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

[barrows]

@Blake, agreed.  BTW, I know Jim, he is a really nice man.

 

Of course, what I would say, is that if one prefers the sound with a preamp in the chain, there is probably a "problem" in the system somewhere (given a set up where the DAC does have an appropriate output stage for driving the amp), which the preamp's additional noise and distortion are covering up.  This is kind of like the person who finds their system too bright, and decides to tamp down the high frequencies a bit by using a highly capacitive cable: the problem with this approach is that it is lossy, "fixing" one problem but adding another.  Such an approach to system building results in less and less fidelity as changes are made by adding more losses to cover up problems.

 

I am interested in hi fidelity playback, and not playback which is intentionally colored, or obscured.  Other's may prefer a colored system, and that is fine with me as long as they recognize that and understand that the colored sound is what they are getting.

 

Personally, I find that systems with a lot of their own colorations can sometimes sound "good" (think SET amp with simple music), but they tend to make different music sound the same, rather than maximizing the differences between different music, and often the reduction of small details from his approach can obscure the greater musical meaning.

[Blake]

1 minute ago, Kimo said:

 

Not according to the guys who make the most transparent electronics in the world, as I pointed out earlier.  

 

 

 

I might have missed that.  Which company makes the most transparent products in the world (sorry if your comment was tongue in cheek)? 

 

[Blake]

6 minutes ago, barrows said:

I am interested in hi fidelity playback, and not playback which is intentionally colored, or obscured.  Other's may prefer a colored system, and that is fine with me as long as they recognize that and understand that the colored sound is what they are getting.

 

 

 

I don't know that all preamp designers are intentionally coloring the sound, in fact I am sure that is not the case with some preamps, but of course, there are probably plenty of designs out there with intentional colorations.  But again, you are speaking from a relative point of view here, right?  Your current system for example is not 100% transparent, you are just attempting to get as close as possible to a theoretical ideal of transparency.

 

[Kimo]

3 minutes ago, Blake said:

 

I might have missed that.  Which company makes the most transparent products in the world (sorry if your comment was tongue in cheek)? 

 

 

Based on SNR, Benchmark.

 

Although, I believe there was an Apogee DAC that measured even better than what they can do.  I suppose if that were true, you would need to substitute the Apogee for the DAC 3 in the Benchmark system.

 

Of course, they may make the only preamp in the world that qualifies, but at least there is one, apparently.

[barrows]

31 minutes ago, Blake said:

 

I don't know that all preamp designers are intentionally coloring the sound, in fact I am sure that is not the case with some preamps, but of course, there are probably plenty of designs out there with intentional colorations.  But again, you are speaking from a relative point of view here, right?  Your current system for example is not 100% transparent, you are just attempting to get as close as possible to a theoretical ideal of transparency.

 

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.

[craighartley]

On 3/1/2020 at 7:11 PM, barrows said:

I have more than one DAC, some have volume controls, and sometimes I may control volume in software.  

 

So, on volume controls:  Digital Volume control, in software on a computer, or in in hardware on most DAC chips, is generally going to perform better than most analog volume control implementations.  As long as one does not need huge amounts of attenuation (more than -40 dB or so).  If one is listening at very low levels, small details will be below the noise floor anyway, so at high levels of attenuation one is not missing anything.  Despite many audiophile myths to the contrary, there is nothing about digital volume control when well implemented (at 32 bits or more, with a properly matched system gain structure).

 

What a lot of people seem to ignore in the discussion of volume controls is the analog volume controls are far from "perfect", they add noise and distortion to the signal of their own.  Digital volume control is actually more transparent than analog within it s limits:

 

Consider a 32 bit volume control in the digital domain, and a 24 bit source file:

 

32-24= 8 bits, so with a 32 bit volume control one has 8 spare bits to use with no impact on resolution.

 

8*6=48, so one has -48 dB of volume reduction before any resolution (of our 24 bit source file) has been lost, this means there is no problem here!

 

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

 

Then consider that actual i room dynamic range of a system is never better than 16 bits...  So in our above example there are actually 16 bits of resolution we can lose without any audible consequences, so we really have 16*6=96, -96 dB of reductio possible with our 32 bit volume control without any impact on real world resolution in room.

 

One can see that there is no "problem" with digital volume control. 

I so want to take my expensive transformer-based ‘pre-amp’ out of my system, but if I do that I get a prominent click out of the speakers on the start of music playing, which is negligible with the ’pre’ inserted. Miska has suggested that this may be due to DC offset from the DAC analogue output, but it disappears if I stream from Roon direct (via MicroRendu in RoonReady mode) rather than Roon>HQPlayer>NAA. 
I know my amps have too much gain (39db) for the software volume solution to be ideal, but it’s the click that prevents me pursuing it. 

[barrows]

6 minutes ago, craighartley said:

I so want to take my expensive transformer-based ‘pre-amp’ out of my system, but if I do that I get a prominent click out of the speakers on the start of music playing, which is negligible with the ’pre’ inserted. Miska has suggested that this may be due to DC offset from the DAC analogue output, but it disappears if I stream from Roon direct (via MicroRendu in RoonReady mode) rather than Roon>HQPlayer>NAA. 
I know my amps have too much gain (39db) for the software volume solution to be ideal, but it’s the click that prevents me pursuing it. 

Wow Craig, 39 dB is really high and quite unusual gain for a power amplifier.  Have you ever contacted the manufacturer and asked if the gain could be lowered?  That much gain is probably also make the amp(s) noisier than they could be.

 

Of course your "click" problem is something other than preamp related.  If i had that "click" problem i would track down the ideal solution for the problem, rather than covering it up by adding a transformer based pre/volume control.

[craighartley]

1 minute ago, barrows said:

Wow Craig, 39 dB is really high and quite unusual gain for a power amplifier.  Have you ever contacted the manufacturer and asked if the gain could be lowered?  That much gain is probably also make the amp(s) noisier than they could be.

 

Of course your "click" problem is something other than preamp related.  If i had that "click" problem i would track down the ideal solution for the problem, rather than covering it up by adding a transformer based pre/volume control.

There’s a switch to reduce the gain by 6dB when using the amps in monobloc mode, but I’m already doing that. I have a pair of these:

https://www.leema-acoustics.com/product.html?prid=59#spec

I may send the T+A DAC8 DSD back to T+A to check if there’s a fault, but that means sending it to Germany (I’m in the UK) and I might wait until things are a bit calmer (I mean in relation to Covid-19, not irritating clicks from my speakers). 

[mevdinc]

In my personal experience I always preferred going direct from DAC to my active system.
Of course, for this to work DAC has to have a very good volume control.
 

[Miska]

22 hours ago, Kimo said:

My DAC employs a log ladder network to create a constant impedance passive attenuator, for whatever that is worth.  I can't tell the difference between fixed mode or the attentuator.   I tried but failed.

 

My amp has a pretty high SNR, so apparently it is possible to make an analog volume transparent to me at least with an ESS chip.

 

You can get some additional transparency by omitting that ladder network and extra buffer stages and going with a good digital volume control instead.

 

[barrows]

@craighartley, cool looking amps.  but I ma confused, looks like the Leema is an integrated with its own volume control?  Why not just use the amp's VC?

[sandyk]

9 hours ago, DuckToller said:

Bonjour Alex,
please allow me to ask, if you believe these figures (0,002%THD) are audible for common audiophiles (60+ years), the majority of whom may not have been able to meet the requirements for the job as Naval Sonar operators even at young age and therefore had to forego the special training associated with it?
Stay safe and sound, DT

You don't need special training to hear distortion, unlike the Sonar requirements.

Quite a few DIY Audio members were able to hear clear differences between the different states of the attached amplifier with front end modifications. The measurements were posted in a DIY Audio thread by a member from Melbourne. See also :

https://www.diyaudio.com/forums/solid-state/134221-silicon-chip-200watt-ld-amplifier-2.html # 13 and 15

They were also able to hear clear differences with Front End balancing as in the attached link to a DIY Audio thread where Nelson Pass was also a participant.

https://www.diyaudio.com/forums/solid-state/133018-current-mirror-discussion-15.html

[craighartley]

1 hour ago, barrows said:

@craighartley, cool looking amps.  but I ma confused, looks like the Leema is an integrated with its own volume control?  Why not just use the amp's VC?

No, the Hydra is not an integrated amp, it’s just a power amp. If it’s used with a Leema pre-amp (Pyxis) or integrated (Tucana) you can use a data cable which controls the gain in the Hydra, but it has no volume control of its own. The circular illuminated display on the front simply shows the volume when controlled by a Leema pre-amp or Integrated using the datalink.  When used with other amps or direct from a DAC the gain is fixed and that display remains centred.

[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?

[barrows]

28 minutes ago, motberg said:

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?

Yes, but software volume controls typically run at bit rates much higher than that of the source file, so there is no loss.  For example, with ROON volume control, it works at 64 bits, so if your file is even 32 bits, you retain all the bits of the original file with no change with attenuation of up to 32 bits.  32 bits equates to about -192 dB, so as you can see, there is no loss of information.

[DuckToller]

4 hours ago, sandyk said:

You don't need special training to hear distortion, unlike the Sonar requirements.

Quite a few DIY Audio members were able to hear clear differences between the different states of the attached amplifier with front end modifications. The measurements were posted in a DIY Audio thread by a member from Melbourne. See also :

https://www.diyaudio.com/forums/solid-state/134221-silicon-chip-200watt-ld-amplifier-2.html # 13 and 15

They were also able to hear clear differences with Front End balancing as in the attached link to a DIY Audio thread where Nelson Pass was also a participant.

https://www.diyaudio.com/forums/solid-state/133018-current-mirror-discussion-15.html

Alex,
I may qualify your answer sadly as smoke and mirrors rather than a substantial response.
Reading the old DIY threads in consideration of my question was simply a waste of time.
My full answer to your post  will arrive tomorrow in the objective-Fi section, as I do not want to derail this thread further.
Stay safe & sound, DT

[Kimo]

4 hours ago, Miska said:

 

You can get some additional transparency by omitting that ladder network and extra buffer stages and going with a good digital volume control instead.

 

 

I am pretty sure Mr. Linnenberg would not agree.  Dynamic range is specified as 138 db.  Anyway, I use the line level inputs for the vinyl rig, so I need an analog control somewhere.

[motberg]

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

[sandyk]

39 minutes ago, DuckToller said:

Alex,
I may qualify your answer sadly as smoke and mirrors rather than a substantial response.
Reading the old DIY threads in consideration of my question was simply a waste of time.
My full answer to your post  will arrive tomorrow in the objective-Fi section, as I do not want to derail this thread further.
Stay safe & sound, DT

Don't bother.

I posted more than enough information already in an area where this was not deemed necessary.

I want nothing further to do with a member like yourself who has already made it crystal clear that he wishes to see me banned from the Objective area, and by the look of it the forum itself .

Any replies from you to me, or quotes from me in that area will be ignored and remain unread.

 

Stay safe & sound

[barrows]

1 hour ago, Kimo said:

Dynamic range is specified as 138 db.

 

I am curious as to what this refers to?  DR of what exactly, as this number is at the extreme end of what is possible in the analog realm (and only for line level, amplifiers, not at all...)

[Miska]

10 hours ago, motberg said:

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?

 

Digital manipulation can have precision that far exceeds any analog capabilities. In digital domain, the errors can be for example a millionth of thermal noise achievable at room temperature.

 

[Miska]

8 hours ago, Kimo said:

I am pretty sure Mr. Linnenberg would not agree.  Dynamic range is specified as 138 db.  Anyway, I use the line level inputs for the vinyl rig, so I need an analog control somewhere.

 

I don't know who is Mr. Linnenberg, I can let him disagree, no problem.

 

Even at 32-bit PCM output, without noise shaping, dynamic range is 192 dB. And with noise shaping you can push it to for example 240 dB or more. And then if the digital volume control errors are at or below -300 dB, I would say that is quite a bit better than you can do in analog domain.

 

[Kimo]

9 hours ago, barrows said:

 

I am curious as to what this refers to?  DR of what exactly, as this number is at the extreme end of what is possible in the analog realm (and only for line level, amplifiers, not at all...)

 

Yeah, who really knows.  We would be talking 23 bits.  I am not even sure that parts exists that could hit that number.  Are there resistors available that are that quiet?

[Kimo]

2 hours ago, Miska said:

 

I don't know who is Mr. Linnenberg, I can let him disagree, no problem.

 

Even at 32-bit PCM output, without noise shaping, dynamic range is 192 dB. And with noise shaping you can push it to for example 240 dB or more. And then if the digital volume control errors are at or below -300 dB, I would say that is quite a bit better than you can do in analog domain.

 

 

But once it hits the analog realm, does any of this matter?  If you built a room quiet enough to hear or not hear any of this, could you actually sit in it very long?

[Miska]

10 minutes ago, Kimo said:

But once it hits the analog realm, does any of this matter?  If you built a room quiet enough to hear or not hear any of this, could you actually sit in it very long?

 

Limiting factor is the analog domain. Since some people continue to worry about digital volume control, I just gave some example figures to compare analog things against.

 

Of course implementation of the digital volume control (or any other DSP) matters, because that's where the figures come from. Just like analog implementations matters too. Not all analog volume controls are the same, and not all digital volume controls are the the same either.