Responses from tls49

Experience with Adio Equipment Trade-Up Promotions
Any trade in will be less than what the item could sell for on an open market. Obviously, it takes more time, effort, and likely some expense to get that best price when selling. Only you can decide if the extra is worth it. 
I Need an XLR Digital Cable.
You are welcome, have fun and enjoy. 
Another amateur in need of advice
Having worked ~25 years in the audio industry, I definitely saw many mistakes made as people assembled their systems. One of the most common was spending the majority of their budget on speakers. The best speaker available can only sound mediocre ... 
I Need an XLR Digital Cable.
IMHO, I would buy an entry-level first, something made from Mogami or Canare 110 ohm cable. This will get you going with a decent proper connection for cheap. That also gives you a reference should you try something with a return privilege. 
bi amping Mcintosh XCS 200 center with Mcintosh 302, Mcintsosh 456 or 601s for Magico S5s
The problem is not a power issue, it's a mismatched speaker system. Get a Magico center and surrounds or McIntosh fronts. 
NEEDED!!! Bi Amp Pros out there that can give me some advice
"Is it even worth it ? or am I headed down a rabbit hole from hell."Yep, you're standing at that rabbit hole. Step over it or go around and move toward the "Super AMP". 
Low power tube amp for Sonus Faber?
"Would really like to try a valve amp on the Elipsa. Is this a mistake?"Why ask the question if you're not willing to accept the answer? 
Anybody know anything about the Marantz SD400 cassette deck? 2 speed?
Seems like Nakamichi made  a 2 speed cassette deck. Can't remember model number and I think it may have been 1/2 of the normal speed. 
DAB+ radio for the wifey?
mtraesboLots of smart speakers available, and some actually sound decent. Google Home Speakers can also play via Bluetooth. If you want to take it a step further, get a Chromecast Audio to connect to a system, then use a Google Home Mini to contro... 
Anybody know anything about the Marantz SD400 cassette deck? 2 speed?
If you want to make higher quality recordings, get a Nakamichi. 
Monitor Audio Center Platinum PLC150 vs Gold 350
The one that matches your L & R. 
Not enough power what does it sound like?
+1 shadorne One of the best comments I got on my HiFi years ago was,That's somewhat loud, but it really don't seem like it. 
DAB+ radio for the wifey?
Get her a smart speaker. Then she can just tell it to play what she wants. 
Bryston 2WSB switch box to choose amp that drives speakers
Here’s a basic selector,https://www.russound.com/products/connectivity-and-control/speaker-selectors/dual-speaker-dual-sourc...You could also look for a Niles SAS-1 or a Niles SPK-1. These are no longer available new but can be found used. They wo... 
terry9Read the entire article at Wiki. It states what cleeds has said.And this,https://www.its.bldrdoc.gov/fs-1037/dir-017/_2498.htmAnd no, you have not addressed my concerns. It’s clear your opinion is different and you are certainly entitled to ...