port (mine was blade/blade). There's lots of glue on the inside of the IC connector, so you'll first disconnect the wires from the crossover on the inside, IDENTIFY THEM with tape!, and then unscrew the connector screws holding it in from the outside. You'll have to pry it up and then pull the wires through the glue one at a time. I replaced the IC connector because I didn't have the IC cable, and went with a Speakon cable with Neutrik connectors. Here it is coming out.

Now, to replace, most likely the connector you choose will be a greater diameter than the hole left by the factory original IC. Drill it out larger, but here's the problem...a hole drill or spade bit will not stay centered trying to enlarge an already existing hole. And you don't want to drill from the inside as it will break and magle the edges when it exits the side we want to keep clean.

So here's what I did. Get your spade bit, and find a pen or something that the inside diameter is the same as the point of the spade. Then find a standard drill bit the same size as the pen. Drill the center of the IC hole with the drill bit. Doesn't have to be exactly centered, but close. But it needs to be a tight fit. Then hammer in the pen into the hole you drilled. This pen will give you a stable hole to keep the spade bit stable.

I'm sure there is a tool for this, but if I don't have one, half of you won't either, so this will work at midnight when you don't have exactly what you need.

More to come.

F1nut

Dremel is your friend.

pitdogg2

you can also use a hole bit. you know the ones that have a drill bit in the center then connect to a round arbor...with those the trick is you go in reverse to get the larger hole started then go fowards after you get it started it will go right through.

example:
http://www.sears.com/shc/s/search_10153_12605?vName=Tools&keyword=hole+saw&viewItems=25&autoRedirect=true&redirectType=CAT_REC_PRED&prop17=hole%20saw&sid=ISx20070515x00001a&psid=21x1337694&knshCrid=30422128777&k_clickID=3f895f55-c2a1-8869-aa9e-0000267ecbe4

bikezappa

nice tip pitdogg

proffitt

I had one of those hole saws too but the center bit wasn't long enough to reach the bottom of the hole. The hole saw touched the sides befor the center bit started into the center.

pitdogg2

proffitt wrote: »

I had one of those hole saws too but the center bit wasn't long enough to reach the bottom of the hole. The hole saw touched the sides before the center bit started into the center.

This is the exact reason i gave the instructions i gave. The instructions were for a hole that is too big for the centering bit. Go slow in reverse until you make a groove so the hole bit don't jump all over the place.

proffitt

oh, i see. I should have read it more closely. I saw the hole saw, but it would walk all over the surface too. Then i read more closely, hole saw... AND reverse. ok, good tip. Thanks.

pitdogg2

proffitt wrote: »

oh, i see. I should have read it more closely. I saw the hole saw, but it would walk all over the surface too. Then i read more closely, hole saw... AND reverse. ok, good tip. Thanks.

go from inside that way if it does walk a little it will not show. I've done this a bunch after an old carpenter scolded me for making a mess of something.....it's ok they were just Cerwin Vegas

proffitt

New IC connector. I used clear silicone sealant instead of hot glue on this, in case i ever had to remove it again. sealant to make sure there are no air leaks. Sealant in the hole, and then built up just a little on the inside.

bikezappa

you should hook up the finished speaker to an ampifier to hear it.

Hate to make the same mistake, if any, twice.

proffitt

Here's the part that I think would have helped me the most. Everybody here has been a HUGE help. But let me take from that, build on it, and help the next nube just a little too.

Here is the hi and lo before mods:

Here are the old components that have been removed (left), compared to new components (right) they replace, before they go on. This first picture is the high crossover:

for the high crossover, its pretty easy, just mark the solder pin hole on the circuit board, on each end of the component. I lettered each component A, B, C, etc. Then lettered the two corresponding holes for each component. A and A, B and B, C and C....and its pretty easy. The very last component on the image, is a 3.5 ohm resistor on the old version. I was given a list of components to buy and was real confused that i had way too many components. The list it turns out, was to give me options on what to replace this 3.5 resistor with. After reading what much smarter people than i opined... i decided to try the 2.5 ohm resistor here to start with. Who knows if I'll ever change it, but i know i could.

And the same for the low crossover, old left... new right.