Using SDA-SRS with a Non Common Ground Amp

Rag Top Day

Sent a note to tech support but thought I would check here also. I have an older pair of Polk SDA-SRS speakers left 4144 and right 3137 which I love. I had to take off the interconect cable a couple of years ago due to the Aragon Paladium amps I am using that were causing a ground problem because they are not common ground amps. I wanted to check in and see if anyone had a "fix" for this or could give me the name/part number of the kit that Polk used to correct this issue. I wanted to buy one but as I recall they were no longer available. Checked with Aragon and they said amps are monoblock and could not make them a common ground. Thanks for any input

heiney9

There isn't a fix. The older SRS's can't be used with non-common ground amps. Newer SRS's (1.2, 2.3, 3.1) can use the AI-1 isolation transformer to enable use of non-common ground amps.

You will need to use a common ground amp since the alternative is to check with the manufacturer to see if the mono's can be strapped together to make a common ground. You asked Aragon and it can't be done.

H9

Rag Top Day

Thanks for the info. Looks like I need to buy another pair of amps, or find someone who wants to trade an Aragon 8008 MKIII for a pair of hardly used Aragon Paladium Monoblock amps :sad:

heiney9

If you insist on Mono's do your homework to make sure they can be strapped.

H9

Rag Top Day

heiney9 wrote: »

If you insist on Mono's do your homework to make sure they can be strapped.

H9

This is the email I got from Aragon,
Hello Michael,

According to what I read on the Polk forums, the SDA-SRS cannot run with monoblock amps. They require common ground amps to work correctly with the speaker interconnect cable. An 8008 could work, assuming the two negative speaker posts are connected together.
However, connecting two monoblock Palladium negative speaker posts together will be a problem as the negative posts are driven by the amp as are the positive posts. I'm not sure about a workaround since I haven't seen a published schematic on these speakers. It MAY be possible to ground the negative input side of an XLR input amp and use a Tee network to connect the negative posts together AC-wise with a cap to block DC. In any case, the Palladium power output would be severely limited in this configuration. (You'd experience less power than when you drove the speakers without the interconnect cable).

Hope that helps - sorry I don't have better news.

Thanks,
Rick
Looks like the 8008's would work but I think your right I need to start looking into this forum and find out which amp/amps (bi-amp?) would be the best choice for these speakers. I will not trust Stereo Design Sales staff this time for my amp choice! I'm sure some people here will have some great ideas for my amp choice!
Thanks H9 for your help with my issue!

heiney9

I don't think you can bi-amp either, as original SRS's have only one set of binding posts. I haven't looked at the back side of a pair of original SRS's in quite some time so someone will correct me if I'm mistaken.

Good luck with your search for amp or amps that will work

H9

Rag Top Day

oops picture upside down
These have dual posts on this model.

Phasewolf

What's the 1k resister for?

Rag Top Day

Phasewolf wrote: »

What's the 1k resister for?

It came loose with the speaker and I can not remember why it was put in. I sort of remember the tech support guys telling me to use it but for the life of me I can not rember why.

Schurkey

1. Aragon Palladium, Palladium II, and Palladium 1K amps are BRIDGED. They CANNOT be turned into common-ground amps; they cannot be "strapped" together in any meaningful way.

2. The only way to use bridged amps with the older SDAs is to remove the SDA crossover interconnect...as you've discovered.

3. Aragon 8008ST or 8008BB amps can be used, but must have a jumper tying the two channel's negative terminals together. There is ~20 ohms resistance between the otherwise common-ground amp modules; I guarantee your speakers will sound like **** without the jumper in place. This is probably also applicable to 8002, and 8008X3 and 8008X5 amps as well--the two channels supplying the SDAs will have to be strapped. HOWEVER, I have not used those amps, and have not confirmed the need for the jumper.

I'm in the same boat--have Palladium II amps to use, but my 1B speakers won't tolerate the monoblocks. Re-wired the speakers internally to use an AI-1; but the rewiring affects the sound quality enough that I switched 'em back.

If it were me, I'd drop that resistor like a broken rubber.

Do you have the original (flat-faced) Palladiums, or the newer (sculpted-face) Palladium II or 1Ks?

Rag Top Day

Schurkey wrote: »

1. Aragon Palladium, Palladium II, and Palladium 1K amps are BRIDGED. They CANNOT be turned into common-ground amps; they cannot be "strapped" together in any meaningful way.

2. The only way to use bridged amps with the older SDAs is to remove the SDA crossover interconnect...as you've discovered.

3. Aragon 8008ST or 8008BB amps can be used, but must have a jumper tying the two channel's negative terminals together. There is ~20 ohms resistance between the otherwise common-ground amp modules; I guarantee your speakers will sound like **** without the jumper in place. This is probably also applicable to 8002, and 8008X3 and 8008X5 amps as well--the two channels supplying the SDAs will have to be strapped. HOWEVER, I have not used those amps, and have not confirmed the need for the jumper.

I'm in the same boat--have Palladium II amps to use, but my 1B speakers won't tolerate the monoblocks. Re-wired the speakers internally to use an AI-1; but the rewiring affects the sound quality enough that I switched 'em back.

If it were me, I'd drop that resistor like a broken rubber.

Do you have the original (flat-faced) Palladiums, or the newer (sculpted-face) Palladium II or 1Ks?

I have the new Palladium II silver with the v notch face with the Aragon 28K MKII
pre amp.
Thanks for the tip on the 1k I had forgot about it as the system has been dormat for the last couple of years.

I am stuck on what to do now that I either change amps or leave the interconect off.

gimpod

Things like this make me sad. First get rid of that resistor, it was most likely used as a misguided attempt to tame the harshness of those SL-2000 tweeters. Replace them (The SL-2000's call Polk and mention your a CP member for free shipping and a discount) with the RD0-194's you'll thank yourself latter. Second dump those mono block amps and get a good high current common ground amp. Third plug that Inter-connect cable back in, as it is now your not getting anywhere close to the full potential of those SRS's . Just my $0.03 worth.

bluecomet

I totally agree with gimpod. Get a kick **** common ground amp and connect the cable. I had the original SRS speakers and hooked it up to a Luxman M-117 amp and that woke up those bad boys in a serious way. Lose the SL2000 they can get harsh after awhile. RDO 194's are the only way to go on that speaker. You need to crank it up to really feel what these speakers can do and will need those 194's. Trust us.

F1nut

gimpod wrote: »

Things like this make me sad. First get rid of that resistor, it was most likely used as a misguided attempt to tame the harshness of those SL-2000 tweeters. Replace them (The SL-2000's call Polk and mention your a CP member for free shipping and a discount) with the RD0-194's you'll thank yourself later. Second dump those mono block amps and get a good high current common ground amp. Third plug that Inter-connect cable back in, as it is now your not getting anywhere close to the full potential of those SRS's . Just my $0.03 worth.

Word!

Rag Top Day

Ok first thanks for all the info. Talk about feeling like I'm in the deep end of the pool. Being new here I really appreciate all the help so let me ask for some more if you do not mind.
This is a picture of the tweets in my SDA's They say Polk Audio Silver Core Dome. I assume these are the SL-2000 version? So I need 8 of the RDO-194's. Any idea on club pricing? Polks service center is just down the road from me, wonder if I could pick them up there?

Before I can update these speakers I need to replace those damn mono block amps. I know there are tons of amps out there to choose from but is there one that seems to work especially well with this speaker design? Am I going to want to Bi-Amp them?
Again thanks for all the help!

inspiredsports

Rag Top Day wrote: »

I have the new Palladium II silver with the v notch face with the Aragon 28K MKII
pre amp.
Thanks for the tip on the 1k I had forgot about it as the system has been dormat for the last couple of years.

I am stuck on what to do now that I either change amps or leave the interconect off.

Your third option that might you might have overlooked would be more economical than buying/selling amps.

You could consider selling your SRS's and purchasing a Polk model that can handle the AI-1.

Your current tweeters ar definitely SL2000's. RDO194-1's are I believe still $48 USD delivered if you call Polk Customer Service at the number top right and mention you are a member of Club Polk.

musky1963

I was also wondering as I have a beautiful 1979 Nikko Alpha VI at 300wpc. So I cannot use this with the original SDA SRS?

heiney9

musky1963 wrote: »

I was also wondering as I have a beautiful 1979 Nikko Alpha VI at 300wpc. So I cannot use this with the original SDA SRS?

If it's non-common ground, then no.

H9

headrott

Schurkey wrote: »

1. Aragon Palladium, Palladium II, and Palladium 1K amps are BRIDGED. They CANNOT be turned into common-ground amps; they cannot be "strapped" together in any meaningful way.

2. The only way to use bridged amps with the older SDAs is to remove the SDA crossover interconnect...as you've discovered.

3. Aragon 8008ST or 8008BB amps can be used, but must have a jumper tying the two channel's negative terminals together. There is ~20 ohms resistance between the otherwise common-ground amp modules; I guarantee your speakers will sound like **** without the jumper in place. This is probably also applicable to 8002, and 8008X3 and 8008X5 amps as well--the two channels supplying the SDAs will have to be strapped. HOWEVER, I have not used those amps, and have not confirmed the need for the jumper.

I'm in the same boat--have Palladium II amps to use, but my 1B speakers won't tolerate the monoblocks. Re-wired the speakers internally to use an AI-1; but the rewiring affects the sound quality enough that I switched 'em back.

If it were me, I'd drop that resistor like a broken rubber.

Do you have the original (flat-faced) Palladiums, or the newer (sculpted-face) Palladium II or 1Ks?

I can absolutely confirm that you need a strap with the 8008bb. I own one (and at that time a pair of 3.1TL's I was using it with) and used a strap for a while which worked.

Greg

cstmar01

I have a pair as well of the SRS's and found my parasound HCA2200 drove them just fine and get louder than what I could bear...

that said Parasound Halo series is a step up and great amps. Can find the A21 for around 1500 bucks or so used and are great amps. All Parasounds are common ground so no need to strap.

I only paid 500 bucks for my Parasound and it works very well. I wouldn't say I have the need to bi amp at all as I feel it does well as is.

Schurkey

Rag Top Day wrote: »

Before I can update these speakers I need to replace those damn mono block amps.

PM sent. Palladiums make me moist.

PolkClyde

wow. I'm glad I have the 1.2's according to RT1. He strapped the two negative together of my Carver silver 7t's mono block. they are still singing like a bird. for many years the negative of the amps were not connected or strapped together. The lord was with me it's time for new Amps when I get back on my feet.Well, I'm on my feet but walking slowly.

autoconsortium

I have Lexicon 501 monoblocks (aka Bryston 7b) strapped grounds (used heavy gauge solid core electrical wiring) have for years. No issues, sound incredible on sda srs.

F1nut

autoconsortium wrote: »

I have Lexicon 501 monoblocks (aka Bryston 7b) strapped grounds (used heavy gauge solid core electrical wiring) have for years. No issues, sound incredible on sda srs.

Alex, it may interest you to know it has been found by more than a few that using the AI-1 or a custom version yields better results than strapping.

headrott

F1nut wrote: »

Alex, it may interest you to know it has been found by more than a few that using the AI-1 or a custom version yields better results than strapping.

Yes, I can say without a doubt that the AI-1 is better than strapping the grounds on the amp.

Greg

Tour2ma

First, this multi-quote tool is really cool...

heiney9 wrote: »

I don't think you can bi-amp either, as original SRS's have only one set of binding posts. I haven't looked at the back side of a pair of original SRS's in quite some time so someone will correct me if I'm mistaken.

I assume you know from the posted pic that you have been corrected...

gimpod wrote: »

-First get rid of that resistor, it was most likely used as a misguided attempt to tame the harshness of those SL-2000 tweeters.
-Replace them (The SL-2000's call Polk and mention your a CP member for free shipping and a discount) with the RD0-194's you'll thank yourself latter.
-Second dump those mono block amps and get a good high current common ground amp.
-Third plug that Inter-connect cable back in, as it is now your not getting anywhere close to the full potential of those SRS's . Just my $0.03 worth.

Agree on three of four recommendations (by my count)... Disagreement is with the urging to replace the 2000's (mine is an admittedly minority opinion). While they have a well-documented FR hump around 13kHz (IIRC), they're hardly harsh, IMO. Bright? Forward? Yes and yes, but not harsh.

RTD,
If you've enjoyed your SRS's all this time (original owner?), you might not like the change. The 2000's are brighter to be sure, but with the right amp they definitely work.

For me and my SRS's the right amp was/ is Sunfire. Sunfires have dual speaker outputs. You can tap the smoother, tube-amp mimicking, "Current" posts for the tweets and the pure SS sound, "Voltage" posts for the MW's in a bi-wire set-up. In my case I opted for the Signature Cinema Grand, so I bi-amp with the above output arrangement.

F1nut wrote: »

Alex, it may interest you to know it has been found by more than a few that using the AI-1 or a custom version yields better results than strapping.

Very true... not sure why owners of any tl model would strap with the AI-1 option on the table.

What is the current Club standard for AI-1 design? RT1 had his Dreadnaught (sp?) a while ago, but seems like DK's monster with the off-axis inductors my have superseded it... yes?

heiney9

Tour2ma wrote: »

I assume you know from the posted pic that you have been corrected...

Yes, that's why I said correct me if I'm wrong, what's your problem, Bruce? You going to quote me all over the board and be an a$$ about it? It seems like you have some sort of problem with me or my posts. Maybe I'm reading it wrong but I doubt it.

H9

heiney9

The sl2000 tweeter is horribly harsh even with the "right gear". Do yourself a favor and buy the RD0194-1 and if for some reason you don't like the sound you can flip them for little loss. I doubt you won't like them unless you are a ****. :biggrin:

H9

autoconsortium

I don't have 1.2's. I have tried to change my profile signature but am too stupid. I thought they were when I first got them, that's why that's in my sig. I have SDA SRS with the blade blade connector. It says SDA-SRS 1095 on the back panel. If there is some other way than strapping grounds, I'd be more than open to it. I've had these speakers paired with the Lexicon non-common ground 501's this way since about 2004 and they've had loads of playing time with no issues. Well, I take that back...recently, one amp is a bit hotter than the other all the time. Also, I am experiencing the right channel not being as loud...but this happened exactly when I ditched my adcom for a lexicon preamp...so it's probably that unit. Not a big difference, but it's there. I certainly hope I'm not doing damage to these amps over time because I absolutely love them (they have GOBS of power and are warm sounding) and they were mucho $$$$

autoconsortium

There...fixed it.

vstarkwell

heiney9 wrote: »

If it's non-common ground, then no.

H9

Not to hijack this thread but I'll picking up a pair of SDA's this weekend and the lady isn't sure if they're SRS or just SDA 2's. I was curious as to the "common ground" question. Will my Sansui AU-717 work on SDA 2's and or the SRS?