Ok - makes sense - I stand corrected.

Two questions:

1. On the 990, does input thru USB use the USB DAC or the regular DAC? I am guessing that it uses the seperior regular DACs.

2. When the computer is sending the PCM stream, is it sending at 44.1 Khz or at 48Khz? I remember reading somewhere that, by default, Windows OS send PCM data at 48Khz - some sound cards allow you to transmit at 44.1 Khz. Any info on this?

On the 990, it'd be the 990's DAC because the signal goes through the DSP section (downstream of the USB module) before being converted from digital to analog. As for the computer's PCM bitstream, it can probably do either. Playing a CD straight from the tray would presumably be 44.1kHz unless there was some processing or manipulation taking place, but I'd expect that bitstreams derived from material like MP3's or Dolby Digital sources would be 48kHz. The 990 can handle either, though, so it shouldn't be an issue if sources like that default to 48.

I had a ground loop problem with connecting my computer to my 2150 using the USB port. I had been troubleshooting with Steve at Outlaw on and off for a few weeks. After much trial and error, connecting and reconnecting, I narrowed it down to the audio output of my satellite receiver which I use to listen to Sirius from Dish . A Ground Loop Isolator (Scosche brand)from Wally World solved it .
I know some others have had ground loop problems with their usb , so if you do, the tech guys at Outlaw are more than willing to help.

Now that I've got it solved , and listening to music connected via usb more, I really can't tell any difference between this and my regular CD player playing discs on my computer or using wav(uncompressed) files. While I'm particular about sound quality to a point, I'm no audio perfectionist , (if I was I'd be in an asylum because I'd be chasing what doesn't exist in my world) .... so your results can and will vary.

The bottom line is the USB input is a completely viable option to use. I wasn't sure at first, listening to compressed files, but uncompressed ones and CD's sound as good as they were intended to be.

Wow, and they say Yanks aren't friendly, I really appreciate the input, not that I assume it was all for me.

I think the same way about the USB port. The 2150 has a Micronas chip (UAC 3553B: USB Audio DAC) and as you can see it has DAC in the name, I didn't know what DAC was before reading this page, still don't, but now, thanks to you guys, I understand that it converts digital to analogue, which means windows is not doing the primary conversion, it is taking place in the 2150. Now why does windows retain some control, so far what I have surmised is the that since the computer can only transmit digital information through a USB port, it is transmitting a series of “0” and “1” and therefore there could only be more or less of it, it cannot be qualitative, so I think it is best to put all the volumes on the computer to the max and let the 2150 control the nuance.

I discussed this with the outlaw guys they did not seem to know, Scott suggested I experiment with the levels, I have and this is the conclusion I have come to. However I think that there must be some sound engineer that Outlaw can access that may clarify the relationship between the 2150, the USB and the PC and how to eliminate or keep windows interference to a minimum. It seems I am not the only person that is somewhat confused or at least uncertain about this issue.

I have downloaded my music library in a loss less format and am very satisfied with the results and in case anyone is in the market for affordable, yet incredible speakers check out Axiom M80’s. Outlaw recommended them and Cannucks (that’s Canadians, for those who are not worldly) make them, a little hick town a couple of hours north of Toronto (same policy as outlaw, only sell over the net, check them out for 30 days etc). Imagine with all that goes on in the old US of A, Massachusetts recommends Dwight Ontario, population 89 … 80 make speakers, the rest … beer; just kidding I have no idea really.

- There's an Axiom M3ti floating over my head right now (OK, it's bracketed to the wall, but it's a well-concealed bracket...). It and its sibling on the far wall have been keeping my other Canadian speakers (Paradigm Reference) company for about three years now.

As you've recognized, the USB connection passes a digital signal (using PCM, the signal format used by the trusty CD) to the 2150, at which point the USB interface on the 2150 uses its DAC (Digital to Analog Converter) to produce the analog signal that the rest of the 2150 wants. Even in the digital domain, though, you can still shuffle those 1's and 0's around. Volume control is an obvious one, as is left/right balance, but you could also have equalization (even simple bass/treble adjustments).

Carlos, My best advice is to keep it simple.

Okay, why does windows have some control over the digital files ? It does for the same reason a Cd walkman or portable mp3 player have control over the volume and tone controls . Computers were not intended to be connected to an amplifier any more than a walkman was, therefore the consumer needs a way to adjust the volume and tone. My point here is the "why" of it matters little because it designed function cannot be changed. How you deal with it right now does.

I don't think you need a sound engineer to keep windows influence to minimum, simply keep the EQ off , if you use windows media player. Keep the volume of the computer on max. This is how I listen to my music and it sounds excellent. I use both speakers and headphones.

Enjoy the music

True that, Garth. I believe you're right about simplicity (no EQ, computer volume to the max), but in my case, I'm still finding that music from the USB input is not quite as nuanced as when routed from my CD player. It's a nominal difference, but I can hear it. Of course, the convenience of the USB port is fast making this a non-issue, especially since I've just recently begun experimenting with Internet radio. Didn't know there were so many choices were out there.

Yes, the world of internet radio kind of blows my mind too with all the choices. I also just got into it now that I've got some high speed access. I like pandora.com for one because you have some choice as far as song selection. Between internet radio and Sirius , I have more choices than I'll ever have time for

Tru blu, I'm not sure if you mean the sound from the usb isn't quite as good when comparing a disc played on your pc vs. your cd player , or you are referring to streaming and or compressed audio (which doesn't sound as good as a real cd, despite the label "cd quality").

Hey Garth. I'm actually noticing a small difference between discs played in my Mac (through iTunes) and those played on my CD player. There's more clarity and nuance using the disc player, and I have to crank RR 2150 volume louder using the USB input. My wife noticed also. Maybe there's a simple solution I'm not aware of, but I'm not all that bothered by it.

That's great Garth, thank you, I use Itunes, lossless format, it sounds great, I just found the equalizer, and turned it off. I like music, I don't claim to understand technology beyond the basics. I tried to find another equalizer in windows, could not, is that the suggestion, turn it off in Itunes, volume to the max and don't worry about windows. I access the music on two different computers, the sound card is called soundmax on both, but I think they must be different versions, because one has a base & treble control the other doesn't. I am less concerned now that I have been listening to the music for a while, I just got the system and am still fiddling, I'll get there.