SDA SRS1.2TL Ohm Graph???

nikolas812

Does anybody have a graph on the 1.2TL 8ohm version speakers that can tell how low the dip on the ohms??

I'm wanting to run two XPA-2's bridged at 1K a piece. There only rated at for 8ohm speakers when bridged. But can handle dips as low as 5ohms when bridged.

So I guess the bottom line is. Will they dip any lower than 5ohms?





Nik

DarqueKnight

Polk is very secretive about this information.

The specs for the TL series SRS's only states that they are "compatible with 8 ohm outputs".

When I (and others) asked what exactly does "compatible with 8 ohm outputs" mean and if impedance response charts were available, we were told, by Ken Swauger, that such information is proprietary.

Systems

If you bridge your amps they cease to be common ground,thus not suited for SDA use unless used with an A1 .

me_myself_I

nikolas812 wrote: »

Does anybody have a graph on the 1.2TL 8ohm version speakers that can tell how low the dip on the ohms??

I'm wanting to run two XPA-2's bridged at 1K a piece. There only rated at for 8ohm speakers when bridged. But can handle dips as low as 5ohms when bridged.

So I guess the bottom line is. Will they dip any lower than 5ohms?

Nik

Is there anybody with a pair of these speakers in Silicon Valley? I have the tools to plot the impedance. You need a signal generator, power resistor, and a oscilloscope to do it the hard way.

There's one more possible way for getting a decent approximation. Let me think about it....

nikolas812

GV#27 wrote: »

If you bridge your amps they cease to be common ground,thus not suited for SDA use unless used with an A1 .

Really? Because its a stereo amp.

I thought only mono blocks were not common ground.


The amp I have is common ground. I've been using it for a week or two now.

Are you saying if I bridge it. It will no longer be a common ground?



Nik

nikolas812

DarqueKnight wrote: »

Polk is very secretive about this information.

The specs for the TL series SRS's only states that they are "compatible with 8 ohm outputs".

When I (and others) asked what exactly does "compatible with 8 ohm outputs" mean and if impedance response charts were available, we were told, by Ken Swauger, that such information is proprietary.

I wonder why?






Nik

leroyjr1

Yes they're common ground amps but thery're not grounded to each other when bridged and running two of them.

You might want to talk to Ben. I was trying to do the same with my two Adcom 555II ( bridged) and he told me it'll blow my amps.

nikolas812

Hmmm.


Seems like another question for emotiva...


Maybe I can strap the grounds..



Nik

heiney9

nikolas812 wrote: »

Hmmm.


Seems like another question for emotiva...


Maybe I can strap the grounds..



Nik

You can not strap the grounds on a stereo amp running in bridged mode. I would NOT recommend running them with SDA's even if you HAVE an AI-1 cable. SDA's dip pretty low and because of the SDA properties and the way the interconnect is wired it does put more stress on the negative side of an amp. Bridged stereo amps see 1/2 the load and it would be a real stress on them (the above statement is IF you own an AI-1 cable). So if you bridge a stereo amp and run it with full 8ohm speakers the amps is actually seeing a 4 ohm load. So if the speakers dip to 6 ohm or 4 ohm load then the bridged amp is seeing 3 and 2 ohms respectively. Not a good thing for a bridged amp.

H9

P.s. well you could but I'd wait until the 4th of July 2010, because it could be one helluva show

nooshinjohn

why not just bi-amp them instead?

nikolas812

nooshinjohn wrote: »

why not just bi-amp them instead?

Thats still not out of the question and might be what has to be done.

If I have to I'll just vertically bi-amp them. Because I'm sticking with the amp(s)





Nik

Systems

nikolas812 wrote: »

Are you saying if I bridge it. It will no longer be a common ground?

Yes thats what I'm saying.When you brigde the amp the negative terminals(ground) are no longer used.Instead the positive terminals for each channel are used( one is inverted 180 degrees) neither of which is tied to ground thus it is no longer common ground.

beemer

Another reason why I like the QSC PLX 3402. Rated for use at a 2 ohm load in stereo mode, and rated for a 4 ohm load bridged. At 700W/channel at 8 ohms in stereo mode, I see no need to add a second and bridge it with the 1.2tl. A capable and well-designed power supply as well. Many "high-end" home audio amps can't match this.

Last but not least, it sounds great. I know this, because I've heard it.

I fully understand that you wish to stick with what you have, however you may get a chance to try one.....
Best to ya no matter which way you go......it's all about the music.

Best,

Paul
"President" of the lead dogs, and "President" of the "BOZO" list

Systems

beemer wrote: »

Another reason why I like the QSC PLX 3402. Rated for use at a 2 ohm load in stereo mode, and rated for a 4 ohm load bridged. At 700W/channel at 8 ohms in stereo mode, I see no need to add a second and bridge it with the 1.2tl. A capable and well-designed power supply as well. Many "high-end" home audio amps can't match this.

An SMPS mated to a Class H output stage can get you lots of power,cool operation within a compact chassis but is not usually a good recipe for sound quality.But having not heard it myself must take your word for it,with your very impressive equipment list I suspect you might be a good judge of sound quality.
My only experience with QSC was 20+ years ago when I worked for a dealer,the models then had linear supplies and IIRC Class A/B output stages.They were extremely powerful and bullet proof but lacked the refinement of the audiophile amps of that time that we compared it to.

"President" of the lead dogs, and "President" of the "BOZO" list

beemer

GV#27 wrote: »

An SMPS mated to a Class H output stage can get you lots of power,cool operation within a compact chassis but is not usually a good recipe for sound quality.But having not heard it myself must take your word for it,with your very impressive equipment list I suspect you might be a good judge of sound quality.
My only experience with QSC was 20+ years ago when I worked for a dealer,the models then had linear supplies and IIRC Class A/B output stages.They were extremely powerful and bullet proof but lacked the refinement of the audiophile amps of that time that we compared it to.

Your experience with the earlier QSC amps parallels mine. The older QSC amps did not impress me with their sonics as well. I was reluctant to try the RMX and PLX series QSC however I have not been disappointed in any way with these. If you get a chance to scare up a higher powered PLX to try please do....and post here your impressions with it.

Back 20 years ago my playout rig consisted of big Crest and Carver Pro series amps. I never had trouble with the Crests, however the Carver pro's were not nearly as reliable as I would have liked, especially as they were used in a biamped and actively crossed over configuration driving the top section of JBL 4732's and 4732A's....which were an easy load.

I also had trouble with Carver's mid 80's Mag powerfield amps. If I recall correctly they were 1.5t's. These could not handle Acoustic Research AR9's at all. After a while I gave up on this configuration and built David Hafler's DH-500 kit amps, which were utterly reliable and bulletproof on the AR9's.

It's been a long ride and there has been quite a parade of amps in and out of my place over the years.

Thanks for the comment on the two house rigs. I have made some sacrifice to put both systems together, however it was well worth it. Music is and has been my "drug of choice" for many years. The Pipedream system in the livingroom is capable of some fairly impressive levels, while remaining completely composed. All instruments have their place, and it does large scale classical music very, very well. Later in life I have been fortunate in developing an appreciation for classical, and now my musical "dinner plate" has quite a variety.

Best,

Paul

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