Does anyone know details about Polk SDA’s?

62vauxhall

62vauxhall

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This morning I warched while audio components were put out for sale at a Value Village. Two Polk SDA-2’s, a pair of (wedge) Axiom bookshelves, a Denon AVR and JBL sub.

The price tag was $34.99 for all of it. I asked if I paid that, can I just take the Polks? That was acceptable so I loaded then in the car. But I have just begun a road trip so can’t experiment with them until Saturday.

The interconnect cable is missing but I have pin & bar plugs at home. I assume just a run of garden variety speaker wire with a plug on each end is all that is needed?

I read that SDA speakers are not for use with non-common ground amplifiers. Do WOPL amps fall into this category or should they not be used with Polk SDA speakers?

And can one tell at a glance if an amp is or is not common grounded?
 
Bradrock

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My SDA's burn nothing but White Oak. They thrive on it.
Any wire for interconnect. Of course audiophile SDA interconnects are available as high as you want to go.
These speakers need to be airtight to get full effect of the passive woofers.
I suspect your going to be quite pleased with your score.
 
VSAT88

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Take a pic of the front of the cabs and the rear. Include a close up of where the interconnect cable attaches on the rear of the speaker. WOPL amps are dead on for Polk SDA speakers. I run a McCormack DNA 1 on mine. Well when I am not running the PS Audio 200C or the B&K EX 442. The Polk SDA's are actually quite efficient but due to the crossover construction really do require an amplifier that is capable of delivering a lot of current. As far as common ground question you may determine common ground amps by using a ohm meter across the negative binding posts of the amp in question. Continuity between those and you are golden. Should be a reading like .002 or whatever your meter shows shorted lead to lead. There is a way to use non common ground amps or mono blocks but we should discuss that later on. You my friend are about to have some fun. One more thing...Be VERY careful with the speakers. do not drop them even slightly hard when you sit them down or while moving them untill you can pull out the mid-woofers both on each cabinet and apply some epoxy to the magnets. The factory glue can loose its bond and the magnet can shift severely damaging or destroying the mid woofers. Ask me how I know.
 
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VSAT88

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Just for you Bradrock a few pics of what I have done lately to the 2b's. Dynamat, Steel lams. Oil caps. 20200926_005858.jpg 20200925_181406.jpg
 
MarkWComer

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62vauxhall said:
I read that SDA speakers are not for use with non-common ground amplifiers. Do WOPL amps fall into this category or should they not be used with Polk SDA speakers?

And can one tell at a glance if an amp is or is not common grounded?
Click to expand...
Yes, since the speaker ground is connected to the neutral bus between the power caps.
Uhm... aren’t ALL amps wired like this?
Check continuity between the ground posts of the amp to czech...

So, not for use with non common ground means you should be safe.
 
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mlucitt

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MarkWComer said:
Yes, since the speaker ground is connected to the neutral bus between the power caps.
Uhm... aren’t ALL amps wired like this?
Click to expand...
Maybe they are referring to a bi-amped speaker installation or dual mono amps? Lack of a common ground could cause phase shift issues that would make the sound muddy or smeared.
 
WOPL Sniffer

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MarkWComer said:
Yes, since the speaker ground is connected to the neutral bus between the power caps.
Uhm... aren’t ALL amps wired like this?
Check continuity between the ground posts of the amp to czech...

So, not for use with non common ground means you should be safe.
Click to expand...

what's a "Neutral Bus"???
 
Bradrock

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VSAT88 said:
Just for you Bradrock a few pics of what I have done lately to the 2b's. Dynamat, Steel lams. Oil caps. View attachment 44819 View attachment 44820
Click to expand...





Looks great! Nice & neat. Is that Supra wire? Let me guess...........you now hear things on recordings you never heard before? Heh...Heh

I just finally put the new tweets in. I like!
Looks like the VR3 mods site is down? I was going to link to their pricy SDA interconnects.
 
Bradrock

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Bradrock said:
Looks great! Nice & neat. Is that Supra wire? Let me guess...........you now hear things on recordings you never heard before? Heh...Heh

I just finally put the new tweets in. I like!
Looks like the VR3 mods site is down? I was going to link to their pricy SDA interconnects.
Click to expand...
 
laatsch55

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"Air core inductors will not saturate"...that was some interesting stuff.

Sidney , the man behind the Ohm Model A's and F's...
 
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