Gain / Amplification


Ok, dumb question maybe….maybe the more troll-like members could chill on this one.    I was just wondering, is there likely a quality-of-sound difference between utilizing maximum gain (say, out of a CD player, to keep it a simple scenario) and needing much less amplification from your amp, or is it in any way different to set your CD gain/output volume at a lower level and let your amp do its job?   Let’s say balanced connections, so that’s added gain as well.    
Question just kind of occurred to me when I fired up my Oppo for first time in awhile and it was **LOUD**.   Which is not an issue, I was just wondering, circuit design-wise and engineering-wise, should one or the other provide a better sound ?

 

JH

jhajeski

This is interesting.  I have a server with software interface volume setting for fixed or variable feeding my DAC ( no vc). Although variable control would be more convenient as my tube preamp has a manual stepped attenuator I set software to fixed output. I've listened both ways and even eliminated the preamp from the chain without noticing much difference. I've thought digital software driven volume control was supposed to be inferior? I like having the tube pre in the mix although unnecessary in my system so it's acting more like a buffer with gain. By the way my preamp has 12db gain. I tend not to go back and forth between configurations so I'm used to getting up to manually adjust volume. 

I can't speak to the Oppo but I have a similar situation with an NAD C-658 DAC/preamp. I used to use it as both a DAC and premap with a set of Rogue M-180 monoblocks. I finally came up with some cash and bought a new Rogue RP-7 so now I use the NAD as a DAC only. What I found is if the NAD is set to higher than 70% output I can only go to 125 or so in volume on the RP-7 before I begin to hear some "noise" in the form of distortion. The NAD has a feature where I can set the output signal to a value and not worry about additional noise from my system. The "70" number mentioned for the Oppo seems to hold true for me too since after I set the NAD to 70% output fixed I no longer have the noise issue. It took a little trial and error but the 70% output set value seems to be te ticket for me.

Let’s put clear cut opinions on the side. To answer this correctly, we need details on each stage, the nature if its gain, and how it is controlled. Its worth everyone understanding that in general the idea that "more or less gain is employed here or there" is a misunderstanding of how circuits re designed. In 90-99% o cases, gain is fixed in both places. What is varied is **attenuation** (some form of variable volume control). These are lossy and passive in most cases, but again there are myriad ways to implement.

In terms of ranking the quality of volume control methods, the digital domain (certainly how its done in PCs, macs, phones, and tablets) is often the worst, except in certain cases using very select DAC chips (among them the ESS 32 bit chips). I believe the Oppo used these. Beyond that -- and again God is in the details -- as you change volume you may change output impedance and matching.

The rule of thumb - big picture -- is set any DAC or PC to 100% volume and control it with the better quality analog volume control in your preamp. In the case of the ESS -- if its implemented correctly, it might actually be better there.

 

Justme

 

note: sometime back on another topic i did a long rant/explanation of various methods of contorting volume and the significant benefits/problems of each.  Sorry i cant be more helpful pointing to it.

itsjustme 

thanks that’s exactly what I think I was looking for.    Yes, it’s an Oppo 205 with great ESS chips, and I run it thru a Parasound Halo Pre to a Parasound A21+.

Despite the ESS chipset, if analog volume control (at the preamp) is [circuit design/engineering wise] “better” than how it’s done in the digital domain, that’s what I was trying to confirm.    Obviously everyone’s situation will be a little different depending on their specific gear and other variables.

 

 Thanks all.  

atmasphere 

 

thanks for the education & confirmation on volume control in digital vs analog domains.    I never really realized the difference til now.