The fan noise is part of the Apogee Symphony!
I guess it doesn't sound like music eh?
Apogee, its seems every time they put out a converter there is one thing that is utter crap or somebody made the wrong decision. Like the power switches on the AD16x and DA16x. Those damm things are worth less. Why can they just use a heavy duty red light up switch as used on furmans. Its not like switches haven't been around for half a century. I am sure there are plenty military grade switches available to choose from or something more basic which allows more dependability.
Simple, done, no more customer returns, repairs that take two weeks or less, for a silly $2 plastic gumball machine looking toy button to get fixed.... Or give me a cheap $2 metal toggle switch that radio shack sells.. I will take ugly over something that consistently fails in operation. That thing will last forever.. Anything that is more reliable than that X series power button..
That button reminds me of those cheap chinese made, one piece plastic coated remotes, that use a watch battery, and you get with a cheap car stereo or something in that realm. They are so darn cheap and worthless, if you use the remote normally for a few months, you wear a hole into the button you use the most, and there goes your car stereo remote. Just from norm wear and use.

Imagine how much money is saved, studio owner/engineer hard aches are saved, shipping expenses saved, laborer expenses/man hours saved, to replace the X switch with a better switch?
But......... its not my company, I thinking they must be a good reason, like they have contracted 10,000,000 of those worthless push button switches for their x units and still got plenty to use up. Thats my best guess. Apogee are nice folks, and their converters are loved and hated by this forum. I use them just fine. but those damm switchess..ugggh
But



the rest of the converter is great. Dig the old school NASA looking pre LCD red digit displays. And tank built quality racks. And they sound great.
Now, you come to the new Symphony. FAN NOISE!!!!

Ruin the entire converter record breaking sales, with FAN NOISE. WTF? Apogee? Its used in a recording studio control room, where noise needs to be outside the control/mastering room and/or minimized to the fullest. I love to have my converters close by, so I can hit those buttons, watch the meters, but I can't do it with all that noise increasing my noise floor, where I critically listen... I guess somebody forgot about that part.
Studios require silent converters, not noise makers. I personally, am tired of buying gear that requires you to buy $1500+ custom cooled ISO box or build a coverter/cpu silence room just for its noisy (included for free) feature. Its more stupid wasted money and these ISO box characters charge a lot of cash for a 20U or so silent box. All for a piece that has a noisy little fan, or noisy power transformers (like on other gear). They make silent time plastic coated power transformers nowadays. that don't make noise. But guys still put those noisy azz vibrating donuts in their gear. For studios! not a good match IMHO.
OP, have you looked what the specs are on that fan? There are zillions of fans in the market that are so quite, you can't hear them. PC geek sites, Mac sites. etc..I got one in my Mac Pro. Never bothers me. And my mac breathes with glee. Not being all cooped up in a ISO BOX.
My hard drives are now louder. Long ago the Mac fan was louder. Oh oh did apogee buy a special discounted bundle of vintage nos computer fans???? hh

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That explains it! Seriously I notice as years go buy. fans are getting quieter by the year... I am sure you can find a better fan replacement part. If you do, let me know. I plan to buy some of these to try out and A/B them with the Avids. I got to hear them both to decide in the next few months. And if the avids are noisy. I might have to go back to Auroras or stick with my X series. Thats one good thing about Auroras. Most hassle free converters I have used to date with PT HD.
Thanks D