Hey Dan,

Did you ever manage to try the Mykerinos with your Alpha? I'm just interested...

Cheers,
Mani.

This makes sense... and kind of concurs with the graphs you posted over at CA.

I'm still interested in the 'DAC is' setting though. Would setting this to '32 bits' allow for digital attenuation up to 48dB without loosing any of the extra resolution created by AP?

Mani.

Yep, I've switched mine off using the BIOS facility (and also gone from 4 to 2 cores, to use XX's core appointment effectively). But this may be mobo-dependent...

Mani.

Aaaahhhh. This might explain what I've been struggling with recently.

When AP was first released, I was an immediate fan. I loved it. But recently, I've become a little more 'critical' of it, both here and on CA. It's virtues are irrefutable IMO, but the sound hasn't seemed quite right. So much so that I've reverted back to playing 16/44.1 tracks natively. BUT... a few months ago, I started using the XX vol control for critical listening (DAC connected directly to power amp) due in most part to Peter's insistence that all preamps corrupt (which I do believe, BTW). Maybe this is the reason why I've gone 'off' AP...

Even though I have a reasonably good preamp (Pass X1), I would very much appreciate a physical vol control on the NOS1.

One final thought. Most of us are setting DAC to 32 bits. Would XX's vol control still be throwing out the 'good' bits created by AP?

Mani.

Yeah, nothing's perfect... right?

Mani.

Hey Gerard, thanks for the write up of your visit with Leon to Peter's place. I really appreciate the time you've taken to do this.

Mani.

Yes. But I think there are ways to optimise the connection.


This pretty much reflects my experience in using spdif (and AES/EBU) interfaces. BUT... this is exactly where slaving the interface to the DAC really, really helps. The brightness disappears and the sound becomes 'organic' and 'whole'. The exact mechanism that is causing this, I'm not sure.

My strong advice to anyone using an spdif interface connected to a DAC: if it is possible, try slaving the interface to the DAC. You will be amazed at the improvement in sound.

My strong, strong advice to everyone: ditch your spdif interface and DAC as soon as the NOS1 is available

Mani.

Hey Peter, I always appreciate your long posts. But I just wanted to say that your above post struck a particularly sweet chord...

For me, this says it all.

In his book, 'Good to Great', Jim Collins talks about the 'hedgehog principle'. A great company has three factors in place:

1) it is passionate about what it does
2) it is the best in the world at what it does
3) it can sustain itself economically from what it does

One of my favourite companies in the world is Rolls Royce (aero engines, not cars!). I think it fits all three factors. But I think you can apply these three factors to individuals as well. When you're doing something that hits the spot on all three, then look no further... you've found your 'calling'.

Mani.

???

Here's what Pat at 'Analog Research Technologies' had to say about it when I asked him:

"Transmitting a word clock, separate by itself, will greatly reduce jitter. But, it will not eliminate it. Most modern DAC chips use the bit clock, as the crucial clock. The word clock merely tells it when all the bits are loaded. (Look at the PCM1704, as an example. The conversion takes place 2 bit clocks pulses after the word clock changes state.) It would seem to me that there has to be some sort of PLL, to derive the bit clock from the word clock. Obviously, this is a much easier matter than getting the bit clock from the SPDIF (or AES/EBU signal), but there will be a measurable amount of jitter.

Audible? Perhaps not. It will be Gaussian in nature, and the threshold of audibility is higher, than with data-correlated jitter."

In any event, my experience is that if you're using an spdif cable to connect a PC-interface to a DAC, the best SQ is achieved when you slave the PC-interface to the DAC via a separate wordclock cable. But of course, eliminating an spdif cable in the first place may be a better solution.

Mani.

Pedal, this is probably not very helpful, but here is what I would look into...

1) Get a wordclock output working from your DAC to your interface. Of course, I understand that this may be very difficult, impossible even. Not only do you have to figure out what to do on the hardware side, but you also need to figure out a way to switch rates at your DAC. Even if this is possible, it's a right PITA.

2) If this is a no-go, then I'd play around with different spdif cables. There is one that not many people know about, which is supposed to be better than any other, irrespective of price. It is the Belkin Platinum Synopsis cable (#F8C310-06-PLT). This will definitely take out any trace of digital sound that you have. But, you won't be able to find this anywhere - people who have this cable will not change it for anything else. However... I have a spare cable (brand new, still in package). Although I'd rather keep it, I'd be happy to sell at the same price I paid for it (~€50 IIRC) .

3) More practical, I'd keep your current settings and play around with the split file size. No doubt you've followed the thread - it really changes the sound, with a higher split file size providing a 'more relaxed' sound - a Red Bull detox.

Mani.

Yes, this is interesting.

But the obvious question is, what is causing the interference? Perhaps anything with a motor has a negative affect on SQ? (I know that many people cite the motor and servo-system as being the main issues with CD-transports.) If so, then you've got to get all the HDDs and fans out of the PC (the route that I've taken). This should lower the power consumption of the PC also, which might help.


This is also interesting. My experience, playing around with wordclocks, PLLs and RAM buffers in DACs is that this is what less jitter sounds like. Some people describe jitter as sounding 'muddy' and 'muffled'. In my experience it sounds more 'edgy' and 'bright'. But perhaps a lot is dependent on the jitter spectrum.

Mani.

That's exactly what I suspected - use the fastest sustain write drive for XX... and for the OS also (why not?). I'll report back if I feel the SQ has changed.

Thanks.

Mani.

I need some advice...

I have two different types of SSD:
i) OCZ Vertex Turbo (120GB) - read up to 270MB/s, write up to 200MB/s, sustained write 120MB/s
ii) OCZ Vertex 2 (90GB) - read up to 285MB/s, write up to 275MB/s, sustained write 250MB/s

Which option do you think will yield the best SQ?
a) both OS and XX on Vertex 2
b) both OS and XX on Vertex Turbo
c) OS on Vertex 2 and XX on Vertex Turbo
d) OS on Vertex Turbo and XX on Vertex 2

EDIT: I should have mentioned that I use the 'Copy to XX drive by standard' function.

Cheers,
Mani.

Just for clarification, I have the following interfaces:

- Weiss AFI1 (firewire) and not the INT202
- RME AES-32 (PCI)
- RME FF800 (firewire)
- MOTU 896HD (firewire)
- M2Tech hiFace (USB)

My only interest is in interfacing my ADC/DAC to my PC, and so I use these in a similar way to pedal.. My strong preference is the RME AES-32 - it simply sounds the best in my setup, easily bettering the Weiss AFI1, which does sound bright and edgy in comparison (maybe a family trait here?). And I'm really not convinced by the DICEII firewire chip. I think Weiss use it because computer audio (as opposed to digital audio) hasn't really been what they've made their name in, in the past, so they simply buy the firewire solution off the shelf.

Incidentally, I chose the AFI1 over the INT202 because the AFI1 can accept wordclock I/O. Over many years of experimentation, I'm absolutely convinced that the master clock needs to sit as close to the ADC/DAC chips as possible for the best SQ, and if you're using a separate ADC/DAC, this just isn't possible without a wordclock I/O. Maybe, as pedal suggests, the RME clock isn't great. But that's not an issue if the unit is being slaved to the ADC/DAC clock...

Mani.

Peter, what SFS were you using during your listening?

What's of particular interest to me is whether changing the SFS causes a consistent change in SQ. For me, starting at 12MB and increasing the SFS makes the sound fuller, but perhaps too woolly if increased too much. Do other people experience the same?

What I am now convinced of though is that we CANNOT come up with a universal 'best SFS' number for everyone. When I had my CPU rate set to 9x, I preferred a SFS of ~60-70 (for 16/44.1 material). But set at 21x, I'm perfectly happy with a SFS of 12MB.

Mani.