I don't know if you saw this thread, but it's a start:

https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1415411351

Also, if you search for Magic Box, you'll probably find some posts by me.

I'll summarize here though.

I got to listen to Steve's prototype - he was using it to convert XLR out from various sources that don't have RCA, and run them into amps that only have RCA. I think he was also using it as a variable output - which is how I played with it a bit. It *does not* have a gain stage - but here is what it does have:

Basically it's the XLR transformers that are installed in my ZMA - with a volume knob to *dial down* the voltage going to the amp. This isn't anything like those $30 XLR to RCA adapters you can get at a music store.

Why would we want this? Two reasons as I see it - #1 XLR can, and IMHO usually does, sound better. You can run longer runs, it's less cable sensitive, filters out noise, and (bringing me to #2) has more voltage!
#2 Voltage - While your RCA output on your gear might output 2.5v or something pretty decent, not all gear does have extra voltage on top And our Decware amps like having voltage on the input - and XLR can have 10v coming from it! Which is why the ZBIT has a volume knob. Take your 10v output, and 20' long XLR cable, plug it into the ZBIT and dial down the voltage to the input of your RCA input on your amp till you find a sound you like!

This was helpful with my PS Audio DirectStream - one of the shortcomings is a 2v RCA output. (which to be fair, is kind of a standard output)  And I was spoiled by my Oppo BDP-105 that has much more. It's not just volume, but density that you gain when you have more voltage going into a Decware amp. Lots of gear builders (PS A included) just didn't get this. I kept getting responses like "well can't you just turn it up?", or "Get a Preamp!"  So when I was at Steve's shop, he let me play with the Magic Box - now called ZBIT, and I took the Balanced XLR out from the DirectStream, ran to the box, and dialed in the input voltage that I liked into the RCA input of the ZMA and there was the density I had been missing, but with all the detail of going direct (no preamp) from the source.

If you have need of it, the ZBIT is a great tool to have. If you've already got the XLR transformers in your Decware amp - it's still useful since it gives you control over the voltage.

It can't hurt to ask Steve if he can fit those transformers in there. But I'm sure it would require drilling holes, and would need room.

I find the Jensen transformers add a nice little sparkle to the sound. I didn't feel I really lost anything going XLR, I felt I gained much more.

Yes, when I bought my ZMA, I had RCA only. Steve originally talked me out of getting XLR because he knows I like to keep things simple, and we both agreed that less (in connections etc) is more.

But once we heard reel to reel tape decks via XLR using those jensen transformers, that changed things really fast. And I ponied up the $$ to have Steve add the XLR jacks to my ZMA. I've been using them ever since...even though I sold my reel to reel - it's still my primary connection.

I find XLR is less cable sensitive, the Jensesns add a little sparkle/air to the sound, the ZMA likes the added voltage, and I didn't feel I was losing much if any detail. And I'm a detail freak so that's saying something.

So I do highly reocmmend the XLR inputs if your amp can support them, or if not, get the ZBIT.

Also, check and make sure your source has a good XLR output circuit. Both my Oppo and DirectStream are proper balanced outputs. This is key to noise reduction.

I'm waiting on ProggRob to get a Yggi. I really want to put it up against the PS Audio DirectStream.

The DS seems to be universally received as a great DAC and it keeps getting better with firmware updates, so it's not the weak link in the system.  Are there better DAC's, probably, but I don't think it matters much when you are at this level of performance.  One likely has other weak links in his/her system....for example, the room.

@ LR - Can't wait to hear some thoughts on the Yggy in comparison to the DS as well.  The DS really set a high bar for what's capable in DACs.  Even if it's not to one's liking, IMO there's just a handful of companies like PSA that set the pace for others to come up with more design elements than just using a good output transformers paired up with an off the shelf chip.  There were obviously other people that had done FGPAs, but I can't recall any of them gaining the momentum that the PSA DS has.

Don't forget that the Yggy needs to be perpetually left on for a full 7 days for it to start blossoming.  I leave my DAC on all the time so that doesn't really bother me.

Although I'm quite happy with my McIntosh D100 and feel it is very resolving without be bright or strident and IME actually close to the level of the DS (not quite but pretty close).  I wouldn't mind moving away from the Sabre stuff and seeing what else is out there.  Like FB, the PSA DS is out of my league price wise though and the Yggy would be the maximum that I would ever consider paying for a DAC (unless a long lost Uncle from Europe passed away and left me his fortune )

@ Lon - what type of TT were you contemplating?  Moving up in the Rega line or moving away from it into another realm of sorts?  Have you seen any of George Merrill designs such as the R.E.A.L., PolyTable or Replica?  These have peaked my interest as of late.