Is there a reason for this?
 

I've been readying myself for the switch from my Apollo X8p to the Apollo X16 that should arrive on Thursday. I completely de-cabled my entire studio and labeled all the cables (about 8 hours of work) to make re-cabling go faster. I peeled all the labels off my patchbays and I'm waiting on a 1/4" cartridge for my label-maker to arrive tomorrow so I can re-label with a new layout. I shifted things around in the 500 rack.

Last night I pulled the X8p and Rosetta 800 from the rack. As I was packing the X8p in its box, just happened to glance at the output monitor connectors on the back panel. They're the only thing on the back in a tall white rectangle, so your eyes get drawn there. Then I started wondering... I don't remember seeing that tall white rectangle on the back of the X16. I pulled up a photo online just to be sure and that's when I noticed the connector is different. The X8p wants a TRS plug and the X16 wants an XLRf plug. It's a good thing I noticed because I don't have the two cables I'd need to hook up my monitors and was able to order a couple of TRSf-XLRf adapters that will be here in time and tide me over until I get cables made.

But it makes me wonder why. Why use TRS on one box and XLR on the other? I can't think of a good reason for the inconsistency. Anyone suspect a reason?

(top photo:X8p, bottom photo:X16)
https://i.imgur.com/byN7ndQ.jpg

It doesn't make any difference. I've seen them both ways. My JBL LSR306s will take either. The XLRs lock (and are more expensive). TRS don't lock.

I know it doesn't make an operational difference. I'm just baffled as to why, within the same series, their top two interfaces have different connectors. These are both $3000+ boxes so I'd be surprised if the minor cost difference is the reason.

The back panel of the older unit looks crowded. A TRS jack takes less space than and XLR connection.

The only "science-y" reason I can think of is that TRS's make a momentary short when you plug and unplug them while XLR's don't. But I highly doubt that's the reason.

I think sdelsolaray and Brent may be on point the physical space and or the "short"
That or perhaps just for the aesthetics on 16 ? I does look very clean and well organized

I actually had to deal with that in reverse with my Avid Omni and the Amphion Amp I use for my passive Amphion monitors. TRS out of the Omni into XLR on the Amp ...

I have noticed a move in newer gear to TRS. 10 years ago or so it wasn't as much of a thing.

That could be it, although, it looks like a pair of TRS connectors could have sat under the word clock connectors, but perhaps this had a better aesthetic look. But as far as reasons go, this makes the most sense so far.

Those two units were released on the same day so there's no older or younger here. The X8p is UA's top interface that has preamps; the X16 is their top interface that has no preamps. They're only priced a couple of hundred apart at $3300 for the X8p and $3500 for the X16.

Hi Jim:
XLR and TRS
XLR cannon plugs have long been considered the more professional connection.
XLR outputs normally will carry a signal of +4dBu
TRS signal will be considerably less at -2dBu line level
So the TRS equipped unit will need to work harder to produce the same signal level that the XLR unit will produce.
In conclusion, the XLR outputs should produce a quieter, more efficient signal.
All that being said. I read that you are waiting on adapters.
Adapters themselves can introduce noise and interference in the line.
Your monitors should be able to accept an XLR input. Which it the more professional way to connect.
So I would eliminate the adapter, and connect monitors directly with an XLR cable.
As to why the two different outputs on similar units?
That would be a question for Apollo
My guess would be, that the X16 was designed for a Pro studio situation, and the X8 for the home base recordings.

My question was not about the differences between XLR and TRS connectors. I was questioning why Universal Audio was using different connectors on the two units. That has nothing to do with what my monitors will accept since cables can be made in various configurations. Also, I'm not sure how you came by the opinion that XLR connections are "more professional," but take a look at consoles being built today and you'll find TRS connections all over them. For example, here's the manual for the Neve Genesys Black. Search for "TRS" in that document.

https://www.ams-neve.com/ekmps/shops...kiss12-min.pdf

The reason for the adapters is because I could get those sooner than I could get new cables made from Redco. When I know the unit is working correctly, I'll order the cables and eliminate the adapters from my system. The adapters were never meant to be permanent. They were a cheap ($13) solution to allow me to use the cables I have on hand.

As for the X8p being targeted at home users and the X16 being targeted at pro studios, I don't see any evidence of that being the case. Neither box is of a quality or price-point that would typically be found in the hobbyist's rack. UA does make gear for the hobbyist/enthusiast market (Solo, Twin, X4) but the X8p and X16 are the top of their line.

They're just connectors. They have nothing to do with the circuitry attached to them.

Looking at the photos, I agree that having TRS on the first one was likely a space-saving design move. With 8 XLR connectors for mic/line inputs, it was pretty crowded.

On the second they dumped all the XLR inputs in favor of the 25 pin connector, freeing up all kinds of space. I'd bet the designers have a bias towards XLR, so they were able to put what they preferred into the back panel.

To say that there is no bias in the professional audio world for XLR vs. TRS is to ignore decades of history. Old habits die hard.

The XLR connectors on the top unit are actually XLR/TRS connectors. If you look closely, the centers of what appear to be XLR connectors are hollow.

The only bias I've noticed is when it comes to microphone cables. The reason, as I understand it, is an XLR allows the ground wire to connect first and that offers some protection against accidental damage. That's the reason I have an XLR pass through patchbay to handle connecting my mics to my preamps. But for everything else, I see plenty of TRS connectors on gear, including very high end gear. Outside of the XLR for mics thing, I don't see any patterm of industry bias. If TRS connectors are good enough to patch modules on $50K Neve boards, they're good enough for me.