Peter, I'd be interested in the A/D and happy to pay €225 for it. But this would be a 'nice-to-have' for me, not a 'I-really-want'.

Mani.

I'm upgrading the cheap SMPS in my Weiss AFI1 interface with a toroidal + Paul Hynes PS. All the parts are on order and I should have everything completed by the end of January. If all goes well and there is a definite improvement in SQ, you may want to do something similar with your INT202.

Mani.

Raj, thanks for your little trick here. There is a definite improvement in sound in my system. Less HF 'hash'.

And thanks Marcin for the headsup in the first place.

Mani

Well, I can't argue with people's direct experiences.

Earlier I wrote:


Can anyone explain to me why a computer would be able to record well but not playback well? I mean, what is more difficult about sending music data from a computer to a DAC vs. receiving it from an ADC and storing it? Surely whatever mechanisms might be messing it up during playback would also be evident during recording. And yet, CDs which have been originally recorded on computer seem to sound great on $$$ CD transports.

Mani.

Marcin, yes recording and playback are different processes. I said that the computer SHOULD be able to play the recording back to the same level of quality that it was recorded. Here's a thought experiment. You are in the studio with Keith Johnson who has just made a new RR recording using Pro Tools (or Pyramix, or Sonic Studio, or whatever) and which sounds stunning. He has the pristine digital file on his hard drive. So, you're going to tell him that he can't play it back on the equipment on which it was recorded because actually, althought this equipment is good enough to make some of the best recordings on the planet, it's not good enough to play these recordings back?

(Of course, Windows X would suggest that he creates a redbook CD of the recording and play it back on a $$$ Esoteric CD player in order to hear it in it's full glory.)

I think most of us here are all too familiar with the foibles of computer playback. But my point is that computer recording is no less easy. If you can get a computer to record well, then there SHOULD be no reason why you can't get the same computer to play back well also... IMHO of course.

Mani.

Windows X, your posts remind me so much of the 'conversation' I had with a certain hifi dealer in the UK. He was convinced that the $20K Spectral CD player that he sells is better than my computer playback system (without actually having any idea of what my system is).

To him and to you, I would ask this: HOW DO YOU THINK THE CDS THAT YOU THINK SOUND GREAT ON YOUR CD PLAYER ARE CREATED????

You can bet your life there was a computer involved. If a computer is good enough to create the CDs that sound so great on your CD player, then it should be good enough to play the files back. Period.

Mani.

From a purely theoretical point of view, I would have thought that DAP-in-XX + 4xOS-in-DAC would have given you the best sound (8x oversampling in total). As Peter said, just DAP-in-XX with filter-off-in-DAC will give lots of HD near the real signal.

With filter-off-in-DAC, I would have thought that the oversampling switches (1x to 8x) would make no difference whatsoever. I mean, the filter is off, after all. And this is what you seem to be finding.

In any event, hopefully DAP + 4xOS is giving you good sound. And count yourself lucky that you have a true multi-bit DAC (i.e. no massive 64x or 128x oversampling) with which to try these things.

If the Ref7 could accept 176.4/192 signals through its BNC input, I think it would make it a very attractive proposition. I bet it'd work really nicely with a BNC-hiFace, XX set to QAP and the filter switched off in the DAC.

Mani.

This is totally crazy. I don't see any reason why Audio-GD have limited the non-USB inputs to 96KHz. Maybe because of the filter... but this can be bypassed!

Mani.

OK, be very, very careful!

If Marcin is right, then you are now using DAP with no filter in the Ref7, right? This may be too low to go filterless - maybe Peter can give his advice.

I strongly advise against not engaging any filter at all either in XX (AP or AI) or in your DAC. You will have a lot of HF stuff coming through. It may sound quite euphonic at first, but it's not a good thing to do... Peter often quotes 30% THD, etc.

Mani.

I'll try this also at some point and let you know what I think.

Mani.

It's just the little dip switch in the unit, isn't it?

Try to use QAP (i.e. 4x) upsampling if you can because DAP (2x) isn't going to be high enough without extra filtering. I think QAP is the filterless lower limit, with OAP (8x) or higher being the ideal.

In any event, keep the volume down as you're trying these things out because you may get some HF stuff coming through (depending on your system).

Let us know how it goes.

Mani.

Flecko, with your Audio-GD Ref 7 DAC, are you bypassing the oversampling filter when you use Arc Prediction? I think you should...

Mani.

I think there's an issue with nomenclature here. Although there are no precise definitions, mine are as follows:

Upsampling is done before the filter in the DAC

Oversampling is done during the filtering in the DAC

So Josef, when you say turn the oversampling off, most people would not be able to do this. 99.9% of DACs are delta-sigma, and therefore by definition need oversampling to work. Some DACs have the capability to upsample 2x or 4x. This is sometimes switchable on/off.

Arc Prediction is a means of upsampling in the software. If you have upsampling in your DAC, try to switch it off if you can. If you have a true multi-bit DAC, try to switch the oversampling filter off, or bypass it. If you have a delta-sigma DAC (highly likely), see if you like the sound of AP - you may, or you may not, depending on your DAC.

Mani.

Marcin, I'm not sure whether Peter still wants to keep the conection type under covers, but a particular type of cable was mentioned in the NOS1 Specs doc under 'Contents of Package'.

Mani.

Hmmm, I can't get low unless I'm playing a video. 'Apple.com' doesn't help. But in any event, it should be possible for Peter to implement something, if other (WASAPI) players can do it.

Mani.