First SDA2's - Need help picking an amplifier

Swordphsh

Hi all, I'm purchasing my first pair of Polks tomorrow, SDA2. I'm trying to figure out what kind of amp is suitable to power them. I'm looking mostly on my local Craigslist and not sure whether to go with a stereo receiver (like the Onkyo TX-8511) or something more powerful, (I found a Kenwood Basic M2A). A receiver would be better suited for my setup, but I don't want to purchase the wrong thing. Most of the prices I've seen seem to run about $1 per watt.

According to the SDA2 seller, one of the woofers has a small tear, which I'll probably be posting about shortly.

Thanks in advance.

PreCd

Swordphsh wrote: »

Hi all, I'm purchasing my first pair of Polks tomorrow, SDA2. I'm trying to figure out what kind of amp is suitable to power them. I'm looking mostly on my local Craigslist and not sure whether to go with a stereo receiver (like the Onkyo TX-8511) or something more powerful, (I found a Kenwood Basic M2A). A receiver would be better suited for my setup, but I don't want to purchase the wrong thing. Most of the prices I've seen seem to run about $1 per watt.

According to the SDA2 seller, one of the woofers has a small tear, which I'll probably be posting about shortly.

Thanks in advance.

Are you talking about 2As, 2Bs, etc...

I have the SDA 2Bs.

You are going to get many options thrown at you here and that is a good thing. If you go receiver make sure it will drive low impedance loads and 200-250 wpch into 6 ohms and 300-400 wpch into the 4ohm dip. I personally use a Adcom GFA-555 amp with Adcom GFP-565 preamp which can be had for around $600 as a pair. If you want it to that amp will bring the speakers to their knees. But you don't want to do that. :cheesygrin:

Just do your research on the advice given here and you will do fine.

Swordphsh

I'm not sure which version they are, I'll find out tomorrow.

From what you're saying, I'm guessing something like that Onkyo would be insufficient? It looks like it only outputs 140wpc at 4ohms and 100wpc at 8ohms. The Kenwood I mentioned does 350wpc at 4ohm and 220wpc at 8ohm.

Sorry for the noob-ish question, but what difference would I see between the 140w vs 350w?

PreCd

Swordphsh wrote: »

I'm not sure which version they are, I'll find out tomorrow.

From what you're saying, I'm guessing something like that Onkyo would be insufficient? It looks like it only outputs 140wpc at 4ohms and 100wpc at 8ohms. The Kenwood I mentioned does 350wpc at 4ohm and 220wpc at 8ohm.

Sorry for the noob-ish question, but what difference would I see between the 140w vs 350w?

Noob questions are excellent and it was not that long ago I was asking a few myself. The important part is to gather what you are told, study it, and then make the educated decision.

The 140wpch @ 4ohms is not adequate for driving SDA2s of any breed. It will cause you nothing but heartache. The Kenwood sounds like a much better fit. If you buy a used receiver ask these questions: Any leaky capacitor issues and what is the offset voltage. You can read more on the offset voltage of the specific model when you decide on the model. The offset voltage is measured with the power connected, the receiver on, and no input source at the speaker out positions. Set your volt meter to vdc millivolts and check each channel.

Swordphsh

From what I've read, the speakers appear to be SDA2Bs Studio edition. They have one tweeter, two woofers, and a passive radiator. The "inner" woofer on the left speaker appears to have ripped around the center circle(?) and has some sort of rubbery glue in a circle about 2/3 around the center. When there is a lot of lower frequencies, that particular woofer sounds awful, almost like a very low crackling sound. The previous owner also replaced the right tweeter in the past few years, gave me the old one in case I knew how to repair it (not a clue).

I hooked them up temporarily to my Yamaha RX-v371. It's rated for 80w@8ohms (2ch driven). It doesn't seem to get overly loud and powerful, even upwards of 90% volume. I'm still looking for a permanent amplifier.

The previous owner misplaced the interconnect cable. The connections are blade/pin, my understanding is that a simple subwoofer cable is suitable, can anyone confirm?

Overall they sound pretty good. The wood finish has several nicks around the edges and corner and is starting to peel in certain spots....if anyone has a suggestion for fixing up these spots.

jaygax

i have the SDA2 speakers too. im not sure if its the 2a or 2b. they said the blade is just for support, so maybe a subwoofer cable will do the job for that IC cable. havent tried it yet because i dont know if my yamaha RX-A1000 is common grounded. you better watch out. dont let your yamaha burn. i just won a bid from ebay last thursday on an adcom GFA 555II amp. im expecting it on wednesday next week. so, my yamaha wont drive those main fronts anymore. and i expect a lot of musical change with the adcom amp.

anyway swordfish, we are on the same level. very NOOB! just starting out. heck, i even got lots of different speakers with my setup.
heres a list:
polk SDA2 = main fronts
klipsch quintet = front presence and back surrounds
klipsch synergy SC1 = center
polk RTi4 = side surrounds

my equipments:

PS3 500gb = upgraded. just took out the hard drive and put a new one in. google it.
dishnetwork
HTPC with 2tb HDD. = streamed to my PS3 via TVersity.
HP HDX18 laptop

what im planning to buy this black friday: epson 8350 lcd projector.

Swordphsh

That looks pretty sick. How do the SDA2s sound on that RX-A1000?

jaygax

i checked out the manual on my A1000. and it can support 4 ohms with 210 watts/channel on the fronts. so, i changed the setting into 4 ohms. theres a huge difference! its an audio NIRVANA for me now. i dont even have the adcom amp yet. but everybody's telling me here that an AVR wont do those speakers justice. thats why i was forced to get an amp. we'll see how it goes next week when i install the amp. i'll post some pics here too.

if you have PS3, get TVersity installed on your PC server. man, im enjoying those MP4 files with full 5.1 surround sound. i just downloaded those mp4 movies from demonoid. i have the pacific, band of bros, jurassic park, lord of the rings. full 1080p. im getting that projector too. its gonna be awesome!!!!

jaygax

right now, im torn between wether to build a six core AMD thuban with ATI6870s crossfired HT/gaming PC, or upgrade my hometheater setup by getting a projector. both costs a lot! i need to do some overtimes. but the wife wants the projector. she wont benefit from a gaming PC. so im getting my fingers crossed for a good deal on black friday at newegg for a projector.

oh, if you're still looking for a sub, i recommend the BIC PL200. 12" sub with 1000 watts. it shakes my house! loud but soft to the ears. oh yeah!!!!

nadams

PreCd wrote: »

The 140wpch @ 4ohms is not adequate for driving SDA2s of any breed.

I disagree... I'm driving mine with an Adcom GFA-545, which is only 100WPC.

Swordphsh- I see you made your way over to the forums . The Kenwood amp would sound a lot better than a receiver, but then you need a preamp, or a receiver with preamp outs. What size room are these going in? That makes a big difference on how much power you'll need.

Swordphsh

nadams wrote: »

The Kenwood amp would sound a lot better than a receiver, but then you need a preamp, or a receiver with preamp outs.

That Kenwood has a volume control...does that still require a preamp?

nadams wrote: »

What size room are these going in? That makes a big difference on how much power you'll need.

For the time being, they're going into a room about 15'x15' with two half-open walls, if that makes a difference.

The Onkyo seems like a good deal, he's asking $125 and claims it's brand new. They were $300 msrp and supposedly pretty high quality.

Nadams- are you using an interconnect cable on your setup?

nadams

Those level controls shouldn't really be considered "volume" controls. They're really just gain correction for each channel. I suppose you could probably use it without a preamp (especially if you're running all the sound through a computer), but it would be quite annoying to have to set two volume controls identically every time.

And yes, I am running the interconnect on my SDA's. It's required for the SDA effect, and on mine, the two outside woofers don't play without it. On yours, I believe both woofers will still work with it disconnected.