Topic: Fireface 400 or UC for iMac

Hi,
i'm new member and have my first Questions.:-))(sorry for my simple english)ed:
Now my Apogee Mini DAC is defect so i decided to try a RME Unit.I will use it mainly for playing Lossless Music-Files (iTunes) on my Imac (24" Intel).Recording is not so important.
I also own a Phase x24 but with Firewire recently i have a high-frequency whistle in my speakers .The same with the Apogee before.
The Dacs are always connected IMac > Glyph FW HD > FW Interface(DAC) > full symmetric to SPL 2 Control > Amp > Speakers
Now i plugged a old Motu828II and the whistle vanished.The Motu has a built in Power supply and all the other Units have this cheap plastic power adaptor.(RME too) Is this the ultimate cause of the noise.
Do Fw Plugs have ground shielding problems.What's about the USB connection.

The Apogee and the Motu Fw Interfaces always bypass the Mac's Volume Control.(i think thats the better way to bypass the Macs sound engine)  The Phase X24 not bypass the Volume Control.
Whats about the RME USB ?


Should i buy a Firewire Unit or is the new Fireface UC the better choice in future ?

Andreas

Re: Fireface 400 or UC for iMac

Hi Andreas,
both FF400 and UC provide you with a digitally controlled gain on the output stages. While the FF400 can be bus-powered, the FF UC has a little lower latencies (which do not matter in your case since you're not into recording) and is uses a more common standard for signal transmission. Firewire itself does not have ground shielding problems, but you could try using a different firewire cable.
The "cheap plastic power adaptor" as you call it is only cheap because it is used with millions of devices in the world. It does not affect the sound quality of your signal. However, there might be problems with a ground loop between your iMac and your amps via your FW-interface. Active speakers usually feature a ground lift switch, that worked for me in most cases.
Anyway, be sure to also go fully symmetrical from DAC to amp. No need for SPL if you use a Fireface.
Just get one from a retailer to test it :-)
Max