Yes, exactly. I'm currently using my new iFi Nano iDSD DAC for internet radio and streaming and it does a great job. (It's actually a great DAC for the money.) So why don't I just use the Nano for internet stuff and the NOS1 for >16/44.1 files? Well because this requires some sort of source switching device and I really want to feed the NOS1 directly into the active speakers. I'm currently using my old Pass Labs X1 - it's a good preamp, but it's obvious that even at this level, preamps are not totally transparent.

Mani.

I think Esau is talking about the CPU and the PC's general performance, and not the PC's power supply. The PC's speed still matters from a usability perspective.

Mani.

Peter, not sure if this is the most appropriate thread for it, but I have question...

When developing the 1.04 driver, would there be any possibility of including some sort of automatic upsampling for use with the NOS1(a)? I'm talking about using internet radio, etc. I'm currently  setting the output to 24/192 in 'Manage Audio Devices', but am uncertain whether this is effective. Certainly, my FM tuner (with roof antenna) sounds better than internet radio through the NOS1, both being fed through a preamp.

It'd be great if I could finally eliminate the preamp.

Mani.

Hey Peter, your traces look very similar to those that Keith Johnson showed in his talk at RMAF2010. I've watched the video of the talk a few times now, and I've found it very helpful. (But you have to persevere.)

Mani

I think it's probably worth noting that what Peter seems to have done is eliminate the influence of the USB interface. The NOS1 will still be heavily influenced by both platform and airborne vibrations. Maybe electrical noise via the AC mains will still play a part? If so, isolating the PC's SMPS from the NOS1's AC power supply may still be beneficial.

Mani.

Joachim, I doubt that's now the case. If Peter's has truly eliminated the affect of the PC/XX, then he's probably back up to full CPU power, and using XX in full OS mode, with background showing too.

Mani.

Alain, remember we're only talking about the upgraded NOS1. XX will still be absolutely necessary to get the best out of all other DACs.

Mani.

Hey Peter, like many people reading your post, I'll admit to not understanding all the technicalities. But even so, it's obvious that what you've done here is beyond superb.

I describe you to my wife jokingly as 'a genius'. I'm seriously beginning to think the joke's on me.

Mani.

I think Coen is right - the future of XX is hard-core digital filtering, using an ultra high-powered PC feeding a PC-immune NOS1.

Wow... no more thoughts of PC linear power supplies necessary. I will sleep well tonight.

Mani.

I'm definitely in... When can I send my NOS1 to you? Next week? No problem.

Mani.

Haha...

It looks like they'll be ready in the next couple of weeks or so. However, the timing on my side isn't great as I'll be travelling for work when they're completed. So realistically, it'll be mid June before I have them here and all up and running.

But someone in the US should have his well before then. Not sure who it is, or whether they even post here. But there may be a 'review' out before mine.

Mani.

Interestingly, I tried 8x only yesterday evening. I was actually just testing some 24/192 files I'd just made from my new turntable and wanted to hear the difference between native and 2xAP and 4xAP (so 192, 384 and 768). And...

... I prefer the 2x AP, i.e. 384! (This is with switch #5 on, i.e. "DAC is a NOS1".) I didn't have time to try 16/44.1 files with 8xAP, but I will try that this evening.

Somehow, I suspect the BB1704s might be optimal at 8fs rates. Maybe this is why some of the best oversampling filters (e.g. PMD100) were 8x also?

Will report back...

Mani.

Oh dear, what have I done?

Whilst walking past the stack of PSUs outside my 'vinyl studio', I noticed that the PS Audio P300 regenerator powering just the NOS1 was quite hot to touch. This seemed strange, as the NOS1 isn't really drawing much current. In any event, I thought I'd try things without the P300 to see if I could eliminate it. And...

... no way! The sound without it is too 'shouty'. In your face. The delicacy has gone. Seems I've become addicted to the sound with the P300 in place.

So what exactly could be going on here?

Well, first the heat being generated. The P300 accepts the UK's 240V no problem. However, it is only designed to output balanced 120V. Because of this, PS Audio fitted a beefy 1:2 step-up transformer at its output. This is obviously not very efficient and gets pretty hot itself. Also, I regularly measure 250V+ AC here. I have the P300 set to output a stready 230V 50Hz. I wonder if this is stressing some of the voltage regulators in the P300. Dunno.

And as for what's causing the obvious improvement in the sound? Well, going back to the 250V+ here, maybe this is simply too high for the NOS1 to work optimally? And there's also the main reason I wanted to try the P300 in the first place - to minimize any affects of running the NOS1 off the same circuit as the power amps.

The upshot of all this is that the NOS1 works much better powered from the P300 than it does powered directly. I'm a little worried about the heat. I can replace a fan that I took out of the P300 when I bought it >10 years ago, knowing that it would only ever power low-current source components. This should obviously help. But beyond that, it's got me thinking about buying a new AC regenerator. Does anyone know of one that outputs balanced 230V (without the need of a step up trannie) and that does NOT use a switch-mode power supply (like the Purepower units, one of which I already have)?

Maybe a much cheaper option would be to replace the NOS1's transformers and PSUs for ones optimized for 240V? Peter?

Mani.

Hey Stanley, I have a PurePower 2000 regenerator. It definitely changes the sound - there's no question about that. And I think you're right to plug both the NOS1 and computer into it. But here's another thing you might want to consider...

The Purepower regenerators having big switch-mode power supplies. These (as all big SMPSs) are prone to inject a lot of noise back into the AC line. If you have other components on the 'regular' AC line, they might be affected by this noise. My feeling is that it might be better for you to run your whole system off your single Purepower regenerator.

Of course, this assumes that your 1050 has a big enough output. If you're using high-efficiency speakers, then you might be OK.

I know people who have bought multiple Purepower regenerators - one for the power amps, one for the digital sources and one for the preamp, etc. But this doesn't really work, apparently. What seems to happen is that the noise injected by each Purepower unit back into the AC line starts interfering with the other Purepower units.

For my part, my Purepower 2000 sits gathering dust in my basement. Having spent a fortune getting a dedicated AC line installed with a couple of balanced transformers, I can't bear the thought of injecting noise back into the AC line. But this is probably more of a psychological issue on my part than anything else.

Feel free to totally ignore this post if it's of no use to you.

Mani.

I couldn't find a nice thread to put this in, so thought I'd start a new one.

As part of my preparation for my new Orelo MkII speakers (see http://www.phasure.com/index.php?topic=2886.0), I now have my NOS1 pretty much totally isolated mechanically from the listening room.

I've been thinking about how best to power it. I already have two separate 5KVA balanced transformers in place - one solely for linear PSUs and one for SMPSs. The PC runs off the latter and the NOS1 and amps together off the former. And it's this that I've been thinking about...

Up until recently, I've been using class-A power amps. So even with loud peaks in the music, there should not have been any voltage modulation on the AC line. But with my current setup (BD-Design gainclone amps and low-efficiency Celestion SL600 speakers), there might be some voltage modulation. My hypothesis was that this might affect the performance of the NOS1 - a tiny, tiny modulation on the supply voltage in sympathy with the music signal. In any event, I thought I'd try to minimise this as much as possible by employing an old PS Audio P300 balanced AC regenerator that I had lying around doing nothing. I now have the P300 plugged directly into the 5KVA balanced transformer and have it powering nothing but the NOS1.

Well, what can I say? The sound seems to have been transformed. Really... transformed.

But before I get too carried away, I'd like to live with this setup for another couple of days and then go back to the setup sans balanced AC regenerator. Will be back with more views...

Meanwhile, I'd be interested in hearing any opinions on my thinking here...

Mani.