Differences in sound: DAC vs. DAC + Pre-amplifier

[motberg]

Is it required to oversample the file (say Redbook 16/44) to get the best performance for using a digital software volume control, using HQPlayer for example ?

[motberg]

On 3/7/2020 at 9:11 PM, Miska said:

 

It depends on the DAC too, but it certainly helps since it allows more resolution and especially with noise shaping curves increase of dynamic range beyond that of output word length within the original bandwidth.

 

 

OK!  I am testing this with my NOS DAC, HQPlayer 3, dual PC, just got a Windows NAA working on Server 2019 GUI and it is sounding great so far.. For HQPlayer, how is best to manage the "gain staging" of the digital volume control? I am upsampling to 384, within the rate family, and have Min Vol set at -60 and Max Vol set at -3.. would this be optimal ?

 

 

 

[motberg]

7 hours ago, Miska said:

 

Suitable range setting depends on how you use the volume control...

 

 

with a good passive pre in my system (Lightspeed LDR), I am guessing I usually use less than 25% attenuation

Speakers are very inefficient, DAC is 4 x PCM1704UK per channel, possible to 768KHz

I do not think I would damage anything if the DAC full level hit the amp

 

my question is, when using HQPlayer, how to adjust the settings to arrive at the most optimal "bit saturation".

[motberg]

8 hours ago, Miska said:

 

Suitable range setting depends on how you use the volume control...

 

Here is real world configuration:

 

Using @ericuco suggestion (thanks!) I set max vol to -10 db

my normal volume level will be a couple db less than max.

 

So - at 44.1/16 -> 176.4 K, HQPlayer vol set at -12db, what am I losing in terms of dynamic range?

Are there any settings available to optimize this (such as increasing bit depth) ?

[motberg]

57 minutes ago, sandyk said:

 

 

IIRC, some years  back, Nelson Pass posted some measurements in DIY Audio highlighting this problem .

The maker has posted also his distortion calculations and seems really low to me....

Not sure if the PS has any effect, but mine is powered by mains regenerator into LPS into 4 x LT3045 regulator

The Lightspeed has been on Stereophile Recommended Components list and gets great comparative reviews.

It certainly subjectively was much clearer to me than my Schiit Saga + in passive mode. (already sold the Saga +)

[motberg]

4 minutes ago, sandyk said:

 

 I would suggest that you do a Search in DIY Audio for Lightspeed and Nelson Pass to see if you can find the posted measurements  of actual LDRs

I already saw them... I am sure was well below audibility... remember some decimal points and zeros, etc...

[motberg]

4 hours ago, sandyk said:

 

 Your idea of audibility may not be the same as others who may have more revealing equipment.

 A Preamp/PA often has distortion levels well below that of most volume controls and many attenuators.

For example, both my DIY Class A Preamp and 15W/Ch. Class A Power Amplifier have distortion figures of well below .0006%

 

https://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-passive-preamp-373.html#post2386530  # 3726 

The quoted figures are far from inaudible when combined with a low distortion Preamp/P.A. 

" 0.25 % THD for -20 dB of attenuation."  

 I saw also that George HiFi also went on the defensive : 

" Get your head out of these finite distortion measurements, and listen to what your ears are telling your brain" 

what is the threshold of audibility ?

[motberg]

7 minutes ago, sandyk said:

That depends on your training, experience,  and the Signal to Noise Ratio of your equipment. Naval Sonar operators can even hear things below the noise floor , as both  Miska and Paul R. can verify

Any scientific back up to the claim 0.25% THD as tested in your example is detectable by average humans?

[motberg]

36 minutes ago, sandyk said:

 I suggest that you do some research for yourself for a change. There is plenty of information available on the subject .

I have not seen any valid study done where the THD was reported detected at less than .5%. That is why I was asking, since you seem to be sure 0.25% is audible.

 

In any case, it certainly is not the bottleneck in my system.

 

And now that I got HQPlayer setup direct out, I am more convinced that the Lightspeed is more representative of the direct signal than any other preamp I have heard in my system.

[motberg]

On 3/2/2020 at 3:11 AM, barrows said:

Then consider that most volume controls in software are running at 64 bits!

 

 

Thanks, can you please advise a couple software volume control options that you consider well implemented.

[motberg]

I just ran AO on the HQPlayer Win2019 GUI NAA machine...

 

Wow.... I was shocked how good this software volume control is using HQPlayer. I have tried other softwares years ago and recently the built in volume control on a Topping D70 and a Gustard A20H without major success (the Gustard was pretty good though).

 

I have not run through all my normal test tracks yet, but my preliminary observations indicate the HQPlayer vol. control has no major audible drawbacks in my system.

 

Thanks to everyone who helped get me this far.... much appreciated....

[motberg]

4 hours ago, barrows said:

Sorry, i guess I was not clear.  In no way do i mean to suggest that those who design preamps are trying to add colorations.  What I am saying is that any component addition (like a preamp) can only result in loss of fidelity; by adding a preamp, where one was not present before, the only possible result is that doing so adds more distortion and noise than there was before.  If one then prefers the sound with that preamp in place, what that person is preferring is the coloration added by that preamp's noise and distortion profile.

 

And, of course no system is 100 % transparent to the recording (electronics can get very close these days, but certainly not speakers!), but to me it is the goal of a good system to be as transparent to the recording as is possible.  Adding unnecessary components to the system is counter-productive to that goal.

But I think to use software volume control, you need modify the source file digitally. So isn't the choice digital manipulation of the source vs. analog manipulation of the DAC output?

[motberg]

I know this is a stretch... but has anyone compared a Schiit Freya S to software volume control ?

[motberg]

What do you guys think about adding sub-woofers in a DAC direct to amp system?

Is it OK to split a 2V RCA output and run a set of cables 1 meter to the amp, and another set to the subs maybe 4 meters each?

 

I get the feeling that most DAC makers generally are expecting the user to use a single set of outputs to a single receiving device.

 

[motberg]

8 hours ago, DuckToller said:

Bonjour, Audiobomber.
Short question about miniDSP, do I assume correctly, that the signal for your Subs and your speakers will run through ADC-DAC conversion at 24/96 during the DSP? Please feel free to correct me about my assumption
I do have a 2x4miniDSP somewhere in the closet and may start testing during the confinement  period...
Cheers, DT

I am also using the MiniDSP for subs... subs only, monitors running full range... the miniDSP 2x4 HD version was an audible upgrade from the prior model in my system.