Weird noise from audio interface when using Thunderbolt port

Interestingly, I picked up a 4Pre a few days ago and am having random, intermittent noise on the Thunderbolt buss myself on my late 2013 iMac. Mails to Focusrite have been met with silence for three days so far, and I've done a LOT of troubleshooting myself.

I've reset SMC, PRAM, tested hardware from OS bootup, uninstalled Focusrite drivers and tried it that way, reinstalled the drivers, disabled journaling, played with sample rates, disabled wireless ethernet and bluetooth, tried different Thunderbolt ports on the machine, tried different power outlets both using a Furman strip as well as a plain wall outlet, unplugged studio monitors and XLR's from the interface to eliminate outside noise entering, even tried the interface on my Macbook Air to isolate the iMac from the equation... Everything was met with the same issue, random noise upon recording and playback at random points in the timeline. The noise also changes the tonality of an instrument so it's very evident that it's occurring.

My particular iMac is not one that is affected by the issue described on the Focusrite page, I have a totally different model year, however I can't be sure as I have no way of testing the Thunderbolt buss/cable itself.

I can at this point only conclude that the interface itself is causing this, some form of noise leaking into the Thunderbolt buss or a fault in the drivers used that is causing some digital noise in the chain, something of that nature. My old Tascam US-1800 USB2 never had issues like this up until it's demise at which point this was to be it's replacement. Now I'm left with two interfaces that are unsuitable for production, lol.

I'll update this post in case we reach a resolution, hopefully this information will help someone else as it seems that there is little to no information on this specific issue. I like the interface, but if this is what I'll be met with using Thunderbolt, forget it. I'll go back to USB interfaces without these glaring issues.

Update1: After speaking with Focusrite support for what seems like ages (more like waiting for them to email me countless days, and never really reaching more than 'try direct monitoring to see if it's a hardware issue'), I've solved my issue after many different machines used for testing and different configurations trying to get this thing to function properly..

Unlike the physical button on the Scarlet range, the Clarett range doesn't have a physical hardware switch to enable direct monitoring to test it's own self noise/issues. Instead you must select your monitor output in Focusrite Control application as "Analogue 1-2" to enable direct monitoring. In doing so, I still heard the white noise/static, indicating it was in fact an issue with the hardware. I'm sending the Clarett back to B+H for another copy which hopefully won't exhibit this issue. My guess is some wiring in the interface wasn't shielded properly or something, causing digital noise to leaking into the Thunderbolt bus, only to then be sent to my computer and put to tape within the DAW. Hopefully that can help if someone is experiencing the same issues.

Will update when the new one arrives.

Try a NVRAM/PRAM reset:

http://support.apple.com/kb/HT1379

Also check applications/utilities/Audio MIDI set up and make sure the settings are correct for your set up 44100.

This is strange, not heard of this before.

You can try a SMC reset, don't know if it will help, but it can't hurt anything.

http://support.apple.com/kb/HT3964

Since you say it recently started, I wonder if the interface has developed an issue, if possible see if you can borrow a different one to check that.

Yeah, no surprise about the smc, but a benign thing to try.

I would try to get my hands on another usb interface and see if that particular unit is not happy with the Mac. Also try changing out cables one at a time to see if there is a cable that is not 100%, doing them one at a time may help isolate the issue.

This kind of thing kinda sounds more hardware related than a software thing. Since you say that recently it started would tend to point towards something has possibly gone into some failure/near failure mode.

I'm having a similar problem while using this setup: "Focusrite Clarett 4pre" thunderbolt audio interface and an early 2011 Macbook Pro

Focusrite has been amazing at trying to figure out what the problem is, but I have a feeling it's our laptop model. That early 2011 Macbook pro edition seems to have so many problems with it.