Audio-gd Reference 7.1 DAC - Page 3  

Apparently, bypassing the DSP1 also defeats oversampling, which is kind of a problem

However, I might have nailed down my issue with the Ref 7.1. Some high res material at 24/96 sounded absolutely stellar (talking only from a timing perspective), while regular CDRB format file simply did not. But if I am not mistaken, I realize that the master clock of the DSP1 only supports 32khz and 48khz (256Fs, 384Fs, 512Fs and 768Fs). So I decided to use Pure Music excellent SRC build in engine to upsample everything to 24/96. Improvements were obvious in my system when playing back native CDRB files. I am very curious to hear what other Ref 7.1 owners think about this.

I will also try to turn off the PLL (the AP2 might not need it) to see if it can get even better. But I need first to figure out how to open it

 

Quote:

Originally Posted by shamu144 

EDIT: does anyone have tried disabling completely the DSP1 ? It seems to me the AP2 does not really need jitter correction and I feel tempted to disable it. Would that still work without damaging anything ? I see there is also a NOS setting that may improve timing and flow but at the expense of separation and clarity.

Seeing as how most audio is presented with 44.1 KHz sampling rate, it's a bit troubling to hear that the DAC performs better when you resample to 96 KHz before feeding in the signal.  From your posts it seems you've been burning the unit in for less than a week.  It would be interesting to hear the results of an A/B comparison between feeding 44.1 and 96 once the unit has been fully burned-in.  I look forward to more of your impressions.

Happy listening!

Quote:

Originally Posted by shamu144 

Apparently, bypassing the DSP1 also defeats oversampling, which is kind of a problem

 

However, I might have nailed down my issue with the Ref 7.1. Some high res material at 24/96 sounded absolutely stellar (talking only from a timing perspective), while regular CDRB format file simply did not. But if I am not mistaken, I realize that the master clock of the DSP1 only supports 32khz and 48khz (256Fs, 384Fs, 512Fs and 768Fs). So I decided to use Pure Music excellent SRC build in engine to upsample everything to 24/96. Improvements were obvious in my system when playing back native CDRB files. I am very curious to hear what other Ref 7.1 owners think about this.

 

I will also try to turn off the PLL (the AP2 might not need it) to see if it can get even better. But I need first to figure out how to open it

 

If the lower res recording was not up to snuff, the 7.1 might be revealing it's flaws ruthlessy. I would suggest taking the 24/96 recording that sounds good to you and down sample it to 16/44.1 and give it a listen. 
 

Also, I will reiterate that you need to live with this dac for a couple of weeks before doing anything or giving final judgement. I have read about a dozen accounts from Ref dac buyers that are a little disappointed at first (myself included) that reach a point where the dac becomes fairly amazing.

Quote:

Originally Posted by LarsHP 


I think 96kHz-24bit should sound better than normal CD format files (even upsampled) or else there was no point in making (and buying) hi res music files.

If the music was originally released as 24/96 or something similar, of course you would expect an improvement over Redbook CD.  If the music was released as 16/44.1, I don't understand how resampling it would introduce any improvements unless the equipment you are feeding it through somehow works better when being fed a signal with a certain sample rate.  For example, I know many sound cards internally resample the signal to 48 Khz and then back to the original because for some reason it can process that signal better.  This led some people to resample the signal to 48Khz in software before sending it out to the sound card, the idea being that the sound card would not have to resample the signal and in many cases the software resampling can be of higher quality than what goes on in the sound card.

Keeping in mind the way sampling works to take an analog signal and convert it into digital form, I would love to learn how REsampling with a higher sample rate would increase quality.  Remember I am not talking about music that was sampled using a high sample rate to begin with.

Anybody else care to comment on this?

Is the DSP still rev 5 ?

Quote:

Originally Posted by glenda 

Is the DSP still rev 5 ?

Yes, it's the final according to Kingwa

Quote:

Originally Posted by shamu144 

My prefered settings so far:
- Pure Music with target upsampling at 96khz.
- "NOS Classic" upsampling (there are 2 minimum phase upsampling method to choose from)
- PLL off
- Stopband attenuation -90dB
Sounds sublime to my ears now even with CD rips. It was certainly not the case prior to these changes.

Are these settings all on your Mac or did you change anything in the DAC?
 

Thanks for the tip ! Look what happens when you don't get a manual in the package  I hope I didn't miss any other crucial information...
 

Do you know if this is intended to limit the premature aging of components due to the heat inside or for another reason... I always thought turning the power on/off every day would also cause some undesirable aging of the components and some manufacturers in fact do recommend to let their unit on at all time (the Lavry for example). I find it a bit cumbersome to have to think about warming up the beast before any serious listening.
 

Quote:

Originally Posted by IPodPJ 

They specifically state that you should not run the DAC for more than 8 hours a day.

The RE7.1 not quite hot.

If it have good heat dissipate, like have not anythings cover on its top board, far to the heat source, it can power on 24 X5 hours. Then want to had a restart.

Great news ! Thank you Kingwa, it is good to know there is some flexibility for powering on/off the Ref 7.1.

Quote:

Originally Posted by Kingwa 

The RE7.1 not quite hot.

If it have good heat dissipate, like have not anythings cover on its top board, far to the heat source, it can power on 24 X5 hours. Then want to had a restart.