Morning Bit.
 
What happens with cans? At various points in the chain?
 
What happens when you swap lefts, rights, and panning?
 
Can you bypass chain elements, wire around them, to reduce signal path to as few devices as possible? if not, can you get to digital ASAP and keep it there?
 
What freqs you hearing? FT or intermittent? What can you turn off in the building that's not audio related? (Word to the wise...set an audible alarm if you kill the circuit the fridge is on...ask me how I know!)
 
I know you've probably tried all this but its Sunday, support isn't going to answer till tomorrow, and you have to be frustrated after waiting so long for an interface.

If I swap left and right cables, the problems move. Panning has no effect on the noise, but I can use the MixControl master pan to compensate for the volume differences until they spontaneously correct themselves.
 
There is no way to reduce the signal path any more. The noise is not dependent on any inputs (persists even with nothing plugged in and gain controls all at minimum), and remains constant regardless of the master volume control, and even when the Mute button is engaged.
 
The noise is there even when there is nothing else powered up. I have a dedicated circuit that I installed myself so I know it's grounded properly. All gear shares a common ground that runs straight back to the N-G bond in the service panel. The only thing non-audio that's plugged into the circuit is the computer. Lights are on a separate circuit. The sub-panel for the garage/studio comes straight off the main panel at the service entrance.
 
The nature of the noise is a combination of broadband hiss and 60 Hz hum. It is primarily in the right channel, although present at a much lower volume in the left channel. If I disconnect the speaker cable (they're powered speakers) the noise stops, which is how I know it's originating in the Focusrite's final amplifiers.
 
This morning it occurred to me that if I was to build an attenuator to insert between the interface and speakers, I could turn the volume up and get probably a 30 dB improvement in S/N. I don't know why I've never thought of this before!
 
I fault the ADAMs for having too-high a gain, such that I have to turn down the interface by 30 dB to get 85 dBSPL with -20 dB pink noise (the MOTU was exactly the same). I'm thinking that a 30 dB attenuator would allow me to turn the master volume up by 30 dB, and since the noise is not related to the master volume that should result in a 30 dB improvement in the signal-to-noise ratio.
 
Unfortunately, it'll cost me $50-60 to build such an attenuator. I'm digging through my spare-parts bins now ...
 
Thanks for making me think about this, Jay.

Whoa...
 
Take me a bit of time to absorb this but...
 
"Swap left and right cables, problems move?"
 
True cable swap means both ends, and I assume you mean just one end when you say the above...otherwise...

OK, you got me; I swapped one end of the cables only, as it's a hassle to crawl behind everything to re-route the speaker ends. But all I have to do is pull the plug out of the interface and the noise stops. That would seem to absolve the cables and speakers.
 
I found these inline attenuators for 20 bucks apiece, cheaper than I can build them myself, but I'll have to wait until after tax time to see if there's any change left over.
 

I had a similar situation a couple months back, and have another now.
 
Back then, laptop dock and tracking room are feeding a mixer in listening room, both 25 foot runs. TR to LR balanced, Lap to LR not, tho I thought it was.
 
Had hum in LR, only when Lap interface was connected to Yamaha H50's. (Also had hum in the Yamahas.) It went away when I ran balanced cables Lap to LP. Key point, Lap faders down, muted, hum still present in LR with audio feed only from TR. Pull the Yamahas, interface or monitor end, hum goes away.
 
Current situation, 2 control room PCs, mixer, and monitor on normal house circuit. Interface and outboard racks both on dedicated circuit. Yesterday, signals from main DAW clean, hum with ancilliary PC audio. Because the interfaces are lightpiped together, I can monitor from the audio outs of either interface, regardless of where the current audio is sourced. Regardless of which side I listened from, primary clean, ancilliary w 60 cycle.
 
Today, the situation is exactly reversed.
 
I haven't chased this one out yet, because I know I have to get all units onto the dedicated circuit, and when I do, there may be no issue to correct, but the point is...most of the time, in my experience anyway, hum is most noticeable on the feed that is most responsible, however, in those two instances, the noise appears at one location, when the key element producing the hum is elsewhere.
 
By itself, this kind of thinking hurts my head, and adding intermittent tendancies, and wider cause and effect loops, I have to really bear down to work thru things like this, so I hope I'm not laying any of that on you.
 
If you have the new interface isolated except for monitors, chances are you have the lay of the noise land as you describe. If however, a conventional approach doesn't correct it, and you don't decide to RMA the interface w Focusrite right away, you might try monitor cables with the shield detached on one end, and or a lift between the two.
 
In my book, hardware failures purchase karmic hassle free operation during new equipment breakin for a period equal to or longer than the utilization denial imposed by the original failure, but...
 
...Karma doesn't always read my report, or follow my recommendations.
 
Hope you clear your decks soon!
 
;-)
 
 

Thanks for the thoughts, Jay. Yeh, hum can sometimes be surprisingly difficult to track down to its source. Sadly, in my case it was not hard at all :(
 
I've got balanced cables to the speakers (TRS to XLR) and they are dead quiet even as open circuits. But plug 'em into the Focusrite and instant hiss 'n hum.
 
Maybe I'm just being too damn picky. If this was a PA system or a guitar amp I'd be remarking how amazingly quiet it is!

In a matrix here, sorting out reasons to proceed in one direction over another, and today is shot in any event, but I'm anxious to see how the Pro-40 performs here now. I don't intend to monitor directly from it, tho I suspect it has better pres than the 2626 on the main DAW.
 
I do, however, hope to be able to bring what I refer to as "second tier" feeds into tracking or the CR from it, via  the ADAT port, and I hope I don't have significant hum issues there. I'm building a collection of nice pres for vocals, acoustic guitars, anywhere the quality might be highly audible, one of which is an ISA 2 which I already love.
 
I know the Pro-40's pres won't eclipse the ISA 2, but I'd hoped they'd be nicer than the Octanes in the 2626, so once I figure outwhat needs to happen in what order and get the Pro-40 inline, I'll holler back at you and let you know how it sounds. Just for laffs, I'll hang a couple sets of monitors off it, short work with the patchbays, and let you know how noisy they are too.

Bit, I enjoyed using the Saffire pro 40.  I didn't have any issues with the hissing noise you describe though.   I was not a fan of the focusrite plugs myself.   I still have mine in my rack along with the ADA 8000 I have lightpipped in for a total of 16 inputs on that system, though I haven't used either of them since I picked up my 24.4.2  I figure I might use them for a mobile rig or something.

That's good to hear, Chuck. I wouldn't want to go to the trouble of RMAing the unit only to find that noisy finals are typical of Focusrite interfaces. It's starting to look as though my unit is just a lemon.

Then...to be fair, (I thought about this while working today) when I was using it.... I was also running M audio BX8A monitors which hiss like a snake anyway so I may not have noticed even if it did!