Got a new set of SDA1Cs

Schurkey · November 4

Let us know how it works out.

F1nut · November 5

Striker2237 wrote: »

Why not? The pre-amp has lines to each of the amps and they have their own cables leading to each section of the speakers, the Mcintosh system is currently running speakers in that exact configuration so I don't see the issue as long as I use the 402 for the midbass sets of the speakers since they need common ground for now.

Gain is all done via the pre-amp since everything on the pre side is balanced outputs and controlled for gain via the pre since it has 6 XLR (3L 3R) balanced outs

Ummm...no.

This is a good article about bi-amping.
https://www.gcaudio.com/tips-tricks/bi-amping-pleasure-or-pain

F1nut · November 5

FYI, the gain levels of your two amps are pretty far apart. Without an active crossover you'll never obtain equal levels.

MC402 - 29dB
MC501 - 23dB

skipshot12 · November 5

Only way you can bi-amp with amps of different gain levels is if your amp's have adjustable gain like this one....

Other wise you will have more bass than treble or more treble than bass, depending on where you insert each amp.
Would make for a discombobulated sounding system.

Striker2237 · November 5

I assume just using the preamp to compensate output voltage isn't good enough from what I am hearing? Never had an issue with that method on the other speakers but I guess we just got lucky

If that's the case I'll just buy two more 501s and wait to run them that way till later once everything is completed. Short term they will be run jumpered off the 402

Thanks for the info

On the SRS 2 what tweeter is the primary? I'm adjusting the room for those now and wanted to know how much to raise the furniture etc to remain on the same level

Striker2237 · November 6

Welp you guys were correct.

Just connecting the monitor sections to the 8ohm taps and the bass sections to the 4ohm taps on the 501s only and leaving 402 out of it entirely is better than using the preamp as a control for the gain issues. There goes $10k I guess.....I'll be looking for two more 501s now.

Thanks again for the info, really appreciated to know we had a system setup wrong for this long haha!

402 is likely just going to be the one used with the 1.2s now, deciding on a preamp still.

skipshot12 · November 6

Much easier to understand something with first hand experience rather than what we're trying to convey.

Good job figuring it out, carry-on and have fun.

Striker2237 · November 6

Listening to the 1.2TLs now, it's absolutely insane how much dynamic range these have.

skipshot12 · November 6

They are incredible with that.
Compares pretty much the same with Infinity Kappa 9’s.
Either one is a coin flip.

Striker2237 · November 6

Funny enough seller had a set of K9s as well. For me there was no comparison.....

I ended up buying a Luxman M117, 1.2TLs, SRS 2s 1987, Adcom 555-2, McIntosh MC2120, and got a free set of Carver amazing silvers as well as some decent speaker cables and an original AL1 dreadnought cable and two NOS SDA cables still in their boxes

https://imgur.com/a/MEuEX7j

pitdogg2 · November 6

You got a AI-1 SDA non-common ground Amplifier Interface cable.
There's no such thing as a AL1 dreadnought cable.

F1nut · November 6

Friendly advice, don't put a penny into the mini barn doors.

Striker2237 · November 6

F1nut wrote: »

Friendly advice, don't put a penny into the mini barn doors.

Are they really that bad? Even if one gets them for free?

I wasn't sure what to call the cable exactly so I just used both names I saw, I also don't exactly know what this one does vs the large external dreadnought. I only ever looked into the large external diy option

F1nut · November 6

Their sound isn't bad, but lots of cheap stuff was used to make them. The ribbons are the most expensive part and subject to buzzing. The ribbons are next to impossible to get fixed and it's impossible to buy new replacements. The woofers have foam surrounds, which should be checked for rot before attempting to use the speakers. They will eat all the power you can throw at them and just when they get to rocking something bad will happen.

The factory isolation transformer/cable is called the AI-1. Best to wrap it in ten individual layers of tin foil. That will improve the sound...no joke. We call it the baked potato.

pitdogg2 · November 6

The factory isolation transformer/cable is called the AI-1. Best to wrap it in ten individual layers of tin foil. That will improve the sound...no joke. We call it the baked potato.

He speaks truth. I had the AI-1 cable, also did the wrap. It is actually just a basic fix, the dreadnought is the mac daddy fix.
Food for thought;

DarqueKnight wrote: »

Joe,

If you are going to be using a common ground amp, you might want to compare the sound using the AI-1 cable with the sound using a fabricated SDA interconnect (only the pin carries a signal). Some people have said they heard no difference between the AI-1 and a regular SDA interconnect. Matt Polk said that the AI-1 slightly diminished soundstage width. Others have said that the AI-1 slightly diminished clarity and detail.

Congrats on the acquisition.:)

https://forum.polkaudio.com/discussion/74604/darqueknights-ai-1-tweak-results?utm_source=community-search&utm_medium=organic-search&utm_term=AI-1

Striker2237 · November 7

That is one of the most bizarre things I have yet seen in audio lol! If I didn't know better I would think the advice to wrap it in foil is a prank

Striker2237 · November 7

https://imgur.com/a/PAoRmx7

Brought the SRS2s downstairs to start on them, they are decently larger than the 1Cs are. Any advice on how to deal with the cracked end caps?

Also is there any way I can reliably check if the new SRSs have 194 or 198 tweeters? These came with a slew of drivers, one had a MW6503 on the right channel right side (SDA array I believe) upper position. Left channel has an unmarked driver on the lower left SDA array position I have no idea how to ID but it is marked on the surround as a Polk.

Tweeters are 194s or 198s, but I have no good way to know unless resistance specs are good enough to know. Same story with the mids, the stereo drivers on both channels are marked as 6510s from 1987 so I think they are original/correct.

Would I be best served by simply replacing all 12 drivers with new production units?

The 1.2s are all original and correct thankfully.

pitdogg2 · November 7

Striker2237 wrote: »

That is one of the most bizarre things I have yet seen in audio lol! If I didn't know better I would think the advice to wrap it in foil is a prank

Not at all. The box basically is a ferrite ring with wire wrapped through the donut hole several times.
Remember that ferrite bar on the back of analog tuners is to pick up AM radio stations SOOOO that naked ring in the AI-1 box will pick up RF really well.

Striker2237 · November 7

Makes total technical sense, just very odd to actually see what the solution looks like. I see why it's called a baked potato mod

F1nut · November 7

The tabs on the RD0194-1 are the same size. One tab on the RD0198-1 is smaller than the other.

Sometimes those cracks can be glued/clamped back up, but often not. There's a damn good reason Polk went to veneered MDF.

Striker2237 · November 7

F1nut wrote: »

The tabs on the RD0194-1 are the same size. One tab on the RD0198-1 is smaller than the other.

Sometimes those cracks can be glued/clamped back up, but often not. There's a damn good reason Polk went to veneered MDF.

Thank you, that's exactly what I needed

I think at this point I'm just going to remove all drivers and check everything. I'll post a few pictures here in a bit of what I find

pitdogg2 · November 7

Your SRS 2 should be mw6510 for stereo and mw6511 for SDA driver, IIRC. There was never a TL model in the SRS 2 so the correct tweeters would be RD0194-1

Striker2237 · November 8

https://www.mcintoshlabs.com/products/preamplifiers/C55

Off topic a bit but I'm swapping out the preamp on the bi-amped system to this to solve the amp gain difference for now. Old preamp didn't have a dedicated system to level match like this one

Got a new set of SDA1Cs

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