SDA-SRS 2.3tl Crossover upgrade

xschop

Welcome to razzville ...Ideally, you should not have the smaller speakers on stands in front of the SDA's. What do you like/dislike about the new addition?

Indyaudio2

Thanks - the Advents are not in front of the SDA's, they are in between them and easily moved out of the way.

So far, post recap, I am loving the sound of the 2.3TLs. I had the 1.2 TLs a few years ago and felt they were one of the best speakers I'd ever heard or owned. They were a bit too large from my smaller dedicated audio room and I sold them. The new 2.3s placed in this larger room really open up well, have tight bass and great imaging. I am driving them bi-wired with a Sunfire 300~2 amp. When I got them, they had the typical blanket somewhat muffled sound. The speakers had never been touched by the original owner and were in storage for the better part of the last decade. With the new caps and bypassed poly switches, they are sounding full and transparent, a lot like the 1.2s I used to own.

I'm putting some time on them now to burn in the caps. Sounding great so far and well worth the effort. Crossovers are easy to access and remove to work on the bench.

Snowlust

Greg[/QUOTE]
Therefore, the 8008BB connected to my 1Bs has a happy little jumper wire connecting the negative terminals between channels, and has been sounding magnificent for years...but it sounds like **** without the jumper.[/quote]

If anyone is still active on this thread.... I just joined and am doing research on my fairly beat up 2.3TL's i scored for $200. I have some spare drivers collected, a good word document collage put together of pictures and data, and a target budget to begin my work. But I have a question that I need answered as detailed as possible......

I DONT understand the common ground and why/what not to do. I read elsewhere about this but Its still going right over my head. So- these speakers are to have an amp connected WITH a common ground? I have many many high power amps and i know a few are dual mono. Im guessing that means they ARE NOT common ground? What does this mean for an amplifier? that they share a ground on the left and right channels? how does this work? And you can actually strap the negative binding posts of a dual mono amp together? What is happening in this world!!!! JK, I struggle to grasp things sometimes for no apparent reason and electricity gets me a lot.

Any help appreciated.

Snowlust

Oh, and to the OP, thanks for the thread, I enjoyed reading it and I learned a few things from it. Nice work!

I would quote it if i could but apparently I haven't mastered that yet.

dkfreebird

Look up the dreadnought threads on here and build you one. That makes the speakers able to use any amp you prefer and improves the sound quality. Welcome to Club Polk.

pkquat

I'm not an electrical engineer, and I didn't stay at a Holiday Inn Express, but here it goes.

Most amps with a single transformer are common ground, meaning the negative posts on both the left and right channels share the same ground. This is needed for the SDA speakers because of the cable that connects the two speakers to each other. It's the Pin Blade SDA cable you should have. Because this cable shares the information between the left and right channels for the left the right SDA speakers, it also needs to share the ground between the left and right speakers. If they have different grounds, it could potentially be like strapping two mono amps together. Bad things could happen.

I've been told that some amps with dual transformers, are wired in such a way that you can connect the negative channels together. I think of it like it's turning the two transformers into one big one. I don't think that's exactly right, but for what its doing close enough.

Polk did make an interconnect called A-1 which would be used instead of the SDA cable if you had two separate mono amps or a non common ground amp. This had a transformer in it to allow the left and right speakers to share information with the other speaker without causing damage to the amps or the speakers. Like everything, people kicked it up a notch and built one bigger and better, AKA the Dreadnought.

F1nut

Never strap a non-common ground amp(s) without consulting the manufacturer first. Even if you can it's a bad idea as it raises the noise floor.

nooshinjohn

What he means is that there are much better caps and resistors out there for these speakers.